209 research outputs found
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Adaptive Slicing With the Sanders Prototype Inkjet Modeling System 259
This paper presents one of the first known in depth studies of the Sanders Prototype inkjet modeling process. A process capability study was performed in order to determine the relationship between process parameter levels and the resulting surface roughness. The data was used to create a predictive model of surface roughness using a backpropagation neural network. Test results indicate that the network is quite effective at generalizing to new process configurations. The predictive surface roughness model is used in a newly developed inkjet modeling adaptive slicing algorithm. On a region-by-region basis, the algorithm determines the fastest machine configuration that can be used to build a part while satisfying the surface roughness requirements. The adaptive slicing system has been tested, and results documenting substantial time and cost savings are presented.Mechanical Engineerin
Measurements of Carrier Generation-Recombination Parameters in Silicon Solar Cell Material Using MOS Techniques
Modified and new measurement techniques were developed for determining the carrier generation-recombination (G-R) parameters in silicon solar cell material under carrier deficit and low-level carrier excess conditions using MOS-based test structures. The structures mainly consisted of ring-dot MOS Capacitors (MOS-C) and Schottky-Drained Gate-Controlled Diodes (SGCD). Sample G-R parameters were extracted from n-type high quality silicon solar cell material. Additional measurements were also performed on low-quality ntype silicon substrates for comparison purposes. The photoaccelerated MOS-C Capacitance-time (C-t) transient measurement technique, modified from the standard C-t method, allows one to drastically reduce the observation time in deducing the carrier generation lifetime (Tg) by simply illuminating the test structure during the transient. In applying the technique to MOS-C’s (which exhibited generation lifetime on the order of I msec) the observation time was reduced by approximately an order of magnitude. This is important in dealing with solar cell material because of typically long generation lifetimes. The SGCD structure, which consisted of an extended Schottky diode located next to an MOS-C, was developed and utilized for extracting the surface generation velocity (sg). The measurement is based on recording two C-t transients at Vd = 0 and at Vd = V t , respectively. The structure has a distinct advantage over the conventional PN junction GCD in that it is only slightly more complicated to fabricate and interrogate than a simple MOS-C. It was also demonstrated that steady-state deep-depletion C-V characteristics can be obtained using the SGCD structure. An MOS-C photo/forward-sweep measurement technique was primarily developed to extract the recombination lifetime (rp for n-type substrates) under low-level carrier excess conditions. The new technique is based on the change in inversion capacitance in response to a set of illumination and forward-sweep voltages applied to the MOS-C. The technique conveniently allows one to extract the recombination lifetime under room temperature conditions and was successfully applied to MOS-C’s fabricated on high quality silicon solar cell substrates
Socioeconomic Determinants of Survival in Laryngeal Squamous Cell Carcinoma Patients
Objective: To determine whether comorbidities, socioeconomic factors, and race affect median survival times and overall survival outcomes for patients with laryngeal squamous cell carcinoma treated at a single institution with a large African American population.
Study Design: Retrospective cohort study
Setting: Tertiary care medical center.
Subjects and Methods: Six-hundred nineteen patients treated for laryngeal squamous cell carcinoma at a single institution between 1999 and 2013. Kaplan-Meier survival curve analysis and Cox proportional hazard models were used.
Results: Median survival time decreased with age ≥ 65 years (P \u3c .001), stage 3 or 4 (P \u3c .001),clinical T stage 3 or 4 (P \u3c .001), and clinical N stage 1, 2, or 3 (P \u3c .001). Living in zip code with increasing proportion of residents with high school degree or less (P \u3c .001),increasing proportion of residents living below the poverty level (P \u3c .001), and increasing Charlson Comorbidity Index (P \u3c .001) were associated with increased risk of death. Increasing median household income was associated with decreased increased risk of death (P \u3c .001). Caucasian, rather than African American, race was associated with decreased median survival time (P = .01).
