Diurnal and environmental characterization of solar photovoltaic panels using a PC-AT add on plug in card

This article describes the development of an instrumentation system for characterizing photovoltaic panels. It uses an add on card (which contains DAC, ADC and digital input/output ports) in conjunction with a PC-AT. The panels in a field are selected in succession through a set of relays actuated by the digital output port. The selected panel is loaded in discreet steps by a transistor loading circuit which is activated by the digital to analog convertor to trace the most significant portion of the I-V curve. The data shows that the power output is invariably lower than that specified by the manufacturer. The reasons for drop in output have been analyzed. It is shown that these effects can be represented by the curvature of I-V characteristic at the maximum power point (OP). The loss of power due to accumulation of dust and the increase in temperature of the panels can be significant.     

Differential cellular response within the rabbit tendon unit following tendon injury

Since 1975, 340 patients were treated by tracheal sleeve resection for tracheal or subglottic laryngeal iatrogenic stenoses in our unit. Preoperative iterative Nd YAG laser sessions have usually been performed, without success. The length of the sleeve specimen was an average of 3 1/4 cm. Twelve patients died on the post operative course (3.5%), 3 more patients died later after failure of the procedure (0.9%) and nineteen had recurrent stenoses treated with use of a tracheostomy tube, a permanent Montgomery tube, or an endotracheal stent (5.6%). Three hundred and six patients are definitely cured (90%), at the first attempt for 265 patients, after a laser session for granulomas for 20 patients, after a second tracheal resection for 6 patients and after a temporary Montgomery tube for 15 patients. Providing there is a good selection of the patients, tracheal sleeve resection is the best treatment for iatrogenic stenosis.     

Activation of large-conductance potassium channels in pregnant human myometrium by pinacidil

OBJECTIVE: The aim was to investigate the effects of the potassium-channel opener pinacidil on single uterine potassium channels and the contribution of the latter to pinacidil-induced myometrial relaxation. STUDY DESIGN: Myometrial strips and freshly dispersed uterine myocytes were prepared from the myometrial biopsy samples of women undergoing elective, nonlabor caesarean section at term gestation. RESULTS: In isometric tension experiments pinacidil potently relaxed pregnant nonlabor human myometrial strips, with an agonist concentration yielding the half maximal response of 0.4 +/- 0.1 micromol/L. This effect was antagonized by 500 nmol/L charybdotoxin. Application of 10 micromol/L glibenclamide also inhibited the pinacidil-induced relaxation. Coapplication of charybdotoxin (500 nmol/L) and glibenclamide (10 micromol/L) produced a biphasic curve, which was fitted to a two-site model with values for agonist concentration yielding the half maximal response of 0.6 +/- 0.2 micromol/L and 189.7 +/- 0.8 micromol/L. Large-conductance calcium-dependent potassium channel activity was dramatically increased after application of pinacidil (between 10 and 100 micromol/L) to both inside-out and outside-out patches. The activation required the presence of calcium ions at the intracellular aspect of the membrane. Charybdotoxin but not glibenclamide blocked pinacidil-induced unitary large-conductance calcium-dependent potassium channel activity. CONCLUSION: Pinacidil-mediated relaxation of human pregnant myometrial strips may be partially attributable to the opening of uterine large-conductance calcium-dependent potassium channels in addition to adenosine triphosphate potassium channel activation. Drugs with specific potassium channel-activating properties may have important clinical application as novel tocolytics in the treatment of preterm labor.     

Macrophage formation of angiostatin during inflammation. A byproduct of the activation of plasminogen

Angiostatin is a potent inhibitor of tumor angiogenesis and the growth of metastatic foci. Recent studies have indicated that neoplastic cells can generate angiostatin directly or in cooperation with tumor-associated macrophages. In studies reported here, we determined whether angiostatin is generated in mice under non-neoplastic settings. Utilizing murine RAW264.7 macrophages and thioglycollate-elicited peritoneal macrophages, we demonstrate that angiostatin-like fragments are generated as a byproduct of the proteolytic regulation of membrane-bound plasmin. Plasmin proteolysis and subsequent loss in membrane-bound plasmin activity requires active plasmin but was unaffected by inhibitors of metalloproteinases. Lysine binding fragments of plasmin, isolated from macrophage-conditioned media utilizing affinity chromatography, appeared as a major (48 kDa) and two minor bands (42 and 50 kDa) in SDS-polyacrylamide gel electrophoresis and were immunoreactive with anti-kringle 1-3 IgG. Each peptide begins with Lys77 and contains the entire sequence of angiostatin. The affinity isolated plasmin fragments inhibited bFGF-induced endothelial cell proliferation. Lavage fluid recovered from the peritoneal cavities of mice previously injected with thioglycollate contained angiostatin-like plasmin fragments similar to those generated in vitro. This is the first demonstration that angiostatin-like plasmin fragments are generated in a non-neoplastic inflammatory setting. Thus, in addition to regulating pericellular plasmin activity, proteolysis of plasmin generates inactive kringle-containing fragments expressing angiostatic properties.     

