632 research outputs found
A B-ISDN-compatible modem/codec
Coded modulation techniques for development of a broadband integrated services digital network (B-ISDN)-compatible modem/codec are investigated. The selected baseband processor system must support transmission of 155.52 Mbit/s of data over an INTELSAT 72-MHz transponder. Performance objectives and fundamental system parameters, including channel symbol rate, code rate, and the modulation scheme are determined. From several candidate codes, a concatenated coding system consisting of a coded octal phase shift keying modulation as the inner code and a high rate Reed-Solomon as the outer code is selected and its bit error rate performance is analyzed by computer simulation. The hardware implementation of the decoder for the selected code is also described
Phase behavior of UCST blends: Effects of pristine nanoclay as an effective or ineffective compatibilizer
The effects of unmodified nanoclay (natural montmorillonite) on the miscibility, phase behavior and phase separation kinetics of polyethylene (PE)/ethylene vinyl acetate copolymer (EVA) blends have been investigated. Depending on the blend composition, it was observed that the intercalated pristine nanoclay influences the biphasic morphology either as an effective compatibilizer or just as an ineffectual modifier. In spite of the presence of micrometer-sized agglomerated tactoids, natural nanoclay can play a thermodynamic role in reducing the interfacial tension of polymer components. The addition of clay nanoparticles was found to change the phase diagram slightly and diminishes the composition dependency of the binodal temperatures. Moreover, it was observed that a small amount of unmodified layered silicate slows down the phase separation process considerably and enhances the solubility of each polymer in the domains of its counterpart. The findings of this study verify that even poorly dispersed nanoclay with high surface tension can act as a conventional compatibilizer and change the immiscible PE/EVA blends to the partially miscible ones
Prevalence of vitamin d deficiency in people aged 18 old referred to Yasuj lab in winter of 2017
No Abstract
Simvastatin decreases hepatic ischaemia/reperfusion-induced liver and lung injury in rats
Liver failure is still a significant clinical problem after transplantation surgery,
tissue resections (the Pringle manoeuvre) and haemorrhagic shock. The restoration
of blood flow to an ischaemic region leads to tissue injury at a greater
rate than the original ischaemic insult, an event termed "ischaemia-reperfusion
injury" (I/R). Despite advances in surgical techniques, I/R still poses a problem
of clinical importance. In this research, we studied the effect of simvastatin
pretreatment on liver and lung injury induced by hepatic I/R.
Rats were subjected to 30 min of ischaemia followed by 24 h of reperfusion.
Simvastatin (10 mg/kg) was administered orally from three days before the
operation. After the reperfusion time, serum ALT, AST, LDH and TNF a levels
were studied and liver and lung tissues were stained with haematoxylin and
eosin and TUNEL to detect apoptotic cells.
Serum aminotransferase activity and LDH and TNFα levels were increased markedly
by hepatic I/R, and these were suppressed significantly by simvastatin. The
tissue injury index and the number of apoptotic cells via TUNEL staining in the
liver and lungs were higher in the I/R group than in the I/R + simvastatin group.
These results suggest that simvastatin ameliorates I/R-induced liver and lung tissue
damage by inhibiting the level of inflammation and the apoptotic pathways.
