Presence Of Alpha Research Articles

Synthesis and characterization of alpha and beta cobalt hydroxide nanostructures for photocatalytic dye degradation and supercapacitor applications

Alpha and beta cobalt hydroxide nanostructures were synthesized by hydrothermal method and characterized using X-ray diffraction and electron microscopy. The turbostatic alpha-Co(OH)2 has large interlayer spacing compared to the beta-Co(OH)2 and is less explored in the literature. Both nanostructures were efficient in degrading methylene blue dye in the presence of visible light. Under identical conditions, the rate constant of photocatalytic dye degradation in the presence of alpha and beta cobalt hydroxide was calculated as 60.22 × 10−3 min−1 and 19.05 × 10−3 min−1, respectively, which is highest when compared to the previous reports. The superior activity of alpha-Co(OH)2 when compared to beta-Co(OH)2 is also demonstrated in this work. Additionally, a Csp value of 137 F/g and 2.4 F/g, respectively, at a current density of 1 A/g, was obtained from the GCD analysis of devices made using alpha-Co(OH)2 and beta-Co(OH)2. A higher cyclic stability and power density were observed for alpha-Co(OH)2 when compared to beta-Co(OH)2. The findings suggest that alpha and beta cobalt hydroxide nanostructures hold promise as effective catalysts for dye degradation and potential materials for high-performance supercapacitors. Further investigations into the unique properties of the relatively superior alpha-Co(OH)2 could lead to advancements in environmental remediation and energy storage technologies.

Presence of Alpha 1 Antitrypsin Risk Variants is Not Associated With Histologic Severity of Pediatric NAFLD.

Among adults with nonalcoholic fatty liver disease (NAFLD), alpha-1-antitrypsin (A1AT) heterozygosity has been linked to advanced liver disease; pediatric data remain unclear. The objective of this study is to determine whether A1AT PiZ or PiS variants are associated with liver disease severity in youth with NAFLD. Retrospective study of youth with confirmed NAFLD. Multivariable logistic regression used to determine independent associations between A1AT risk variants and histologic severity [NAFLD activity score (NAS) ≥5 and/or significant fibrosis (stage ≥2)]. The cohort included 269 patients, mean age 12 [±3] years with NAFLD and A1AT phenotyping (n = 260) and/or A1AT levels (n = 261). The mean NAS of the cohort was 4.2 [±1.5]; 50% had any, and 18% had significant fibrosis. Most (86%) had the MM A1AT phenotype, while 7% had the MS and 3% the MZ phenotype (the rest had other, nonpathogenic variants). Mean A1AT level was 123 mg/dL [±20]. A1AT levels did not differ by low versus high NAS (122 ± 2 vs 126 ± 19 mg/dL, P = 0.12) or by no/mild versus significant fibrosis (123 ± 20 vs 126 ± 20 mg/dL, P = 0.23, respectively). Carriers and noncarriers of the PiS or PiZ variants had similar NAS (mean NAS 3.8 ± 1.6 vs 4.2 ± 1.4; P = 0.25, respectively). Fibrosis severity did not differ by carrier vs noncarrier group: 38% versus 52% had any fibrosis ( P = 0.17) and 14% versus 18% had significant fibrosis ( P = 0.80, respectively). Multivariable modeling showed no association between A1AT risk variants and histologic severity. While not uncommon, carriage of the A1AT PiZ or PiS risk variants was not associated with histologic severity in children with NAFLD.

Determination of Type and Molecular Identity of Clostridium perfringens Isolated from Patients with Multiple Sclerosis (MS)

Background & Objectives: Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system (CNS). Clostridium perfringens ε-toxin (ETX) can cause emerging complications of MS due to its tendency to the blood-brain barrier. This study aimed to determine the presence of toxin-producing genes in intestinal C.perfringens in patients with multiple sclerosis.
 Materials & Methods: Stool samples were taken from 70 MS patients and 70 without MS individuals. The samples were enriched in cooked meat media, and cultural and biochemical methods separated Clostridium isolates. PCR tested these isolates to identify C. perfringens species. In addition, the presence of alpha, beta, epsilon and iota toxin-producing genes was evaluated in all isolates by Multiplex PCR.
 Results: Isolates containing the etx gene were observed in 10 patients, while no itxA gene was identified in any isolates. The results showed that isolates in 8 patients were type D. Also, the gene encoding toxin type D was identified in 2 isolates obtained from the control group.
 Conclusion: Our findings indicated the high frequency of C. Perfringens in MS patients. In the studied samples with clinical presentations, most of these organisms were type D bacteria that produce ε-toxin.

