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Temperature dependence of photoluminescence in non-crystalline silicon
No full textCrystalline silicon being ubiquitous throughout the microelectronics industry has an indirect bandgap, and therefore is incapable of light emission. However, strong room temperature visible and near-IR luminescence from non-crystalline silicon, e.g., amorphous silicon, porous silicon, and black silicon, has been observed. These silicon based materials are morphologically similar to each other, and have similar luminescence properties. We have studied the temperature dependence of the photoluminescence from these non-crystalline silicons to fully characterize and optimize these materials in the pursuit of obtaining novel optoelectronic devices
Optimization based tumor classification from microarray gene expression data
No full textBackground: An important use of data obtained from microarray measurements is the classification of tumor types with respect to genes that are either up or down regulated in specific cancer types. A number of algorithms have been proposed to obtain such classifications. These algorithms usually require parameter optimization to obtain accurate results depending on the type of data. Additionally, it is highly critical to find an optimal set of markers among those up or down regulated genes that can be clinically utilized to build assays for the diagnosis or to follow progression of specific cancer types. In this paper, we employ a mixed integer programming based classification algorithm named hyper-box enclosure method (HBE) for the classification of some cancer types with a minimal set of predictor genes. This optimization based method which is a user friendly and efficient classifier may allow the clinicians to diagnose and follow progression of certain cancer types. Methodology/Principal Findings: We apply HBE algorithm to some well known data sets such as leukemia, prostate cancer, diffuse large B-cell lymphoma (DLBCL), small round blue cell tumors (SRBCT) to find some predictor genes that can be utilized for diagnosis and prognosis in a robust manner with a high accuracy. Our approach does not require any modification or parameter optimization for each data set. Additionally, information gain attribute evaluator, relief attribute evaluator and correlation-based feature selection methods are employed for the gene selection. The results are compared with those from other studies and biological roles of selected genes in corresponding cancer type are described. Conclusions/Significance: The performance of our algorithm overall was better than the other algorithms reported in the literature and classifiers found in WEKA data-mining package. Since it does not require a parameter optimization and it performs consistently very high prediction rate on different type of data sets, HBE method is an effective and consistent tool for cancer type prediction with a small number of gene markers
Ambivalent stereotypes link to peace, conflict, and inequality across 38 nations
No full textA cross-national study, 49 samples in 38 nations (n = 4,344), investigates whether national peace and conflict reflect ambivalent warmth and competence stereotypes: High-conflict societies (Pakistan) may need clearcut, unambivalent group images distinguishing friends from foes. Highly peaceful countries (Denmark) also may need less ambivalence because most groups occupy the shared national identity, with only a few outcasts. Finally, nations with intermediate conflict (United States) may need ambivalence to justify more complex intergroup-system stability. Using the Global Peace Index to measure conflict, a curvilinear (quadratic) relationship between ambivalence and conflict highlights how both extremely peaceful and extremely conflictual countries display lower stereotype ambivalence, whereas countries intermediate on peace-conflict present higher ambivalence. These data also replicated a linear inequality-ambivalence relationship
Ultrasensitive proteomic quantitation of cellular signaling by digitized nanoparticle-protein counting
No full textMany important signaling and regulatory proteins are expressed at low abundance and are difficult to measure in single cells. We report a molecular imaging approach to quantitate protein levels by digitized, discrete counting of nanoparticle-tagged proteins. Digitized protein counting provides ultrasensitive molecular detection of proteins in single cells that surpasses conventional methods of quantitating total diffuse fluorescence, and offers a substantial improvement in protein quantitation. We implement this digitized proteomic approach in an integrated imaging platform, the single cell-quantum dot platform (SC-QDP), to execute sensitive single cell phosphoquantitation in response to multiple drug treatment conditions and using limited primary patient material. The SC-QDP: 1) identified pAKT and pERK phospho-heterogeneity and insensitivity in individual leukemia cells treated with a multi-drug panel of FDA-approved kinase inhibitors, and 2) revealed subpopulations of drug-insensitive CD34+ stem cells with high pCRKL and pSTAT5 signaling in chronic myeloid leukemia patient blood samples. This ultrasensitive digitized protein detection approach is valuable for uncovering subtle but important differences in signaling, drug insensitivity, and other key cellular processes amongst single cells
Variations in multiple syndromic deafness genes mimic non-syndromic hearing loss
No full textThe genetics of both syndromic (SHL) and non-syndromic hearing loss (NSHL) is characterized by a high degree of genetic heterogeneity. We analyzed whole exome sequencing data of 102 unrelated probands with apparently NSHL without a causative variant in known NSHL genes. We detected five causative variants in different SHL genes (SOX10, MITF, PTPN11, CHD7, and KMT2D) in five (4.9%) probands. Clinical re-evaluation of these probands shows that some of them have subtle syndromic findings, while none of them meets clinical criteria for the diagnosis of the associated syndrome (Waardenburg (SOX10 and MITF), Kallmann (CHD7 and SOX10), Noonan/LEOPARD (PTPN11), CHARGE (CHD7), or Kabuki (KMT2D). This study demonstrates that individuals who are evaluated for NSHL can have pathogenic variants in SHL genes that are not usually considered for etiologic studies
Energy scaling of a multipass-cavity mode-locked femtosecond bulk laser with a carbon nanotube saturable absorber