Simvastatin administration may therefore provide protection against the adverse
effects of I/R injury in liver transplantation
The effects of pronated foot posture and medial heel and forefoot wedge orthoses on static balance in older people
Aging has been associated with increasing foot pronation [1] and changes in foot mobility and posture which may influence standing balance [2, 3]. Orthotic interventions change foot posture [4] and load distribution under the foot [5] and therefore may have important effects on balance in older people
Impact assessment of skidding extraction: Effects on physical and chemical properties of forest soils and on maple seedling growing along the skid trail
Several studies investigated soil disturbances caused on skid trails by forest logging. However, there is still a lack of knowledge about the severity and the distance of disturbances along both sides from the trails. The aims of this study were: i) to investigate the changes in physical and chemical properties of soil along the sides of skidding trails; ii) to measure the effects of soil compaction on of maple seedlings growth. Two levels of trail gradient ( < 20% and > 20 %), four levels of traffic frequency (3, 8, 15, and 30 passes) and four distance buffer strip zones (0.5 m intervals from 0 to 2 m in distance) on both sides of skid trail edges were analyzed. Each treatment included three replicate plots. In order to investigate the effect of compaction on seedlings emergence and growth, maple seeds were sown after logging. The results highlighted significant changes in physical and chemical properties of soil for each traffic frequency in the closest buffer strip (from 0 to 0.5 m from the skid trail edges). The largest changes in soil properties were identified at 0.5 m distance zones for a slope gradient > 20% after 3, 8, 15, and 30 skidding cycles. The highest changes were recorded on slope category > 20%. The higher the soil compaction the lower the germination rate, root length, and stem height of seedlings
Targeted therapy of the XIAP/proteasome pathway overcomes TRAIL-resistance in carcinoma by switching apoptosis signaling to a Bax/Bak-independent 'type I' mode
TRAIL is a promising anticancer agent, capable of inducing apoptosis in a wide range of treatment-resistant tumor cells. In 'type II' cells, the death signal triggered by TRAIL requires amplification via the mitochondrial apoptosis pathway. Consequently, deregulation of the intrinsic apoptosis-signaling pathway, for example, by loss of Bax and Bak, confers TRAIL-resistance and limits its application. Here, we show that despite resistance of Bax/Bak double-deficient cells, TRAIL-treatment resulted in caspase-8 activation and complete processing of the caspase-3 proenzymes. However, active caspase-3 was degraded by the proteasome and not detectable unless the XIAP/proteasome pathway was inhibited. Direct or indirect inhibition of XIAP by RNAi, Mithramycin A or by the SMAC mimetic LBW-242 as well as inhibition of the proteasome by Bortezomib overcomes TRAIL-resistance of Bax/Bak double-deficient tumor cells. Moreover, activation and stabilization of caspase-3 becomes independent of mitochondrial death signaling, demonstrating that inhibition of the XIAP/proteasome pathway overcomes resistance by converting 'type II' to 'type I' cells. Our results further demonstrate that the E3 ubiquitin ligase XIAP is a gatekeeper critical for the 'type II' phenotype. Pharmacological manipulation of XIAP therefore is a promising strategy to sensitize cells for TRAIL and to overcome TRAIL-resistance in case of central defects in the intrinsic apoptosis-signaling pathway
Simvastatin attenuates intestinal ischaemia/reperfusion-induced injury in rat
Ischaemia/reperfusion (I/R) injury is commonly seen in the field of intestine surgical
interventions, shock, trauma, and many other clinical conditions. Simvastatin
is known to have antioxidant and anti-inflammatory properties. This study investigated
the effect of simvastatin administration in a warm intestinal I/R model on
TNF-α, antioxidant enzymes and intestinal tissue morphology.
Thirty-six male wistar rats underwent laparotomy under general anaesthesia. Simvastatin
was administered from four days before ischaemia induction. The
rats were divided in to three groups (n = 12): the sham goup, the I/R group, and
the I/R + simvastatin group. Intestinal ischaemia was induced by superior mesenteric
artery ligation with microvascular clamps for 60 minutes, and after ischaemia,
blood perfusion was released into the tissue and a reperfusion phase
was started, which lasted for 3 hours. After 3 hours, the animals were sacrificed
and serum and tissue obtained for biochemical and histological study.
In the simvastatin treated group, intestinal tissue injury, TNF-α level, and tissue
malondealdehyde levels were significantly lower than in the I/R group (p < 0.05).
Glutathion peroxidase and superoxide dismutase levels were significantly higher
in the simvastatin treated group than in the I/R group (p < 0.05).