Estimating the Number of COVID-19 Cases and Impact of New COVID-19 Variants and Vaccination on the Population in Kerman, Iran: A Mathematical Modeling Study.

COVID-19 is spreading all over Iran, and Kerman is one of the most affected cities. We conducted this study to predict COVID-19-related deaths, hospitalization, and infected cases under different scenarios (scenarios A, B, and C) by 31 December 2021 in Kerman. We also aimed to assess the impact of new COVID-19 variants and vaccination on the total number of COVID-19 cases, deaths, and hospitalizations (scenarios D, E, and F) using the modified susceptible-exposed-infected-removed (SEIR) model. We calibrated the model using deaths reported from the start of the epidemic to August 30, 2021. A Monte Carlo Markov Chain (MCMC) uncertainty analysis was used to estimate 95% uncertainty intervals (UI). We also calculated the time-varying reproductive number (Rt) following time-dependent methods. Under the worst-case scenario (scenario A; contact rate = 10, self‐isolation rate = 30%, and average vaccination shots per day = 5,000), the total number of infections by December 31, 2021, would be 1,625,000 (95% UI: 1,112,000–1,898,000) with 6,700 deaths (95% UI: 5,200–8,700). With the presence of alpha and delta variants without vaccine (scenario D), the total number of infected cases and the death toll were estimated to be 957,000 (95% UI: 208,000–1,463,000) and 4,500 (95% UI: 1,500–7,000), respectively. If 70% of the population were vaccinated when the alpha variant was dominant (scenario E), the total number of infected cases and deaths would be 608,000 (95% UI: 122,000–743,000) and 2,700 (95% UI: 700–4,000), respectively. The Rt was ≥1 almost every day during the epidemic. Our results suggest that policymakers should concentrate on improving vaccination and interventions, such as reducing social contacts, stricter limitations for gathering, public education to promote social distancing, incensing case finding and contact tracing, effective isolation, and quarantine to prevent more COVID-19 cases, hospitalizations, and deaths in Kerman.

Utilizing the VirIdAl Pipeline to Search for Viruses in the Metagenomic Data of Bat Samples.

According to various estimates, only a small percentage of existing viruses have been discovered, naturally much less being represented in the genomic databases. High-throughput sequencing technologies develop rapidly, empowering large-scale screening of various biological samples for the presence of pathogen-associated nucleotide sequences, but many organisms are yet to be attributed specific loci for identification. This problem particularly impedes viral screening, due to vast heterogeneity in viral genomes. In this paper, we present a new bioinformatic pipeline, VirIdAl, for detecting and identifying viral pathogens in sequencing data. We also demonstrate the utility of the new software by applying it to viral screening of the feces of bats collected in the Moscow region, which revealed a significant variety of viruses associated with bats, insects, plants, and protozoa. The presence of alpha and beta coronavirus reads, including the MERS-like bat virus, deserves a special mention, as it once again indicates that bats are indeed reservoirs for many viral pathogens. In addition, it was shown that alignment-based methods were unable to identify the taxon for a large proportion of reads, and we additionally applied other approaches, showing that they can further reveal the presence of viral agents in sequencing data. However, the incompleteness of viral databases remains a significant problem in the studies of viral diversity, and therefore necessitates the use of combined approaches, including those based on machine learning methods.

Performance Analysis of ZF-SIC and MMSE Equalizers for MIMO System in the Presence of Alpha(α)-MU(µ) Fading Channel

Performance Analysis of ZF-SIC and MMSE Equalizers for MIMO System in the Presence of Alpha(α)-MU(µ) Fading Channel

Toxin typing of Clostridium perfringens Associated with Enterotoxaemia in Sheep in Fars Province.

