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Introduction Armed conflicts exacerbate the spread of infectious diseases. We assessed the impact of the 2022 armed conflict in Ukraine on common sexually, bloodborne, and respiratory-transmitted infectious diseases in internally displaced people (IDP) in Ukraine. Methods A cross-sectional study (#aware.id) was conducted in Lviv, Ukraine, from 3 May 2023 to 24 June 2024, including IDP seeking care for HIV, hepatitis B and C, COVID-19, tuberculosis, and sexually transmitted infections. After medical screening to evaluate disease risk, we used rapid point-of-care tests followed by confirmatory standard of care testing. The main endpoints were the infectious disease case positivity rate in IDP compared to a local at-risk population, the association with war related risk factors including shelter use and experienced violence, and linkage to care. Results Among 695 enrolled participants (250 IDP and 445 locals), the median age was 37 years (IQR 30-45) and 58.7% were women. Both groups disclosed a high HIV and viral hepatitis disease risk. Among IDP, rates of HIV (4.8% in IDP vs. 7.1% in local at-risk population), hepatitis C (33.9% vs. 40.0%) and syphilis (4.7% vs. 2.7%) were comparable with the local at-risk controls (all p>0.05), while the hepatitis B rate was lower in IDP (6.3% vs. 26.9%, p<0.01). COVID-19, tuberculosis, chlamydia, and gonorrhea were infrequent and comparable (all p>0.05). Despite higher war-related risk factors, we found no clear association with infectious disease burden in IDP disclosing these factors. All those diagnosed were linked to care within 4 weeks. Conclusions The undiagnosed infectious disease burden in IDP was high and comparable to a highrisk local population. [ABSTRACT FROM AUTHOR]

While voltage-gated sodium channels Nav1.7 and Nav1.8 both contribute to electrogenesis in dorsal root ganglion (DRG) neurons, details of their interactions have remained unexplored. Here, we studied the functional contribution of Nav1.8 in DRG neurons using a dynamic clamp to express Nav1.7L848H, a gain-of-function Nav1.7 mutation that causes inherited erythromelalgia (IEM), a human genetic model of neuropathic pain, and demonstrate a profound functional interaction of Nav1.8 with Nav1.7 close to the threshold for AP generation. At the voltage threshold of -21.9 mV, we observed that Nav1.8 channel open-probability exceeded Nav1.7WT channel open-probability ninefold. Using a kinetic model of Nav1.8, we showed that a reduction of Nav1.8 current by even 25-50% increases rheobase and reduces firing probability in small DRG neurons expressing Nav1.7L848H. Nav1.8 subtraction also reduces the amplitudes of subthreshold membrane potential oscillations in these cells. Our results show that within DRG neurons that express peripheral sodium channel Nav1.7, the Nav1.8 channel amplifies excitability at a broad range of membrane voltages with a predominant effect close to the AP voltage threshold, while Nav1.7 plays a major role at voltages closer to resting membrane potential. Our data show that dynamic-clamp reduction of Nav1.8 conductance by 25-50% can reverse hyperexcitability of DRG neurons expressing a gain-of-function Nav1.7 mutation that causes pain in humans and suggests, more generally, that full inhibition of Nav1.8 may not be required for relief of pain due to DRG neuron hyperexcitability. [ABSTRACT FROM AUTHOR]

Background Confirming the efficacy of dolutegravir/lamivudine in clinical practice solidifies recommendations on its use. Methods Prospective cohort study (DUALING) in 24 human immunodeficiency virus (HIV) treatment centers in the Netherlands. HIV RNA–suppressed cases were on triple-drug antiretroviral regimens without prior virological failure or resistance and started dolutegravir/lamivudine. Cases were 1:2 matched to controls on triple-drug antiretroviral regimens by the use of dolutegravir-based regimens, age, sex, transmission route, CD4+ T-cell nadir, and HIV RNA zenith. The primary endpoint was the treatment failure rate in cases versus controls at 1 year by intention-to-treat and on-treatment analyses with 5% noninferiority margin. Results The 2040 participants were 680 cases and 1380 controls. Treatment failure in the 390 dolutegravir-based cases versus controls occurred in 8.72% and 12.50% (difference: −3.78% [95% confidence interval {CI}, −7.49% to.08%]) by intention-to-treat and 1.39% and 0.80% (difference: 0.59% [95% CI, –.80% to 1.98%]) by on-treatment analyses. The treatment failure risk in 290 non-dolutegravir-based cases was also noninferior to controls. Antiretroviral regimen modifications unrelated to virological failure explained the higher treatment failure rate by intention-to-treat. A shorter time on triple-drug antiretroviral therapy and being of non-Western origin was associated with treatment failure. Treatment failure, defined as 2 consecutive HIV RNA >50 copies/mL, occurred in 4 cases and 5 controls but without genotypic resistance detected. Viral blips occured comparable in cases and controls but cases gained more weight, especially when tenofovir-based regimens were discontinued. Conclusions In routine care, dolutegravir/lamivudine was noninferior to continuing triple-drug antiretroviral regimens after 1 year, supporting the use of dolutegravir/lamivudine in clinical practice. Clinical Trials Registration NCT04707326. [ABSTRACT FROM AUTHOR]

Transionospheric radio signals might undergo random modulations of their amplitude and phase caused by scattering on irregular structures in the ionosphere. These scintillation phenomena are highly anisotropic, depend on local geomagnetic field configuaration and on the relative position of the signal receiver and scattering irregularity. We derive analytical expressions of anisotropic amplitude and phase scintillation indices using the model of a thin random phase screen. These results extend the classical derivations of [C. Rino, Radio Sci. 14 , 1135 (1979)] to a larger domain of applicability including very slant propagation links of the radio wave signals. The derived generalization is based on the assumption that the ionospheric scattering layer has a spherical symmetry as opposed to the original Rino's assumption of a plan-parallel ionospheric layer. The derived scintillation indices have the simpler analytical form, determine the regions of enhanced scintillation by taking into account the finite curvature of the Earth and of the ionospheric shell, and are divergence-free for large zenith angles of propagation links. For the illustration we discuss the geometric enhancement of scintillation for communication links via a geostationary beacon satellite over the equator. [ABSTRACT FROM AUTHOR]

The growing share of renewable energy sources in the energy mix and the liberalization of electricity markets has drastically affected the operation of electricity generators. Especially, in the last decade, fossil fuel-based generators have shifted their role from providing continuous base load to covering the peak demand and providing backup capacity to stabilize the grid. At the same time, a large amount of storage capacity is foreseen to be integrated into electricity grids in the coming years to shave demand peaks, mitigate price volatility, and provide services to the grid. In such a situation, in order to properly manage these crucial technologies, and thus guarantee the economic viability of the operation, it is essential to properly optimize the dispatch and define the best scheduling. This paper considers a gas turbine combined cycle and battery energy storage to study the problem of dispatch optimization of both generators and storage technologies. Different optimization algorithms have been considered and mixed integer linear programming is selected for its ability to identify the global optimum and the reduced optimization time. The impact of optimization windows (i.e., the forecast horizon of electricity prices) is also investigated. It is highlighted that an increase in forecasting ability, at least up to 36 h, guarantees more effective scheduling; on the other hand, it may require a significantly longer time. Subsequently, different approaches to account for the operation and maintenance costs at the optimization stage are assessed, and, finally, a sensitivity analysis is carried out with respect to market parameters (price average and variability) and technology features (conversion efficiency, cycle cost, etc.). [ABSTRACT FROM AUTHOR]

