PCrNi3MoV steel is a medium-carbon,low-alloy quenched and tempered steel that finds its applications in military gun barrels due to the high wear resistance and ablation resistance.To study the penetration and failure...PCrNi3MoV steel is a medium-carbon,low-alloy quenched and tempered steel that finds its applications in military gun barrels due to the high wear resistance and ablation resistance.To study the penetration and failure modes of PCrNi3MoV plates impacted by tungsten spheres,tungsten spheres of various diameters(5 mm,8 mm,and 10 mm)were used to impact PCrNi3MoV steel plates with thicknesses of 6 mm,9 mm,and 14 mm.The penetration performance of the spheres was analyzed for different velocities,and the ultimate penetration velocity of the plate was obtained.It was found that the primary failure modes of the PCrNi3MoV plate were compression pitting failure and shear failure.Using the dimensional analysis method,a relationship between the bulge height of the steel plate and the fragment velocity,an equation for the ultimate penetration velocity,and a relationship between the target penetration energy and the fragment velocity were obtained.Then,a projectile-target action index was proposed to describe the process of tungsten spheres with different velocities impacting target plates.The results suggested that under the same thickness of the target plate,a larger-diameter fragment required more kinetic energy to obtain the same ultimate penetration effect as a smaller-diameter fragment.The equations obtained through dimensional analysis predicted values that agreed well with experimental values,indicating that these equations can be applied to engineering applications.展开更多
Rarely,penetrating injuries to the spinal cord result from wooden objects,creating unique challenges to mitigate neurological injury and high rates of infection and foreign body reactions.We report a man who sustained...Rarely,penetrating injuries to the spinal cord result from wooden objects,creating unique challenges to mitigate neurological injury and high rates of infection and foreign body reactions.We report a man who sustained a penetrating cervical spinal cord injury from a sharpened stick.While initially tetraparetic,he rapidly recovered function.The risks of neurological deterioration during surgical removal made the patient reluctant to consent to surgery despite the impalement of the spinal cord.A repeat MRI on day 3 showed an extension of edema indicating progressive inflammation.On the 7~(th)day after injury,fever and paresthesias occurred with a large increase in serum inflammatory indicators,and the patient agreed to undergo surgical removal of the wooden object.We discuss the management nuances related to wood,the longitudinal evolution of MRI findings,infection risk,surgical risk mitigation and technique,an inflammatory marker profile,long-term recovery,and the surprisingly minimal neurological deficits associated with low-velocity midline spinal cord injuries.The patient had an excellent clinical outcome.The main lessons are that a wooden penetrating central nervous system injury has a high risk for infection,and that surgical removal from the spinal cord should be performed soon after injury and under direct visualization.展开更多
BACKGROUND Penetrating arrow injuries of the head and neck are exceedingly rare in pediatric patients.This pathology has high morbidity and mortality because of the presence of vital organs,the airway,and large vessel...BACKGROUND Penetrating arrow injuries of the head and neck are exceedingly rare in pediatric patients.This pathology has high morbidity and mortality because of the presence of vital organs,the airway,and large vessels.Therefore,the treatment and removal of an arrow is a challenge that requires multidisciplinary management.CASE SUMMARY A 13-year-old boy was brought to the emergency room after an arrow injury to the frontal region.The arrowhead was lodged in the oropharynx.Imaging studies showed a lesion of the paranasal sinuses without compromising vital structures.The arrow was successfully removed by retrograde nasoendoscopy without complications,and the patient was discharged.CONCLUSION Although rare,maxillofacial arrow injuries have high morbidity and mortality and require multidisciplinary management to preserve function and aesthetics.展开更多
The study presented in this manuscript aimed to relate the sedimentary strata imaged by the ground penetrating radar(GPR)method through numerical modeling with the mapping of sedimentary strata acquired through geotec...The study presented in this manuscript aimed to relate the sedimentary strata imaged by the ground penetrating radar(GPR)method through numerical modeling with the mapping of sedimentary strata acquired through geotechnical surveys.The study aimed to expose how obtaining subsoil information through noninvasive/destructive electromagnetic waves is beneficial,as they are reliable and less costly than drilling holes beyond what is necessary to have a subsurface mapping.In this sense,physical-geological modeling was carried out.The information on the type of sediments,acquired through simple recognition surveys carried out in the city of Belém-PA,helped to create a model of a sedimentary package with its respective intrinsic physical properties.The result shows that the GPR recovered with good vertical and horizontal resolution at the beginning and end of the layers of the sedimentary package studied,proving to be very effective for locating geotechnical sounding points and safely reducing costs.展开更多
This paper presents failure mechanisms of the soil at the caisson-tip with fillet during suction-assisted penetration of suction caissons in undrained clay.Theoretical solutions of resistance factor N_c of the caisson...This paper presents failure mechanisms of the soil at the caisson-tip with fillet during suction-assisted penetration of suction caissons in undrained clay.Theoretical solutions of resistance factor N_c of the caisson-tip are obtained in terms of the caisson-tip geometry ratio of the flat section of the caisson-tip to the caisson wall thickness m/t and adhesion factorsα_i along inside of caisson wall andα_b at the base of the caisson-tip.It is indicated that the factor N_c increases with the increase of m/t,α_i and a_b.The resistance factors N_c for the rough base(α_b=1)are larger by 0.57than that for the smooth base(α_b=0).Besides,the factors N_c of caisson-tip with flat base(m=t)are larger by 1.14 than that with full internal fillet(m=0).The required suction to penetrate suction caissons with various fillets is obtained in terms of the force equilibrium in vertical direction.The finite element limit analysis and centrifuge model test results are used to verify the rationality of the presented failure mechanisms and theoretical predictions.展开更多