Clostridium perfringens is implicated in the etiology of some diseases including fatal enterotoxaemia. Determining dominant toxin types of this microorganism can be helpful in epidemiologic surveys and the formulation of more proper vaccines. To understand the pathogenicity of this bacterium, it seems necessary to describe the toxin and virulence genes content of strains involved in enterotoxaemia and other associated diseases. The current study aimed to isolate and type the toxins of C. perfringens in sheep with suspected enterotoxaemia in Fars province by culture-PCR and ELISA methods and to compare them to isolates of a healthy group. Samples of intestinal contents were collected from enterotoxaemia cases and a healthy group of sheep. The presence of alpha, beta, and epsilon toxins were evaluated by ELISA method. After culture and isolation of C. perfringens, toxin typing and screening of isolates for the presence of beta-2 and enterotoxin were performed by PCR method. C. perfringens was isolated from 102 of 167 suspected enterotoxaemia cases of sheep and from 22 of 50 healthy sheep. The PCR results showed that type A was the most prevalent toxin type in both groups, but according to ELISA type D was the dominant toxin type in the clinical group. The enterotoxin gene was detected in 10% of all isolates from healthy and suspected group isolates of types A and D. The beta-2 gene was identified in 35% and 63.6% of enterotoxaemia-associated isolates and isolates not associated with disease, respectively. In conclusion, Type D of C. perfringens was the dominant causative organism of fatal enterotoxaemia in sheep in Fars province.

Ozračenost pripadnika vojske SR Jugoslavije na Kosovu i Metohiji u toku NATO agresije 1999. godine

Introduction/purpose: The paper indicates the radiation doses the military personnel of the Federal Republic of Yugoslavia were exposed to, and in particular the military personnel of the motorized brigades in the territory of Kosovo and Metohia on the Albanian-Yugoslav border. Methods: Gammaspectrometry measurements have confirmed that round penetrators contained depleted uranium, and the presence of alpha, beta and gamma radiation was determined by the method of dosimetric measurement. Results: The use of ammunition with 238U depleted uranium, with added plutonium, pollutes the environment, water, and soil in the long term, causing various disorders and diseases, primarily malignant ones. The radioactivity of 239Pu, compared to its toxicity, is several thousand times higher and the inhalation of plutonium dust is harmful and causes cancer. Uranium is a pyrophoric metal, toxic, radioactive and easy to ignite. Its oxides are toxic and partially soluble in water. After ignition, the round releases radioactive aerosol particles which burn in contact with the air causing short or long term damage when inhaled. In Kosovo and Metohia, a large amount of radioactivity was measured during the NATO aggression against the FR Yugoslavia. In Metohia, radioactivity was 1,100 times that of natural background radiation. Conclusion: During the war, the Army of the FR Yugoslavia was exposed to high radioactive doses, so that among the members of the army after the war there was an increased incidence of various malignancies, many of them lethal.

Water Distillation Extraction of Essential Oil from Sideritis Raeseri Herb

Water distillation extraction is a well known and popular method for obtaining essential oils from medicinal and aromatic herbs. Additionally, it represents an environmentally friendly process. In the current work, Sideritis raeseri, also known as mountain tea herb, is used to attain essential oils by means of Clevenger apparatus exploiting water as extracting solvent. Essential oils are recognized for their applications in folk medicine. The Sideritis herbs are widely distributed in Mediterranean regions and the Balkans (Albania, Greece and Bulgaria). The primary goal of the present work is to utilize an eco-friendly process, i.e., hydro-distillation to obtain essential oils from Sideritis raesieri. Secondly, to identify the main chemical components in the essential oils of Sideritis herbs by utilizing spectral characterization by means of FTIR spectroscopy. Several samples were considered for the water distillation extraction of Sideritis herbs from different localities of southern Albania, i.e., Zagori (Gjirokastra), Dry Mountain (Korҫa) and Tomorr Mountain (Korҫa). FTIR analyses indicated presence of alpha- and beta-pinene, and bicyclogermacrene as main chemical constituents in the essential oil samples. FTIR spectra featured signals in the range 1437–1374 cm−1 and 1637 cm−1 attributed to bicyclogermacrene, and alpha- and beta-pinene, respectively, in good agreement with reported FTIR relevant studies.

