Particle-sounding of the spatial structure of kinetic Alfvén waves.

Kinetic Alfvén waves (KAWs) are ubiquitous throughout the plasma universe. Although they are broadly believed to provide a potential approach for energy exchange between electromagnetic fields and plasma particles, neither the detail nor the efficiency of the interactions has been well-determined yet. The primary difficulty has been the paucity of knowledge of KAWs' spatial structure in observation. Here, we apply a particle-sounding technique to Magnetospheric Multiscale mission data to quantitatively determine the perpendicular wavelength of KAWs from ion gyrophase-distribution observations. Our results show that KAWs' perpendicular wavelength is statistically 2.4[Formula: see text] times proton thermal gyro-radius. This observation yields an upper bound of the energy the majority proton population can reach in coherent interactions with KAWs, that is, roughly 5.76 times proton perpendicular thermal energy. Therefore, the method and results shown here provide a basis for unraveling the effects of KAWs in dissipating energy and accelerating particles in a number of astrophysical systems, e.g., planetary magnetosphere, astrophysical shocks, stellar corona and wind, and the interstellar medium.

[Feasibility on the Internet-based HIV nucleic acid testing with dry blood spots and risk factors associated with HIV infection in men having sex with men in Beijing].

Objectives: To understand the prevalence of HIV nucleic acid using internet-based dry blood spots HIV testing strategy in men who had sex with men (MSM) and to probe the factors associated with HIV infection. Methods: Using convenient sampling method, 1 375 MSM were recruited and their dry blood spots samples were collected before being mailed to the laboratories for HIV nucleic acid testing. Results were showed to these MSM on a specific website by inputting their codes to it. Non-conditional binary logistic regression method was used to identify the associated factors on HIV infection. Results: The overall proportions of HIV nucleic acid positives appeared as 9.7% (131/1 349) and HIV antibody positives as 8.3% (112/1 349). Fresh infections accounted for 14.5% (19/131) among the newly-identified HIV nucleic acid positives, and the interval was ranging from 6 to 120 days, between the laboratory testings and the closest date that experiencing high risk behavior. Risk factors that related to HIV infection would include: 30 to 39 years of age (comparing to those under the age of 30, OR=1.88, 95%CI: 1.07-3.29), ≥8 000 Yuan of monthly income (comparing to those without income, OR=0.42, 95%CI: 0.19-0.96), inconsistent condom use during anal sexual contacts in the last six months (compared with those who had not anal sex or used condoms consistently in anal sex in the past six months, OR=2.22, 95%CI: 1.45-3.40), ever use of Rush Poppers (compared with those who never used Rush Poppers, OR=2.33, 95%CI: 1.49-3.64), addictive drug abuse (compared with those who never abused addictive drugs, OR=5.43, 95%CI: 2.32-12.69), and not having regular sexual partners (compared with having regular sexual partners, OR=1.74, 95%CI: 1.13-2.68) etc.. Conclusions: Dry blood spots HIV nucleic acid testing could help to identify the fresh HIV infections at an early stage, so as to prevent further transmission in the MSM population, among which fresh HIV infections accounted for a fairly large proportion. It is necessary to set up programs in reducing the abuse of drugs or Rush Poppers, and to promote condom use and advocate on stable sexual partnership etc., among the MSM population.

[Long-term efficacy of robotic radical total gastrectomy for gastric cancer and analysis of prognostic factors].

