Signature of a silver phase percolation threshold in microscopically phase separated ternary Ge0.15Se0.85-xAgx (0 <= x <= 0.20) glasses

Temperature modulated Alternating Differential Scanning Calorimetric (ADSC) studies show that Se rich Ge0.15Se0.85-xAgx (0 <= x <= 0.20) glasses are microscopically phase separated, containing Ag2Se phases embedded in a Ge0.15Se0.85 backbone. With increasing silver concentration, Ag2Se phase percolates in the Ge-Se matrix, with a well-defined percolation threshold at x = 0.10. A signature of this percolation transition is shown up in the thermal behavior, as the appearance of two exothermic crystallization peaks. Density, molar volume and micro-hardness measurements, undertaken in the present study, also strongly support this view of percolation transition. The super-ionic conduction observed earlier in these glasses at higher silver proportions, is likely to be connected with the silver phase percolation.Comment: 4 pages, 7 figure

Синтез алкил-гем-дихлорциклопропанов на основе изоамиленовой фракции

Objectives. The study aims to analyze the dichlorocarbenation of the isoamylene fraction, which is a mixture of 2-methyl-butene-1 and 2-methyl-butene-2, in order to obtain the corresponding alkyl-gem-dichlorocyclopropanes in quantitative yield, and also to determine their structure.Methods. In order to determine the qualitative and quantitative composition of the reaction masses, the following analysis methods were used: gas-liquid chromatography (using the Crystal 2000 hardware complex), mass spectrometry (using a Chromatec-Crystal 5000M device with NIST 2012 database), and nuclear magnetic resonance (NMR) spectroscopy (using a Bruker AM-500 device at operating frequencies of 500 and 125 MHz).Results. Alkyl-gem-dichlorocyclopropanes were synthesized from an isoamylene fraction in the presence of catamine AB as a catalyst. Alternatively, isomeric alkenyl-gem-dichlorocyclopropanes were obtained on the basis of isoprene, and by reduction, the corresponding alkyl-gemdichlorocyclopropanes were synthesized. The synthesized substances were analyzed by gasliquid chromatography, mass spectrometry, and NMR spectroscopy, as previously mentioned above.Conclusions. The results show that the dichlorocyclopropanation of the isoamylene fraction proceeds quantitatively with the formation of a mixture of 2-methyl-2-ethyl-1,1dichlorocyclopropane and 2,3,3-trimethyl-1,1-dichlorocyclopropane. Using isoprene, countersynthesis through successive dichlorocarbenation and hydrogenation was used to synthesize 2-methyl-2-ethyl-1,1-dichlorocyclopropane, one of the products of dichlorocarbenation of the isoamylene fraction.Цели. Изучить дихлоркарбенирование изоамиленовой фракции, представляющей собой смесь 2-метил-бутена-1 и 2-метил-бутена-2, получить соответствующие алкил-гем-дихлорциклопропаны с количественным выходом и установить их строение.Методы. Для определения качественного и количественного состава реакционных масс были использованы газожидкостная хроматография (на аппаратно-программном комплексе «Кристалл 2000»), хроматомасс-спектрометрия (на приборе «Хроматэк-Кристалл 5000М» с базой NIST 2012), и спектроскопия ядерного магнитного резонанса (ЯМР-спектроскопия) (на приборе «Bruker AM-500» с рабочими частотами 500 и 125 МГц).Результаты. Алкил-гем-дихлорциклопропаны синтезированы из изоамиленовой фракции в присутствии катализатора катамина АВ. Альтернативным путем на основе изопрена получены изомерные алкенил-гем-дихлорциклопропаны, восстановлением которых синтезированы соответствующие алкил-гем-дихлорциклопропаны. Вещества проанализированы и доказаны методами газожидкостной хроматографии, хроматомасс-спектрометрии и ЯМР-спектроскопии.Выводы. Установлено, что дихлорциклопропанирование изоамиленовой фракции протекает количественно с образованием смеси 2-метил-2-этил-1,1-дихлорциклопропана и 2,3,3-триметил-1,1-дихлорциклопропана. С использованием изопрена встречным синтезом через последовательное дихлоркарбенирование и гидрирование был синтезирован 2-метил-2-этил-1,1-дихлорциклопропан – один из продуктов дихлоркарбенирования изоамиленовой фракции