We present six epochs of optical spectropolarimetry of the Type IIP supernova (SN) 2021yja ranging from ∼25 to 95 d after the explosion. An unusually high continuum linear polarization of |$p \approx 0.9~{{\ \rm per\ cent}}$| is measured during the early photospheric phase, followed by a steady decrease well before the onset of the nebular phase. This behaviour has not been observed before in Type IIP supernovae (SNe IIP). The observed continuum polarization angle does not change significantly during the photospheric phase. We find a pronounced axis of symmetry in the global ejecta that is shared in common with the Hα and Ca  ii near-infrared triplet lines. These observations are consistent with an ellipsoidal geometry. The temporal evolution of the continuum polarization is also compatible with the SN ejecta interacting with aspherical circumstellar matter (CSM), although no spectroscopic features that may be associated with strong interaction can be identified. Alternatively, we consider the source of the high polarization to be an extended hydrogen envelope that is indistinguishable from low-density CSM. [ABSTRACT FROM AUTHOR]

We show here that hyperpolarization‐activated current (Ih) unexpectedly acts to inhibit the activity of dorsal root ganglion (DRG) neurons expressing WT Nav1.7, the largest inward current and primary driver of DRG neuronal firing, and hyperexcitable DRG neurons expressing a gain‐of‐function Nav1.7 mutation that causes inherited erythromelalgia (IEM), a human genetic model of neuropathic pain. In this study we created a kinetic model of Ih and used it, in combination with dynamic‐clamp, to study Ih function in DRG neurons. We show, for the first time, that Ih increases rheobase and reduces the firing probability in small DRG neurons, and demonstrate that the amplitude of subthreshold oscillations is reduced by Ih. Our results show that Ih, due to slow gating, is not deactivated during action potentials (APs) and has a striking damping action, which reverses from depolarizing to hyperpolarizing, close to the threshold for AP generation. Moreover, we show that Ih reverses the hyperexcitability of DRG neurons expressing a gain‐of‐function Nav1.7 mutation that causes IEM. In the aggregate, our results show that Ih unexpectedly has strikingly different effects in DRG neurons as compared to previously‐ and well‐studied cardiac cells. Within DRG neurons where Nav1.7 is present, Ih reduces depolarizing sodium current inflow due to enhancement of Nav1.7 channel fast inactivation and creates additional damping action by reversal of Ih direction from depolarizing to hyperpolarizing close to the threshold for AP generation. These actions of Ih limit the firing of DRG neurons expressing WT Nav1.7 and reverse the hyperexcitability of DRG neurons expressing a gain‐of‐function Nav1.7 mutation that causes IEM. Key points: Hyperpolarization‐activated cyclic nucleotide‐gated (HCN) channels, the molecular determinants of hyperpolarization‐activated current (Ih) have been characterized as a 'pain pacemaker', and thus considered to be a potential molecular target for pain therapeutics.Dorsal root ganglion (DRG) neurons express Nav1.7, a channel that is not present in central neurons or cardiac tissue. Gain‐of‐function mutations (GOF) of Nav1.7 identified in inherited erythromelalgia (IEM), a human genetic model of neuropathic pain, produce DRG neuron hyperexcitability, which in turn produces severe pain.We found that Ih increases rheobase and reduces firing probability in small DRG neurons expressing WT Nav1.7, and demonstrate that the amplitude of subthreshold oscillations is reduced by Ih.We also demonstrate that Ih reverses the hyperexcitability of DRG neurons expressing a GOF Nav1.7 mutation (L858H) that causes IEM.Our results show that, in contrast to cardiac cells and CNS neurons, Ih acts to stabilize DRG neuron excitability and prevents excessive firing. [ABSTRACT FROM AUTHOR]

We present three epochs of early-time ultraviolet (UV) and optical HST/STIS spectroscopy of the young, nearby Type IIP supernova (SN) 2021yja. We complement the HST data with two earlier epochs of Swift UVOT spectroscopy. The HST and Swift UVOT spectra are consistent with those of other well-studied Type IIP SNe. The UV spectra exhibit rapid cooling at early times, while less dramatic changes are seen in the optical. We also present Lick/KAIT optical photometry up to the late-time tail phase, showing a very long plateau and shallow decline compared with other SNe IIP. Our modeling of the UV spectrum with the TARDIS radiative transfer code produces a good fit for a high-velocity explosion, a low total extinction E (B âˆ' V) = 0.07 mag, and a subsolar metallicity. We do not find a significant contribution to the UV flux from an additional heating source, such as interaction with the circumstellar medium, consistent with the observed flat plateau. Furthermore, the velocity width of the Mg ii λ 2798 line is comparable to that of the hydrogen Balmer lines, suggesting that the UV emission is confined to a region close to the photosphere. [ABSTRACT FROM AUTHOR]

A new analytical approximation for the Chapman mapping integral, Ch , for exponential atmospheres is proposed. This formulation is based on the derived relation of the Chapman function to several classes of the incomplete Bessel functions. Application of the uniform asymptotic expansion to the incomplete Bessel functions allowed us to establish the precise analytical approximation to Ch , which outperforms established analytical results. In this way the resource consuming numerical integration can be replaced by the derived approximation with higher accuracy. The obtained results are useful for various branches of atmospheric physics such as the calculations of optical depths in exponential atmospheres at large grazing angles, physical and chemical aeronomy, atmospheric optics, ionospheric modeling, and radiative transfer theory. [ABSTRACT FROM AUTHOR]