The Study of Rhythmic Component Coupling at the First Stage of Day Sleep

Coupling of EEG rhythms is an important indicator of the functional state of the human brain. There currently exist three theories explaining this coupling: (1) communication of neuronal populations, (2) neuronal coupling, and (3) coupling between generators of the frequencies being studied. It is known that the theta rhythm is associated with the functioning of cortico-hippocampal and alpha-rhythm-thalamo-cortical systems, and the beta rhythm can be included in the activity of both cortico-subcortical systems. The present work may clarify the features of the above-mentioned cortico-subcortical systems. There is a number of publications devoted to the study of EEG rhythm coupling in various types of psychical activity. At the same time, a concern for coupling of the rhythms at different sleep stages appeared in recent years. The task of our work included the study of coupling between theta, alpha, and beta EEG rhythms at the first stage of sleep. The study involved 22 subjects from 18 to 22 years old. Multichannel EEG was recorded during daytime sleep of the experiment participants. EEG segments with well-expressed theta rhythm were selected for the processing since it is “dominant” at the first stage of sleep. Bandpass filtering of the EEG signal was then performed. The following rhythms were discriminated: theta rhythm (4–7 Hz), alpha rhythm (8–13 Hz), beta-1 (14–19 Hz), and beta-2 (20–25 Hz) rhythms. Afterwards, for each range at each second, the average amplitude was calculated as the square root of the EEG signal dispersion. The Pearson correlation coefficient was used as a measure to evaluate coupling of EEG rhythms. As a result, it was established that the first stage of sleep is characterized by: (1) a lack of connections between the theta rhythm and other rhythms, (2) the presence of alpha–beta-1, alpha–beta-2, and beta-1–beta-2 links, (3) the increase in theta amplitude, and (4) the decrease in the amplitudes of alpha and beta rhythms. As was noted above, the theta rhythm is associated with functioning of the cortico-hippocampal system, and the alpha rhythm is associated with the thalamo-cortical system. In our work, two coexisting types of functioning of these systems are shown: (1) the “independent” one of the cortico-hippocampal circuit and (2) the thalamo-cortical one, connected with other rhythms, particularly with the beta rhythm. This heterogeneity is probably a condition for the first stage of sleep to be potentially unstable. An increase in theta rhythm amplitude at the first stage of sleep against the state of quiet wakefulness is shown. This is traditionally associated with the increase in ascending effects of limbic structures of the brain. Amplitudes of alpha and beta rhythms at the first stage of sleep significantly decreased, which indicates an attenuation of the influence of prefrontal cortical regions on posterior hypothalamus centers. Hence, it can be assumed that the onset of the first stage of sleep can be provided by the heterogenous character of rhythm coupling, and, correspondingly, different functioning of cortico-hippocampal and thalamo-cortical systems.

On the Generation Mechanism of Electromagnetic Cyclotron Waves in the Solar Wind: Statistical Results from Wind Observations

Abstract Electromagnetic cyclotron waves (ECWs) near the proton cyclotron frequency are frequently observed in the solar wind, yet their generation mechanism is still an open question. Based on the Wind data from 2005−2015, this paper carries out a statistical study on the plasma characteristics associated with the occurrence of ECWs. The probability density distributions (PDDs) of proton temperature anisotropy (T ⊥/T ∥) and proton parallel beta (β ∥) are investigated, where ⊥ and ∥ refer to perpendicular and parallel to the background magnetic field, respectively. The PDDs depend on solar wind types as well as wave polarizations, and those for ECWs with left-handed (LH) polarization exhibit considerable differences from the PDDs for ambient solar winds. The distributions of occurrence rates of LH ECWs in (β ∥, T ⊥/T ∥) space show a tendency that the occurrence rates increase with proton temperature anisotropies. The β ∥ with the maximum of occurrence rates is near 0.1 when T ⊥/T ∥ > 1, while it is around 1 when T ⊥/T ∥ < 1. The presence of alpha−proton differential flow with large kinetic energy corresponds to a much higher occurrence rate as well as the domination of LH polarization of ECWs. Based on these observations and existing theories, we propose that the proton cyclotron and parallel firehose instabilities with effects of alpha−proton differential flow are likely responsible for the local generation of LH ECWs in the solar wind. The generation mechanism of right-handed (RH) ECWs seems to be complicated and more discussions are needed in future research.