Синтез и реакции алкенил-гем-дихлорциклопропанов на основе пиперилена

Objectives. This study aims to obtain alkenyl-gem-dichlorocyclopropanes from piperylene. The products are then subjected to thermocatalytic isomerization and hydrogenation.Methods. To determine the qualitative and quantitative composition of the reaction crudes, the following analytical methods were used: gas-liquid chromatography using the Crystal 2000 hardware complex, mass spectrometry using a Chromatec-Crystal 5000M device with the NIST 2012 database, and nuclear magnetic resonance (NMR) spectroscopy using a Bruker AM-500 device at operating frequencies of 500 and 125 MHz.Results. Alkenyl-gem-dichlorocyclopropanes were synthesized in the presence of triethylbenzyl ammonium chloride as catalyst. Their isomerization and hydrogenation gave the corresponding gem-dichlorocyclopentene and isomers of alkyl-gem-dichlorocyclopropanes. The structure of synthesized substances were analyzed by gas-liquid chromatography, mass spectrometry, and NMR spectroscopy.Conclusions. The results show that formation of four isomeric substituted gem-dichlorocyclopropanes occurs in high yield during incomplete dichlorocyclopropanation of piperylene. The thermocatalytic isomerization of substituted gem-dichlorocyclopropanes in the presence of SAPO-34 zeolite leads to the formation of one product, i.e., gem-dichlorocyclopentene, and hydrogenation of substituted gem-dichlorocyclopropanes in the presence of Pd/C catalyst gives three isomeric alkyl-gem-dichlorocyclopropanes.Цели. Получить алкенил-гем-дихлорциклопропаны на основе пиперилена, провести их термокаталитическую изомеризацию и гидрирование.Методы. Для определения качественного и количественного состава реакционных масс использованы следующие методы анализа: газожидкостная хроматография (на аппаратно-программном комплексе «Кристалл 2000»), хроматомасс-спектрометрия (на приборе «Хроматэк-Кристалл 5000М» с базой NIST 2012) и спектроскопия ядерного магнитного резонанса (ЯМР) (на приборе «Bruker AM-500» с рабочими частотами 500 и 125 МГц).Результаты. Алкенил-гем-дихлорциклопропаны синтезированы в присутствии катализатора триэтилбензиламмоний хлористый. Дальнейшей их изомеризацией и восстановлением получены соответствующие гем-дихлорциклопентен и изомеры алкил-гем-дихлорциклопропанов. Строение синтезированных веществ проанализировано и доказано методами газожидкостной хроматографии, масс-спектрометрии и ЯМР-спектроскопии.Выводы. Установлено, что неполное дихлорциклопропанирование пиперилена протекает количественно с образованием четырех изомерных замещенных гем-дихлорциклопропанов, при термокаталитической изомеризации которых в присутствии цеолита SAPO-34 происходит образование одного продукта – гем-дихлорциклопентена, а при их восстановлении с помощью катализатора Pd/C наблюдается образование трех изомерных алкил-гем-дихлорциклопропанов

Синтез простых эфиров, содержащих 1,3-диоксолановый и гем-дихлорциклопропановый фрагменты

