Quantitative estimation of retinal nerve fiber layer height in glaucoma and the relationship with optic nerve head topography and visual field

Purpose: The authors estimated the retinal nerve fiber layer height (RNFLH) measurements in patients with glaucoma compared with those in age-matched healthy subjects as obtained by the laser scanning tomography and assessed the relationship between RNFLH measurements and optic and visual field status. Methods: Parameters of optic nerve head topography and RNFLH were evaluated in 125 eyes of 21 healthy subjects and 104 patients with glaucoma using the Heidelberg Retina Tomograph ([HRT] Heidelberg Engineering GmbH, Heidelberg, Germany) for the entire disc area and for the superior 70°(50°temporal and 20°nasal to the vertical midline) and inferior 70°sectors of the optic disc. The mean deviation of the visual field, as determined by the Humphrey program 24-2 (Humphrey Instruments, Inc., San Leonardo, CA, U.S.A) was calculated in the entire field and in the superior and inferior Bjerrum area. Result: Retinal nerve fiber layer height parameters (mean RNFLH and RNFL cross-sectional area) were decreased significantly in patients with glaucoma compared with healthy individuals. Retinal nerve fiber layer height parameters was correlated strongly with rim volume, rim area, and cup/disc area ratio. Of the various topography measures, retinal nerve fiber layer (RNFL) parameters and cup/disc area ratio showed the strongest correlation with visual field mean deviation in patients with glaucoma. Conclusion: Retinal nerve fiber layer height measures were reduced substantially in patients with glaucoma compared with age-matched healthy subjects. Retinal nerve fiber layer height was correlated strongly with topographic optic disc parameters and visual field changes in patients with glaucoma.

Reduced soluble receptor for advanced glycation end-products (sRAGE) scavenger capacity precedes pre-eclampsia in Type 1 diabetes

Objective Increased advanced glycation end-products (AGEs) and their soluble receptors (sRAGE) have been implicated in the pathogenesis of pre-eclampsia (PE). However, this association has not been elucidated in pregnancies complicated by diabetes. We aimed to investigate the serum levels of these factors in pregnant women with Type 1 diabetes mellitus (T1DM), a condition associated with a four-fold increase in PE. Design Prospective study in women with T1DM at 12.2 ± 1.9, 21.6 ± 1.5 and 31.5 ± 1.7 weeks of gestation [mean ± standard deviation (SD); no overlap] before PE onset. Setting Antenatal clinics. Population Pregnant women with T1DM (n = 118; 26 developed PE) and healthy nondiabetic pregnant controls (n = 21). Methods Maternal serum levels of sRAGE (total circulating pool), N -(carboxymethyl)lysine (CML), hydroimidazolone (methylglyoxal-modified proteins) and total AGEs were measured by immunoassays. Main outcome measures Serum sRAGE and AGEs in pregnant women with T1DM who subsequently developed PE (DM PE+) versus those who remained normotensive (DM PE-). Results In DM PE+ versus DM PE-, sRAGE was significantly lower in the first and second trimesters, prior to the clinical manifestation of PE (P <0.05). Further, reflecting the net sRAGE scavenger capacity, sRAGE:hydroimidazolone was significantly lower in the second trimester (P <0.05) and sRAGE:AGE and sRAGE:CML tended to be lower in the first trimester (P <0.1) in women with T1DM who subsequently developed PE versus those who did not. These conclusions persisted after adjusting for prandial status, glycated haemoglobin (HbA1c), duration of diabetes, parity and mean arterial pressure as covariates. Conclusions In the early stages of pregnancy, lower circulating sRAGE levels, and the ratio of sRAGE to AGEs, may be associated with the subsequent development of PE in women with T1DM. © 2012 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2012 RCOG.

Serum carotenoids and fat-soluble vitamins in women with type 1 diabetes and preeclampsia:a longitudinal study

Increased oxidative stress and immune dysfunction are implicated in preeclampsia (PE) and may contribute to the two- to fourfold increase in PE prevalence among women with type 1 diabetes. Prospective measures of fat-soluble vitamins in diabetic pregnancy are therefore of interest.