We present a test of the statistical method introduced by Bernard F. Shutz in 1986 using only gravitational waves to infer the Hubble constant (H0) from GW190814, the first high-probability neutron-star–black hole (NS–BH) merger candidate detected by the Laser Interferometer gravitational-wave Observatory (LIGO) and the Virgo interferometer. We apply a baseline test of this method to the binary neutron star (BNS) merger GW170817 and find km s−1 Mpc−1 (maximum a posteriori and 68.3% highest density posterior interval) for a galaxy B-band luminosity threshold of with a correction for catalog incompleteness. Repeating the calculation for GW190814, we obtain km s−1 Mpc−1 and km s−1 Mpc−1 for and , respectively. Combining the posteriors for both events yields km s−1 Mpc−1, demonstrating the improvement on constraints when using multiple gravitational-wave events. We also confirm the results of other works that adopt this method, showing that increasing the LB threshold enhances the posterior structure and slightly shifts the distribution's peak to higher H0 values.We repeat the joint inference using the low-spin PhenomPNRT and the newly available combined (SEOBNRv4PHM + IMRPhenomPv3HM) posterior samples for GW170817 and GW190814, respectively, achieving a tighter constraint of km s−1 Mpc−1. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is a highly prevalent joint disease that causes substantial disability, yet effective approaches to disease prevention or to the delay of OA progression are lacking. Emerging evidence has pinpointed ion channels as pivotal mediators in OA pathogenesis and as promising targets for disease-modifying treatments. Preclinical studies have assessed the potential of a variety of ion channel modulators to modify disease pathways involved in cartilage degeneration, synovial inflammation, bone hyperplasia and pain, and to provide symptomatic relief in models of OA. Some of these modulators are currently being evaluated in clinical trials. This review explores the structures and functions of ion channels, including transient receptor potential channels, Piezo channels, voltage-gated sodium channels, voltage-dependent calcium channels, potassium channels, acid-sensing ion channels, chloride channels and the ATP-dependent P2XR channels in the osteoarthritic joint. The discussion spans channel-targeting drug discovery and potential clinical applications, emphasizing opportunities for further research, and underscoring the growing clinical impact of ion channel biology in OA. Ion channels have key functions in chondrocytes, bone cells, immune cells and neurons. Liu and colleagues discuss how these functions might contribute to cartilage degeneration, bone formation inflammation and pain in osteoarthritis, and highlight the therapeutic potential of ion channel modulators. Key points: Ion channels have key functions in the joints and emerge as important contributors to pathogenic processes in osteoarthritis (OA). Dysregulation of mechanical and biochemical stimuli activates ion channels such as TRPV4 and Piezo channels, leading to Ca2+ and Na+ influx, which contributes to cartilage destruction, inflammation and pain in OA. Some ion channels typically associated with peripheral neurons are also expressed in chondrocytes and immune cells, and have a crucial role in the pathophysiology of OA. Exploration of ion channel expression, interactions, and properties in joints, along with development of specific channel agonists and antagonists, has helped to accelerate research on their potential roles in OA. Several ion channel modulators have been recently tested in animal models and patients with OA, with encouraging results. Targeting of ion channels holds promise for the development of new and more effective OA treatment strategies. [ABSTRACT FROM AUTHOR]

Introduction: People who inject drugs (PWID) are one of the key populations most vulnerable to HIV infection, with 28 times higher prevalence compared to the rest of the population. PWID are known to have many physical, psychological and lifestyle challenges that can influence access to care. Depression is common among PWID living with HIV. It has major effect on health-related quality of life (HRQoL) and is influencing adherence to antiretroviral therapy. This study was conducted to explore how anxiety and depression affect HRQoL among HIVpositive PWID in Ukraine. It will provide knowledge for the further policy development. Methodology: A descriptive cross-sectional study using data from interviewer-administrated questionnaires was performed. The questionnaire was based on the Hospital Anxiety and Depression Scale. The questionnaire on HRQoL was based on the SF-36. Results: Among the 90 HIV positive PWID 74% (67) and 61% (55) had anxiety and depression scores higher than 7 respectively, indicating that most patients had mental health problems. Average scores for general health (40), role limitations due to physical (44) and emotional health (34), vitality (41) and mental health (45) had mean scores less than 50 along with total physical (43) and mental health scores (35). Having an HIV positive partner or partner with unknown HIV status increases anxiety in HIV positive PWID. Conclusion: There are increased depressive and anxiety symptoms and poorer QoL among HIV-positive PWID in Ukraine. Strategies focusing on psychosocial support addressing QoL as part of HIV care could improve health outcomes for these comorbid and debilitating conditions. [ABSTRACT FROM AUTHOR]

Abstract The present paper considers the problem of the low-temperature deposition of the hard coatings on the alloys having a low melting point and a high affinity for oxygen, like aluminum or magnesium alloys. It is demonstrated that a hard ZrN coating can be produced on the 2024 aluminum alloy by the low-temperature vacuum-arc deposition method. To achieve high adhesion strength between the coating and substrate, the substrate was sputtered by low-energy inert Ar+ ions before the deposition process in order to remove the natural oxide layer. The optimal technological regimes selected and used allowed obtaining the stoichiometric ZrN coating of extremely low roughness (0.061 μm), uniform thickness (~1 μm) with nano-scale columnar microstructure with the cross-sectional size of the columnar grains of ~20–50 nm. The layered microstructure of the obtained coating respectively consisted of the columnar and V-shaped grains in the lower and upper layers comes to be in the 'transition zone' on the 'structure-zone diagram'. The lower layers consist of a number of Al x Zr y phases along with the Zr 3 N 4 orthorhombic phase, while the outmost layer of the film contains the single ZrN fcc phase. In comparison with the substrate alloy, the produced ZrN coating is shown to possess the superior anti-corrosion properties in saline solution, a high hardness (~20 GPa) and elastic modulus (196 GPa), high adhesion strength both at the progressively increased load and at cyclic dry sliding of the conical diamond indenter with the 50 μm tip, low friction coefficients and high wear resistance at the reciprocating sliding both in the dry and wet (liquid paraffin) conditions against the conical diamond indenter with the 50 μm tip and 8 mm Si 3 N 4 ball, respectively. Highlights • Method of low-temperature arc deposition of hard coatings on the low melting point alloys • Preliminary sputtering by low-energy inert Ar+ ions for removing the natural oxide and achieving high coating/substrate adhesion • Vacuum arc deposited ZrN coating of 1 μm thick with nano-scale (20–50 nm) columnar microstructure • The ZrN coating of high hardness (~20 GPa) and wear resistance, and low friction and corrosion rate [ABSTRACT FROM AUTHOR]

The iron-containing layers were produced on the 2024 alloy surface using ultrasonic impact treatment (UIT) in the ambient air and argon environment. Multiple high-energy collisions of the pin of Armco-iron by the treated surface induce the iron cladding by means of solid-state welding of Fe dopants and Al substrate. SEM and EDX analysis and microhardness measurements showed a formation of oxide/intermetallic layers, which thickness ranges from 15–20 to 30–35 μm and hardness achieves ∼4 and ∼9 GPa after the argon-UIT and air-UIT processes, respectively. The polarisation tests in 3.5%NaCl medium showed that the layers are characterised by lower corrosion rates and more positive corrosion potentials than those of the original alloy owing to the formation of Alx-Feyintermetallics. The noblest behaviour was registered for the air-UIT-processed 2024 alloy. [ABSTRACT FROM AUTHOR]

The article provides more detailed study on the establishing and the initial phase of Grigoriy Vitalyevich Khlopin's scientific and hygienic school during the Yuriev period of his activity. Khlopin's Yuriev period was followed by his stay in Odessa, where he was joined also by some of his Yuriev students, including Alexander Rammul, Konstantin Dobrovolsky, and Ivan Brickman. The study includes several archival materials from the Moscow and Novorossiysk (Odessa) universities.