Objective: To analyze long-term outcomes and prognostic factors of gastric cancer patients after robotic radical total gastrectomy. Methods: A retrospective case-control study was conducted. Inclusion criteria: (1) receiving robotic radical total gastrectomy; (2) gastric adenocarcinoma was confirmed by postoperative pathology; (3) no previous history of other malignant tumors; (4) no preoperative chemotherapy or radiation therapy performed. Exclusion criteria: (1) age <18 years old or age >80 years old;(2)distant metastasis before surgery, or palliative surgery; (3) conversion to laparotomy;(4) R1 or R2 resection; (5)emergency surgery; (6) remnant gastric cancer or recurrence; (7)died of severe complications during hospitalization or within 1 month after surgery. Overall survival rates (OS) and disease-free survival rates (DFS) were evaluated using the Kaplan-Meier method. Cox regression analysis was used to identify prognosis factors for overall survival. Results: According to the above criteria, 166 gastric cancer patients who underwent robotic radical total gastrectomy between March 2010 and November 2018 were included in this study. Roux-en-Y reconstruction was performed in all patients. Reconstruction were achieved using extracorporeal method through a minilaparotomy in 149 case and intracorporeal anastomosis in 17 cases. The number of harvested lymph nodes was (34.8±17.5), and the number of harvested lymph nodes at group 2 was (10.1±6.7). The number of patients with lymph node metastasis of group 2 was 73 (44.0%). The median follow-up time was 25 months (range 2-109). There were 55 (33.1%) cases of recurrence during follow-up. The 3- and 5-year overall survival rates were 55.8% and 46.2% respectively. The 3- and 5-year disease-free survival rates were 53.4% and 45.4% respectively. The 5-year overall survival rates grouped based on TNM stage were 78.9% for stage I, 58.5% for stage II, and 37.1% for stage III. The 5-year disease-free survival rates grouped based on TNM stage were 78.9% for stage I, 59.2% for stage II, and 34.6% for stage III. Univariate analysis suggested that TNM stage, the number of harvested lymph nodes and number of harvested lymph nodes at group 2 were associated with overall survival rates (all P<0.05). Multivariate analyses revealed that TNM stage (P<0.001; stage IIIB: HR=5.357, 95%CI:1.182 to 24.275; stage IIIC: HR=11.937, 95%CI: 2.677 to 53.226) and number of harvested lymph nodes at group 2 (P=0.034; 6-10: HR=0.562,95%CI:0.326 to 0.969; >10: HR=0.388, 95%CI: 0.176 to 0.857) were independent prognostic factors for overall survival. Conclusion: The long-term outcomes of robotic radical total gastrectomy were satisfactory. TNM stage and number of harvested lymph nodes at group 2 were independent prognostic factors for overall survival.

[The present situation and future development for robotic gastrointestinal surgery in China].

After ten years of development in robotic gastrointestinal surgery in China, although the number of robot surgical systems is small, the growth rate of robotic gastrointestinal surgery has grown up. Robotic gastrointestinal surgeons used the advantage of robots to perform a variety of surgical procedures with high complexity and technical difficulty, and achieved satisfactory clinical results. The robotic gastrointestinal surgeons in China are also paying attention to clinical research while carrying out robotic surgery. The number of international publications on robotic gastrointestinal surgery is at the forefront. However, the development of a robotic surgical system with independent intellectual property rights, and the further standardization of robotic gastrointestinal surgery indications and operational procedures are issues that urgently need to be addressed.

[Application of ultrasound for evaluation of anterosuperior acetabular labral tear].

OBJECTIVE: To explore the value of ultrasound in the diagnosis of anterosuperior acetabular labral tear. METHODS: A total of 102 patients [(42 males and 60 females, age from 13 to 60 years, average age was (35.14±9.16) years] with suspected anterosuperior acetabular labral tear were included in this study, including 44 left hip joints and 58 right hip joints. All the patients received hip joint ultrasound and magnetic resonance imaging (MRI) evaluation before arthroscopy surgery. Using arthroscopy as golden standard, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy between ultrasound and MRI were calculated and compared. RESULTS: There were 91 antero-superior acetabular labral tears of 102 patients which were confirmed during arthroscopy surgery. Sixty-nine patients were diagnosed correctly by ultrasound, including 60 anterosuperior acetabular labral tears and 9 with no acetabular labral tears, whereas 2 were false-positive and 31 were found to be false-negative. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy by ultrasound were respectively 65.93%, 81.82%, 96.77%, 22.50% and 67.65%. In contrast, seventy-seven patients were diagnosed correctly by MRI, including 70 anterosuperior acetabular labral tears and 7 with no acetabular labral tears, whereas 4 were false-positive and 21 were found to be false-negative. For MRI, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were respectively 76.92%, 63.64%, 94.59%, 25.00% and 75.49%. The results of ultrasound and MRI were in accordance in 68 of the 102 patients. There were 51 anterosuperior acetabular labral tears of the 68 patients who were diagnosed by both ultrasound and MRI, whereas there were 17 with no acetabular labral tears of the 68 patients who were diagnosed by both ultrasound and MRI. The results of ultrasound and MRI were inconsistent in 34 of the 102 patients. In 11 of the 34 patients, in which case ultrasound diagnosed anterosuperior acetabular labral tear, MRI found no acetabular labral tear. Whereas, in 23 of the 34 patients, in which case MRI diagnosed anterosuperior acetabular labral tear, ultrasound found no acetabular labral tear. As compared with MRI findings, ultrasound had a lower accuracy for anterosuperior acetabular labral tear than MRI, there was statistical difference on the accuracy for anterosuperior acetabular labral tear (P<0.01). CONCLUSION: Although ultrasound had a slightly lower sensitivity for anterosuperior acetabular labral tear, it had a higher specificity than MRI. Dynamic evaluation of antero-superior acetabular labral tear is an advantage of ultrasound. Ultrasound could be used as a feasible method to evaluate anterosuperior acetabular labral tear.

