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AbstractIn this paper, we consider the Cayley regression problem of the cyclic groups and the dihedral groups. We give the sufficient and necessary conditions for the cyclic group ℤnto be a Cayley regression. Moreover, the dihedral group D2nis a 3-Cayley regression if n is a prime power.

Purpose: Parathyroid carcinoma (PC) is an endocrine malignancy with a poor prognosis. The tumour immune microenvironment is a critical factor influencing the outcomes of multiple cancer types. However, knowledge of the immune microenvironment in PC remains limited. Methods: The intratumoural density of immunocytes and the Ki-67 index were evaluated immunohistochemically in 51 PC patient samples and were compared with clinicopathological features and parafibromin staining results. The Kaplan–Meier method and Cox proportional hazards analysis were used to estimate the effects of these variables on clinical outcomes. Results: Intratumoural immunocyte density was not correlated with age, gender, urolithiasis, or palpation of a neck mass. The Ki-67 index was correlated with the intratumoural density of CD3+cells (P= 0.022) and CD8+cells (P= 0.021) and serum calcium levels (P= 0.022). In the intratumoural area of primary foci, Kaplan–Meier method showed that the risk factors associated with recurrence/metastasis were a low density of CD3+(P= 0.017), CD8+(P= 0.019) and CD45+cells (P= 0.047), a high density of CD163+cells (P= 0.003) and a high Ki-67 index (P= 0.004). Cox regression multivariate analysis revealed that CD163+cell density (hazard ratio (HR) 16.19, 95% confidence interval (CI) 1.99—131.66; P= 0.009) and CD8+cell density (HR 0.13, 95% CI 0.02—0.76, P= 0.024) were independent factors associated with PC relapse. Conclusion: The immune microenvironment is an important factor influencing the relapse of PC. The intratumoural density of CD3+, CD8+, CD45+, and CD163+immunocytes was correlated with disease-free survival (DFS) in patients with PC. Immunotherapy based on T lymphocytes or tumour-associated macrophages may be a promising treatment strategy.

It is not clear how coherent ordered nanoparticles affect characteristics of FCC⇌HCP martensitic transformation in disordered alloys. In this paper, the precipitations of coherent ordered nanoparticles and their effects on the FCC⇌HCP martensitic transformation were systematically investigated in a solution-treated Co24Ni6Si shape memory alloy. The results showed that both the coherent ordered L12structured and L11structured nanoparticles could precipitate even in the solution-treated Co24Ni6Si alloy followed by water quenching. The L12structured nanoparticles strongly hindered the occurrence of stress-induced HCP martensitic transformation and its reverse transformation, but their hindrance dramatically reduced with the decrease of size when below 1.5 nm. The coherent ordered nanoparticles did not convert the non-thermoelastic FCC⇌HCP martensitic transformation to the thermoelastic ones owing to the absence of group-subgroup relation between the parent phase and martensite. A maximal recovery strain of 6.7 % was obtained after only aging at 1073 K for 1 min. This value was 1∼2 % higher than the reported maximal ones in conventional FeMnSi-based alloys subjected to complicated thermomechanical treatments. The enhanced reversibility of HCP martensitic transformation could account for this larger recovery strain by the ultrafine coherent ordered L12structured nanoparticles.

Drugs that mimic prostacyclin appear to lower blood pressure in rats with preeclampsia. Preeclampsia is a complication of pregnancy in women characterized by high blood pressure, swelling, and mild kidney disease. Researchers induced a condition similar to preeclampsia in rats and then gave them intravenous infusions of drugs that mimic prostacyclin, a hormone that occurs naturally in the body. The drugs iloprost and cicaprost both lowered blood pressure in this animal model of preeclampsia. On the other hand, indomethacin, which inhibits an enzyme called cyclooxygenase, did not.

