169 research outputs found

    Correlation of measured neon soft X-ray pulses of the INTI plasma focus with the reflected shock phase at 12KV

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    The six-phase Lee Model Code is used to fit the computed current waveform to the measured waveform of the INTI Plasma Focus (PF;2.2 kJ at 12 kV), a T2 PF device, operated as a source of Neon soft X-ray (SXR) with optimum yield around 2.5 - 3 Torr of neon. The characteristic He-like and H-like neon line SXR pulse is measured using a pair of SXR detectors with selected filters that, by subtraction, have a photon energy window of 900 to 1550 eV covering the region of the characteristic neon SXR lines. The aim of this paper is to investigate the correlation between the time histories of the measured Neon soft X-ray pulse and the reflected shock phase of the computed current waveform which has been fitted to the measured current waveform. Results shows that the characteristic neon SXR measured at 3.17 J with a pulse duration of 249 ns starts typically after the radial inward shock phase and increases in magnitude few ns before the pinch phase. It tails unto the first anomalous resistance, and decays at the second anomalous resistance

    Pressurized Device for Mitigating Atrophy in Soleus During Long-Duration Spaceflight

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    A major concern with long duration spaceflight, skeletal muscle atrophy is most detrimental in lower limb musculature, particularly in muscles critical for proper gait, such as the soleus. The decline of muscle activation and the suppression of sensory input from plantar sole mechanoreceptors can add to the attenuation of skeletal muscle health during spaceflight. More specifically, inhibition of sensory input from sole receptors, such as with gravitational unloading, decreases selective activation, thereby negatively affecting muscle tone and inevitably resulting in lower limb atrophy. PURPOSE: To design, fabricate, and test a specialized boot with an insole that applies oscillating pneumatic pressure for set periods of time to augment neuromuscular activation of the soleus through the plantar sole\u27s mechanoreceptors, which may minimize atrophy of lower extremity muscles. METHODS: The custom boot was originally designed in three-dimensional modeling software (Solidworks Premium, Waltham, MA). Components of the boot included: a lightweight medical walking brace, Metro-ATmega circuit board, air pump and vacuum DC motor, force resistive sensor, and kPa sensor. The boot was programmed using C++ to allow the user to wear the boot for 20 minutes (oscillating continuously) at the start of every hour with an automatic timer for 6 hours per day. Surface electromyography (EMG) measured electrical activity in lower extremity muscles while wearing the boot. The location of all electrodes were determined according to the SENIAM project (Surface Electromyography for the Non-Invasive Assessment of Muscles): 1) for soleus, electrode placed at two-thirds of the line between the medial condyle of the femur to the medial malleolus; 2) for medial head of the gastrocnemius, electrode placed at one-third of the line between the head of the fibula and the heel; 3) for ground, electrode placed at the tibial tuberosity. Muscle activation of the gastrocnemius was measured to investigate any co-activation of nearby musculature on the posterior leg. RESULTS: Upon airbag inflation, the soleus exhibited the greatest amplitude (30 to 50 µV versus 5 to 15 µV) when the ankle attempted to plantarflex while maintaining a neutral position. When the airbags are inflated, the pressure output corresponds to approximately 111 kPa. When the airbags are deflated, the pressure output corresponds to approximately 66 kPa, creating a pressure difference of 45 kPa. During the 20 min runtime, the airbags take 3.3 sec to inflate and 3.0 sec to deflate, creating the oscillating effect. When fully charged, the battery can sustain one full, 6-hour session with each lasting 20 minutes. CONCLUSION: Pneumatic pressure integrated into a customized therapeutic walking boot may elicit neuromuscular activity in the lower extremity musculature, which indicates that the device may help in attenuating the negative neuromuscular adaptations in the soleus via afferent signaling

    Thermal conductivity, microstructure and hardened characteristics of foamed concrete composite reinforced with raffia fiber

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    Researchers have become enthralled with using natural fiber, which is a waste product from industrial processes, as an additive in cement-based materials. This is due to the fact that natural fiber is inexpensive, has principal carbon neutrality, and is obtainable in large quantities. Additionally, this fiber is made from a renewable resource. Hence it has a low density and is amenable to undergoing chemical alteration. The idea of this investigation is to discover the reactivity of raffia (raphia vinifera) fiber (RF) in low-density foamed concrete (FC). FC density of 950 kg/m3 was utilized. Workability, density, thermal conductivity, SEM analysis, compressive, bending, and tensile strengths were the parameters that were quantified and assessed. Based on the outcomes, it has been determined that the mechanical properties and thermal conductivity of FC-RF composites may be enhanced by using RF with an ideal reinforcing fraction content of 6%. Slump flow gradually decreased from 2% to 8% RF fraction content. The lowest slump flow was achieved by adding RF to the FC mixture at a fraction content of 8%. The density of FC-RF composites shows a developing tendency, likely because of the RF's comparatively high specific gravity and increasing fraction content. The addition of RF to FC considerably enhances the material's compressive, bending, and tensile strength. The optimal strength characteristics emerged when 6% RF was added to FC. Besides, the FC thermal conductivity improves as the weight percent of RF increases because the porous structure of FC with RF allows it to absorb heat