Role of secreted protein acidic in hematogenous metastasis of gastric cancer.

OBJECTIVE: To investigate tumor microenvironment of metastasis (TMEM) and the expression of SPARC (secreted protein acidic and rich in cysteine) in gastric cancer, and their relationships with hematogenous metastasis. PATIENTS AND METHODS: Twenty-six pairs of cases with gastric cancer were enrolled, in which there were 26 cases with distant organ metastases and 26 cases of gastric cancer without organ metastases as controls. TMEM (by double-stained immunohistochemistry) and the expression of SPARC were determined in twenty-six pairs of cases. In addition, we selected 48 patients to detect the expression of SPARC, VEGF (vascular endothelial growth factor), and evaluated TAMs (tumor associated macrophages), MVD (the microvessel density), MPI (microvessel pericyte coverage index), and TMEM in gastric cancer tissues by immunohistochemistry. RESULTS: TMEM count was significantly higher in the metastatic gastric cancer tissues than that in non-metastatic cancer tissues in a case-control study (p<0.01). On the contrary, SPARC expression was lower in the metastatic gastric cancer tissues than that in non-metastatic cancer tissues. TMEM count, TAMs, and MVD were significantly correlated with invasion depth, histological type and TNM stage (p<0.05 or p<0.01). Expression of SPARC and VEGF were significantly correlated with tumor histological types, invasion depth, differentiation and lymph node metastasis of patients (p<0.05). SPARC and VEGF expression in stromal cells of gastric cancer tissues were significantly correlated with TAMs, MVD and MPI (p<0.05). In addition, SPARC expression was significantly inversely correlated with VEGF expression in gastric cancer tissues (p<0.05). CONCLUSIONS: TMEM was detected in initial gastric cancer resection and closely correlated with hematogenous metastasis. Furthermore, SPARC may be involved in gastric cancer metastasis by effecting on tumor microenvironment.

[Analysis of Spatial Clustering of HIV infected in men who have sex with men in Chongqing of 2004-2015].

Objective: To analyze the spatial clustering characteristics of HIV/AIDS among men who have sex with men (MSM) in Chongqing from January 2004 to December 2015 and understand the HIV/AIDS related behaviors among MSM by interview. Methods: Data related to MSM who were infected with HIV and whose present address were in Chongqing, were collected from Information System on the HIV/AIDS Prevention and Control. Information included the age when the information was inputted, address, occupation, education level, and marital status. The total number of MSM who were infected with HIV and reported was 6 604 in Chongqing. Those with unknown address were ruled out. The spatial autocorrelation analysis and the local spatial autocorrelation analysis were carried out by using ArcGIS 10.3. In addition, in November 2015 and May 2016, using a convenience sampling, we conducted one-on-one interviews among 23 MSM in the Chongqing Center for Disease Control and prevention. INCLUSION CRITERIA: Receiving voluntary counseling and testing in the urban area of Chongqing and willing to participate in the interview by oral informed consent; male and self-described as MSM. The content of the interview included basic information, sexual orientation, sexual role, the main place of making friends, the main place of sexual behavior, a long-term experience in other provinces and drug abuse. Results: The HIV/AIDS reported number in Chongqing from 2004 to 2015 showed an uptrend, except in 2010. The age distribution of 6 604 cases of HIV positive patients was mainly concentrated in the 15-34 years old, about 68.5% (4 522 cases). There was a positive spatial autocorrelation in MSM, except 2005 (Moran's I=-0.046, P=0.823), form 2004 to 2015, Global Moran's I values were 0.308, 0.254, 0.335, 0.683, 0.673, 0.558, 0.620, 0.673, 0.685, 0.654 and 0.649, respectively; all P values were <0.01. The result of local spatial autocorrelation analysis showed that high-high accumulation area development in Chongqing city was divided into two stages in 2004-2015, which were Yuzhong, Jiangbei, and Shapingba district in 2004-2007 and the expanded Jiulongpo, Nan'an, and Yubei district in 2008-2015. Qualitative interviews results revealed that the age of the respondents was 20-44, and the mainly way of making friends were using mobile phone App and internet (17 participants). Most of the participants (11 participants) were making friends in the bar. The majority of respondents would ask the friends or themselves to use condoms when meeting with them the first time (19 participants), and 8 of respondents reported that they would not use condoms when their old friends refused to use condoms. Conclusion: The HIV infected MSM mainly aged between 15-34 years old and the spatial distribution of HIV/AIDS among MSM was clustered in economically developed main area in Chongqing. MSM began to make friends on the Internet, and could not adhere to using condom, which indicated that we should focus on internet intervention to find more efficacious interventions.

