Introducing a Linear Empirical Correlation for Predicting the Mass Heat Capacity of Biomaterials.

This study correlated biomass heat capacity (Cp) with the chemistry (sulfur and ash content), crystallinity index, and temperature of various samples. A five-parameter linear correlation predicted 576 biomass Cp samples from four different origins with the absolute average relative deviation (AARD%) of ~1.1%. The proportional reduction in error (REE) approved that ash and sulfur contents only enlarge the correlation and have little effect on the accuracy. Furthermore, the REE showed that the temperature effect on biomass heat capacity was stronger than on the crystallinity index. Consequently, a new three-parameter correlation utilizing crystallinity index and temperature was developed. This model was more straightforward than the five-parameter correlation and provided better predictions (AARD = 0.98%). The proposed three-parameter correlation predicted the heat capacity of four different biomass classes with residual errors between -0.02 to 0.02 J/g∙K. The literature related biomass Cp to temperature using quadratic and linear correlations, and ignored the effect of the chemistry of the samples. These quadratic and linear correlations predicted the biomass Cp of the available database with an AARD of 39.19% and 1.29%, respectively. Our proposed model was the first work incorporating sample chemistry in biomass Cp estimation.

Numerical investigation of compressible flow around nose cone with Multi-row disk and multi coolant jets.

Due to sever aerodynamic heating, the protection of forebody of scramjet is crucial for hypersonic flight. In present work, a new cooling system is proposed and investigated for the protection of nose cone at hypersonic flight. Computational fluid dynamic is used for the simulation of the lateral and axial coolant jet released from the spike at high-velocity condition. The primary goal is to find optimum jet location for efficient cooling of nose and spike assembly. Influence of two coolant jets (Carbon dioxide and Helium) on the mechanism of cooling system are fully investigated. For simulation, RANS equations are coupled with species transport equation and SST turbulence model. Two different jet configurations (axial disk positions) are investigated to obtain efficient condition for protection of nose cone at hypersonic flight. Our results indicate that the presence of the spike on the nose cone decreases pressure up to 33% on the main body and the shifts the maximum pressure to higher angles because of the deflection of the air stream. Maximum pressure drops about 50% by injection of the coolant disk jet (C2) at angle of 55 deg.

Evaluation of AGM and FEM method for thermal radiation on nanofluid flow between two tubes in nearness of magnetism field.

The nanofluid flow through two orbicular cylinders is explored utilizing the overall Koo-Kleinstreuer-Li (KKL) model within the nearness of a magnetic field. The impact of thermal radiation is considered in the energy equation. The novelty of this study is examining convective heat transfer for nanofluid flow between two flat tubes with the Akbari-Ganji method and Finite Element Techniques to examine the heat flux field by implies of 2D forms of temperature and velocity at unprecedented Reynolds numbers. The approaches for solving ODEs are AGM and FEM. Semi-analytical methods are assessed for specific parameters of aspect ratio, Hartmann number, Eckert number, and Reynolds quantity with various values. Adding Ha, Ec, and G causes the temperature gradient to grow, while adding the Reynolds number causes it to decrease. As the Lorentz forces increase, the velocity decreases; nevertheless, as the Reynolds number rises, the velocity decreases. With the reduction of the fluid's dynamic viscosity, the temperature will decrease, which will decrease the thermal trend along the vertical length of the pipes.

Wavelet-artificial neural network to predict the acetone sensing by indium oxide/iron oxide nanocomposites.

This study applies a hybridized wavelet transform-artificial neural network (WT-ANN) model to simulate the acetone detecting ability of the Indium oxide/Iron oxide (In2O3/Fe2O3) nanocomposite sensors. The WT-ANN has been constructed to extract the sensor resistance ratio (SRR) in the air with respect to the acetone from the nanocomposite chemistry, operating temperature, and acetone concentration. The performed sensitivity analyses demonstrate that a single hidden layer WT-ANN with nine nodes is the highest accurate model for automating the acetone-detecting ability of the In2O3/Fe2O3 sensors. Furthermore, the genetic algorithm has fine-tuned the shape-related parameters of the B-spline wavelet transfer function. This model accurately predicts the SRR of the 119 nanocomposite sensors with a mean absolute error of 0.7, absolute average relative deviation of 10.12%, root mean squared error of 1.14, and correlation coefficient of 0.95813. The In2O3-based nanocomposite with a 15 mol percent of Fe2O3 is the best sensor for detecting acetone at wide temperatures and concentration ranges. This type of reliable estimator is a step toward fully automating the gas-detecting ability of In2O3/Fe2O3 nanocomposite sensors.