AIM: To evaluate the effect of corneal graft diameter on therapeutic penetrating keratoplasty(PKP) for fungal keratitis. METHODS: A total of 116 patients (116 eyes) suffered from fungal keratitis underwent PKP at the ...AIM: To evaluate the effect of corneal graft diameter on therapeutic penetrating keratoplasty(PKP) for fungal keratitis. METHODS: A total of 116 patients (116 eyes) suffered from fungal keratitis underwent PKP at the Affiliated Hospital of Medical College Qingdao University from May 2006 to May 2010. They were divided into two groups according to the corneal graft diameter. 64 eyes' corneal graft diameter was 8.00mm or larger and 52 eyes' graft diameter was smaller than 8.00mm. The follow-up time was 2 years. The postoperative visual acuity and complications were documented and compared. RESULTS: Sixty-two (96.88%) eyes and fifty (96.15%) eyes preserved eyeballs respectively in two groups. There was no statistical difference in postoperative visual acuity (P =0.961), corneal graft clear rate (P =0.132) or the incidence of recurred fungal infection (P =0.770) between two groups. But there was a higher incidence of graft rejection (P =0.020) and secondary glaucoma (P =0.039) in group with corneal graft diameter 8.00mm or larger. CONCLUSION: PKP is an effective treatment approach for fungal keratitis. There is a higher incidence of complications in large-diameter PKP for fungal keratitis.Effective, preventive and therapeutic measures can improve the prognosis.展开更多
BACKGROUND: The development of a harmless and effi- cient nonviral gene delivery system that can facilitate the penetration of nucleic acids through the plasma membrane is a key to successful gene therapy. The aim of ...BACKGROUND: The development of a harmless and effi- cient nonviral gene delivery system that can facilitate the penetration of nucleic acids through the plasma membrane is a key to successful gene therapy. The aim of this study was to test a nonviral gene transferring vector’s function of delivering DNA into liver cells to provide an important clue for gene transfer in liver gene therapy. METHODS: The complex of DNA and DNA delivering protein was injected into mice through their tail veins. Then the mice were killed and their liver tissue was sec- tioned. The gene transferring results were detected using a confocal laser scanning microscope. RESULTS: Fluorescence analysis indicated that both DNA- membrane penetrating peptide (MPP) complex and DNA- hepatocyte specific receptor binding domain ( HSRBD) - MPP complex could go into liver cells. The fluorescence value of liver cells in the DNA-HSRBD-MPP group was higher than that in the DNA-MPP group. CONCLUSIONS; MPP can successfully deliver DNA and protein into cells, and MPP with a HSRBD can specifically deliver DNA into liver cells. These have laid a foundation for further study on the nonviral liver cell gene delivering system.展开更多
AIM:To identify the current indications and the trend shifts for penetrating keratoplasty(PKP) in Shandong.METHODS:The medical charts of all patients who underwent PKP at Shandong Eye Institute from June 1,2005 to May...AIM:To identify the current indications and the trend shifts for penetrating keratoplasty(PKP) in Shandong.METHODS:The medical charts of all patients who underwent PKP at Shandong Eye Institute from June 1,2005 to May 31,2010 were analysed retrospectively.RESULTS:A total of 875 patients(875 eyes) received PKP in this 5-year period,accounting for 61.6% of all corneal transplantation surgeries.The leading indications for PKP were infectious keratitis(37.1%),HSK(19.1%),keratoconus(11.2%),bullous keratopathy(8.5%),regrafting(6.7%) and corneal scarring(4.8%).The percentage of PKP for keratoconus declined year by year,whereas the percentage of bullous keratopathy had a mild annual increase.Fungal infections accounted for 65.2% of the infectious keratitis cases,remaining the leading cause of corneal infection.In addition,54.1% of bullous keratopathy cases were associated with cataract surgery.The leading initial diagnoses associated with regrafting were infectious keratitis(38.9%),HSK(18.6%) and corneal burn(16.9%).The major causes of regrafting included graft endothelial dysfunction(39.0%),graft ulcer(28.8%) and primary disease recurrence(15.3%).CONCLUSION:Infectious keratitis remained the leading indication for PKP in Shandong,and fungal infections were still the major cause of corneal infections.There was an increasing trend in the percentage of PKP cases indicated for bullous keratopathy but a decline in the same for keratoconus.Even with a decline in the overall proportion among all corneal transplantation surgeries,PKP is still the major corneal transplant choice in Shandong.展开更多
Lunar Penetrating Radar(LPR) has successfully been used to acquire a large amount of scientific data during its in-situ detection. The analysis of penetrating depth can help to determine whether the target is within t...Lunar Penetrating Radar(LPR) has successfully been used to acquire a large amount of scientific data during its in-situ detection. The analysis of penetrating depth can help to determine whether the target is within the effective detection range and contribute to distinguishing useful echoes from noise.First, this study introduces two traditional methods, both based on a radar transmission equation, to calculate the penetrating depth. The only difference between the two methods is that the first method adopts system calibration parameters given in the calibration report and the second one uses high-voltage-off radar data. However, some prior knowledge and assumptions are needed in the radar equation and the accuracy of assumptions will directly influence the final results. Therefore, a new method termed the Correlation Coefficient Method(CCM) is provided in this study, which is only based on radar data without any a priori assumptions. The CCM can obtain the penetrating depth according to the different correlation between reflected echoes and noise. To be exact, there is a strong correlation in the useful reflected echoes and a random correlation in the noise between adjacent data traces. In addition, this method can acquire a variable penetrating depth along the profile of the rover, but only one single depth value can be obtained from traditional methods. Through a simulation, the CCM has been verified as an effective method to obtain penetration depth. The comparisons and analysis of the calculation results of these three methods are also implemented in this study. Finally, results show that the ultimate penetrating depth of Channel 1 and the estimated penetrating depth of Channel 2 range from 136.9 m to 165.5 m(ε_r = 6.6) and from 13.0 m to 17.5 m(ε_r = 2.3), respectively.展开更多