Numerical investigation of the effects of drill geometry on drilling induced delamination of carbon fiber reinforced composites

Drilling is a major process in the manufacturing of holes required for the assemblies of composite laminates in aerospace industry. Simulation of drilling process is an effective method in optimizing the drill geometry and process parameters in order to improve hole quality and to reduce the drill wear. In this research we have developed three-dimensional (3D) FE model for drilling CFRP. A 3D progressive intra-laminar failure model based on the Hashin's theory is considered. Also an inter-laminar delamination model which includes the onset and growth of delamination by using cohesive contact zone is developed. The developed model with inclusion of the improved delamination model and real drill geometry is used to make comparison between the step drill of different stage ratio and twist drill. Thrust force, torque and work piece stress distributions are estimated to decrease by the use of step drill with high stage ratio. The model indicates that delamination and other workpiece defects could be controlled by selection of suitable step drill geometry. Hence the 3D model could be used as a design tool for drill geometry for minimization of delamination in CFRP drilling. © 2013 Elsevier Ltd.

Dietary fiber and the risk of precancerous lesions and cancer of the esophagus:a systematic review and meta-analysis

Dietary fiber has several anticarcinogenic effects and is thought to be protective against esophageal cancer. The aim of this systematic review was to quantify the association between dietary fiber and the risk of esophageal cancer by investigating histological subtypes of esophageal cancer and the stage at which fiber may influence the carcinogenic pathway. Systematic search strategies were used to identify relevant studies, and adjusted odds ratios (ORs) were combined using random-effects meta-analyses to assess the risk of cancer when comparing extreme categories of fiber intake. Ten relevant case-control studies were identified within the timeframe searched. Pooled estimates from eight studies of esophageal adenocarcinoma revealed a significant inverse association with the highest fiber intakes (OR 0.66; 95% confidence interval [CI] 0.44-0.98). Two studies also identified protective effects of dietary fiber against Barrett's esophagus. Similar, though nonsignificant, associations were observed when results from five studies of fiber intake and risk of squamous cell carcinoma were combined (OR 0.61; 95%CI 0.31-1.20). Dietary fiber is associated with protective effects against esophageal carcinogenesis, most notably esophageal adenocarcinoma. Potential methods of action include modification of gastroesophageal reflux and/or weight control.

Commissioning and Evaluation of a Fiber-Optic Sensor System for Bridge Monitoring

This paper describes the design, commissioning, and evaluation of a ?ber-optic strain sensor system for the structural health monitoring of a prestressed concrete posttensioned box girder railway bridge in Mumbai, India, which shows a number of well-documented structural problems. Preliminary laboratory trials to design the most appropriate sensor system that could be readily transported and used on site are described, followed by a description of load tests on the actual bridge undertaken in collaboration with Indian Railways and using locomotives of known weight. Results from the load tests using the optical system are compared with similar results obtained using electrical resistance strain gages. Conclusions are summarized concerning the integrity of the structure and for the future use of the sensor system for monitoring bridges of this type. Crack width measurements obtained during the load tests are also described.

Delamination and wear in drilling of carbon-fiber reinforced plastic composites using multilayer TiAlN/TiN PVD-coated tungsten carbide tools

This study aims to investigate drilling process in carbon-fiber reinforced plastic (CFRP) composites with multilayer TiAlN/TiN PVD-coated tungsten carbide drill. The effect of process parameters have been investigated in drilling of Hexcel M21-T700GC. Thrust force and torque were measured online throughout the drilling experiments. Delamination were observed using optical microscope and analyzed via a developed algorithm based on digital image processing technique. Surface roughness of each hole was measured using a surface profilometer. In addition, the progression of tool wear in various surfaces of drill was observed using tool microscope and measured using image software. Our results indicate that the thrust force and torque increased with the increasing cutting speed and feed rate. Delamination and average surface roughness that rose with the increase in feed rate, however, decreased with the increasing cutting speed. The average surface roughness tended to increase with the increase in feed rate and decrease with the increasing cutting speed in drilling of carbon-fiber reinforced plastic (CFRP). Feed rate was found as the predominant factor on the drilling outputs. Abrasive wear was observed on both flank and relief surfaces, which created edge wear on cutting edges. No sign of chipping or plastic deformation has been observed on the surfaces of drills. © 2012 The Author(s).