Objectives: LEUKOSPECT was a retrospective, multicenter, epidemiologic study carried out in Russia and Ukraine, aiming to assess the prevalence and cumulative 5-year incidence of chronic lymphocytic leukemia (CLL) in the adult population. Methods: All data were collected manually from patient medical records at each of the study sites and from official censuses. CLL prevalence and incidence were determined from a count of CLL cases (previously diagnosed and new cases) in the population who made at least one clinic visit for CLL during the period from 1 January 2009 to 31 December 2013. Results: The recorded cumulative 5-year incidence of CLL during the study ranged from 1.46 per 100 000 persons (95% CI: 0.85–2.34) in Yekaterinburg, Russia, to 4.34 per 100 000 persons (95% CI: 2.48–7.04) in Luhansk, Ukraine. In 2013, the lowest prevalence of CLL was also recorded in Yekaterinburg: 7.11 per 100 000 persons (95% CI: 5.67–8.81). This was approximately 3.1 times lower than in Luhansk (21.92 per 100 000 population; 95% CI: 17.38–27.28). Conclusion: The results of this study show diverse CLL incidence and prevalence patterns in the adult population of the Russian Federation and Ukraine. Authors propose a more comprehensive study with large region involvement to provide a more precise description of the incidence and prevalence of CLL in Eastern European countries and to better understand disparities reported versus the USA and other Western countries. [ABSTRACT FROM AUTHOR]

Scanning electron microscopy with energy dispersive X-ray microanalysis, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were employed to study the effect of mechanical treatment on the structure, morphology, surface chemical state, and composition of Ti6Al4V alloy. The ultrasonic impact treatment of Ti6Al4V in air with a duration ranging from 30 to 150 s was revealed to result in the build-up of an amorphous mixed oxide layer the thickness of which increased with treatment time, attaining a maximum value of about 12.3 μm. The mechanochemical oxidation of the alloy was accompanied by incorporation of nitrogen from the atmosphere and concurrent strong segregation of carbon atoms from the bulk to form dispersed nitride/oxynitride, carbide/oxycarbide, and oxycarbonitride phases. The nitrogen atoms, penetrating deep into the alloy, seemed to produce a nitrogen-enriched α-Ti(N) phase. Alongside with this, the material transfer from the hardened steel pin to the alloy was detected. At the oxide-metal interface, the oxidation induced segregation of Al, V and Fe was observed. The impact treatment of the alloy in air gave rise to an increase in the microhardness and improvement of tribological properties. A possible mechanism of mechanochemical oxidation of the alloy is suggested. [ABSTRACT FROM AUTHOR]

This paper reports our recent studies on structural changes of a brass alloy (Cu–37Zn) after sandblasting. Investigation of the alloy foils using transmission electron microscopy (TEM) obtained at different distance from the treated surface. The existence of three structural surface layers after sandblasting was shown. The upper surface layer about 5 μm, corresponds to nano-crystalline state, the second one, consisting of nano-crystalline, ultra-microcrystalline and microcrystalline grains with FCC and orthorhombic structure mixture, occurs deeper than 5 μm and reaches the depth of 30 μm. The third layer can be attributed to the FCC disoriented cellular structure with multi-layer stacking-faults. The parameters characterizing changes of the nano-crystalline grains and polygonal structures are given. The role of the structural changes from one layer to another is discussed. [ABSTRACT FROM AUTHOR]

Objective: Painful small fibre neuropathy (SFN) represents a significant public health problem, with no cause apparent in one-half of cases (termed idiopathic, I-SFN). Gain-of-function mutations of sodium channel NaV1.7 have recently been identified in nearly 30% of patients with biopsy-confirmed I-SFN. More recently, gain-of-function mutations of NaV1.8 have been found in patients with I-SFN. These NaV1.8 mutations accelerate recovery from inactivation, enhance the response to slow depolarisations, and enhance activation at the channel level, thereby producing hyperexcitability of small dorsal root ganglion (DRG) neurons, which include nociceptors, at the cellular level. Identification and functional profiling of additional NaV1.8 variants are necessary to determine the spectrum of changes in channel properties that underlie DRG neuron hyperexcitability in these patients.Methods: Two patients with painful SFN were evaluated by skin biopsy, quantitative sensory testing, nerve conduction studies, screening of genomic DNA for mutations in SCN9A and SCN10A and electrophysiological functional analysis.Results: A novel sodium channel NaV1.8 mutation G1662S was identified in both patients. Voltage-clamp analysis revealed that the NaV1.8/G1662S substitution impairs fast-inactivation, depolarising the midpoint (V1/2) by approximately 7 mV. Expression of G1662S mutant channels within DRG neurons rendered these cells hyperexcitable.Conclusions: We report for the first time a mutation of NaV1.8 which impairs inactivation, in patients with painful I-SFN. Together with our earlier results, our observations indicate that an array of NaV1.8 mutations, which affect channel function in multiple ways, can contribute to the pathophysiology of painful peripheral neuropathy. [ABSTRACT FROM AUTHOR]

Objective Painful small fibre neuropathy (SFN) represents a significant public health problem, with no cause apparent in one-half of cases (termed idiopathic, I-SFN). Gain-of-function mutations of sodium channel NaV1.7 have recently been identified in nearly 30% of patients with biopsy-confirmed I-SFN. More recently, gain-of-function mutations of NaV1.8 have been found in patients with I-SFN. These NaV1.8 mutations accelerate recovery from inactivation, enhance the response to slow depolarisations, and enhance activation at the channel level, thereby producing hyperexcitability of small dorsal root ganglion (DRG) neurons, which include nociceptors, at the cellular level. Identification and functional profiling of additional NaV1.8 variants are necessary to determine the spectrum of changes in channel properties that underlie DRG neuron hyperexcitability in these patients. Methods Two patients with painful SFN were evaluated by skin biopsy, quantitative sensory testing, nerve conduction studies, screening of genomic DNA for mutations in SCN9A and SCN10A and electrophysiological functional analysis. Results A novel sodium channel NaV1.8 mutation G1662S was identified in both patients. Voltage-clamp analysis revealed that the NaV1.8/G1662S substitution impairs fast-inactivation, depolarising the midpoint (V1/2) by approximately 7 mV. Expression of G1662S mutant channels within DRG neurons rendered these cells hyperexcitable. Conclusions We report for the first time a mutation of NaV1.8 which impairs inactivation, in patients with painful I-SFN. Together with our earlier results, our observations indicate that an array of NaV1.8 mutations, which affect channel function in multiple ways, can contribute to the pathophysiology of painful peripheral neuropathy. [ABSTRACT FROM AUTHOR]