AIM:To compare visual,surgical and topographic outcomes of deep anterior lamellar keratoplasty(DALK)and penetrating keratoplasty(PK)for keratoconus(KC).METHODS:In this multicenter,prospective,randomized clinical trial...AIM:To compare visual,surgical and topographic outcomes of deep anterior lamellar keratoplasty(DALK)and penetrating keratoplasty(PK)for keratoconus(KC).METHODS:In this multicenter,prospective,randomized clinical trial 76 eyes of 71 KC patients operated between January 2011 and July 2014 in 2 tertiary referral hospitals were included. Consecutive patients were alternately selected to receive one of the two surgical methods. Thirty eight eyes underwent DALK with the big-bubble technique and 38 eyes underwent PK.RESULTS:Mean best spectacle corrected visual acuity(BSCVA)at the first postoperative week(P=0.012)and the first postoperative month(P<0.001)was statistically significantly higher in DALK group. The mean BSCVA at12 mo was not significantly different for DALK(0.30±1.99 log MAR)versus PK(0.40±0.33 log MAR)(P=0.104). The76.3% of the eyes had a BSCVA over 0.5 in DALK and 47.4%in PK group(P=0.009). The 7.9% of the eyes had a BSCVA of 1.0 in DALK and 5.3% in PK group(P=0.644). Mean spherical equivalent was-2.94 D in DALK and-3.09 D in PK group.Mean topographic astigmatism was 4.62 D and 4.18 D respectively. Regular topographic patterns were observed in 31(81.6%)of DALK and 29(76.3%)of PK(P=0.574). The most frequent topographic pattern was oblate asymmetric bow tie,seen in 39.5% in DALK and 23.7% in PK. CONCLUSION:Big bubble DALK provides an earlier visual improvement compare to PK. However,visual and topographic outcomes are similar to those in PK at 1y. Postoperative complications including rejection and intraocular pressure elevation are more frequent in PK. DALK is a safer alternative to PK for KC. However,intraoperativeperforation of the Descemet's membrane is a significant complication.展开更多
The behavior of eutectic liquid penetrating into the Al base during Al/Cu contact reactive brazing process was studied. Analysis results show that the eutectic liquid prefers to expand along the grain boundary in the ...The behavior of eutectic liquid penetrating into the Al base during Al/Cu contact reactive brazing process was studied. Analysis results show that the eutectic liquid prefers to expand along the grain boundary in the depth direction. Meanwhile, dissolution of solid Al and Cu into the eutectic liquid promotes the eutectic reaction and the continuously formed eutectic liquid leads to the reactive penetrating.展开更多
Twenty samples of endothelia removed from normal and post penetrating keratoplas-ty (0.5,1,2,3 months after penetrating keratoplasty) were observed by scanning electron mi-croscopy.The photographs of the endothelia in...Twenty samples of endothelia removed from normal and post penetrating keratoplas-ty (0.5,1,2,3 months after penetrating keratoplasty) were observed by scanning electron mi-croscopy.The photographs of the endothelia in graft-host junction were analyzed by computer-assisted image analysis system,and the morphometric indexes examined were area of the cells,perimeters,density,figure coefficient,long axis,coefficient of variation of the area,and oth-ers.Results showed that the morphology and the density of the endothelial cells changed obvi-ously after operation and improved slowly but progressively with time although at 3 monthspostoperatively some differences still existed.By using the new techniques,the experiment con-firmed and enriched the theories on the corneal endothelial wound-healing,revealing some ofthe new characters of the endothelial wound-healing following penetrating keratoplasty.展开更多
The coastal dunes located near the Ashirmata region, south of Mandvi beach lies near the straight coast have been stud-ied by making use of sedimentological information and Ground Penetrating Radar (GPR) data. Sedimen...The coastal dunes located near the Ashirmata region, south of Mandvi beach lies near the straight coast have been stud-ied by making use of sedimentological information and Ground Penetrating Radar (GPR) data. Sedimentological analy-sis reveals the NNW-SSE trending longitudinal dunes consists of well sorted fine sands with unimodal distribution pos-sibly formed by constant wind gust and also the point out to the origin of sediments from single source;mostly the sediments derived from Indus delta transported to beach by long shore drift and tidal waves, carried inland by local on-shore winds. The radargram confirms, the homogenous sand layers with paleosols at shallow depth slip faces are proba-bly formed due to extreme storm activity of Recent.展开更多
AIM: To report the outcomes of penetrating canaloplasty for corticosteroid-induced glaucoma in a case series.METHODS: Penetrating canaloplasty is a blebindependent filtering surger y unifying canaloplasty and trabecul...AIM: To report the outcomes of penetrating canaloplasty for corticosteroid-induced glaucoma in a case series.METHODS: Penetrating canaloplasty is a blebindependent filtering surger y unifying canaloplasty and trabeculectomy. In this study, the surger y was performed to restore the natural outflow through surgically expanded Schlemm’s canal and generated trabeculum ostium. A total of 10 eyes of 8 patients were treated with penetrating canaloplasty for corticosteroid-induced glaucoma. Intraocular pressure(IOP) and the number of glaucoma medications at postoperative 3, 6, 12, 18, 24,36, and 48mo were documented as primary endpoint.Complications after the surgery were recorded as secondary endpoint.RESULTS: Penetrating canaloplasty was accomplished successfully for all 10 eyes, with a mean follow-up of 20.4±13.0mo(range 6-48mo). The mean preoperative IOP and number of anti-glaucoma medications were 45.1±6.5 mm Hg and 3.3±0.5 respectively. The mean post-operative IOP at 3, 6, 12, 18, 24, 36, and 48mo were 15.8±6.0, 14.7±3.3,15.3±2.0, 15.6±2.6, 17.5±1.8, 16.5±4.9, and 14.0 mm Hg.The number of anti-glaucoma medications at these time points were all 0. This surgery failed to control the IOP in 1 eye at 1mo after surgery. Hyphaema occurred in 3 eyes on the first day after surgery. Postoperative transient IOP increasing was encountered with in two eyes from 1wk to 1mo after surgery. Choroidal detachment developed in one eye but responded well to conservative treatment.CONCLUSION: Penetrating canaloplasty is effective for corticosteroid-induced glaucoma without serious complications, making it a viable or preferred alternative option.展开更多
· AIM: To compare the corneal endothelial cell density (ECD) of clear grafts after penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK). · METHODS: The study included 44 and 54 patien...· AIM: To compare the corneal endothelial cell density (ECD) of clear grafts after penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK). · METHODS: The study included 44 and 54 patients treated with PK and DALK, respectively, between March 2006 and April 2010. Corneal ECD was examined using specular microscopy at postoperative 1, 3, 6, 12, and 18 months, and the values were compared. · RESULTS: Corneal ECD reduction in the PK group was 7.4%, 15.2%, 23.5%, and 28.9% at 3, 6, 12 and 18 months respectively after surgery, compared with 4.2 % in the first month (P <0.01). These figures were 3.0%, 6.7%, 7.2%, and 7.7% at 3, 6, 12 and 18 months respectively, compared with 2.2 % in the first month in the DALK group (P >0.05). · CONCLUSION: Compared with DALK,PK significantly reduced ECD of the clear grafts. These results suggest that survival of endothelial cells in grafts is better after DALK than after PK. ·展开更多