Phytochemical composition and antioxidant characteristics of traditional cold pressed seed oils in South India

Abstract Cold press extraction is the ultimate method to extract essential phytonutrients from oil seeds. Other extractions such as chemical and hot press extraction include processes like deodorizing and refining which affect the quality of phytocompounds (essential fatty acids, tocopherols and phytosterols). In this study, antioxidant capacity, tocopherol and fatty acid profiles of six cold-pressed oils (sesame, coconut, peanut, neem, castor and iluppai) were determined. Lipophilic extracts showed excellent DPPH-free radical scavenging activity compared to hydrophilic extracts. Lipophilic extract of sesame oil showed the highest antioxidant capacity in both DPPH (0.61 ± 0.02 TEAC µM/g dw) and ABTS (0.85 ± 0.05 TEAC µM/g dw) free radical scavenging assays. The presence of alpha (α), gamma (γ) and delta (δ) tocopherols were detected and quantified in all the six seed oil samples through UPLC analysis. From the results it was confirmed that γ- tocopherol content is predominant in castor (395.32 ± 2.12 mg/kg), sesame (278.72 ± 2.80 mg/kg) and peanut (104.11 ± 2.86 mg/kg) oils. GC-MS analysis of all the six seed oil samples exhibited fatty acids such as myristic, palmitic, stearic, oleic and linoleic acid in various compositions. The highest levels of total saturated (SFA) in coconut oil, monounsaturated (MUFA) in castor oil and polyunsaturated (PUFA) in sesame oil were quantified at the range of 85.51%, 64.09%, and 31.72% respectively. In conclusion these phytoconstituents from cold pressed oil play a promising role in improving human health without side effects.

Optimization of pressure-less microwave sintering of Ti6Al4V by response surface methodology

ABSTRACTPressure-less microwave sintering of titanium alloy (Ti6Al4V) is an economical and viable solution for obtaining near net shape fabrication of complex shapes. Input process parameters such as sintering temperature (St), heating rate (Hr), and holding (Ht) were optimized in this work for maximal compressive yield strength, maximal density, and minimal volumetric shrinkage by response surface methodology (RSM). The individual and interactive influence/effects of the process parameters on each of the responses were studied. A statistical model was developed to predict each of the output responses. Analysis by X-ray diffractometry indicates the presence of alpha and beta phase Ti6Al4V. The optimal sintering parameters identified were: St of 1280°C, Hr of 8°C/minute, and Ht of 78 minutes. At the optimized parameters, a compressive yield strength of 541.34 ± 48.81 MPa, density of 4022.59 ± 87.38 kg/m3, and volumetric shrinkage of 16.86 ± 5% were obtained. The results of this study will help rapidly manufacture higher-strength titanium customized components using pressure-less microwave sintering method.

Identification of Hemolysine Genes and their Association with Antimicrobial Resistance Pattern among Clinical Isolates of Staphylococcus aureus in West of Iran

Background:Staphylococcus aureus is expressing a broad range of different hemolysins enhancing its ability to establish and maintain infection in humans. The aim of this study was to identify the types of hemolysins in different clinical isolates of S. aureus and their association with antibiotic resistance patterns.Materials and Methods:In this cross-sectional and descriptive study, clinical isolates of S. aureus were collected from Hamedan's hospitals during an 11-month period from June 2016 to January 2017 and identified by using biochemical tests. To determine the antibiotic resistance pattern, disk diffusion method and minimum inhibitory concentration (MIC) were conducted. Genomic DNA was extracted using extraction kit. The polymerase chain reaction was done with specific primers for identification of hla, hlb, hld, and hld genes.Results:Among a total of 389 clinical samples, 138 isolates (35.45%) of S. aureus were identified, which 87 isolates (63.04%) were cefoxitin MIC of >4 μg/ml and resistant to methicillin. The highest frequency of antibiotic resistance was observed against erythromycin in 108 isolates (78.26%) and penicillin in 133 isolates (96.37%) and the lowest resistance was against gatifloxacin in 50 isolates (36.23%) and Cefazolin in 11 isolates (97.7%). Furthermore, the hla, hlb, hld, and hlg genes were detected among 11 (7.97%), 7 (5.07%), 16 (11.59%), and 4 (2.89%) isolates, respectively. There was a significant relationship between the presence of alpha and delta hemolysin-encoding genes and the antibiotic resistance pattern of isolates (P < 0.05).Conclusion:The results exhibited that the association between the presence of the hemolysin genes and the antibiotic resistance pattern can be considered as a serious issue.