Surgical outcomes after massive subretinal hemorrhage secondary to age-related macular degeneration.

PURPOSE: Massive subretinal hemorrhage (SRH), defined as a thick submacular bleed that extends past the equator in at least two quadrants, is a rare sequela of age-related macular degeneration. This report describes outcomes after surgical intervention for massive SRH. METHODS: The study design is a retrospective interventional case series. Records of consecutive patients who underwent surgical intervention for massive SRH were reviewed. Outcomes included change from baseline in postoperative acuity at Months 1, 3, 6, 9, and 12 and postoperative complications. RESULTS: Fifteen consecutive eyes of 13 patients who underwent surgery for massive SRH were included. Procedures performed on initial surgery included subretinal instillation of 25 µg/0.1 mL tissue plasminogen activator (15 of 15), gas tamponade (12 of 15), oil tamponade (3 of 15), 180° or greater retinotomy (4 of 15), and/or cataract extraction (2 of 15). Patients were followed for a median of 20 months (range, 3-66 months). The median visual acuity at baseline and postoperative Month 1 was hand motions but improved to counting fingers at postoperative Months 3 (P = 0.04), 6 (P = 0.04), 9 (P = 0.04), and 12 (P = 0.10). Of the 15 eyes, 9 required at least 1 additional procedure for an indication of hyphema and/or vitreous hemorrhage (n = 6), retinal detachment (n = 2), glaucoma (n = 1), cataract (n = 1), and aphakia (n = 1). At the time of the onset of SRH, 5 of 13 patients were anticoagulated with warfarin (4 patients) or clopidogrel (1 patient), and 1 was diagnosed with a coagulopathy, factor XI deficiency. CONCLUSION: Massive SRH related to age-related macular degeneration has a grave prognosis. Risk factors may include anticoagulation and coagulopathy. Limitations of the study include its retrospective nature, small sample size, imprecision in acuity measurements below 20/400, and lack of a control group. In this series, surgical intervention was associated with a modest improvement in median visual acuity up to 1 year postoperatively.

Pascal dynamic contour tonometry versus goldmann applanation tonometry in gas and air-filled eyes after vitrectomy surgery.

PURPOSE: To compare Pascal Dynamic Contour Tonometry with Goldmann Applanation Tonometry in eyes after vitrectomy surgery with intraocular tamponade of air, silicone oil or perfluorocarbon gas. METHODS: Prospective clinical comparative study. Eighty-two consecutive patients undergoing vitrectomy surgery with postoperative air, gas or oil tamponade were recruited. Intraocular pressure was measured with both devices. RESULTS: Mean Goldmann intraocular pressure was 16.6 mmHg (range, 1.0-46.0; SD = 8.80) and the mean Pascal intraocular pressure was 21.70 (range, 4.7-58.5; SD = 9.8) The mean difference between the Pascal and Goldmann readings was 5.09 mmHg (range, -14.7 to +12.9; 95% CI = 4.2-6.0; SD, 4.0; P < 0.001). Mean differences for the different tamponades were 5.09 mmHg for silicone oil, 4.02 mmHg for air, and 5.38 mmHg for perfluorocarbon gas. CONCLUSION: Pascal dynamic contour tonometry gives readings that are highly correlated with Goldmann applanation tonometry, but on average 5 mmHg higher in eyes after vitrectomy surgery with air, gas or silicone oil tamponades. The difference between Goldmann and Pascal readings does not appear to be altered by the presence of a scleral buckle, or the size of the intraocular gas bubble.

Outcomes of 77 consecutive cases of 23-gauge transconjunctival vitrectomy surgery for posterior segment disease.