Prediction of failure and fracture mechanisms of polymeric composites using finite element analysis. Part 2:Fiber reinforced composites

A robust finite element scheme for the micro-mechanical modeling of the behavior of fiber reinforced polymeric composites under external loads is developed. The developed model is used to simulate stress distribution throughout the composite domain and to identify the locations where maximum stress concentrations occur. This information is used as a guide to predict dominant failure and crack growth mechanisms in fiber reinforced composites. The differences between continuous fibers, which are susceptible to unidirectional transverse fracture, and short fibers have been demonstrated. To assess the validity and range of applicability of the developed scheme, numerical results obtained by the model are compared with the available experimental data and also with the values found using other methods reported in the literature. These comparisons show that the present finite element scheme can generate meaningful results in the analysis of fiber reinforced composites.

The role of salt and shear on the storage and assembly of spider silk proteins

Major ampullate silk fibers of orb web-weaving spiders have impressive mechanical properties due to the fact that the underlying proteins partially fold into helical/amorphous structures, yielding relatively elastic matrices that are toughened by anisotropic nanoparticulate inclusions (formed from stacks of beta-sheets of the same proteins). In vivo the transition from soluble protein to solid fibers involves a combination of chemical and mechanical stimuli (such as ion exchange, extraction of water and shear forces). Here we elucidate the effects of such stimuli on the in vitro aggregation of engineered and recombinantly produced major ampullate silk-like proteins (focusing on structure-function relationships with respect to their primary structures), and discuss their relevance to the storage and assembly of spider silk proteins in vivo. (C) 2009 Elsevier Inc. All rights reserved.

The reduction of serum soluble Flt-1 in patients with neovascular age-related macular degeneration

PURPOSE: To evaluate serum soluble Flt-1 (sFlt-1) in age-related degeneration (AMD) patients.

DESIGN: Case control study.

METHODS: Fifty-six non-AMD participants, fifty-three early AMD patients and ninety-seven neovascular AMD patients from Belfast in Northern Ireland. Serum samples were collected from each patient. Serum sFlt-1 was measured by human sVEGFR1/sFlt-1 ELISA kit. The results were analyzed by Excel and SPSS.

RESULTS: Serum sFlt-1 concentration of non-AMD, early AMD, and neovascular AMD were 90.8±2.9 pg/mL (±SEM), 88.2±2.6 pg/mL and 79.9±2.2 pg/mL. sFlt-1 from neovascular AMD patients was significantly decreased compared to non-AMD and early AMD patients (ANOVA, p<0.01). For each 10 point increase in sFlt-1, the odds for having neovascular AMD compared with non-AMD and neovascular AMD decreases by 27.8% OR=0.722 (95% CI: 0.588-0.888, p=0.002) and 27.0% OR=0.730 (95% CI: 0.594-0.898, p=0.003), respectively. In patients over 73 years of age, serum sFlt-1 <80 pg/mL was associated with a >6-fold higher risk of neovascular AMD.

CONCLUSIONS: Reduced serum sFlt-1 differentiates those patients with neovascular AMD from both early AMD and non-AMD participants. In those aged over 73, serum sFlt <80 pg/mL seems to indicate a particularly high risk of neovascular AMD. Our results indicate serum sFlt-1 could be a biomarker for development of neovascular AMD.

The use of water soluble mucoadhesive gels for the intravesical delivery of epirubicin to the bladder for the treatment of non-muscle invasive bladder cancer

Objectives: To develop an epirubicin-loaded, water-soluble mucoadhesive gels that have the correct rheological properties to facilitate their delivery into the bladder via a catheter, while allowing for their spread across the bladder wall with limited expansion of the bladder and increasing the retention of epirubicin in the bladder and flushing with urine.

Methods: Epirubicin-loaded hydroxyl ethyl cellulose (HEC) and hydroxy propyl methyl cellulose (HPMC) gels were manufactured and tested for their rheological properties. Their ability to be pushed through a catheter was also assessed as was their in-vitro drug release, spreading in a bladder and retention of epirubicin after flushing with simulated urine.

Key findings: Epirubicin drug release was viscosity-dependent. The 1 and 1.5% HEC gels and the 1, 1.5 and 2% HPMC gels had the correct viscosity to be administered through a model catheter and spread evenly across the bladder wall under the pressure of the detrusor muscle. The epirubicin-loaded gels had an increased retention time in the bladder when compared with a standard intravesical solution of epirubicin, even after successive flushes with simulated urine.

Conclusion: The increased retention of epirubicin in the bladder by the HEC and HPMC gels warrant further investigation, using an in-vivo model, to assess their potential for use as treatment for non-muscle-invasive bladder cancer.