Spontaneous wound separation may be developed even months after suture removal especially in the context of long-term corticosteroid therapy. A 68-yearold Caucasian woman presented to our cornea clinic with spontaneou...Spontaneous wound separation may be developed even months after suture removal especially in the context of long-term corticosteroid therapy. A 68-yearold Caucasian woman presented to our cornea clinic with spontaneous wound dehiscence after her third penetrating keratoplasty(PKP) which was performed three years ago. An Ahmed glaucoma valve(New World Medical, Ranchos Cucamonga, CA) was inserted ten months after the third PKP, which successfully controlled intraocular pressure(IOP). At the examination, the last sutures were removed eight months ago and she was using flourometholone 0.1%(Sina Darou, Tehran, Iran)with a dose of once a day. There was one quadrant of wound dehiscence from 8 to 11 o`clock associated with anterior wound gape and severe corneal edema.Resuturing was performed for the patient. At the one month examination, the corneal edema was resolved and best corrected visual acuity was 20/200 mainly due to previous glaucomatous optic neuropathy. Caution about the prolonged use of corticosteroids is necessary. Topical immunosuppressives could be a promising choice in this field.展开更多
AIM: To evaluate the indications, complications, and visual and graft survival outcomes in eyes that had undergone simultaneous cataract extraction and penetrating keratoplasty (PKP). ·METHODS: We described a ret...AIM: To evaluate the indications, complications, and visual and graft survival outcomes in eyes that had undergone simultaneous cataract extraction and penetrating keratoplasty (PKP). ·METHODS: We described a retrospective study of 101 patients who had undergone simultaneous cataract extraction and PKP at King Khaled Eye Specialist Hospital between January 1, 2001, and December 31, 2002. All patients were followed up postoperatively with maximum follow-up 68 months. ·RESULTS: The mean age of patients was 61 years. The mean overall follow -up was 27 months. The most common indications for surgery were corneal scarring (45.5% ), previous failed graft (15.8% ), corneal ulcer (12.9% ), Fuchs endothelial dystrophy (8.9% ), stromal dystrophy (2.9% ), and other conditions (14.5% ). Overall, 69 grafts (68.3% ) remained clear at final follow -up. Previous glaucoma or postoperative glaucoma had no statistically significant effects on graft outcome (P >0.05). The graft rejection rate (17.8% ) was a significant risk factor for failure (P =0.00). Age, gender, indications for surgery, corneal graft diameter, and intraoperative vitreous loss had no statistically significant effects on the PKP outcome (P >0.05). Postoperative visual acuity was significantly associated with preoperative visual acuity (P <0.01). ·CONCLUSION: The present study provides evidence that performing a combined procedure results in more rapid visual rehabilitation and good graft clarity.展开更多
AIM: To analyse the impact of ultrasound and optical intraocular lens(IOL) calculation methods on refractive outcomes of cataract phacoemulsification performed after penetrating keratoplasty(PK) in keratoconus. METHOD...AIM: To analyse the impact of ultrasound and optical intraocular lens(IOL) calculation methods on refractive outcomes of cataract phacoemulsification performed after penetrating keratoplasty(PK) in keratoconus. METHODS: Phacoemulsification cataract surgery was performed on 42 eyes of 34 patients with keratoconus who had previously undergone PK. The IOL power was determined by using both standard and corneal topography-derived keratometry using the SRK/T formula. We used two independent methods-ultrasound biometry(UB) and interferometry [optical biometry(OB)] for IOL calculation. The analysed data from medical records included demographics, medical history, best corrected visual acuity(BCVA) on Snellen charts, technique of IOL calculation and calculation formula and its impact on final refractive result.RESULTS: BCVA ranged from 0.01 to 0.4(mean 0.09±0.19) before surgery and ranged from 0.2 to 0.7(mean 0.38±0.14) at 1 mo and from 0.2 to 1.0(mean 0.56±0.16)(P<0.05) at 3 mo, postoperatively. The refractive aim differed significantly from the refractive outcome in both the UB and OB groups(P<0.05). There was no statistically significant difference in the accuracy of the two biometry methods.CONCLUSION: The refractive aim in keratoconus eyes post-PK is not achieved with either ultrasound or OB.展开更多
Background: The pattern and presentation of penetrating abdominal trauma vary according to places and the structure of the present health system. As well controversies in management exist ranging from mandatory explor...Background: The pattern and presentation of penetrating abdominal trauma vary according to places and the structure of the present health system. As well controversies in management exist ranging from mandatory exploration to selective non-operative management. Objectives: To determine the pattern of penetrating abdominal trauma, current management practiced and outcome in Khartoum. Patients and Methods: The study was prospective, descriptive and hospital-based. It was carried out at the main three hospitals in Khartoum State. It was conducted over a period of one year from 2012 Mar to 2013 Mar. All patients who presented penetrating injury to their abdomen were included. Results: The study included 85 patients with a mean age of 28 years (SD ± 10). The male to female ratio was 11:1. Most of the patients (89.4%) were in the first four decades of their life. Twenty-three patients (27.1%) presented shock. Stab wound is the commonest mode of trauma seen in 83.5% of our patients. The majority of our patients were managed by exploratory laparotomy (81.2%), however 16 (18.8%) underwent conservative measures. Of the operated group, solid organ injuries were found in 22.9%, yet hollow viscous injuries were reported in 86.9% of the patients. Registrars operated on 78.26% of the patients. The rate of negative laparotomy of this study was 8.7%. Complications and mortality were encountered in 25.9% and 4.7% respectively. The mean hospital stay was 8.47 days (SD ± 10.6). Conclusion: This study demonstrates no difference in the pattern of intra-abdominal injuries. The rate of operative treatment is acceptable, but more laparotomies can be avoided if the haemodynamic stable patients without features of peritonitis were given a period of observation. The overall outcome was satisfactory.展开更多