Effects of Inhibition of Carotenoids on the Lipids Synthesis by Micrococcus colpogenes

Effect of glucose concentration and the inhibition of carotenoids on the lipids synthesis by Micrococcus colpogenes were studied. It was observed that the maximum lipid production was obtained when 2 % glucose was used as carbon source. The inhibition of carotenoids with diphenylaminc (25 mg/L) showed 37 % increase in the lipid synthesis.     

Wireless transmission of HD video using H.264 compression over UWB channel

With the technological advancement, entertainment has become revolutionized and the high-definition (HD) video has become an integral feature of our modern amusement system. The demand for wireless transmission of HD video is rapidly rising for its ubiquitous nature, easy installation and relocation. Such wireless transmissions of HD video streams require very high bandwidth. The ultra-wideband (UWB) offers a large bandwidth, and short-range high-speed data transmission at low cost and low power consumption. In this paper, we present the feasibility study to transmit HD video wirelessly using H.264/AVC compression over the UWB communication channel. Simulations are carried out by controlling key H.264/AVC encoder parameters such as, in-loop deblocking filter, group of pictures, and quantization parameter. Based on the analysis, an optimum setting of these parameters is proposed for different bandwidth requirements, as well as acceptable video quality. The bandwidth achieved is restricted between 1.5 and 20?Mbps with a minimum reconstruction quality of 34?dB. The HD bit stream is then transmitted over the UWB communication channel and the demonstration shows that the overall encoder performance is satisfactory with the transmission bit-error-rate (BER) in the range of 10^?5?C10^?8.     

The effect of composition,substrate temperature and annealing on the paramagnetic centres in SiO x /SnO co-evaporated thin films

The effects of composition and substrate temperature during evaporation and annealing, on the electron spin resonance spectra of co-evaporated SiO _x /SnO (300 nm) thin films have been investigated. The spin density is observed to decrease with increasing SnO content. This effect is attributed to the saturation of some of the paramagnetic defects such as dangling bonds and other structural defects like E₁ centres. The decrease in spin density in the composite thin films of SiO _x /SnO of constant thickness and composition with annealing and with increase in the substrate temperature during evaporation, is related to the conversion of some of the paramagnetic E₁ centres to E₁ (probable non-paramagnetic precursor of E₁) centres as well as to the saturation of some of the dangling bonds.     

A novel method for the classification of Alzheimer's disease from normal controls using magnetic resonance imaging

Alzheimer's disease (AD) is the most prevalent form of dementia. Although fewer people, who suffer from AD are correctly and promptly diagnosed, due to a lack of knowledge of its cause and unavailability of treatment, AD is more manageable if the symptoms of mild cognitive impairment (MCI) are in an early stage. In recent years, computer‐aided diagnosis has been widely used for the diagnosis of AD. The main motive of this paper is to improve the classification and prediction accuracy of AD. In this paper, a novel approach is developed to classify MCI, normal control (NC), and AD using structural magnetic resonance imaging (sMRI) from the Alzheimer's disease Neuroimaging Initiative (ADNI) dataset (50 AD, 50 NC, 50 MCI subjects). FreeSurfer is used to process these MRI data and obtain cortical features such as volume, surface area, thickness, white matter (WM), and intrinsic curvature of the brain regions. These features are modified by normalizing each cortical region's features using the absolute maximum value of that region's features from all subjects in each group of MCI, NC, and AD independently. A total of 420 features are obtained. To address the curse of dimensionality, the obtained features are reduced to 30 features using a sequential feature selection technique. Three classifiers, namely the twin support vector machine (TSVM), least squares TSVM (LSTSVM), and robust energy‐based least squares TSVM (RELS‐TSVM), are used to evaluate the classification accuracy from the obtained features. Five‐fold and 10‐fold cross‐validation are used to validate the proposed method. Experimental results show an accuracy of 100% for the studied database. The proposed approach is innovative due to its higher classification accuracy compared to methods in the existing literature.