Predictions of the state-of-health (SOH) of Li-ion batteries is an important goal in the monitoring and management of electric vehicles. In recent years, a number of pure machine-learning methods have been proposed for such predictions. In this paper, we instead consider autoregression methods and embedding strategies, which are specifically tailored to time-series problems. For the first time, we comprehensively compare both linear and nonlinear approaches, including six deep learning architectures, autoregressive integrated moving average (ARIMA) models and seasonal ARIMA models. In particular, for the first time we introduce Gaussian process nonlinear autoregression (GPNAR) for SOH prediction and show that it is superior in terms of accuracy and computational costs to the other autoregressive approaches. On the basis of two different datasets, we also demonstrate that accurate early predictions of the end-of-life (based on 50% of the data) is achievable with GPNAR without the use of features, which keeps data acquisition and processing to a minimum. Finally, we show that GPNAR is capable of capturing seasonal trends such as regeneration without additional time-consuming data analyses. Comparisons to other state-of-the-art methods in the recent literature confirm the superior performance of GPNAR.

In this work we highlight the importance of radiative convection as a mixing mechanism in a large, ice‐free lake (Lake Michigan, USA), where solar heating of waters below the temperature of maximum density drives vertical convection during the vernal turnover. Measurements taken over a 2‐week period at a 55‐m deep site demonstrate the ability of radiative convection to mix the entire water column. Observations show a diurnal cycle in which solar heating drives a steady deepening of the convective mixed layer throughout the day (dHCML/dt= 12.8 m/hr), followed by surface‐cooling‐induced restratification during the night. Radiative convection is linked to a dramatic enhancement in turbulence characteristics, including both turbulent kinetic energy dissipation (ϵ: 10−9–10−7W/kg) and turbulent scalar diffusivity (Kz: 10−3–10−1m2/s), suggesting that radiative convection plays a major role in driving vertical mixing throughout the water column during the isothermalspring. When freshwater lakes fall below the temperature of maximum density (TMD≈4 °C), solar‐driven radiative convection can become a major source of turbulent mixing. As the sun heats near‐surface waters, the denser (warmer) waters sink rapidly throughout the water column, driving increased mixing and vertical transport. In the current paper, we highlight the importance of this mixing mechanism as observed during a 2‐week experiment at a 55‐m deep site in a large, ice‐free lake (Lake Michigan, USA). Observations demonstrate a daily cycle in which solar heating drives energetic, full water column mixing throughout the day, followed by significant surface cooling and restratification overnight. We show that radiative convection is linked to dramatic enhancements in turbulence characteristics. This suggests that convection plays a major role in setting spring mixing conditions throughout the Laurentian Great Lakes, with important implications for both biological and chemical species. This work represents one of the first observations of radiative convection in an ice‐free lake, providing important insight for other large midlatitude lakes. Radiative convection drives strong, deep mixing during the vernal turnover in a large, ice‐free lake (Lake Michigan)Temperature profiles show a diurnal cycle of full water column mixing each day followed by surface‐cooled restratification overnightRadiative convection is linked to a multiple‐order enhancement in turbulence characteristics, including both dissipation and diffusivity

Passenger leukocyte transfer from the donor lung to the recipient is intrinsically involved in acute rejection. Direct presentation of alloantigen expressed on donor leukocytes is recognized by recipient T cells, promoting acute cellular rejection. We utilized ex vivolung perfusion (EVLP) to study passenger leukocyte migration from donor lungs into the recipient and to evaluate the effects of donor leukocyte depletion prior to transplantation. For this purpose, female pigs received male left lungs either following 3 h of EVLP or retrieved using standard protocols. Recipients were monitored for 24 h and sequential samples were collected. EVLP‐reduced donor leukocyte transfer into the recipient and migration to recipient lymph nodes was markedly reduced. Recipient T cell infiltration of the donor lung was significantly diminished via EVLP. Donor leukocyte removal during EVLP reduces direct allorecognition and T cell priming, diminishing recipient T cell infiltration, the hallmark of acute rejection. In a randomized porcine lung transplant study, the authors demonstrate that ex vivolung perfusion reduces passenger leukocyte transfer from the donor to the recipient, which results in impaired recipient Tcell recruitment to the lung after transplantation.