    In polycistronic Qβ RNA, single-strandedness at one ribosome binding site directly affects translational initiations at a distal upstream cistron

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    In Qβ RNA, sequestering the coat gene ribosome binding site in a putatively strong hairpin stem structure eliminated synthesis of coat protein and activated protein synthesis from the much weaker maturation gene initiation site, located 1300 nucleotides upstream. As the stability of a hairpin stem comprising the coat gene Shine–Dalgarno site was incrementally increased, there was a corresponding increase in translation of maturation protein. The effect of the downstream coat gene ribosome binding sequence on maturation gene expression appeared to have occurred only in cis and did not require an AUG start codon or initiation of coat protein synthesis. In all cases, no structural reorganization was predicted to occur within Qβ RNA. Our results suggest that protein synthesis from a relatively weak translational initiation site is greatly influenced by the presence or absence of a stronger ribosome binding site located elsewhere on the same RNA molecule. The data are consistent with a mechanism in which multiple ribosome binding sites compete in cis for translational initiations as a means of regulating protein synthesis on a polycistronic messenger RNA

    Overexpression of DNA Polymerase Zeta Reduces the Mitochondrial Mutability Caused by Pathological Mutations in DNA Polymerase Gamma in Yeast

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    In yeast, DNA polymerase zeta (Rev3 and Rev7) and Rev1, involved in the error-prone translesion synthesis during replication of nuclear DNA, localize also in mitochondria. We show that overexpression of Rev3 reduced the mtDNA extended mutability caused by a subclass of pathological mutations in Mip1, the yeast mitochondrial DNA polymerase orthologous to human Pol gamma. This beneficial effect was synergistic with the effect achieved by increasing the dNTPs pools. Since overexpression of Rev3 is detrimental for nuclear DNA mutability, we constructed a mutant Rev3 isoform unable to migrate into the nucleus: its overexpression reduced mtDNA mutability without increasing the nuclear one

    Systemic importance of financial institutions: regulations, research, open issues, proposals

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    In the field of risk management, scholars began to bring together the quantitative methodologies with the banking management issues about 30 years ago, with a special focus on market, credit and operational risks. After the systemic effects of banks defaults during the recent financial crisis, and despite a huge amount of literature in the last years concerning the systemic risk, no standard methodologies have been set up to now. Even the new Basel 3 regulation has adopted a heuristic indicator-based approach, quite far from an effective quantitative tool. In this paper, we refer to the different pieces of the puzzle: definition of systemic risk, a set of coherent and useful measures, the computability of these measures, the data set structure. In this challenging field, we aim to build a comprehensive picture of the state of the art, to illustrate the open issues, and to outline some paths for a more successful future research. This work appropriately integrates other useful surveys and it is directed to both academic researchers and practitioners

    Achlya mitochondrial DNA: gene localization and analysis of inverted repeats

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    Mitochondrial DNA from four strains of the oomycete Achlya has been compared and nine gene loci mapped, including that of the ribosomal protein gene, var1 . Examination of the restriction enzyme site maps showed the presence of four insertions relative to a map common to all four strains. All the insertions were found in close proximity to genic regions. The four strains also cotained the inverted repeat first observed in A. ambisexualis (Hudspeth et al. 1983), allowing an examination by analysis of retained restriction sites of the evolutionary stability of repeated DNA sequences relative to single copy sequences. Although the inverted repeat is significantly more stable than single copy sequences, more detailed analysis indicated that this stability is limited to the portion encoding the ribosomal RNA genes. Thus, the apparent evolutionary stability of the repeat does not appear to derive from the inverted repeat structure per se.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47563/1/438_2004_Article_BF00330510.pd

    Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

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    Background: The EMPA KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population. Methods: EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110. Findings: Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5–2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62–0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16–1·59), representing a 50% (42–58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1). Interpretation: In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease. Funding: Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council

    Analysis of the mitochondrial and nuclear genomes of two basidiomycetes, Coprinus cinereus and Coprinus stercorarius

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    The mitochondrial and nuclear genomes of Coprinus stercorarius and C. cinereus were compared to assess their evolutionary relatedness and to characterize at the molecular level changes that have occurred since they diverged from a common ancestor. The mitochondrial genome of C. stercorarius (91.1 kb) is approximately twice as large as that of C. cinereus (43.3 kb). The pattern of restriction enzyme recognition sites shows both genomes to be circular, but reveals no clear homologies; furthermore, the order of structural genes is different in each species. The C. stercorarius mitochondrial genome contains a region homologous to a probe derived from the yeast mitochondrial var1 gene, whereas its nuclear genome does not. By contrast, the C. cinereus nuclear, but not mitochondrial, genome contains a region homologous to the var1 probe. Only a small fraction of either the nuclear or mitochondrial genomes, perhaps corresponding to the coding sequences, is capable of forming duplexes in interspecies solution reassociations, as measured by binding to hydroxylapatite. Those sequences capable of reassociating were found to have approximately 15% divergence for the mitochondrial genomes and 7%–15% divergence for the nuclear genomes, depending on the conditions of reassociation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46959/1/294_2004_Article_BF00447385.pd
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