The link between sodium channel Nav1.7 and pain has been strengthened by identification of gain-of-function mutations in patients with inherited erythromelalgia (IEM), a genetic model of neuropathic pain in humans. A firm mechanistic link to nociceptor dysfunction has been precluded because assessments of the effect of the mutations on nociceptor function have thus far depended on electrophysiological recordings from dorsal root ganglia (DRG) neurons transfected with wild-type (WT) or mutant Nav1.7 channels, which do not permit accurate calibration of the level of Nav1.7 channel expression. Here, we report an analysis of the function of WT Nav1.7 and IEM L858H mutation within small DRG neurons using dynamic-clamp. We describe the functional relationship between current threshold for action potential generation and the level of WT Nav1.7 conductance in primary nociceptive neurons and demonstrate the basis for hyperexcitability at physiologically relevant levels of L858H channel conductance. We demonstrate that the L858H mutation, when modeled using dynamic-clamp at physiological levels within DRG neurons, produces a dramatically enhanced persistent current, resulting in 27-fold amplification of net sodium influx during subthreshold depolarizations and even greater amplification during interspike intervals, which provide a mechanistic basis for reduced current threshold and enhanced action potential firing probability. These results show, for the first time, a linear correlation between the level of Nav1.7 conductance and current threshold in DRG neurons. Our observations demonstrate changes in sodium influx that provide a mechanistic link between the altered biophysical properties of a mutant Nav1.7 channel and nociceptor hyperexcitability underlying the pain phenotype in IEM. [ABSTRACT FROM AUTHOR]

Abstract: Osmoregulation in mammals is tightly controlled by the release of vasopressin and oxytocin from magnocellular neurosecretory cells (MSC) of the supraoptic nucleus (SON). The release of vasopressin and oxytocin in the neurohypophysis by axons of MSC is regulated by bursting activity of these neurons, which is influenced by multiple sources, including intrinsic membrane properties, paracrine contributions of glial cells, and extrinsic synaptic inputs. Previous work has shown that bursting activity of MSC is tetrodotoxin (TTX)-sensitive, and that TTX-S sodium channels Nav1.2, Nav1.6 and Nav1.7 are expressed by MSC and upregulated in response to osmotic challenge in rats. The TTX-resistant sodium channels, NaV1.8 and Nav1.9, are preferentially expressed, at relatively high levels, in peripheral neurons, where their properties are linked to repetitive firing and subthreshold electrogenesis, respectively, and are often referred to as “peripheral” sodium channels. Both sodium channels have been implicated in pain pathways, and are under study as potential therapeutic targets for pain medications which might be expected to have minimal CNS side effects. We show here, however, that Nav1.9 is expressed by vasopressin- and oxytocin-producing MSC of the rat supraoptic nucleus (SON). We also show that cultured MSC exhibit sodium currents that have characteristics of Nav1.9 channels. In contrast, Nav1.8 is not detectable in the SON. These results suggest that Nav1.9 may contribute to the firing pattern of MSC of the SON, and that careful assessment of hypothalamic function be performed as NaV1.9 blocking agents are studied as potential pain therapies. [Copyright &y& Elsevier]

Abstract: A Ni–ScSZ cermet is widely used as the anode in a solid oxide fuel cell because it possesses the appropriate electrochemical properties. However, it is susceptible to degradation during operation. Samples of a NiO–ScSZ composite were reduced in pure and diluted hydrogen to determine the microstructural evolution and the degradation behavior of the material. The resulting changes in microstructure were investigated using scanning transmission electron microscopy, X-ray energy dispersive spectroscopy and electron energy loss spectroscopy. The resulting data revealed that the various conditions during the reduction processes had a significant effect on the microstructures. The high porosity of the reduced nickel phase and cracking between the Ni and the ZrO2 phases after reduction resulted in a reduction in the strength of the anode material. [Copyright &y& Elsevier]

Voltage-gated potassium channel Kv10.2 (KCNH5) is expressed in the nervous system, but its functions and involvement in human disease are poorly understood. We studied a human Kv10.2 channel mutation (R327H) recently identified in a child with epileptic encephalopathy and autistic features. Using multistate structural modeling, we demonstrate that the Arg327 residue in the S4 helix of voltage-sensing domain has strong ionic interactions with negatively charged residues within the S1-S3 helices in the resting (closed) and early-activation state but not in the late-activation and fully-activated (open) state. The R327H mutation weakens ionic interactions between residue 327 and these negatively charged residues, thus favoring channel opening. Voltage-clamp analysis showed a strong hyperpolarizing (~70mV)shift of voltage dependence of activation and an acceleration of activation. Our results demonstrate the critical role of the Arg327 residue in stabilizing the channel closed state and explicate for the first time the structural and functional change of a Kv10.2 channel mutation associated with neurological disease. [ABSTRACT FROM AUTHOR]

Abstract: Sodium channel NaV1.7 is preferentially expressed in dorsal root ganglion (DRG) and sympathetic ganglion neurons. Gain-of-function NaV1.7 mutations/variants have been identified in the painful disorders inherited erythromelalgia and small-fiber neuropathy (SFN). DRG neurons transfected with these channel variants display depolarized resting potential, reduced current-threshold, increased firing-frequency and spontaneous firing. Whether the depolarizing shift in resting potential and enhanced spontaneous firing are due to persistent activity of variant channels, or to compensatory changes in other conductance(s) in response to expression of the variant channel, as shown in model systems, has not been studied. We examined the effect of wild-type NaV1.7 and a NaV1.7 mutant channel, D623N, associated with SFN, on resting potential and membrane potential during interspike intervals in DRG neurons. Resting potential in DRG neurons expressing D623N was depolarized compared to neurons expressing WT-NaV1.7. Exposure to TTX hyperpolarized resting potential by 7mV, increased current-threshold, decreased firing-frequency, and reduced NMDG-induced-hyperpolarization in DRG neurons expressing D623N. To assess the contribution of depolarized resting potential to DRG neuron excitability, we mimicked the mutant channel′s depolarizing effect by current injection to produce equivalent depolarization; the depolarization decreased current threshold and increased firing-frequency. Voltage-clamp using ramp or repetitive action potentials as commands showed that D623N channels enhance the TTX-sensitive inward current, persistent at subthreshold membrane voltages, as predicted by a Hodgkin–Huxley model. Our results demonstrate that a variant of NaV1.7 associated with painful neuropathy depolarizes resting membrane potential and produces an enhanced inward current during interspike intervals, thereby contributing to DRG neuron hyperexcitability. [Copyright &y& Elsevier]