Objectives. This study aimed to obtain ethers containing gem-dichlorocyclopropane and 1,3-dioxolane fragments and evaluate their cytotoxic properties against HEK293, SH-SY5Y, MCF-7, and A549 cell lines.Methods. The qualitative and quantitative compositions of the reaction masses were determined using mass spectrometry (using a Chromatek-Kristall 5000M device with the 2012 National Institute of Standards and Technology, USA database) and nuclear magnetic resonance spectroscopy (using a Bruker AM-500 device with operating frequencies of 500 and 125 MHz).Results. Ethers containing gem-dichlorocyclopropane and 1,3-dioxolane fragments were synthesized in the presence of a catamine AB catalyst. The structures of the obtained substances were confirmed using gas-liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectroscopy. The cytotoxicity of the esters was studied against HEK293, SH-SY5Y, MCF-7, and A549 cell lines.Conclusions. Ethers containing gem-dichlorocyclopropane and 1,3-dioxolane fragments were obtained in quantitative yields; however, only 4-{[(2,2-dichloro-3-{[(2,2-dichlorocyclopropyl) methoxy]methyl}cyclopropyl)methoxy]methyl}-2,2-dimethyl-1,3-dioxolane exhibited cytotoxic activity against HEK293, SH-SY5Y, MCF-7, and A549 cell lines. Цели. Получить простые эфиры, содержащие гем-дихлорциклопропановый и 1,3-диоксолановый фрагменты и оценить их цитотоксические свойства в отношении клеточных линий HEK293, SH-SY5Y, MCF-7 и A549.Методы. Для определения качественного и количественного состава реакционных масс были использованы следующие методы анализа: газожидкостная хроматография (на аппаратно-программном комплексе «Кристалл 2000»), масс-спектрометрия (на приборе «Хроматэк-Кристалл 5000М» с базой NIST 2012), и спектроскопия ядерного магнитного резонанса (ЯМР-спектроскопия) (на приборе «Bruker AM-500» с рабочими частотами 500 и 125 МГц).Результаты. Синтезированы простые эфиры, содержащие гем-дихлорциклопропановый и 1,3-диоксолановый фрагменты в присутствии катализатора катамина АВ. Строение полученных веществ было подтверждено с помощью газожидкостной хроматографии, масс-спектрометрии и ЯМР-спектроскопии. Для эфиров изучена цитотоксическая активность в отношении клеточных линий HEK293, SH-SY5Y, MCF-7 и A549.Выводы. С количественными выходами получены простые эфиры, содержащие гем-дихлорциклопропановый и 1,3-диоксолановый фрагменты. Установлено, что цитотоксическую активность в отношении клеточных линий HEK293, SH-SY5Y, MCF-7 и A549 среди ряда полученных соединений проявляет только 4-{[(2,2-дихлоро-3-{[(2,2-дихлорциклопропил)метокси]метил}циклопропил)метокси]метил}-2,2-диметил-1,3-диоксолан.

The Thermally Reversing Window in Ternary GexPxS1-2x glasses

GexPxS1-2x glasses in the compositional range 0.05 < x < 0.19 have been synthesized and examined in temperature modulated differential scanning calorimetry (MDSC) and Raman scattering experiments. Trends in the non-reversing enthalpy DHnr(x) near Tg show the term to almost vanish in the 0.090(5) < x < 0.135(5) range, and to increase by an order of magnitude at x < 0.09, and at x > 0.135. In analogy to previous results on chalcogenide glasses, we identify compositions at x < 0.09 to be elastically floppy, those in the 0.090 0.135 to be stressed rigid. MDSC results also show the DHnr term ages in the stressed-rigid and floppy phases but not in the intermediate phase. The intermediate phase is viewed to be a self-organized phase of a disordered network. It consists of at least four isostatically rigid local structures; corner-sharing GeS4, edge-sharing GeS2, pyramidal P(S1/2)3 and quasi-tetrahedral S=P(S1/2)3 units for which evidence comes from Raman scattering. The latter method also shows existence of P4S7 and P4S10 molecules in the glasses segregated from the backbone. These aspects of structure contribute to an intermediate phase that is significantly narrower in width than in corresponding selenide glasses.Comment: 1 PDF file has text, 9 figures and 3 table

Immunoglobulin, glucocorticoid, or combination therapy for multisystem inflammatory syndrome in children: a propensity-weighted cohort study