In this paper,a layer-constrained triangulated irregular network( LC-TIN) algorithm is proposed for three-dimensional( 3 D) modelling,and applied to construct a 3 D model for geological disease information based on gr...In this paper,a layer-constrained triangulated irregular network( LC-TIN) algorithm is proposed for three-dimensional( 3 D) modelling,and applied to construct a 3 D model for geological disease information based on ground penetrating radar( GPR) data. Compared with the traditional TIN algorithm,the LCTIN algorithm introduced a layer constraint to the discrete data points during the 3 D modelling process,and it can dynamically construct networks from layer to layer and implement 3 D modelling for arbitrary shapes with high precision. The experimental results validated this method,the proposed algorithm not only can maintain the rationality of triangulation network,but also can obtain a good generation speed. In addition,the algorithm is also introduced to our self-developed 3 D visualization platform,which utilized GPR data to model geological diseases. Therefore the feasibility of the algorithm is verified in the practical application.展开更多
文摘PCrNi3MoV steel is a medium-carbon,low-alloy quenched and tempered steel that finds its applications in military gun barrels due to the high wear resistance and ablation resistance.To study the penetration and failure modes of PCrNi3MoV plates impacted by tungsten spheres,tungsten spheres of various diameters(5 mm,8 mm,and 10 mm)were used to impact PCrNi3MoV steel plates with thicknesses of 6 mm,9 mm,and 14 mm.The penetration performance of the spheres was analyzed for different velocities,and the ultimate penetration velocity of the plate was obtained.It was found that the primary failure modes of the PCrNi3MoV plate were compression pitting failure and shear failure.Using the dimensional analysis method,a relationship between the bulge height of the steel plate and the fragment velocity,an equation for the ultimate penetration velocity,and a relationship between the target penetration energy and the fragment velocity were obtained.Then,a projectile-target action index was proposed to describe the process of tungsten spheres with different velocities impacting target plates.The results suggested that under the same thickness of the target plate,a larger-diameter fragment required more kinetic energy to obtain the same ultimate penetration effect as a smaller-diameter fragment.The equations obtained through dimensional analysis predicted values that agreed well with experimental values,indicating that these equations can be applied to engineering applications.
文摘Rarely,penetrating injuries to the spinal cord result from wooden objects,creating unique challenges to mitigate neurological injury and high rates of infection and foreign body reactions.We report a man who sustained a penetrating cervical spinal cord injury from a sharpened stick.While initially tetraparetic,he rapidly recovered function.The risks of neurological deterioration during surgical removal made the patient reluctant to consent to surgery despite the impalement of the spinal cord.A repeat MRI on day 3 showed an extension of edema indicating progressive inflammation.On the 7~(th)day after injury,fever and paresthesias occurred with a large increase in serum inflammatory indicators,and the patient agreed to undergo surgical removal of the wooden object.We discuss the management nuances related to wood,the longitudinal evolution of MRI findings,infection risk,surgical risk mitigation and technique,an inflammatory marker profile,long-term recovery,and the surprisingly minimal neurological deficits associated with low-velocity midline spinal cord injuries.The patient had an excellent clinical outcome.The main lessons are that a wooden penetrating central nervous system injury has a high risk for infection,and that surgical removal from the spinal cord should be performed soon after injury and under direct visualization.
文摘BACKGROUND Penetrating arrow injuries of the head and neck are exceedingly rare in pediatric patients.This pathology has high morbidity and mortality because of the presence of vital organs,the airway,and large vessels.Therefore,the treatment and removal of an arrow is a challenge that requires multidisciplinary management.CASE SUMMARY A 13-year-old boy was brought to the emergency room after an arrow injury to the frontal region.The arrowhead was lodged in the oropharynx.Imaging studies showed a lesion of the paranasal sinuses without compromising vital structures.The arrow was successfully removed by retrograde nasoendoscopy without complications,and the patient was discharged.CONCLUSION Although rare,maxillofacial arrow injuries have high morbidity and mortality and require multidisciplinary management to preserve function and aesthetics.
文摘The study presented in this manuscript aimed to relate the sedimentary strata imaged by the ground penetrating radar(GPR)method through numerical modeling with the mapping of sedimentary strata acquired through geotechnical surveys.The study aimed to expose how obtaining subsoil information through noninvasive/destructive electromagnetic waves is beneficial,as they are reliable and less costly than drilling holes beyond what is necessary to have a subsurface mapping.In this sense,physical-geological modeling was carried out.The information on the type of sediments,acquired through simple recognition surveys carried out in the city of Belém-PA,helped to create a model of a sedimentary package with its respective intrinsic physical properties.The result shows that the GPR recovered with good vertical and horizontal resolution at the beginning and end of the layers of the sedimentary package studied,proving to be very effective for locating geotechnical sounding points and safely reducing costs.
基金financially supported by the National Natural Science Foundation of China (Grant No.51879044)the Youth Foundation of Shandong Natural Science Foundation (Grant No.ZR2020QE258)+1 种基金Qingdao Postdoctoral Applied Research Project (Grant No.ZX20220202)SDUST Research Fund (Grant No.2015KYJH104)。
文摘This paper presents failure mechanisms of the soil at the caisson-tip with fillet during suction-assisted penetration of suction caissons in undrained clay.Theoretical solutions of resistance factor N_c of the caisson-tip are obtained in terms of the caisson-tip geometry ratio of the flat section of the caisson-tip to the caisson wall thickness m/t and adhesion factorsα_i along inside of caisson wall andα_b at the base of the caisson-tip.It is indicated that the factor N_c increases with the increase of m/t,α_i and a_b.The resistance factors N_c for the rough base(α_b=1)are larger by 0.57than that for the smooth base(α_b=0).Besides,the factors N_c of caisson-tip with flat base(m=t)are larger by 1.14 than that with full internal fillet(m=0).The required suction to penetrate suction caissons with various fillets is obtained in terms of the force equilibrium in vertical direction.The finite element limit analysis and centrifuge model test results are used to verify the rationality of the presented failure mechanisms and theoretical predictions.