The current work presents a one-step procedure for the synthesis of amphiphilic silver nanoparticles suitable for production of silver-filled polymeric materials. This solvent free synthesis via reduction of Tollens' reagent as silver precursor in melts of amphiphilic polyesters consisting of hydrophilic poly(ethylene glycol) blocks and hydrophobic alkyl chains allows the production of silver nanoparticles without any by-product formation. This makes them especially interesting for the production of medical devices with antimicrobial properties. In this article the influences of the chain length of the hydrophobic block in the amphiphilic polyesters and the process temperature on the particle size distribution (PSD) and the stability of the particles against agglomeration are discussed. According to the results of spectroscopic and viscosimetric investigations the silver precursor is reduced to elemental silver nanoparticles by a single electron transfer process from the poly(ethylene glycol) chain to the silver ion. [ABSTRACT FROM AUTHOR]

Some detailed astronomical and applied aspects deflection of hazardous near-Earth objects (NEO) by direct high concentrated sunlight, causing intensive local ablation of their surfaces, are considered. The major requirements to solar concentrating optics within a single collector (a large mirror) approach, along with the asteroid properties being most substantial in achieving the predetermined effect for the period less than a year (mid-thrust action), are discussed. Such a hastened strategy may become topical in the case of late detection of potential danger, and also, if required, in providing the possibility for some additional action. It is also more acceptable in the public perception and keeping the peace for mankind rather than a long-run expectation of the incorrigible deflection resulting shortly ahead of the predicted hazard. The conventional concave reflectors have been graved to be practically inapplicable within the high concentrating geometry. This is primarily because of the dramatic spread of their focal spots at needful inclinations of optical axis from the direction toward the Sun, as well as of problematic use of the secondary optics. An alternative design of a mirrored ring-array collector is presented (as a tested and approved point-focus version of innovative reflective lenses for sunlight concentration within this approach), and comparative analysis was made. The assessment argues in favor of such a type of high-aperture optics having more capabilities than conventional devices. Mainly, this is because of the underside position (as respects the entrance aperture) of its focal area that allows avoidance of target shadowing the reflecting surfaces and minimizes their coating by the ejected debris. By using the modern asteroids database, some key estimations have been obtained. The surface irradiance around 4-5 MW/m (average across the focal spot concentration level ~5 × 10) for the ring-array collector size ~0.5 of asteroid diameter might suffice to deflect a 0.5-km-diameter NEO during several months. For the larger diameter NEOs, to 1.3-2.2 km, the required collector sizes are about the asteroid diameters, and they are even greater for more massive objects. [ABSTRACT FROM AUTHOR]

Abstract: X-ray photoelectron spectroscopy and scanning electron microscopy with energy dispersive X-ray microanalysis were employed to study the effect of mechanical treatment on the surface chemical state, composition and morphology of commercial Tiyph name="sbnd" />4V alloy. It has been demonstrated that ultrasonic impact treatment of Tiyph name="sbnd" />4V in a liquid nitrogen (LN2) environment results in substantial grain refinement and formation of nitrides and oxynitrides of all the alloy components. The mechanochemical synthesis of the nitrides and oxynitrides from LN2 was found to efficiently occur not only within the impacted area but outside it as well. The layer with a high content of incorporated nitrogen and average atomic ratio N/Ti=0.94 was estimated to be at least ∼2μm thick. As a result of the combined effect of cryogenic deformation, nanoscale grain refinement and nitriding, a 3-fold increase in the microhardness of Tiyph name="sbnd" />4V alloy is obtained. The impact treatment in LN2 was observed to be accompanied by material transfer from the hardened steel pin to the alloy followed by incorporation of the pin components into Tiyph name="sbnd" />4V and formation of the Feglyph name="sbnd" />C and Ti/ce:simple-para> [Copyright &y& Elsevier]

The structure of Ceria doped Scandia Stabilized Zirconia (1Ce10ScSZ) electrolyte film deposited by EB-PVD (Electron Beam-Physical Vapour Deposition) technique on NiO-ZrO substrate was characterized by electron microscopy. The highly porous substrate was densely covered by deposited film without any spallation. The produced electrolyte layer was of a columnar structure with bushes, bundles of a diameter up to 30 μm and diverse height. Between the columns, delamination cracks of few microns length were visible. The annealing of zirconia film at 1000 °C resulted in its densification. The columnar grains and delaminating cracks changed their shape into a bit rounded. High magnification studies revealed nanopores 5-60 nm formed along the boundaries of the columnar grains during annealing. High-quality contacts between the electrolyte film and anode substrate ensured good conductivity of the electrolyte film and high efficiency of SOFC. [ABSTRACT FROM AUTHOR]

Although it is generally thought that sensory transduction occurs at or close to peripheral nerve endings, with action potentials subsequently propagating along the axons of dorsal root ganglia (DRG) neurons toward the central nervous system, the small diameter of nociceptive axons and their endings have made it difficult to estimate their membrane properties and electrogenic characteristics. Even the resting potentials of nociceptive axons are unknown. In this study, we developed the capability to record directly with patch-clamp electrodes from the small-diameter distal axons of DRG neurons in vitro. We showed using current-clamp recordings that 1) these sensory axons have a resting potential of -60.2 ± 1 mV; 2) both tetrodotoxin (TTX)-sensitive (TTX-S) and TTX-resistant (TTX-R) Na+ channels are present and available for activation at resting potential, at densities that can support action potential electrogenesis in these axons; 3) TTX-sensitive channels contribute to the amplification of small depolarizations that are subthreshold with respect to the action potential in these axons; 4) TTX-R channels can support the production of action potentials in these axons; and 5) these TTX-R channels can produce repetitive firing, even at depolarized membrane potentials where TTX-S channels are inactivated. Finally, using voltage-clamp recordings with an action potential as the command, we confirmed the presence of both TTX-S and TTX-R channels, which are activated sequentially during action potential in these axons. These results provide direct evidence for the presence of TTX-S and TTX-R Na+ channels that are functionally available at resting potential and contribute to electrogenesis in small-diameter afferent axons. [ABSTRACT FROM AUTHOR]

Tap-proof long-distance quantum communication requires a deep understanding of the strong losses in transmission channels. Here we provide a rigorous treatment of the effects of beam wandering, one of the leading disturbances in atmospheric channels, on the quantum properties of light. From first principles we derive the probability distribution of the beam transmissivity, with the aim to completely characterize the quantum state of light. It turns out that beam wandering may preserve nonclassical effects, such as entanglement, quadrature and photon number squeezing, much better than a standard attenuating channel of the same losses. [ABSTRACT FROM AUTHOR]

Abstract: The influence of the impulse laser irradiation (Nd:YAG laser λ =1.06μm) in an inert atmosphere (Ar) with different power density on the surface morphology of the dental Co–Cr–Mo alloy surface was studied. It is set that periodic ring relief appears at the modes of the treatment with melting and evaporation of the material. The analysis of the periodic structure main characteristics was performed. [Copyright &y& Elsevier]