No full textIn the design of mode-locked lasers, single-walled carbon nanotube saturable absorbers (SWCNT-SAs) have emerged as important alternatives to semiconductor saturable absorber mirrors (SESAMs) due to their favorable optical characteristics, low cost, and relatively simple fabrication scheme. Therefore, it is of great interest to explore the limits of energy scaling in solid-state lasers mode-locked with SWCNT-SAs. Due to their unique wavelength range for biomedical applications, a room-temperature Cr4+:forsterite laser operating near 1.3 mu m was used in the mode-locking experiments. The laser was end-pumped with a continuous-wave Yb-fiber laser at 1064 nm. Furthermore, a q-preserving multipass-cavity (MPC) was added to the short resonator to lower the pulse repetition rate to 4.51 MHz and to scale up the output pulse energy at low average power. The SWCNT-SA was fabricated with SWCNTs grown by the high-pressure CO conversion (HiPCO) technique. With dispersion compensation optics, the net group delay dispersion of the resonator was estimated to be around -4440 fs(2). When mode-locked with the SWCNT-SA, the resonator produced 10-nJ, 121-fs pulses at 1247 nm with a spectral bandwidth of 16 nm, corresponding to a time-bandwidth product of 0.37. To our knowledge, this represents the highest peak power (84 kW) generated to date from a bulk femtosecond solid-state laser, mode-locked by using a SWCNT-SA. The results also suggest that the peak power achieved in our experiments was limited only by the self-focusing in the Cr4+:forsterite gain medium and further increase in output energy should in principle be possible in other gain media mode-locked with SWCNT-SAs
Effect of a hypercholesterolemia as a starting factor on spinal degeneration in rabbits and role of vitamin E (α-tocopherol)
No full textBackground: To identify the role of the hypercholesterolemia as a starting factor in discovertebral degeneration that ultimately causes lower back pain, and investigate the role of Vitamin E in this process. Methods: The rabbits (n = 32) were divided into two broad experimental groups: A control group, and a hypercholesterolemia group, namely cholesterol, and cholesterol plus Vitamin E groups and they were fed sequentially for 4 or 8 weeks. Serum cholesterol and Vitamin E (a-tocopherol) levels were determined; vascular tissue was prepared for histopathological analyses and vertebra was decalcifed for the study. Results: Cholesterol diet group resulted approximately 44-fold of increase plasma cholesterol levels over the 4-week control values. Additional supplementation with Vitamin E group induced a plasma cholesterol level increase of only 37-fold as compared to the control group. In the cholesterol groups, light microscope examination revealed atherosclerotic plaque in major arteries. However, in the cholesterol plus Vitamin E treatment groups, no lipid accumulation or foam cell formation was visible in the abdominal aorta and vertebral segmental artery. In histopathological examination, we found degenerative changes in the discovertebral unit in cholesterol treated groups. Conclusion: Hypercholesterolemia causes fat accumulation in the disc endplate and vertebral body that causes blood supply disturbances which might be a starting factor of discovertebral degeneration. This event was not reversed by the elimination of cholesterol from the diet. Vitamin E supplementation was not effective in reducing fat accumulation in vertebral bone marrow. As a result, we conclude that degeneration of the discovertebral unit is not related to atherosclerotic changes in the major blood vessels. © 2016 Surgical Neurology International | Published by Wolters Kluwer-Medknow
Continuous-wave fiber-pumped Cr2+: ZnSe laser
No full textPower performance of a compact, broadly tunable, continuous-wave (cw) Cr2+:ZnSe laser pumped by a thulium fiber laser at 1800 nm was investigated. In the lasing experiments, a Cr2+:ZnSe sample with a small-signal differential absorption coefficient of 11 cm(-1) and a fluorescence lifetime of 4.6 mu s was used. An astigmatically compensated x-cavity with 15% output coupler produced as high as 640 mW of output power at 2480 nm with 2.5 W of incident pump power. Resonator losses were investigated using three different methods, and an in-depth analysis of the results was performed. The stimulated emission cross section values determined from laser threshold data and fluorescence measurements were in good agreement with each other. Finally, broad, continuous tuning of the laser was demonstrated between 2240 and 2900 nm by using an intracavity Brewster-cut MgF2 prism and a single set of optics
Adaptive Q control for tapping-mode nanoscanning using a piezoactuated bimorph probe
No full textA new approach, called adaptive Q control, for tapping-mode atomic force microscopy (AFM) is introduced and implemented on a homemade AFM setup utilizing a laser Doppler vibrometer and a piezoactuated bimorph probe. In standard Q control, the effective Q factor of the scanning probe is adjusted prior to the scanning depending on the application. However, there is a trade-off in setting the effective Q factor of an AFM probe. The Q factor is either increased to reduce the tapping forces or decreased to increase the maximum achievable scan speed. Realizing these two benefits simultaneously using standard Q control is not possible. In adaptive Q control, the Q factor of the probe is set to an initial value as in standard Q control, but then modified on the fly during scanning when necessary to achieve this goal. In this article, we present the basic theory behind adaptive Q control, the electronics enabling the online modification of the probe's effective Q factor, and the results of the experiments comparing three different methods: scanning (a) without Q control, (b) with standard Q control, and (c) with adaptive Q control. The results show that the performance of adaptive Q control is superior to the other two methods
Fitokontakt dermatit: Olgu sunumu
No full textIntroduction: Herbal medicines are used for different purposes by applying them directly to the skin. Case Report: A 57-year-old female patient presented with erythema and swelling of the left knee. On examination, erythematous and bullous lesions were observed. In the story of 'Ranunculus Scleratus' plants 12 hours knee closed contact of the learned. Diagnosis; Fitokontakt thought of as Dermatitis patients to wet dressing is recommended. 1 month after hyperemia outside of a clinical finding out. Conclusion: Treatment with plants in our community are used as often as incorrect use can lead to harmful effects