The promotion of the transformation of quiescent gastric cancer stem cells by IL-17 and the underlying mechanisms.

Postoperative recurrence and metastasis have crucial roles in the poor prognosis of gastric cancer patients. Previous studies have indicated that gastric cancer originates from cancer stem cells (CSCs), and some investigators have found that a particular subset of CSCs possesses higher metastatic capacity. However, the specific mechanism remains uncertain. In the present study, we aimed to explore the biological functions of the inflammatory cytokine interleukin-17 (IL-17) in gastric cancer metastasis and the distinct IL-17-induced transformation of quiescent gastric CSCs. Our results showed that invasive gastric CSCs were CD26+ and CXCR4+ and were closely associated with increased metastatic ability. The quiescent gastric CSCs, which were CD26- and CXCR4-, were exposed to appropriate concentrations of IL-17; this resulted in the decreased expression of E-cadherin and the increased expression of vimentin and N-cadherin. In addition, the upregulation of IL-17 both in vitro and in vivo resulted in a significant induction of invasion, migration and tumor formation ability in gastric CSCs compared with the control group, which was not treated with IL-17. Further experiments indicated that the activation of the downstream phosphorylated signal transducer and activator of transcription 3 (STAT3) transcription factor pathway was facilitated by IL-17. On the contrary, the downregulation of STAT3 by the specific inhibitor Stattic significantly reversed the IL-17-induced epithelial-mesenchymal transition (EMT)-associated properties of quiescent gastric CSCs. Moreover, tumorigenesis and metastasis were suppressed. Taken together, we suggest that IL-17 is positively correlated with the transformation of quiescent gastric CSCs into invasive gastric CSCs and that targeting IL-17 may emerge as a possible novel therapeutic strategy for gastric cancer.

[Application of da Vinci robotic surgical system in radical resection of gastric and colorectal cancer: a report of 647 cases].

OBJECTIVE: To investigate the feasibility and safety of robotic-assisted radical resection of gastric and colorectal cancer. METHODS: The clinical data of 305 patients who received radical resection of gastric cancer and 342 patients who received radical resection of colorectal cancer both accomplished by the da Vinci robotic surgical system at the Southwest Hospital, Third Military Medical University from March 2010 to December 2014 were retrospectively analyzed. In gastric cancer group, radical total gastrectomy were performed in 69 cases, proximal gastrectomy in 11 cases, distal gastrectomy in 213 cases and 12 cases of gastric stump cancer.In colorectal cancer group, radical resection of the right colon were performed in 6 cases, left colon in 4 cases, transverse colon in 1 case, sigmoid colon low anterior resection procedure in 24 cases, rectal low anterior resection procedure in 222 cases, abdominoperineal excision procedure in 79 cases and Hartmann procedure in 6 cases. RESULTS: All cases had robotic-assisted radical resection successfully. In gastric cancer group, the mean operation time was (226±62) minutes, the mean blood loss was (125±77) ml, the mean number of harvested lymph nodes was 34±10; the mean time for patients taking normal activity was (3.2±1.5) days, the mean time for gastrointestinal function recovery was (3.1±1.3) days, the mean time for taking liquid food was (3.5±1.9) days. The mean hospitalization was (7.9±3.7) days postoperatively. In colorectal group, the mean operation time was (181±61) minutes, the mean blood loss was (110±93) ml, the mean number of harvested lymph nodes was 19±6; the mean time for patients taking normal activity was (2.9±1.5) days, passage of first flatus was (2.7±1.7) days. The mean hospitalization was (7.1±1.6) days postoperatively. Surgical complications occurred in 28 patients (9.2%) of gastric cancer group and 30 patients (8.8%) of colorectal cancer group, all the cases were recovery before leaving hospital with non-operation therapy. The short-term efficiency was obvious. CONCLUSION: Robotic-assisted radical resection for gastric and colorectal cancer is a feasible and safe surgical procedure combined the minimal trauma and fast recovery.