Epithelial Sodium Channel-α Mediates the Protective Effect of the TNF-Derived TIP Peptide in Pneumolysin-Induced Endothelial Barrier Dysfunction.

Streptococcus pneumoniae is a major etiologic agent of bacterial pneumonia. Autolysis and antibiotic-mediated lysis of pneumococci induce release of the pore-forming toxin, pneumolysin (PLY), their major virulence factor, which is a prominent cause of acute lung injury. PLY inhibits alveolar liquid clearance and severely compromises alveolar-capillary barrier function, leading to permeability edema associated with pneumonia. As a consequence, alveolar flooding occurs, which can precipitate lethal hypoxemia by impairing gas exchange. The α subunit of the epithelial sodium channel (ENaC) is crucial for promoting Na+ reabsorption across Na+-transporting epithelia. However, it is not known if human lung microvascular endothelial cells (HL-MVEC) also express ENaC-α and whether this subunit is involved in the regulation of their barrier function. The presence of α, β, and γ subunits of ENaC and protein phosphorylation status in HL-MVEC were assessed in western blotting. The role of ENaC-α in monolayer resistance of HL-MVEC was examined by depletion of this subunit by specific siRNA and by employing the TNF-derived TIP peptide, a specific activator that directly binds to ENaC-α. HL-MVEC express all three subunits of ENaC, as well as acid-sensing ion channel 1a (ASIC1a), which has the capacity to form hybrid non-selective cation channels with ENaC-α. Both TIP peptide, which specifically binds to ENaC-α, and the specific ASIC1a activator MitTx significantly strengthened barrier function in PLY-treated HL-MVEC. ENaC-α depletion significantly increased sensitivity to PLY-induced hyperpermeability and in addition, blunted the protective effect of both the TIP peptide and MitTx, indicating an important role for ENaC-α and for hybrid NSC channels in barrier function of HL-MVEC. TIP peptide blunted PLY-induced phosphorylation of both calmodulin-dependent kinase II (CaMKII) and of its substrate, the actin-binding protein filamin A (FLN-A), requiring the expression of both ENaC-α and ASIC1a. Since non-phosphorylated FLN-A promotes ENaC channel open probability and blunts stress fiber formation, modulation of this activity represents an attractive target for the protective actions of ENaC-α in both barrier function and liquid clearance. Our results in cultured endothelial cells demonstrate a previously unrecognized role for ENaC-α in strengthening capillary barrier function that may apply to the human lung. Strategies aiming to activate endothelial NSC channels that contain ENaC-α should be further investigated as a novel approach to improve barrier function in the capillary endothelium during pneumonia.

Failure of a nickel aluminium bronze (NAB) canned motor pump impeller working under polluted sea water – Influence of material selection, section thickness dependent microstructure and temper annealing heat treatment

Abstract In the present study, a damaged pump impeller working under highly polluted sea water was taken up for investigation on probable cause(s) for its failure. Major steps in the investigation were visual examination, thorough microstructural observation of the affected (surface and sub-surface) and unaffected portions of the base material at different locations on the impeller having varying section thickness. An effort has been made for correlating unaffected microstructural attributes to corroded features with respect to various section thicknesses. Failure of the impeller is found to be due to combined effect of a corrosion susceptible microstructure and highly polluted corroding medium that resulted in selective phase corrosion (SPC) of certain phases in the microstructure leading to surface roughening and perforation, predominantly through pitting mechanism governed by dealuminification initiated at phase interfaces. Networked alpha plus kappaIII eutectoids, Cu-O type of precipitates, dendritic Cu-Al phase and retained beta have been found to be corrosion susceptible microstructure. Principle c orroding features in thick sections were found to be kappaII and alpha plus kappaIII eutectoids, while that in thin sections include severe cracking involving Cu-S-O rich coarse precipitate (of 15 μm approx size), corrosion along interfaces of dendritic Cu-Al phase and retained beta with alpha matrix. Presence of alpha plus kappaIII eutectoids and retained beta has been the result of combined effect of improper selection of material (aluminium) composition, complex cast shape of the impeller and ineffective temper annealing treatment, while dendritic Cu-Al phase and high level of porosity are casting defects.