Abstract: Electron Energy Loss Spectroscopy has been employed for investigation of the surface and bulk plasmon excitations versus heating in the Co–Cr–Mo alloy surface for the primary electron beam energies Е 0 ranging from 150 to 800 eV. For the annealed alloy the experimental values of the plasmon energy are localized at more energies as compared to the non–annealed alloy. It was established that heating of the alloy promotes to insignificant deviations of the plasmon excitations. Damping of the intensity line of surface plasmon with a increase of heating was established. Physical processes which can influence on the energy displacements of long wavelength plasmon oscillations and damping of surface plasmon in the characteristic loss spectra at heating are considered. [Copyright &y& Elsevier]

Abstract: Electron Energy Loss Spectroscopy has been employed for investigation of the electronic states of amorphous and crystalline Fe73.6Cu1Nb2.4Si15.8B7.2 (FINEMET) alloy surface and alloy components. Electron energy losses have been measured for primary electron beam energies E 0 from 150 to 650 eV. The characteristic energy loss spectra were composed of main peaks which we have interpreted due to surface and bulk plasmons, a combination of surface and bulk losses, high harmonics of plasma losses, inter-band transitions and ionization of core levels. The measured energies for the plasmon excitations were found not to agree with calculated values according to the classical theory for the collective oscillations in solids. Changes in the intensity lines of the surface and bulk plasmons were observed for all specimens depending on primary electron energy E 0. The present results are compared with characteristic energy loss data reported in the literature. [ABSTRACT FROM AUTHOR]

Transition-metal-catalyzed hydroformylation has become an essential tool for the synthesis of aldehydes. In this paper, we highlight several examples of synthetically useful applications of homogeneous and heterogeneous rhodium-catalyzed hydroformylation, as well as several examples of tandem processes involving hydroformylation as a reaction step developed in our laboratory. [ABSTRACT FROM AUTHOR]

Reductive allylation of aryl and alkenyl aldehydes with allyl acetate catalyzed by the ionic diamine carbonyl rhodium complex, [Rh(TMEDA)(CO)2][RhCl2(CO)2], under a carbon monoxide atmosphere afforded the corresponding homoallylic alcohols in good isolated yields. [ABSTRACT FROM AUTHOR]

Electron energy loss spectroscopy has been used for the investigation of the surface and bulk plasmon excitations depending on the heating in the ultra-thin layers of ordering Pt80Co20(111) alloy from the primary electron beam energies E0 ranging from 200 to 650 eV. Thermo-induced shift of plasmon energy and damping of intensity line of the surface plasmon relative to the bulk plasmon were observed. With an increase in alloy heating, the energy of surface and bulk plasmons is shifted with lowering energy in the whole range E0 and the higher the temperature the higher the shifts of plasmon energy. The physical processes that can influence on the energy shift of plasmon oscillations in the energy loss spectra at heating are considered. The relationship between the damping of oscillating concentration depth profile and the surface plasmon damping at heating was established. [ABSTRACT FROM AUTHOR]

Abstract: Ionization Spectroscopy has been used to study thermo-induced surface segregation in the near-surface region of the ternary Co–Cr–Mo alloy. For the non-annealed alloy the Mo atoms preferred segregation in the outermost layers and Cr atoms segregation in the underlying layers of surface was observed at room temperature. Heating of the alloy promotes increasing of Co concentration and decreasing of Mo concentration in the near-surface region. For the annealed alloy the insignificant Mo atoms segregation on the outermost layers and enrichment with Co and Cr atoms in underlayers are displayed. The present results are compared with several theories of segregation. [Copyright &y& Elsevier]

Abstract: The effect of periodic pulsed laser irradiation (λ =1.06μm and power density of 0.6–0.8×104 W/cm2) on the solid-phase reaction in thin-film Ni/Cu/Cr structure (each layer of 100nm thick) is studied by means of Auger electron spectroscopy and scanning electron microscopy. Thin-film structure is found to transform under irradiation into eutectic Cr–Ni structure with the particles of the leading Cr(Ni) phase having the radii equal to the total thickness of the film (300nm). Eutectic colonies of these particles form the surface microstructure which consists of periodic arc-shaped bands with bars between them. The laser-induced diffusion is shown to occur under the sign-variable temperature gradient (∼105 K/s), high deformation rate (∼20s−1), and large dislocation flow at low deformation degree (∼0.01). [Copyright &y& Elsevier]

Surface and bulk plasmon excitations from the ordering Pt80Co20(111) alloy surface are studied by means electron energy loss spectroscopy in the low energy range of the primary electron energy E0. Deviation of the plasmon excitations from the theoretical value was found for Pt, Co metals, and Pt80Co20(111) alloy as calculated in the free-electron gas model. For the ordered alloy, the bulk plasmon energy is 2–3 eV more than for the disordered alloy, whereas the difference for surface plasmon energy is 4–7 eV in the range E0 = 150–800 eV. The ration of intensity lines of plasmons η from E0 was investigated for the (dis)ordered state of the Pt80Co20(111) alloy surface. For the ordered alloy, η has prolonged dependence from energy E0 in comparison with the disordered alloy. The relationship between layer-by-layer surface concentration and surface plasmon damping was observed. [ABSTRACT FROM AUTHOR]

Abstract: The surface active properties of aqueous solutions of invertible amphiphilic alternated polyesters differing by hydrophilic–lipophilic balance (HLB) and molecular weight have been determined over the wide concentration range. The polyesters are based on poly(ethylene glycol) (PEG) of two molecular weights and aliphatic dicarboxylic acids (decanedioic and dodecanedioic). The surface activity of the polyesters and their ability to form micellar assemblies (which was recently shown for organic solvents) has been confirmed in water. The central role of the balance of hydrophilic to hydrophobic groups ratio in the formation of polymeric arrangements having hydrophobic pockets and external hydrophilic shell has been shown. The effect of molecular weight has been found considerable as well. Two changes in slope have been observed for the more hydrophobic polyesters in the surface tension vs log concentration curve. The change at low concentration is believed to originate from the formation of polyester assemblies with a hydrophobic interior and hydrophilic exterior due to the interaction of hydrophobic fragments and macromolecular flexibility. The higher concentration region exhibits behavior consistent with a cmc, which was confirmed by additional dye solubilization experiments. Molecular structure of the polyester micelles is determined by the solubilization of a solvatochromic dye. The experiment confirmed that micellization of polyesters is accompanied by the association of more hydrophobic (aliphatic) constituents forming the micelle interior. The hydrophilic fragments (ethylene oxide groups) are involved in the formation of micelle exterior. [Copyright &y& Elsevier]

Abstract: Nature of the characteristic electron energy losses in the second electron emission spectra from the ternary Co–Cr–Mo alloy surface are studied in the low energy range of the primary electron energy E 0. The main types of losses were found: surface and bulk plasmons and their hybrid modes, interband transitions and ionization losses. For Co, Cr, Mo and Co–Cr–Mo alloy the experimental values of the plasmon energy were established to be less than it was predicted by free-electron gas model. Excess of conductive electrons in the surface layers for Co, Cr and Mo was observed by dependence of the surface plasmon dispersion from E 0, while for Co–Cr–Mo alloy the situation is quit opposite. Such behavior is explained by the complex phase structure of the ternary alloy. The analysis of intensity lines of plasmons from E 0 showed deeply changed alloy profile. Ionization Spectroscopy was used for studying the alloy elements distributing on the depth. Mo atoms preferred segregation in the outermost layers of Co–Cr–Mo alloy and enrichment with Cr competitive atoms in underlayers is displayed. [Copyright &y& Elsevier]