基金National Natural Science Foundation of China (No.81170825)
文摘AIM: To evaluate the effect of corneal graft diameter on therapeutic penetrating keratoplasty(PKP) for fungal keratitis. METHODS: A total of 116 patients (116 eyes) suffered from fungal keratitis underwent PKP at the Affiliated Hospital of Medical College Qingdao University from May 2006 to May 2010. They were divided into two groups according to the corneal graft diameter. 64 eyes' corneal graft diameter was 8.00mm or larger and 52 eyes' graft diameter was smaller than 8.00mm. The follow-up time was 2 years. The postoperative visual acuity and complications were documented and compared. RESULTS: Sixty-two (96.88%) eyes and fifty (96.15%) eyes preserved eyeballs respectively in two groups. There was no statistical difference in postoperative visual acuity (P =0.961), corneal graft clear rate (P =0.132) or the incidence of recurred fungal infection (P =0.770) between two groups. But there was a higher incidence of graft rejection (P =0.020) and secondary glaucoma (P =0.039) in group with corneal graft diameter 8.00mm or larger. CONCLUSION: PKP is an effective treatment approach for fungal keratitis. There is a higher incidence of complications in large-diameter PKP for fungal keratitis.Effective, preventive and therapeutic measures can improve the prognosis.
基金This study was supported by grants from the National Natural Science Foun-dation of China( No:30472251 )and the Shanxi Youth Science Fund ( No.020011028).
文摘BACKGROUND: The development of a harmless and effi- cient nonviral gene delivery system that can facilitate the penetration of nucleic acids through the plasma membrane is a key to successful gene therapy. The aim of this study was to test a nonviral gene transferring vector’s function of delivering DNA into liver cells to provide an important clue for gene transfer in liver gene therapy. METHODS: The complex of DNA and DNA delivering protein was injected into mice through their tail veins. Then the mice were killed and their liver tissue was sec- tioned. The gene transferring results were detected using a confocal laser scanning microscope. RESULTS: Fluorescence analysis indicated that both DNA- membrane penetrating peptide (MPP) complex and DNA- hepatocyte specific receptor binding domain ( HSRBD) - MPP complex could go into liver cells. The fluorescence value of liver cells in the DNA-HSRBD-MPP group was higher than that in the DNA-MPP group. CONCLUSIONS; MPP can successfully deliver DNA and protein into cells, and MPP with a HSRBD can specifically deliver DNA into liver cells. These have laid a foundation for further study on the nonviral liver cell gene delivering system.
基金Supported by National Natural Science Foundation of China(No.30630063)
文摘AIM:To identify the current indications and the trend shifts for penetrating keratoplasty(PKP) in Shandong.METHODS:The medical charts of all patients who underwent PKP at Shandong Eye Institute from June 1,2005 to May 31,2010 were analysed retrospectively.RESULTS:A total of 875 patients(875 eyes) received PKP in this 5-year period,accounting for 61.6% of all corneal transplantation surgeries.The leading indications for PKP were infectious keratitis(37.1%),HSK(19.1%),keratoconus(11.2%),bullous keratopathy(8.5%),regrafting(6.7%) and corneal scarring(4.8%).The percentage of PKP for keratoconus declined year by year,whereas the percentage of bullous keratopathy had a mild annual increase.Fungal infections accounted for 65.2% of the infectious keratitis cases,remaining the leading cause of corneal infection.In addition,54.1% of bullous keratopathy cases were associated with cataract surgery.The leading initial diagnoses associated with regrafting were infectious keratitis(38.9%),HSK(18.6%) and corneal burn(16.9%).The major causes of regrafting included graft endothelial dysfunction(39.0%),graft ulcer(28.8%) and primary disease recurrence(15.3%).CONCLUSION:Infectious keratitis remained the leading indication for PKP in Shandong,and fungal infections were still the major cause of corneal infections.There was an increasing trend in the percentage of PKP cases indicated for bullous keratopathy but a decline in the same for keratoconus.Even with a decline in the overall proportion among all corneal transplantation surgeries,PKP is still the major corneal transplant choice in Shandong.
基金supported by the National Natural Science Foundation of China (Grant No. 41403054)
文摘Lunar Penetrating Radar(LPR) has successfully been used to acquire a large amount of scientific data during its in-situ detection. The analysis of penetrating depth can help to determine whether the target is within the effective detection range and contribute to distinguishing useful echoes from noise.First, this study introduces two traditional methods, both based on a radar transmission equation, to calculate the penetrating depth. The only difference between the two methods is that the first method adopts system calibration parameters given in the calibration report and the second one uses high-voltage-off radar data. However, some prior knowledge and assumptions are needed in the radar equation and the accuracy of assumptions will directly influence the final results. Therefore, a new method termed the Correlation Coefficient Method(CCM) is provided in this study, which is only based on radar data without any a priori assumptions. The CCM can obtain the penetrating depth according to the different correlation between reflected echoes and noise. To be exact, there is a strong correlation in the useful reflected echoes and a random correlation in the noise between adjacent data traces. In addition, this method can acquire a variable penetrating depth along the profile of the rover, but only one single depth value can be obtained from traditional methods. Through a simulation, the CCM has been verified as an effective method to obtain penetration depth. The comparisons and analysis of the calculation results of these three methods are also implemented in this study. Finally, results show that the ultimate penetrating depth of Channel 1 and the estimated penetrating depth of Channel 2 range from 136.9 m to 165.5 m(ε_r = 6.6) and from 13.0 m to 17.5 m(ε_r = 2.3), respectively.