Consecutive transcranial magnetic stimulation twitches reduce flow limitation during sleep in apnoeic patients

What is the central question of this study? A transcranial magnetic stimulation (TMS)-induced twitch applied on isolated single breaths over the motor cortex somatotopic representation of the tongue briefly recruits submental muscles and improves airflow dynamics of flow-limited respiratory cycles without arousing sleep apnoea patients. However, the mechanical impact of the TMS-induced twitch applied during consecutive breathing cycles on airflow dynamics remains unknown. What is the main finding and what is its importance? Our results show that application of TMS with the stimulator output set at the sleep submental motor threshold intensity on consecutive respiratory cycles increases inspiratory flow and reduces the turbulent airflow component. These results indicate an improvement of airflow pattern after two single consecutive TMS-induced twitches without arousing sleep apnoea patients. Transcranial magnetic stimulation (TMS)-induced twitches applied on isolated breaths briefly recruit upper airway dilator muscles and improve airflow and inspiratory volume without arousing apnoeic patients from sleep, but the effects of applying such twitches consecutively on airflow dynamics is unknown. The objective of this study was to quantify the effects of five consecutive TMS-induced twitches applied on sleep-induced obstructive hypopnoeic breaths in 10 obstructive sleep apnoea patients. Submental muscle motor threshold (SUBMT) and motor-evoked potential were measured during wakefulness and sleep. The TMS-induced twitches were applied during stable non-rapid eye movement (NREM) sleep, at the beginning of inspiration of consecutive flow-limited respiratory cycles, with the stimulator output set at sleep SUBMT. Maximal inspiratory flow, inspiratory volume, inspiratory time, shifts of electroencephalogram frequency and pulse rate variability were assessed. During sleep, SUBMT increased (wakefulness, 25.3 ± 4.9%; NREM sleep, 27.0 ± 6.2%; P = 0.02). During each series of stimulations there was a rise in maximal inspiratory flow (from 306.7 ± 123.2 to 359.8 ± 154.1 ml s(-1); P = 0.0002) and in inspiratory volume (from 346.1 ± 128.1 to 414.9 ± 171.2 ml; P = 0.02) without differences in thoraco-abdominal efforts and inspiratory time. These responses were observed in the absence of arousals and ceased immediately after TMS interruption. Transcranial magnetic stimulation-induced cortical and/or autonomic arousal was observed in 30.2% of all series of stimulation. Consecutive twitch TMS of submental muscles may lead to arousals in a minority of patients but can be applied on consecutive respiratory cycles during sleep and can significantly improve maximal inspiratory flow and inspiratory volume of flow-limited cycles.

Some pharmacological properties of the circular smooth muscle layer of the rat vas deferens.

Vas deferens preparations were perfused in-vitro through the lumen and externally with a modified Tyrode solution alone or containing drugs. Contractions of the circular (internal) smooth muscle layer were recorded as changes in the pressure of internal perfusion. Contractions of the longitudinal (external) layer were simultaneously recorded through a tension transducer. When the organ was perfused through the lumen, the circular layer contracted after addition of methacholine (pD2 = 4.13), and noradrenaline (pD2 = 5.00), and relaxed after addition of isoprenaline (pD2 = 5.22). These effects were also observed when the drugs were perfused externally, although with lower values of pD2 for noradrenaline and methacholine. The circular fibres were less sensitive when compared with the longitudinal fibres perfused externally with the above agonists. Methacholine-induced contractions of the circular layer were competitively antagonized by atropine (pA2 = 8.53), indicating the presence of muscarinic receptors. The effects induced by noradrenaline and isoprenaline were antagonized by indoramin (pA2 = 7.78), and timolol (pA2 = 8.68), respectively, indicating the presence of alpha- and beta-adrenoceptors. The effect of noradrenaline was potentiated by cocaine and denervation, indicating the presence of neuronal uptake, and by corticosterone, indicating the presence of extraneuronal uptake in the circular layer.