PURPOSE: To describe the initial experience, effectiveness, and safety profile of 23-gauge instrumentation for a variety of vitreoretinal conditions. DESIGN: Single-center, retrospective, noncomparative, consecutive interventional case series. PARTICIPANTS: Seventy-seven eyes of consecutive patients who underwent 23-gauge transconjunctival vitrectomy surgery by a single surgeon at the Manhattan Eye, Ear, and Throat Hospital from October 2004 through October 2005. INTERVENTION: All patients underwent 3-port 23-gauge vitrectomy using Dutch Ophthalmic Research Corporation instrumentation and an Alcon Accuris Vitrector. MAIN OUTCOME MEASURES: Postoperative visual acuity at months 1 and 3, intraoperative and postoperative complications, and operative time. RESULTS: Mean acuity improved from 20/190 at baseline to 20/108 (P<0.0001) and 20/74 (P<0.0001) at months 1 and 3, respectively. By diagnosis, patients with epiretinal membrane (n = 20) improved from 20/124 to 20/93 (P = 0.0046), macular hole (n = 18) from 20/174 to 20/57 (P = 0.0007), rhegmatogenous retinal detachment (RD) (n = 14) from 20/248 to 20/51 (P = 0.0004), tractional RD (n = 12) from 20/175 to 20/62 (P = 0.0159), nonclearing vitreous hemorrhage (n = 12) from 20/1345 to 20/189 (P = 0.0004), vitreomacular traction (n = 4) from 20/145 to 20/124 (P = 0.7525), and retained lens fragments (n = 4) from 20/308 to 20/140 (P = 0.0972). One patient who underwent diagnostic vitrectomy had stable 20/50 acuity. Two patients had hypotony on postoperative day 1, 1 patient required a sutured sclerotomy intraoperatively, and no patients developed choroidal effusions. No intraoperative tears were noted. Surgical times collected on 17 patients during the final month of the study demonstrated a mean opening time (range) of 103 seconds (70-162), mean closing time of 75 seconds (17-470), and net operating time of 24.1 minutes (7.1-74.6). CONCLUSIONS: Twenty-three-gauge instrumentation is effective for a variety of vitreoretinal surgical indications. The safety profile compared favorably with published rates for 25-gauge systems.

Macular hole formation following thermal laser photocoagulation in a patient with choroidal neovascular membrane and age-related macular degeneration.

A woman with age-related macular degeneration and an extrafoveal choroidal neovascularization was treated with thermal laser photocoagulation. Three years later, an optical coherence tomography image showed a full-thickness macular hole with some contracture toward the adjacent atrophic laser scar, suggestive of some presumptive tangential forces.

Development of subretinal fibrosis after anti-VEGF treatment in neovascular age-related macular degeneration.

BACKGROUND AND OBJECTIVE: to describe the development or progression of subfoveal fibrosis after anti-vascular endothelial growth factor (VEGF) therapy in the absence of significant subfoveal hemorrhage in neovascular age-related macular degeneration. PATIENTS AND METHODS: retrospective case series. RESULTS: seven eyes of seven patients with neovascular age-related macular degeneration developed subfoveal fibrosis after anti-VEGF therapy in the absence of significant subfoveal hemorrhage. Five of seven patients experienced vision loss of 0.3 logarithm of the minimum angle of resolution units or greater. CONCLUSION: subfoveal fibrosis may develop or progress in neovascular age-related macular degeneration despite the absence of significant subfoveal hemorrhage and treatment with anti-VEGF. Development of anti-fibrotic therapeutics may be beneficial in reducing the incidence of subretinal fibrosis.

Exudative retinal detachment in castleman disease.

PURPOSE: To describe the course of a case of Castleman disease (CD) that presented with visual symptoms and retinal disease. METHODS: Clinical examination, fundus photography, and fluorescein and indocyanine green angiography were used to characterize the presence of bilateral exudative retinal detachments in a patient who was subsequently identified as having systemic lymphadenopathy. RESULTS: After an extensive medical workup including CT scans, blood testing, and a lymph node and renal biopsy, the patient was diagnosed with CD. Steroids were administered to treat CD. During the course of treatment, the patient developed renal failure, which was successfully treated with plasmapheresis. Four weeks later, the bilateral retinal detachments had resolved without local treatment. CONCLUSION: Exudative retinal detachments as manifestations of CD may be observed under systemic treatment for resolution before considering local therapy.

Polypoidal choroidal vasculopathy associated with tilted disk syndrome.

PURPOSE: To describe a complication of tilted disk syndrome-macular serous retinal detachment caused by development of polypoidal choroidal vasculopathy. METHODS: A 65-year-old patient with visual loss and metamorphopsia was evaluated with fluorescein and indocyanine green angiography (ICG) and optical coherence tomography. Subsequently, photodynamic therapy (PDT) with verteporfin was administered. RESULTS: Fundus examination showed classic features of tilted disk syndrome as well as a unilateral macular serous detachment secondary to a polypoidal lesion, which was clearly outlined by ICG angiography at the site of a macular lacquer crack. The lesion resolved after PDT. Two years after treatment, no recurrence was observed, and visual acuity was 20/25 without distortion. CONCLUSIONS: In this patient with tilted disk syndrome, unilateral polypoidal choroidal vasculopathy was diagnosed by ICG angiography and treated successfully with PDT.