Ultra-low-frequency wave-driven diffusion of radiation belt relativistic electrons.

Van Allen radiation belts are typically two zones of energetic particles encircling the Earth separated by the slot region. How the outer radiation belt electrons are accelerated to relativistic energies remains an unanswered question. Recent studies have presented compelling evidence for the local acceleration by very-low-frequency (VLF) chorus waves. However, there has been a competing theory to the local acceleration, radial diffusion by ultra-low-frequency (ULF) waves, whose importance has not yet been determined definitively. Here we report a unique radiation belt event with intense ULF waves but no detectable VLF chorus waves. Our results demonstrate that the ULF waves moved the inner edge of the outer radiation belt earthward 0.3 Earth radii and enhanced the relativistic electron fluxes by up to one order of magnitude near the slot region within about 10 h, providing strong evidence for the radial diffusion of radiation belt relativistic electrons.

Effects of CO(2) pneumoperitoneum on peritoneal macrophage function and peritoneal metastasis in mice with gastric cancer.

BACKGROUND: Whether laparoscopy with CO(2) pneumoperitoneum affects the peritoneal metastasis of gastric cancer is a pressing question. In light of the important impact change in peritoneal macrophage function has on the peritoneal metastasis of gastric cancer, this study investigated the change in peritoneal macrophage function in gastric cancer in the CO(2) pneumoperitoneum environment, as well as its effect on the peritoneal metastasis of gastric cancer. METHODS: An orthotopic transplantation model of murine forestomach carcinoma was established using the 615 mouse line. The mice bearing tumors were randomly divided into four groups (30 mice each group): anesthesia alone, laparotomy, mini-laparotomy, and CO(2) insufflation. After the operation, peritoneal macrophages were collected from 6 mice in each group and cultured. The phagocytosis of neutral red by macrophages and the levels of NO, TNF-α, IL-10, and VEGF produced by macrophages were measured after 12, 24, 48, and 72 h of culture. The remaining mice were observed after 2 weeks for the rate of peritoneal metastasis of forestomach carcinoma cells and the total weight of implanted nodules. RESULTS: In the laparotomy group, 4 mice died intraoperatively and 2 died in the CO(2) insufflation group. The uptake of neutral red by peritoneal macrophages and the levels of NO, TNF-α, IL-10, and VEGF secreted by peritoneal macrophages in the laparotomy group and mini-laparotomy group after 12 h of culture were all significantly higher than those in the anesthesia-alone group (p < 0.05). The corresponding levels in the CO(2) insufflation group after 12 h were all significantly lower than those in the anesthesia-alone group (p < 0.05). There were no significant differences among the four groups at 24, 48, and 72 h after culture. Comparing with those in the laparotomy group, the uptake of neutral red by peritoneal macrophages and the levels of NO, TNF-α, IL-10, and VEGF secreted by peritoneal macrophages in the CO(2) insufflation group were all significantly lower after 12 h of culture (p < 0.05), but did not differ significantly at 24, 48, and 72 h of culture (p > 0.05), and did not differ significantly in the mini-laparotomy group at all the time (p > 0.05). The rate of peritoneal metastasis of mouse forestomach carcinoma was 50% in the laparotomy group, 45.83% in the mini-laparotomy group, and 45.45% in the CO(2) insufflation group; this difference was not statistically significant (p > 0.05). The total weight of implanted nodules of mouse forestomach carcinoma was 1.02 ± 0.38 g in the laparotomy group, 0.97 ± 0.41 g in the mini-laparotomy group, and 0.93 ± 0.45 g in the CO(2) insufflation group, which was not a statistically significant difference (p > 0.05). CONCLUSION: CO(2) pneumoperitoneum neither significantly changes the phagocytosis and cytokine secretion functions of peritoneal macrophages in gastric cancer-bearing mice nor significantly promotes peritoneal metastasis of gastric cancer.