Enhanced Stability of PEG-block-poly(N-hexyl stearate l-aspartamide) Micelles in the Presence of Serum Proteins

Polyethylene glycol-phospholipid micelles form a major class of nanocarriers in pharmacy and medicine due to proven capability in drug solubilization, sustained drug release, and evidence for targeted drug delivery in vivo. In this report, we have prepared micelles composed of PEG-block-poly(N-hexyl stearate l-aspartamide) (PEG-b-PHSA), having nine stearic acid side chains, and have studied their stability in the presence of serum proteins by Forster resonance energy transfer (FRET) experiments. In the presence of serum albumin, alpha and beta globulins, or gamma globulins, there are minimal changes in FRET over two hours in vitro, indicating integrity of PEG-b-PHSA micelles. In contrast, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-5000] (PEG-DSPE) micelles lose FRET over two hours in vitro, especially in the presence of alpha and beta globulins, indicating the disruption of PEG-DSPE micelles and leakage of fluorescent probes. Owing to the aliphatic nature of DSPE and PHSA, both PEG-b-PHSA and PEG-DSPE micelles efficiently solubilize amphotericin B (AmB), a poorly water-soluble antifungal agent used to combat systemic mycoses. However, only PEG-b-PHSA micelles gradually liberate AmB in the presence of alpha and beta globulins, based on time-dependent changes in the self-aggregation state of AmB, monitored by UV/vis spectroscopy. PEG-b-PHSA micelles are remarkably stable in the presence of serum proteins and a more stable alternative for poorly water-soluble drugs, which have been solubilized by PEG-DSPE micelles.

Two Distinct Mechanisms of Inactivation of the Class Ic Ribonucleotide Reductase fromChlamydia trachomatisby Hydroxyurea: Implications for the Protein Gating of Intersubunit Electron Transfer

Catalysis by a class I ribonucleotide reductase (RNR) begins when a cysteine (C) residue in the alpha(2) subunit is oxidized to a thiyl radical (C(*)) by a cofactor approximately 35 A away in the beta(2) subunit. In a class Ia or Ib RNR, a stable tyrosyl radical (Y(*)) is the C oxidant, whereas a Mn(IV)/Fe(III) cluster serves this function in the class Ic enzyme from Chlamydia trachomatis (Ct). It is thought that, in either case, a chain of Y residues spanning the two subunits mediates C oxidation by forming transient "pathway" Y(*)s in a multistep electron transfer (ET) process that is "gated" by the protein so that it occurs only in the ready holoenzyme complex. The drug hydroxyurea (HU) inactivates both Ia/b and Ic beta(2) subunits by reducing their C oxidants. Reduction of the stable cofactor Y(*) (Y122(*)) in Escherichia coli class Ia beta(2) is faster in the presence of alpha(2) and a substrate (CDP), leading to speculation that HU might intercept a transient ET pathway Y(*) under these turnover conditions. Here we show that this mechanism is one of two that are operant in HU inactivation of the Ct enzyme. HU reacts with the Mn(IV)/Fe(III) cofactor to give two distinct products: the previously described homogeneous Mn(III)/Fe(III)-beta(2) complex, which forms only under turnover conditions (in the presence of alpha(2) and the substrate), and a distinct, diamagnetic Mn/Fe cluster, which forms approximately 900-fold less rapidly as a second phase in the reaction under turnover conditions and as the sole outcome in the reaction of Mn(IV)/Fe(III)-beta(2) only. Formation of Mn(III)/Fe(III)-beta(2) also requires (i) either Y338, the subunit-interfacial ET pathway residue of beta(2), or Y222, the surface residue that relays the "extra electron" to the Mn(IV)/Fe(IV) intermediate during activation of beta(2) but is not part of the catalytic ET pathway, and (ii) W51, the cofactor-proximal residue required for efficient ET between either Y222 or Y338 and the cofactor. The combined requirements for the catalytic subunit, the substrate, and, most importantly, a functional surface-to-cofactor electron relay system imply that HU effects the Mn(IV)/Fe(III) --> Mn(III)/Fe(III) reduction by intercepting a Y(*) that forms when the ready holoenzyme complex is assembled, the ET gate is opened, and the Mn(IV) oxidizes either Y222 or Y338.