ZnO has been regarded as a promising anode material for the next-generation lithium-ion battery. Unfortunately, the structure broken caused by the volume change of ZnO and the capacity degression due to the irreversible electrochemical reaction of ZnO still remain two major challenges. Here, we design a novel kind of in situ growth binder-free ZnO-based anodes via ZnO anchored on vertically aligned graphene. The composite anode retains physical integrity post cycling. Especially, the good conductivity of graphene and the ultrasmall size of ZnO particles help to produce a completely reversible electrochemical reaction of ZnO-based anode. The composite material exhibits a high capacity (810 mAh g–1), long cycle life, good cycle stability, and fast charge/discharge rate.

We analyze the dependence of attosecond streaked photoelectron spectra and photoemission time delays from valence band (VB) and 2p core-level (CL) states of a single-crystalline Mg(0001) thin film on the (i) modeling of the substrate electronic structure, (ii) electron mean free path (MFP), (iii) screening of the near-infrared (NIR) streaking laser field, and (iv) chirp of the attosecond extreme ultraviolet (XUV) pulse. Our quantum-mechanical numerical simulations predict streaked photoemission spectra that depend sensitively on the XUV chirp and weakly on the screening of the streaking laser field by the substrate. They furthermore show that streaking time delays for VB emission are relatively insensitive to the modeling of the initial quantum states, electron MFP, and NIR skin depth of the Mg substrate, in contrast to the stronger dependence of streaking time delays for 2p CL emission on these factors. [ABSTRACT FROM AUTHOR]

On‐site experiments on low temperature fuel cells revealed that water droplets tend to emerge into the gas channel at the corner. This motivates the present investigation on the effects of the location where water emerges from and the wettability of sidewall on the dynamic behaviour of liquid water in gas channel by numerical simulations that employ the volume‐of‐fluid method. A microchannel with a square cross‐section of 0.25 mm in width and a pore of 0.05 mm in diameter is adopted. The simulation results for different pore locations and wettabilities of sidewall show that the behaviour of water droplet only depends on the wettability of bottom wall when it emerges from the centreline without attaching to the sidewall and gains the highest pressure drop. When the emergence location shifts towards the corner, the water droplet unavoidably attaches to the sidewall and thus the wettability of sidewall is found to have significant effects on its dynamics: hydrophobic sidewall results in droplet detachment and fast removal with the highest pressure drop and the minimal water saturation, whereas hydrophilic sidewall leads to a water film and accumulation with the lowest pressure drop and the minimal water coverage on the bottom wall.

Oxygen transport in the porous gas diffusion layer (GDL), which is generally characterised by the oxygen effective diffusivity, is of great importance for the performance of proton exchange membrane fuel cells (PEMFCs). The determination of the oxygen effective diffusivity is challenging due to the complex structure of the porous GDL samples. In the present study, a two‐dimensional network consisting of arms and nodes is adopted to illustrate how oxygen effective diffusivity is affected by the GDL structure under the condition with/without water invasion. Water permeation in the network is simulated using the invasion percolation algorithm and oxygen transport in the arms is described by Fick's law. The simulation results reveal that oxygen effective diffusivity under dry condition decreases with increase in the network heterogeneity. With water permeation, the oxygen effective diffusivity goes to zero even though water saturation is rather less than unity. The critical water saturation, above which the oxygen effective diffusivity becomes zero, is found to decrease with increasing heterogeneity. To enhance oxygen transport, four different modified networks are introduced in the present study. It is found that the network with large arms in oxygen transport direction has the best oxygen and water transport properties.