Background: Multisystem inflammatory syndrome in children (MIS-C), a hyperinflammatory condition associated with SARS-CoV-2 infection, has emerged as a serious illness in children worldwide. Immunoglobulin or glucocorticoids, or both, are currently recommended treatments. Methods: The Best Available Treatment Study evaluated immunomodulatory treatments for MIS-C in an international observational cohort. Analysis of the first 614 patients was previously reported. In this propensity-weighted cohort study, clinical and outcome data from children with suspected or proven MIS-C were collected onto a web-based Research Electronic Data Capture database. After excluding neonates and incomplete or duplicate records, inverse probability weighting was used to compare primary treatments with intravenous immunoglobulin, intravenous immunoglobulin plus glucocorticoids, or glucocorticoids alone, using intravenous immunoglobulin as the reference treatment. Primary outcomes were a composite of inotropic or ventilator support from the second day after treatment initiation, or death, and time to improvement on an ordinal clinical severity scale. Secondary outcomes included treatment escalation, clinical deterioration, fever, and coronary artery aneurysm occurrence and resolution. This study is registered with the ISRCTN registry, ISRCTN69546370. Findings: We enrolled 2101 children (aged 0 months to 19 years) with clinically diagnosed MIS-C from 39 countries between June 14, 2020, and April 25, 2022, and, following exclusions, 2009 patients were included for analysis (median age 8·0 years [IQR 4·2–11·4], 1191 [59·3%] male and 818 [40·7%] female, and 825 [41·1%] White). 680 (33·8%) patients received primary treatment with intravenous immunoglobulin, 698 (34·7%) with intravenous immunoglobulin plus glucocorticoids, 487 (24·2%) with glucocorticoids alone; 59 (2·9%) patients received other combinations, including biologicals, and 85 (4·2%) patients received no immunomodulators. There were no significant differences between treatments for primary outcomes for the 1586 patients with complete baseline and outcome data that were considered for primary analysis. Adjusted odds ratios for ventilation, inotropic support, or death were 1·09 (95% CI 0·75–1·58; corrected p value=1·00) for intravenous immunoglobulin plus glucocorticoids and 0·93 (0·58–1·47; corrected p value=1·00) for glucocorticoids alone, versus intravenous immunoglobulin alone. Adjusted average hazard ratios for time to improvement were 1·04 (95% CI 0·91–1·20; corrected p value=1·00) for intravenous immunoglobulin plus glucocorticoids, and 0·84 (0·70–1·00; corrected p value=0·22) for glucocorticoids alone, versus intravenous immunoglobulin alone. Treatment escalation was less frequent for intravenous immunoglobulin plus glucocorticoids (OR 0·15 [95% CI 0·11–0·20]; p<0·0001) and glucocorticoids alone (0·68 [0·50–0·93]; p=0·014) versus intravenous immunoglobulin alone. Persistent fever (from day 2 onward) was less common with intravenous immunoglobulin plus glucocorticoids compared with either intravenous immunoglobulin alone (OR 0·50 [95% CI 0·38–0·67]; p<0·0001) or glucocorticoids alone (0·63 [0·45–0·88]; p=0·0058). Coronary artery aneurysm occurrence and resolution did not differ significantly between treatment groups. Interpretation: Recovery rates, including occurrence and resolution of coronary artery aneurysms, were similar for primary treatment with intravenous immunoglobulin when compared to glucocorticoids or intravenous immunoglobulin plus glucocorticoids. Initial treatment with glucocorticoids appears to be a safe alternative to immunoglobulin or combined therapy, and might be advantageous in view of the cost and limited availability of intravenous immunoglobulin in many countries. Funding: Imperial College London, the European Union's Horizon 2020, Wellcome Trust, the Medical Research Foundation, UK National Institute for Health and Care Research, and National Institutes of Health

SiPM-matrix readout of two-phase argon detectors using electroluminescence in the visible and near infrared range

Proportional electroluminescence (EL) in noble gases is used in two-phase detectors for dark matter searches to record (in the gas phase) the ionization signal induced by particle scattering in the liquid phase. The “standard” EL mechanism is considered to be due to noble gas excimer emission in the vacuum ultraviolet (VUV). In addition, there are two alternative mechanisms, producing light in the visible and near infrared (NIR) ranges. The first is due to bremsstrahlung of electrons scattered on neutral atoms (“neutral bremsstrahlung”, NBrS). The second, responsible for electron avalanche scintillation in the NIR at higher electric fields, is due to transitions between excited atomic states. In this work, we have for the first time demonstrated two alternative techniques of the optical readout of two-phase argon detectors, in the visible and NIR range, using a silicon photomultiplier matrix and electroluminescence due to either neutral bremsstrahlung or avalanche scintillation. The amplitude yield and position resolution were measured for these readout techniques, which allowed to assess the detection threshold for electron and nuclear recoils in two-phase argon detectors for dark matter searches. To the best of our knowledge, this is the first practical application of the NBrS effect in detection science

Design and construction of a new detector to measure ultra-low radioactive-isotope contamination of argon

Large liquid argon detectors offer one of the best avenues for the detection of galactic weakly interacting massive particles (WIMPs) via their scattering on atomic nuclei. The liquid argon target allows exquisite discrimination between nuclear and electron recoil signals via pulse-shape discrimination of the scintillation signals. Atmospheric argon (AAr), however, has a naturally occurring radioactive isotope, 39Ar, a β emitter of cosmogenic origin. For large detectors, the atmospheric 39Ar activity poses pile-up concerns. The use of argon extracted from underground wells, deprived of 39Ar, is key to the physics potential of these experiments. The DarkSide-20k dark matter search experiment will operate a dual-phase time projection chamber with 50 tonnes of radio-pure underground argon (UAr), that was shown to be depleted of 39Ar with respect to AAr by a factor larger than 1400. Assessing the 39Ar content of the UAr during extraction is crucial for the success of DarkSide-20k, as well as for future experiments of the Global Argon Dark Matter Collaboration (GADMC). This will be carried out by the DArT in ArDM experiment, a small chamber made with extremely radio-pure materials that will be placed at the centre of the ArDM detector, in the Canfranc Underground Laboratory (LSC) in Spain. The ArDM LAr volume acts as an active veto for background radioactivity, mostly γ-rays from the ArDM detector materials and the surrounding rock. This article describes the DArT in ArDM project, including the chamber design and construction, and reviews the background required to achieve the expected performance of the detector