Conclusion: Socioeconomic factors and medical comorbidities were negative prognostic indicators of survival in patients with laryngeal squamous cell carcinoma. Contrary to previous reports, African American race was associated with improved overall survival in univariate analysis. However, once socioeconomic factors were controlled for, race conferred no effect on survival. Rather, living in neighborhoods with higher median household income was protective.https://scholarlycommons.henryford.com/merf2019hcd/1001/thumbnail.jp
The clinical features and diagnosis of Metachromatic leukodystrophy: A case series of Iranian Pediatric patients
How to Cite This Article: Jabbehdari S, Rahimian E, Jafari N, Sanii S, Khayatzadeh Kakhki S, Nejad Biglari H. The Clinical Features and Diagnosis of Metachromatic Leukodystrophy: A Case Series of Iranian Pediatric Patients. Iran J Child Neurol. Summer 2015;9(3):57-61.AbstractObjectiveMetachromatic leukodystrophy disorder (MLD) is one of the rare neurometabolicdiseases caused due to lack of saposin B and arylsulfatase A enzyme deficiency.Materials & MethodsEighteen patients diagnosed as metachromatic leukodystrophy in the NeurologyDepartment of Mofid Children’s Hospital in Tehran, Iran between 2010 and2014 were included in our study. The disorder was confirmed by clinical,EMG-NCV, arylsulfatase A enzyme checking and neuroimaging findings alongwith neurometabolic and genetic assessment from reference laboratory in Iran.We assessed age, gender, past medical history, developmental status, clinicalmanifestations, and neuroimaging findings of 18 patients with metachromaticleukodystrophy.ResultsFrom 18 patients, 80% were offspring from consanguineous marriages. A familyhistory of metachromatic leukodystrophy disease was positive for four patients.Twelve patients had late infantile form of this disorder and six patients had juvenile form. A history of tonic type seizure was positive in 20% of the patients and tonic spasm was confirmed with clinical information. Electromyographgraphy (EMG) in 96% of patients was abnormal with demyelinating sensorimotor neuropathy pattern. MRI in all patients showed the leukodystrophic pattern as arcuate fibers sparing and subcortical rim in white matter and periventricular involvement. Our diagnosis was confirmed by EMG-NCV findings with sensorimotor neuropathy pattern and the assessment of arylsulfatase A enzyme function. ConclusionMLD is an inheritance metabolic disorder, which was confirmed by theassessment of arylsulfatase A enzyme function, peripheral blood leukocyte thatassessed in a referral laboratory in Iran
The Clinical Features and Diagnosis of Adrenoleukodystrophy: A Case Series of Iranian Family
How to Cite This Article: Karimzadeh P, Jafari N, Nejad Biglari Hb, Jabbehdari S, Alizadeh M, Alizadeh Gh, Nejad Biglari Hm, Sanii S. The Clinical Features and Diagnosis of Adrenoleukodystrophy: A Case Series of Iranian Family. Iran J Child Neurol. Winter 2016; 10(1):61-64.AbstractObjectiveAdrenoleukodystrophy disorder is one of the x-linked genetic disorders caused by the myelin sheath breakdown in the brain. In this study, we present 4 yr experience on this disorder.Materials & MethodsThe patients diagnosed as adrenoleukodystrophy in the Neurology Department of Mofid Children’s Hospital in Tehran, Iran from 2010 to 2014 were enrolled into the study. The disorder was confirmed by neuroimaging and clinical findings along with genetic and neurometabolic assessment at Reference Laboratory in Germany. We assessed age, gender, past medical history, developmental status, clinical manifestations, and neuroimaging findings of populous family with adrenoleukodystrophy.ResultsAll of the patients were one populous family with high rate of consanguineous marriages. This disorder was confirmed by genetic assessment, VLCFA and brain MRI.c.253_254insC, p.R85Pfs112* was found in heterozygote state and the VLCFA assessment showed the typical pattern for adrenoleukodystrophy/ adrenomyeloneuropathy. This diagnosis was in agreement with the family history and the clinical history of the patient. Since there have been a number of cases in patient’s family in the past, so intensive follow-up on the family especially detection the female members of the family of childbearing age was recommended. The amount of C-26, C24/C22 and C26/C22 was elevated. All patients with the same genotype had wide ranges of clinical presentation.ConclusionEarly diagnose of this disease might help us for early intervention and prenatal diagnosis for the disease in next siblings
Diffusion in low-dimensional lipid membranes
The diffusion behavior of biological components in cellular membranes is vital to the function of cells. By collapsing the complexity of planar 2D membranes down to one dimension, fundamental investigations of bimolecular behavior become possible in one dimension. Here we develop lipid nanolithography methods to produce membranes, under fluid, with widths as low as 6 nm but extending to microns in length. We find reduced lipid mobility, as the width is reduced below 50 nm, suggesting different lipid packing in the vicinity of boundaries. The insertion of a membrane protein, M2, into these systems, allowed characterization of protein diffusion using high-speed AFM to demonstrate the first membrane protein 1D random walk. These quasi-1D lipid bilayers are ideal for testing and understanding fundamental concepts about the roles of dimensionality and size on physical properties of membranes from energy transfer to lipid packing
Programmed Bending Reveals Dynamic Mechanochemical Coupling in Supported Lipid Bilayers
In living cells, mechanochemical coupling represents a dynamic means by which membrane components are spatially organized. An extra-ordinary example of such coupling involves curvature-dependent polar localization of chemically-distinct lipid domains at bacterial poles, which also undergo dramatic reequilibration upon subtle changes in their interfacial environment such as during sporulation. Here, we demonstrate that such interfacially-triggered mechanochemical coupling can be recapitulated in vitro by simultaneous, real-time introduction of mechanically-generated periodic curvatures and attendant strain-induced lateral forces in lipid bilayers supported on elastomeric substrates. In particular, we show that real-time wrinkling of the elastomeric substrate prompts a dynamic domain reorganization within the adhering bilayer, producing large, oriented liquid-ordered domains in regions of low curvature. Our results suggest a mechanism in which interfacial forces generated during surface wrinkling and the topographical deformation of the bilayer combine to facilitate dynamic reequilibration prompting the observed domain reorganization. We anticipate this curvature-generating model system will prove to be a simple and versatile tool for a broad range of studies of curvature-dependent dynamic reorganizations in membranes that are constrained by the interfacial elastic and dynamic frameworks such as the cell wall, glycocalyx, and cytoskeleton
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Self-assembly of bioactive peptides, peptide conjugates, and peptide-mimetic materials
Molecular self-assembly is a multi-disciplinary field of research, with potential chemical and biological applications. One of the main driving forces of self-assembly is molecular amphiphilicity, which can drive formation of complex and stable nanostructures. Self-assembling peptide and peptide conjugates have attracted great attention due to their biocompatibility, biodegradability and biofunctionality. Understanding assembly enables the better design of peptide amphiphiles which may form useful and functional nanostructures. This review covers self-assembly of amphiphilic peptides and peptide mimetic materials, as well as their potential applications
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