Estrogen-dependent breast cancer (EDBC) is a kind of common malignant tumor in postmenopausal women with growing tendency in recent years. Aromatase (AR) is the key enzyme responsible for estrogen biosynthesis and has been considered as an important target for designing inhibitors as potent therapeutic agents for EDBC. AR inhibitors (AIs) are divided into steroidal and nonsteroidal compounds, and the latter shows high inhibitory potency against AR. This review summarizes recent advancement in nonsteroidal AIs.

A new parallel mechanism 1CCC–5SPS which has distance and angle constraints is introduced in this article. Degree of freedom and forward kinematic analysis of this new parallel mechanism are presented, in which four equivalent polynomial equations are obtained from the original six geometrical constraint equations. The Gröbner basis theory is used with the four equations and the problem of forward displacement is reduced to a 40th degree polynomial equation in a single unknown from a constructed 10 × 10 Sylvester's matrix which is small in size, from which 40 different locations of the moving platform can be derived. A numerical example confirms the efficiency of the procedure.

Chemical reaction knowledge is usually summarized and retrieved by chemists from references, journals, and reaction databases. To rigorously extract chemical reaction knowledge from large data sets, computer algorithms become much more important. This paper presents a new approach, superstructure searching (SSS) algorithm, for generic reaction retrieval. The algorithm considers all known reaction patterns from the targeted structure and assigns synthetic routes for new chemical compounds. This algorithm consists of screening, atom-by-atom comparison, and computation of R-groups' similarity.

Osmotic coefficients and counterion distribution functions of rodlike and flexible polyelectrolyte chains have been studied using molecular dynamics simulations of multichain systems with explicit counterions in salt-free solutions. Using the counterion density profile, we have verified different regimes in the phase diagram of rodlike and flexible chains predicted by the two-zone model of Deshkovski et al. The agreement between our simulation results and predictions of the two-zone model is reasonably good for weakly charged rodlike chains. However, for flexible chains our results for the distance dependence of the counterion density profile in different regions of the phase diagram are only in qualitative agreement with the predictions of the two-zone model. The osmotic coefficient changes nonmonotonically with polymer concentration, in agreement with predictions of the two-zone model. The osmotic coefficient decreases with increasing polymer concentration in dilute solutions of both rodlike and flexible polyelectrolytes. In semidilute solutions of flexible chains the osmotic coefficient is an increasing function of polymer concentration. We have found that position of the minimum in the osmotic coefficient is close to the overlap concentration.

We present the results of molecular dynamics simulations of polyelectrolyte solutions in near-Θ-solvent conditions for polymer backbone. Polyelectrolyte solutions are modeled as an ensemble of bead-spring chains of charged Lennard-Jones particles with explicit counterions. Simulations were performed for both fully and partially charged polyelectrolyte chains with the number of monomers N varying from 25 to 300 in the range of polymer concentrations covering both dilute and semidilute regime. Polyelectrolyte chains in dilute solutions are nonuniformly stretched with the projection of the linear monomer density onto the end-to-end vector increasing logarithmically from the middle of the chain. The simulation results for chain size dependence on the degree of polymerization at different polymer concentrations are in good qualitative agreement with predictions of the modified scaling model that takes into account nonuniform stretching of polyelectrolyte chains. In semidilute solutions we confirm that the correlation length is inversely proportional to the square root of polymer concentration. By measuring the bond angle correlation function, we have determined that polyelectrolyte chains can be viewed as flexible chains with the persistence length proportional to the correlation length. Our results for the concentration dependence of chain size Re on polymer concentration for the longest chains (N = 187 and N = 300) are approaching the power law c^-1/4, predicted by the scaling model of salt-free polyelectrolyte solutions.

To examine the association between HIV RNA levels, patterns of antiretroviral resistance, and neurologic status.