文摘AIM:To compare visual,surgical and topographic outcomes of deep anterior lamellar keratoplasty(DALK)and penetrating keratoplasty(PK)for keratoconus(KC).METHODS:In this multicenter,prospective,randomized clinical trial 76 eyes of 71 KC patients operated between January 2011 and July 2014 in 2 tertiary referral hospitals were included. Consecutive patients were alternately selected to receive one of the two surgical methods. Thirty eight eyes underwent DALK with the big-bubble technique and 38 eyes underwent PK.RESULTS:Mean best spectacle corrected visual acuity(BSCVA)at the first postoperative week(P=0.012)and the first postoperative month(P<0.001)was statistically significantly higher in DALK group. The mean BSCVA at12 mo was not significantly different for DALK(0.30±1.99 log MAR)versus PK(0.40±0.33 log MAR)(P=0.104). The76.3% of the eyes had a BSCVA over 0.5 in DALK and 47.4%in PK group(P=0.009). The 7.9% of the eyes had a BSCVA of 1.0 in DALK and 5.3% in PK group(P=0.644). Mean spherical equivalent was-2.94 D in DALK and-3.09 D in PK group.Mean topographic astigmatism was 4.62 D and 4.18 D respectively. Regular topographic patterns were observed in 31(81.6%)of DALK and 29(76.3%)of PK(P=0.574). The most frequent topographic pattern was oblate asymmetric bow tie,seen in 39.5% in DALK and 23.7% in PK. CONCLUSION:Big bubble DALK provides an earlier visual improvement compare to PK. However,visual and topographic outcomes are similar to those in PK at 1y. Postoperative complications including rejection and intraocular pressure elevation are more frequent in PK. DALK is a safer alternative to PK for KC. However,intraoperativeperforation of the Descemet's membrane is a significant complication.
文摘The behavior of eutectic liquid penetrating into the Al base during Al/Cu contact reactive brazing process was studied. Analysis results show that the eutectic liquid prefers to expand along the grain boundary in the depth direction. Meanwhile, dissolution of solid Al and Cu into the eutectic liquid promotes the eutectic reaction and the continuously formed eutectic liquid leads to the reactive penetrating.
文摘Twenty samples of endothelia removed from normal and post penetrating keratoplas-ty (0.5,1,2,3 months after penetrating keratoplasty) were observed by scanning electron mi-croscopy.The photographs of the endothelia in graft-host junction were analyzed by computer-assisted image analysis system,and the morphometric indexes examined were area of the cells,perimeters,density,figure coefficient,long axis,coefficient of variation of the area,and oth-ers.Results showed that the morphology and the density of the endothelial cells changed obvi-ously after operation and improved slowly but progressively with time although at 3 monthspostoperatively some differences still existed.By using the new techniques,the experiment con-firmed and enriched the theories on the corneal endothelial wound-healing,revealing some ofthe new characters of the endothelial wound-healing following penetrating keratoplasty.
文摘The coastal dunes located near the Ashirmata region, south of Mandvi beach lies near the straight coast have been stud-ied by making use of sedimentological information and Ground Penetrating Radar (GPR) data. Sedimentological analy-sis reveals the NNW-SSE trending longitudinal dunes consists of well sorted fine sands with unimodal distribution pos-sibly formed by constant wind gust and also the point out to the origin of sediments from single source;mostly the sediments derived from Indus delta transported to beach by long shore drift and tidal waves, carried inland by local on-shore winds. The radargram confirms, the homogenous sand layers with paleosols at shallow depth slip faces are proba-bly formed due to extreme storm activity of Recent.
基金Supported by National Key Research and Development Project of China (No.2020YFC2008200)Program for Zhejiang Leading Talent of S&T Innovation (No.2021R52012)+1 种基金Key Research and Development Projects of Zhejiang Province (No.2022C03112)Zhejiang Provincial Program for the Cultivation of Leading Talents in Colleges and Universities (No.2020099)。
文摘AIM: To report the outcomes of penetrating canaloplasty for corticosteroid-induced glaucoma in a case series.METHODS: Penetrating canaloplasty is a blebindependent filtering surger y unifying canaloplasty and trabeculectomy. In this study, the surger y was performed to restore the natural outflow through surgically expanded Schlemm’s canal and generated trabeculum ostium. A total of 10 eyes of 8 patients were treated with penetrating canaloplasty for corticosteroid-induced glaucoma. Intraocular pressure(IOP) and the number of glaucoma medications at postoperative 3, 6, 12, 18, 24,36, and 48mo were documented as primary endpoint.Complications after the surgery were recorded as secondary endpoint.RESULTS: Penetrating canaloplasty was accomplished successfully for all 10 eyes, with a mean follow-up of 20.4±13.0mo(range 6-48mo). The mean preoperative IOP and number of anti-glaucoma medications were 45.1±6.5 mm Hg and 3.3±0.5 respectively. The mean post-operative IOP at 3, 6, 12, 18, 24, 36, and 48mo were 15.8±6.0, 14.7±3.3,15.3±2.0, 15.6±2.6, 17.5±1.8, 16.5±4.9, and 14.0 mm Hg.The number of anti-glaucoma medications at these time points were all 0. This surgery failed to control the IOP in 1 eye at 1mo after surgery. Hyphaema occurred in 3 eyes on the first day after surgery. Postoperative transient IOP increasing was encountered with in two eyes from 1wk to 1mo after surgery. Choroidal detachment developed in one eye but responded well to conservative treatment.CONCLUSION: Penetrating canaloplasty is effective for corticosteroid-induced glaucoma without serious complications, making it a viable or preferred alternative option.