Reduced serologic response to avian influenza vaccine in specific-pathogen-free chicks inoculated with Cryptosporidium baileyi.

Immunosuppression in chickens as a consequence of Cryptosporidium baileyi infection may compromise the effectiveness of vaccination for control of avian influenza (AI) H5N1. In a 13-wk study using 260 specific-pathogen-free chicks, immunological response and bursa weight:body weight ratios following vaccination against AI strain H5N1 were compared between uninfected and C baileyi-infected birds. The four experimental treatments were the following: infection with C. baileyi (5 x 10(5) oocysts dosed orally on day 0); C baileyi infection + vaccination against H5N1 (0.3 ml inactivated vaccine administered subcutaneously on day 7 and day 21; CB+VAC); vaccination only (VAC); and sham infection/vaccinations using sterile distilled water (control). At weekly intervals serum samples were analyzed by hemagglutination inhibition assay (HI), and five chicks/group were euthanatized for determination of bursa weights. In all but week 8, proportional bursa weights (bursa weight/body weight) were lower for CB+VAC chicks than for VAC chicks (i.e., the bursa index was below 1.0; average 0.81). Throughout the 13 wk, HI titres were lower (P < 0.01) in CB+VAC than in the VAC group, and compared with VAC, chicks in CB+VAC had a slightly shorter period of negative seroconversion. These data indicate bursal atrophy and immunosuppressive effects of C. baileyi infection on day-old chicks vaccinated against AI strain H5N1 and suggest that C. baileyi infection in chicks may increase the host susceptibility to AI virus.

Expression of matrix metalloproteinases 2 and 9 and tissue inhibitors of metalloproteinase 1 and 2 in inflammation-induced corneal neovascularization.

PURPOSE: Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase (TIMPs) have been linked to the angiogenic process in general. In order to understand the potential roles of MMP-2, MMP-9 and TIMPs in the corneal neovascularization process, we examined the expression and activities of MMP-2, MMP-9 and TIMPs during the course of cauterization-induced corneal neovascularization in a rat model. METHODS: Neovascularization of rat corneas was induced by silver nitrate cauterization. The expression of MMP-2, MMP-9, TIMP-1 and TIMP-2 was examined by immunohistochemistry and RT-PCR. The protein activities of MMPs and TIMPs were compared in pre- and postcauterization corneas by gelatin zymography and reverse zymography, respectively. RESULTS: MMP-2, TIMP-1 and TIMP-2 immunoreactivities were expressed in normal corneas, predominantly in the corneal epithelium. After injury, immunoreactivities of both MMPs and TIMPs were increased, notably in the healing corneal epithelium, infiltrating inflammatory cells, stromal fibroblasts and ingrowing vascular endothelial cells. The increase in gross MMP-2 enzymatic activity paralleled the maximal vascular ingrowth on day 4, while the gross MMP-9 enzymatic activity rose immediately on day 1, then decreased steadily, which paralleled the magnitude of inflammatory cell infiltration. The immunoreactivity of MMPs/TIMPs decreased significantly 2 weeks after cauterization. On day 35, MMP-2, TIMP-1 and TIMP-2 staining was seen only in corneal epithelium and vascular endothelial cells. Both the RT-PCR and reverse zymography results revealed a more constant expression of TIMP-2, while the TIMP-1 expression appeared to be more inducible. CONCLUSION: MMPs as well as TIMPs were upregulated in cauterization-induced corneal neovascularization, suggesting that both may participate in extracellular matrix remodeling in the corneal wound healing, inflammation and neovascularization processes.

[Experimental study of the 50% damage threshold of Nd:YAG laser on IOL].

The 50% damage threshold (DT50) of Nd:YAG laser was determined for IOLs of PMMA (lathed or molded), silicone and glass. The laser resistances in increasing order were silicone 79.22 gW/cm2, glass 100.82 gW/cm2, lathed PMMA 115.23 gW/cm2 and molded PMMA 142.49 gW/cm2. The authors recommended that only dosages below the DT50 be used in posterior capsulotomy to minimize the risk of IOL damage. The various laser damage patterns on IOL were studied by scanning electron microscopy.