Abstract:  A single-camera coupled particle tracking velocimetry–laser-induced fluorescence (PTV–LIF) technique and validation results from an experiment in a neutrally buoyant turbulent round jet are presented. The single-camera implementation allows the use of a 12-bit 60 frame-per-second 1024 × 1024 pixel digital CCD camera capable of streaming images in real time to hard disk resulting in very accurate PTV and LIF with excellent spatial and temporal resolution. The technique is capable of determining the turbulent scalar flux, as well as the Reynolds stress and mean and fluctuating velocity and concentration fields. Details of dye choice, corrections for attenuation due to dye, particles and water, photobleaching, vignetting, CCD calibration, and illumination power and geometry corrections are presented. Detailed results from the validation experiment confirm the accuracy and resolution of the technique, and in particular, the ability to measure . Bootstrap 95% uncertainty intervals are presented for the calculated statistics.

Technical advancements in ultrasonography, contrast-enhanced computed tomography and magnetic resonance imaging, as well as the wider availability of these ultramodern imaging techniques, have resulted in the early detection and a better classification of various asymptomatic and symptomatic pancreatico-biliary lesions. Pre-malignant biliary and pancreatic lesions are rare disorders, and no clear data are available to define their malignant potential. Because of the lack of controlled epidemiological data, the time span for malignant transformation and its frequency cannot be defined in the majority of these lesions. Adenomyomatosis of the gallbladder and gallbladder polyps larger than 10mm should be treated by cholecystectomy even in asymptomatic patients because of an increased risk of malignant transformation. Chronic cholangitis, primary sclerosing cholangitis and choledochal cysts are also pre-malignant conditions. The timing of surgery, once it is advised for a pre-malignant condition that is still benign, should, however, be individualized to the particular patient situation. In patients with chronic pancreatitis, surgery may be indicated for disease-related complications. In as much as chronic pancreatitis predisposes to a higher risk of pancreatic cancer, any suspicion of malignancy should warrant a surgical exploration. Intraductal papillary tumours and mucin-producing pancreatic tumours are other pre-malignant pancreatic lesions whose malignant potential cannot be precisely determined pre-operatively. They should be resected in situations where there is a high degree of suspicion even without a clear objective diagnosis. In conclusion, pre-malignant hepato-biliary and pancreatic lesions of uncertain pathology should undergo early resection in view of treatment limitations and the dismal prognosis of established cancers. While hepato-biliary and pancreatic surgery is nowadays performed in specialized centres, with a low post-operative morbidity and mortality, it is equally important to understand that observation alone with regular computed tomography or magnetic resonance imaging control can no longer be recommended in the management of these lesions.

Eleven maleic acid derivatives are synthesized and authenticated, then used as wool protective agents for dyeing wool at 120°C with Isolan Red S-RL. The protective effects are evaluated in terms of tensile properties (initial modulus, tensile strength, extension at break, and work to rupture) for both conditioned and wet-state fabrics, chemical damage is assessed in terms of alkali solubility, and hygral expansion is also measured. N-naphthyl and trifluorophenyl maleamic acid and N-benzyl and N-trifluorophenyl maleimides pro vide beneficial effects in terms of increased tensile strength, reduced hygral expansion, and minimal yellowing. However, N-benzyl and N-trifluorophenyl maleimides produce higher alkali solubilities. These results are in contrast to those for Irgasol HTW NEW treated wool, which has relatively low alkali solubility yet higher hygral expansion and poorer tensile properties.

Molecular dynamics simulations of a single-chain polystyrene particle adsorbed on the substrate surface of silicon were investigated. The particles, with various molecular weights, were prepared from the initial conformation of a Flory state coil after a 1000 ps dynamics run at 300 K. The morphology of the single-chain particles on the surface and the process from the Flory state to the collapse regime in vacuum were examined. It was found that the height of the particles depends weakly on molecular weight, and the particles have an irregular shape, findings which are in good agreement with experiment observations. A simulated heating process for a polystyrene particle of 100 repeat units adsorbed on the surface was performed from 320 up to 460 K with a heating rate of 20 K/ns for 8 ns. When the temperature is lower than 400 K, the particle shape tends to round with time. The results correspond to the AFM observation of single-chain PMMA particles with a long period of standing at room temperature. When the temperature is higher than 400 K, it is found that the particle tends to spread on the surface with a heat release of about 400 kJ/mol chain.