文摘· AIM: To compare the corneal endothelial cell density (ECD) of clear grafts after penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK). · METHODS: The study included 44 and 54 patients treated with PK and DALK, respectively, between March 2006 and April 2010. Corneal ECD was examined using specular microscopy at postoperative 1, 3, 6, 12, and 18 months, and the values were compared. · RESULTS: Corneal ECD reduction in the PK group was 7.4%, 15.2%, 23.5%, and 28.9% at 3, 6, 12 and 18 months respectively after surgery, compared with 4.2 % in the first month (P <0.01). These figures were 3.0%, 6.7%, 7.2%, and 7.7% at 3, 6, 12 and 18 months respectively, compared with 2.2 % in the first month in the DALK group (P >0.05). · CONCLUSION: Compared with DALK,PK significantly reduced ECD of the clear grafts. These results suggest that survival of endothelial cells in grafts is better after DALK than after PK. ·
文摘Spontaneous wound separation may be developed even months after suture removal especially in the context of long-term corticosteroid therapy. A 68-yearold Caucasian woman presented to our cornea clinic with spontaneous wound dehiscence after her third penetrating keratoplasty(PKP) which was performed three years ago. An Ahmed glaucoma valve(New World Medical, Ranchos Cucamonga, CA) was inserted ten months after the third PKP, which successfully controlled intraocular pressure(IOP). At the examination, the last sutures were removed eight months ago and she was using flourometholone 0.1%(Sina Darou, Tehran, Iran)with a dose of once a day. There was one quadrant of wound dehiscence from 8 to 11 o`clock associated with anterior wound gape and severe corneal edema.Resuturing was performed for the patient. At the one month examination, the corneal edema was resolved and best corrected visual acuity was 20/200 mainly due to previous glaucomatous optic neuropathy. Caution about the prolonged use of corticosteroids is necessary. Topical immunosuppressives could be a promising choice in this field.
文摘AIM: To evaluate the indications, complications, and visual and graft survival outcomes in eyes that had undergone simultaneous cataract extraction and penetrating keratoplasty (PKP). ·METHODS: We described a retrospective study of 101 patients who had undergone simultaneous cataract extraction and PKP at King Khaled Eye Specialist Hospital between January 1, 2001, and December 31, 2002. All patients were followed up postoperatively with maximum follow-up 68 months. ·RESULTS: The mean age of patients was 61 years. The mean overall follow -up was 27 months. The most common indications for surgery were corneal scarring (45.5% ), previous failed graft (15.8% ), corneal ulcer (12.9% ), Fuchs endothelial dystrophy (8.9% ), stromal dystrophy (2.9% ), and other conditions (14.5% ). Overall, 69 grafts (68.3% ) remained clear at final follow -up. Previous glaucoma or postoperative glaucoma had no statistically significant effects on graft outcome (P >0.05). The graft rejection rate (17.8% ) was a significant risk factor for failure (P =0.00). Age, gender, indications for surgery, corneal graft diameter, and intraoperative vitreous loss had no statistically significant effects on the PKP outcome (P >0.05). Postoperative visual acuity was significantly associated with preoperative visual acuity (P <0.01). ·CONCLUSION: The present study provides evidence that performing a combined procedure results in more rapid visual rehabilitation and good graft clarity.
文摘AIM: To analyse the impact of ultrasound and optical intraocular lens(IOL) calculation methods on refractive outcomes of cataract phacoemulsification performed after penetrating keratoplasty(PK) in keratoconus. METHODS: Phacoemulsification cataract surgery was performed on 42 eyes of 34 patients with keratoconus who had previously undergone PK. The IOL power was determined by using both standard and corneal topography-derived keratometry using the SRK/T formula. We used two independent methods-ultrasound biometry(UB) and interferometry [optical biometry(OB)] for IOL calculation. The analysed data from medical records included demographics, medical history, best corrected visual acuity(BCVA) on Snellen charts, technique of IOL calculation and calculation formula and its impact on final refractive result.RESULTS: BCVA ranged from 0.01 to 0.4(mean 0.09±0.19) before surgery and ranged from 0.2 to 0.7(mean 0.38±0.14) at 1 mo and from 0.2 to 1.0(mean 0.56±0.16)(P<0.05) at 3 mo, postoperatively. The refractive aim differed significantly from the refractive outcome in both the UB and OB groups(P<0.05). There was no statistically significant difference in the accuracy of the two biometry methods.CONCLUSION: The refractive aim in keratoconus eyes post-PK is not achieved with either ultrasound or OB.
文摘Background: The pattern and presentation of penetrating abdominal trauma vary according to places and the structure of the present health system. As well controversies in management exist ranging from mandatory exploration to selective non-operative management. Objectives: To determine the pattern of penetrating abdominal trauma, current management practiced and outcome in Khartoum. Patients and Methods: The study was prospective, descriptive and hospital-based. It was carried out at the main three hospitals in Khartoum State. It was conducted over a period of one year from 2012 Mar to 2013 Mar. All patients who presented penetrating injury to their abdomen were included. Results: The study included 85 patients with a mean age of 28 years (SD ± 10). The male to female ratio was 11:1. Most of the patients (89.4%) were in the first four decades of their life. Twenty-three patients (27.1%) presented shock. Stab wound is the commonest mode of trauma seen in 83.5% of our patients. The majority of our patients were managed by exploratory laparotomy (81.2%), however 16 (18.8%) underwent conservative measures. Of the operated group, solid organ injuries were found in 22.9%, yet hollow viscous injuries were reported in 86.9% of the patients. Registrars operated on 78.26% of the patients. The rate of negative laparotomy of this study was 8.7%. Complications and mortality were encountered in 25.9% and 4.7% respectively. The mean hospital stay was 8.47 days (SD ± 10.6). Conclusion: This study demonstrates no difference in the pattern of intra-abdominal injuries. The rate of operative treatment is acceptable, but more laparotomies can be avoided if the haemodynamic stable patients without features of peritonitis were given a period of observation. The overall outcome was satisfactory.
基金Supported by the National Science Foundation of China(61302157)the National High Technology Research and Development Program of China(863 Program)(2012AA12A308)the Yue Qi Young Scholars Project of China University of Mining&Technology(Beijing)(800015Z1117)
文摘In this paper,a layer-constrained triangulated irregular network( LC-TIN) algorithm is proposed for three-dimensional( 3 D) modelling,and applied to construct a 3 D model for geological disease information based on ground penetrating radar( GPR) data. Compared with the traditional TIN algorithm,the LCTIN algorithm introduced a layer constraint to the discrete data points during the 3 D modelling process,and it can dynamically construct networks from layer to layer and implement 3 D modelling for arbitrary shapes with high precision. The experimental results validated this method,the proposed algorithm not only can maintain the rationality of triangulation network,but also can obtain a good generation speed. In addition,the algorithm is also introduced to our self-developed 3 D visualization platform,which utilized GPR data to model geological diseases. Therefore the feasibility of the algorithm is verified in the practical application.