Immunoglobulin, glucocorticoid, or combination therapy for multisystem inflammatory syndrome in children: a propensity-weighted cohort study

Background Multisystem inflammatory syndrome in children (MIS-C), a hyperinflammatory condition associated with SARS-CoV-2 infection, has emerged as a serious illness in children worldwide. Immunoglobulin or glucocorticoids, or both, are currently recommended treatments. Methods The Best Available Treatment Study evaluated immunomodulatory treatments for MIS-C in an international observational cohort. Analysis of the first 614 patients was previously reported. In this propensity-weighted cohort study, clinical and outcome data from children with suspected or proven MIS-C were collected onto a web-based Research Electronic Data Capture database. After excluding neonates and incomplete or duplicate records, inverse probability weighting was used to compare primary treatments with intravenous immunoglobulin, intravenous immunoglobulin plus glucocorticoids, or glucocorticoids alone, using intravenous immunoglobulin as the reference treatment. Primary outcomes were a composite of inotropic or ventilator support from the second day after treatment initiation, or death, and time to improvement on an ordinal clinical severity scale. Secondary outcomes included treatment escalation, clinical deterioration, fever, and coronary artery aneurysm occurrence and resolution. This study is registered with the ISRCTN registry, ISRCTN69546370. Findings We enrolled 2101 children (aged 0 months to 19 years) with clinically diagnosed MIS-C from 39 countries between June 14, 2020, and April 25, 2022, and, following exclusions, 2009 patients were included for analysis (median age 8·0 years [IQR 4·2–11·4], 1191 [59·3%] male and 818 [40·7%] female, and 825 [41·1%] White). 680 (33·8%) patients received primary treatment with intravenous immunoglobulin, 698 (34·7%) with intravenous immunoglobulin plus glucocorticoids, 487 (24·2%) with glucocorticoids alone; 59 (2·9%) patients received other combinations, including biologicals, and 85 (4·2%) patients received no immunomodulators. There were no significant differences between treatments for primary outcomes for the 1586 patients with complete baseline and outcome data that were considered for primary analysis. Adjusted odds ratios for ventilation, inotropic support, or death were 1·09 (95% CI 0·75–1·58; corrected p value=1·00) for intravenous immunoglobulin plus glucocorticoids and 0·93 (0·58–1·47; corrected p value=1·00) for glucocorticoids alone, versus intravenous immunoglobulin alone. Adjusted average hazard ratios for time to improvement were 1·04 (95% CI 0·91–1·20; corrected p value=1·00) for intravenous immunoglobulin plus glucocorticoids, and 0·84 (0·70–1·00; corrected p value=0·22) for glucocorticoids alone, versus intravenous immunoglobulin alone. Treatment escalation was less frequent for intravenous immunoglobulin plus glucocorticoids (OR 0·15 [95% CI 0·11–0·20]; p<0·0001) and glucocorticoids alone (0·68 [0·50–0·93]; p=0·014) versus intravenous immunoglobulin alone. Persistent fever (from day 2 onward) was less common with intravenous immunoglobulin plus glucocorticoids compared with either intravenous immunoglobulin alone (OR 0·50 [95% CI 0·38–0·67]; p<0·0001) or glucocorticoids alone (0·63 [0·45–0·88]; p=0·0058). Coronary artery aneurysm occurrence and resolution did not differ significantly between treatment groups. Interpretation Recovery rates, including occurrence and resolution of coronary artery aneurysms, were similar for primary treatment with intravenous immunoglobulin when compared to glucocorticoids or intravenous immunoglobulin plus glucocorticoids. Initial treatment with glucocorticoids appears to be a safe alternative to immunoglobulin or combined therapy, and might be advantageous in view of the cost and limited availability of intravenous immunoglobulin in many countries. Funding Imperial College London, the European Union's Horizon 2020, Wellcome Trust, the Medical Research Foundation, UK National Institute for Health and Care Research, and National Institutes of Health