Simvastatin pretreatment reduced intestinal I/R injury and was associated with down-
-regulation of serum TNF-α and tissue malondealdehyde level, and simvastatin
administration maintained cellular antioxidant enzyme contents compared to the
I/R group after 3 hours reperfusion time
Long-term outcomes of allogeneic haematopoietic stem cell transplantation for adult cerebral X-linked adrenoleukodystrophy
The adult cerebral inflammatory form of X-linked adrenoleukodystrophy is a rapidly progressive neurodegenerative disease, as devastating as childhood cerebral adrenoleukodystrophy. Allogeneic haematopoietic stem cell transplantation has been demonstrated to provide long-term neurological benefits for boys with the childhood cerebral form, but results in adults are sparse and inconclusive. We analysed data from 14 adult males with adult cerebral adrenoleukodystrophy treated with allogeneic haematopoietic stem cell transplantation on a compassionate basis in four European centres. All presented with cerebral demyelinating lesions and gadolinium enhancement. Median age at diagnosis of adult cerebral adrenoleukodystrophy was 33 years (range 21–48 years). In addition to cerebral inflammation, five patients had established severe motor disability from adrenomyeloneuropathy affecting only the spinal cord and peripheral nerves (Expanded Disability Status Scale score ≥ 6). Eight patients survived (estimated survival 57 ± 13%) with a median follow-up of 65 months (minimum 38 months). Death was directly transplant-/infection-related (n = 3), due to primary disease progression in advanced adult cerebral adrenoleukodystrophy (n = 1), or secondary disease progression (n = 2) after transient multi-organ failure or non-engraftment. Specific complications during stem cell transplantation included deterioration of motor and bladder functions (n = 12) as well as behavioural changes (n = 8). Arrest of progressive cerebral demyelination and prevention of severe loss of neurocognition was achieved in all eight survivors, but deterioration of motor function occurred in the majority (n = 5). Limited motor dysfunction (Expanded Disability Status Scale score < 6) prior to transplantation was associated with significantly improved survival [78 ± 14% (n = 9) versus 20 ± 18%(n = 5); P < 0.05] and maintenance of ambulation (Expanded Disability Status Scale score < 7) post-transplant (78% versus 0%; P = 0.021). In contrast, bilateral involvement of the internal capsule on brain MRI was associated with poorer survival [20 ± 18% (n = 5) versus 78 ± 14% (n = 9); P < 0.05]. This study is the first to support the feasibility, complications and potential long-term neurological benefit of allogeneic haematopoietic stem cell transplantation in adult cerebral adrenoleukodystrophy. Further studies are warranted to attempt to improve outcomes through patient selection and optimization of transplantation protocols
Beyond Spheroids and Discs: Classifications of CANDELS Galaxy Structure at 1.4 < z < 2 via Principal Component Analysis
Important but rare and subtle processes driving galaxy morphology and
star-formation may be missed by traditional spiral, elliptical, irregular or
S\'ersic bulge/disk classifications. To overcome this limitation, we use a
principal component analysis of non-parametric morphological indicators
(concentration, asymmetry, Gini coefficient, , multi-mode, intensity
and deviation) measured at rest-frame -band (corresponding to HST/WFC3 F125W
at 1.4 ) galaxy morphologies. Principal component analysis (PCA) quantifies
the correlations between these morphological indicators and determines the
relative importance of each. The first three principal components (PCs) capture
75 per cent of the variance inherent to our sample. We interpret the
first principal component (PC) as bulge strength, the second PC as dominated by
concentration and the third PC as dominated by asymmetry. Both PC1 and PC2
correlate with the visual appearance of a central bulge and predict galaxy
quiescence. PC1 is a better predictor of quenching than stellar mass, as as
good as other structural indicators (S\'ersic-n or compactness). We divide the
PCA results into groups using an agglomerative hierarchical clustering method.
Unlike S\'ersic, this classification scheme separates compact galaxies from
larger, smooth proto-elliptical systems, and star-forming disk-dominated clumpy
galaxies from star-forming bulge-dominated asymmetric galaxies. Distinguishing
between these galaxy structural types in a quantitative manner is an important
step towards understanding the connections between morphology, galaxy assembly
and star-formation.Comment: 31 pages, 24 figures, accepted for publication in MNRA
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