The problem of the description of absorption and scattering losses in high- Q cavities is studied. The considerations are based on quantum noise theories, hence the unwanted noise associated with scattering and absorption is taken into account by introduction of additional damping and noise terms in the quantum Langevin equations and input-output relations. Completeness conditions for the description of the cavity models obtained in this way are studied and corresponding replacement schemes are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Electron energy-loss spectroscopy has been employed for investigation of the electronic structure of the metals Pd, Cu and the ordered Cu75Pd25(100) alloy surfaces. Electron energy losses have been collected using primary electron beam energies ranging from 150 to 800eV. All of the energy losses observed in these samples can be explained in terms of three types of loss mechanisms, namely, electronic transitions involving excited states, excitation of plasma oscillations and ionization of core levels. An essential deviation of the plasmon losses from the theoretical value as calculated on the basis of the free-electron gas model was found for Pd, Cu and the Cu75Pd25(100) alloy. Using analysis of the intensity of surface and bulk plasmons we can define the interval of primary electron energy Е 0, where the electron beam scans only the near surface region. Experimental data are compared with optical data obtained by LMTO–ASA calculations. [Copyright &y& Elsevier]

Abstract: In this paper, a method of Ionization Spectroscopy (IS) is proposed for the non-destructive layer-by-layer analysis of the elemental composition of a solid surface. Using ionization energy loss spectra, a layer-by-layer concentration profile of the Pt80Co20(111) alloy surface is obtained for different annealing temperatures. For the disordered Pt80Co20(111) at room temperature, the first atomic layer consists of pure Pt with damped oscillations in the deeper layers. Heating the sample reduces the oscillations. However, at a temperature of 823K, a sandwich-like structure of the type Pt/Co/Pt was found in the first three atomic layers. For the ordered state the first atomic layer also consists of pure Pt with bulk concentration in other layers. LEED analysis shows a p(2×2) superstructure for the surface of the ordered Pt80Co20(111) alloy. The segregation behavior in this alloy is further studied by Monte Carlo (MC) simulations combined with the Constant Bond Energy (CBE) model. The results of the MC simulations agree well with the experiments at the higher temperatures, both for the surface composition and the concentration depth profile. At lower temperatures, some discrepancies exist between the MC results and the measured concentration profile. [Copyright &y& Elsevier]

Abstract: Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was employed as an in situ tool to study the temperature-induced alteration of the surface composition of amorphous Finemet, Fe73Si15.8B7.2Cu1Nb3. Temperature was changed reversibly by cooling from room temperature to 118K and warming back to room temperature. As a general result, the ion intensities and, consequently, the surface concentrations of the alloy constituents were found to vary non-monotonously. Therefore segregation processes were in operation the extent of which was element-specific. Most importantly, while cycling the temperature hysteresis behaviour was observed with concentration of Fe developing just opposite to that of the alloying elements. Accordingly, on cooling the alloy, the surface enrichment with B, Si, Nb, Cu attained first a maximum in the range of 248–193K before the segregation changed the trend to establish appreciable depletion of these elements at 118K (as compared to room temperature). By contrast, the surface iron content developed inversely and decreased first to a minimum at ∼223K before reaching enrichment at 118K. During warming, a maximum segregation of boron and silicon was observed at about 223K – similar as on cooling – so that this temperature can be considered characteristic of the segregation process. Dissociative adsorption of water from the residual atmosphere occurring at low temperatures was responsible for the formation of surface hydroxides of iron, silicon and niobium; an enhanced adsorption of molecular water was observed at temperatures below 153K. The temperature-dependent segregation and adsorption–desorption processes were found to be largely reversible, so that the surface composition of Finemet was practically restored after finishing the cooling–warming cycle. The processes and factors governing the non-monotonous temperature dependence of the surface segregation in the amorphous alloy are discussed within the frame of segregation theory and the influence of temperature-induced tensile stress on segregation. [Copyright &y& Elsevier]

Abstract: Results of specific heat and thermal conductivity measurements performed on the ErCo2 and Er(Co0.95Si0.05)2 compounds are presented with the emphasis on the phenomena associated with the magnetic ordering transition and their evolution with varying the chemical composition and the applied magnetic field. From specific heat data the magnetocaloric effect (MCE) in a wide temperature interval around the transition has been evaluated for several values of magnetic field. The maximum determined size of MCE makes these materials potentially applicable in magnetic cooling. The sensitivity of the Curie temperature (T C) to the Si substitution for Co without any dramatic suppression of MCE offers an effective way for tuning the temperature range available for magnetocaloric applications. The pronounced sharp thermal-conductivity anomaly in ErCo2 in the vicinity of T C is nearly suppressed in Er(Co0.95Si0.05)2. The role of spin fluctuations in these phenomena is discussed. [Copyright &y& Elsevier]

Abstract: Electron energy loss spectroscopy has been employed for investigation of the effect of 600eV Ar+-ion irradiation in the dose range 7×1016–4×1017ions/cm2 on the atomic structure and surface composition of alloy Pt80Co20(111). A method of the layer-by-layer reconstruction of the lattice interplanar distance changes based on the analysis of the plasmon spectra excitation was proposed. The ion bombardment was shown to result in a non-monotonic variation of the lattice interplanar distance due to formation of the stable defects, with the topmost layer being in the state of compression. Using the ionization energy loss spectra, a layer-by-layer concentration profile of the alloy components was reconstructed for different doses of ion irradiation of the surface. The Ar+-ion bombardment of the alloy was found to result in the preferential sputtering of Co and in the enrichment of the near-surface region by Pt atoms with formation of an altered layer, which is characterized by a non-monotonic concentration profile dependent on the irradiation dose. The results obtained are discussed in the framework of the models of preferential sputtering and radiation-induced segregation. [Copyright &y& Elsevier]

The liquid crystal director-colloidal particle surface interaction in filled liquid crystals causes the thermally-induced director fluctuation correlations to be screened. This is consistent with the experimentally observed reduction in the thermal director fluctuation-induced Rayleigh light scattering in filled liquid crystals. The colloid-mesogen interaction also induces director non-uniformity in filled liquid crystals, thus further modifying the spatial dependence of the director fluctuation correlations, and shifts the critical temperature at which the isotropic phase loses its stability with respect to nematic fluctuations. The shift is specifically particle-size dependent, and this will enable the phenomenon to be recognized experimentally. [ABSTRACT FROM AUTHOR]