A novel mutation and phenotypes in phosphodiesterase 6 deficiency.

PURPOSE: To develop a systematic approach for the molecular diagnosis of retinitis pigmentosa (RP) and to report new genotype-phenotype correlations for phosphodiesterase 6 (PDE6)-based RP mutations. DESIGN: Clinical and molecular studies on a retrospective case series. METHODS: We screened 40 unrelated RP patients with an autosomal recessive RP microarray. Individuals with RP caused by PDE6 deficiency underwent genetic segregation and phenotype analysis. RESULTS: A disease-associated allele was identified in 32% of patients. Two probands (5%) had PDE6 mutations. The first proband was a compound heterozygote for known R102C and N216S alleles in PDE6A (MIM#180071). Pedigree analysis determined that the N216S variant was benign and direct sequencing discovered a novel, S303C allele. The second proband had a homozygous D600N mutation in the PDE6B gene (MIM#180072). Visual acuities of PDE6-deficient patients ranged from 20/40 to 20/200. Clinical studies showed unusual vitreomacular traction, cystoid macular edema, macular atrophy, and ring hyperfluorescence in PDE6-deficient patients. Such extensive vitreoretinal degeneration is not characteristic of photoreceptor-specific enzyme deficiencies. CONCLUSION: High-throughput deoxyribonucleic acid microarray chips can be used in combination with clinical imaging to precisely characterize patients with RP. Identifying the precise mutation in RP may become the standard of care as gene therapy emerges.

Outcomes of macular hole surgery in patients treated intraoperatively for retinal breaks and/or lattice degeneration.

PURPOSE: To assess the outcome of macular hole surgery in patients treated intraoperatively for retinal breaks and/or lattice degeneration. METHODS: Retrospective review of patients who underwent macular hole surgery from September 1998 to August 2005. Outcomes in eyes that received intraoperative endolaser photocoagulation for retinal breaks and/or lattice degeneration were compared to outcomes in a case-matched control group without retinal breaks or lattice degeneration. RESULTS: A total of 235 consecutive macular hole surgery cases were reviewed. Twenty-four eyes from 24 patients received intraoperative endolaser photocoagulation for retinal breaks and/or lattice degeneration. Macular hole closure occurred in all case and control eyes without any incidence of postoperative retinal detachment. Best-corrected visual acuity improvement of at least three Snellen lines occurred in 100% of case eyes and 92% of control eyes. CONCLUSION: Outcomes of macular hole surgery in patients with retinal breaks and/or lattice degeneration are similar to outcomes in the overall population when these conditions are treated with intraoperative endolaser photocoagulation. Postoperative retinal detachment does not appear to be correlated with treated retinal tears and greater attention should focus on detecting and managing intraoperative breaks. In our hands, routine use panoramic viewing has replaced indirect ophthalmoscopy, by saving time, and reducing the risk of contamination.

Giant epidermoid cyst as an unusual presentation of hypoglobus and ptosis.

A 24-year-old man presented with a large right frontal epidural epidermoid cyst that resulted in right hypoglobus and right upper eyelid ptosis. CT and MRI revealed a bone-destroying mass involving the right frontal bone and eroding through the right orbital roof. Complete surgical removal was performed through a frontal craniotomy. After surgery, there was near-complete resolution of the hypoglobus and ptosis.

Acute central serous chorioretinopathy and fundus autofluorescence.

OBJECTIVES: To describe fundus autofluorescence (FAF) in a series of patients with acute central serous chorioretinopathy (CSC). METHODS: Nine eyes of six patients with acute CSC were evaluated with fluorescein angiography (FA) and FAF imaging to evaluate the nature of the focal retinal pigment epithelial (RPE) leak evident with FA. RESULTS: All nine eyes in this series demonstrated hypo-autofluorescence corresponding precisely to the site of the focal RPE leak seen on FA. CONCLUSIONS: In this group of patients, the acute focal RPE leaks seen with FA corresponded precisely to an area of hypo-autofluorescence imaged with FAF. This observation supports the concept that a mechanical defect or absence of the RPE accounts for the leakage from the inner choroid to the sub-neurosensory space in CSC. FAF is also a useful noninvasive diagnostic adjunct to identify the focal RPE leak in patients with acute CSC.