The densities, kinematic viscosities, and specific conductances of mixtures of benzene with the Lewis acidic room-temperature chloroaluminate molten salt aluminum chloride + 1-methyl-3-ethylimidazolium chloride (AlCl3 + MeEtimCl) were determined at 298.2 K. Benzene was added to melts containing 51.00, 60.00, and 66.67 mol % AlCl3. Simple polynomial equations were fitted to the experimental results as a function of the mass fraction of benzene. The addition of small amounts of benzene resulted in a decrease in the kinematic viscosity and an increase in the specific conductance of the mixture. However, the addition of benzene beyond 35 mass % caused the specific conductance to decrease due to a decrease in the concentration of charge-carrying ions.

Treatment of pregnant rats with the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), has been shown to produce symptoms similar to pre-eclampsia (i.e. elevated blood pressure, proteinuria and fetal growth retardation). After L-NAME infusion is initiated on day 17 or 18 of gestation, the blood pressure proceeds in a biphasic pattern (immediate rise, followed by a decline, then increasing again in the post-partum period). The blood pressure actually begins to rise prior to delivery on days 21-22, i.e. after progesterone withdrawal occurs, suggesting that these responses may be regulated by changes in steroid hormone concentrations during pregnancy. Therefore, we evaluated the effects of the different steroid hormones: progestins (progesterone, promegestone, levonorgestrel), antiprogestins (mifepristone), 17 beta-oestradiol or androgens (testosterone, dihydrotestosterone) on systolic blood pressure in pregnant, non-pregnant female and normal male rats with and without L-NAME treatment and spontaneously hypertensive male rats. The animals received continuous infusions of L-NAME (150 mg/kg/day) or vehicle through osmotic mini-pumps and daily s.c. injections of steroid hormones. In pregnant rats the pump was inserted on day 17 or 18 of gestation and steroid hormone injections were started on the first day following delivery at term and continued daily until post-partum day 10. In non-pregnant female or male rats steroid hormone injections were initiated 5 days after the L-NAME pump was inserted. Systolic blood pressure was measured daily from the tail with a pneumatic tail-cuff device. R5020 (1.5 mg/kg/day) significantly attenuated the blood pressure elevation induced by L-NAME during the post-partum period. Similarly, it lowered blood pressure in L-NAME treated non-pregnant female rats or male rats. R5020 also lowered blood pressure in spontaneously hypertensive male rats. Progesterone (6 mg/kg/day) had similar effects on blood pressure in the post-partum period, although it also lowered the blood pressure in control animals. Interestingly, administration of two different doses of levonorgestrel (0.3 and 1.5 mg/kg/day) did not decrease the blood pressure in either L-NAME-infused rats or controls. Mifepristone (RU486, 30 mg/kg/day) further increased blood pressure in L-NAME-treated rats post-partum. 17 beta-oestradiol (30 micrograms/kg/day) had no effect on blood pressure in either L-NAME infused rats in the post-partum period or controls, whereas both testosterone (0.3 mg/kg/day) and dihydrotestosterone (0.3 mg/kg/day) significantly attenuated the blood pressure increase after L-NAME, while raising the blood pressure in vehicle-infused animals. These results suggest that the control of systemic blood pressure during pregnancy may be modulated by steroid hormones. Progesterone may be the steroid hormone with the major action on vascular tension during pregnancy.

Presented is the forward positional (kinematic) solution for the general case of the 4–6 in-parallel platform mechanism; in particular, the spherical joints of the moving and base platforms are not restricted to lie in planes, but can be freely chosen. The forward positional analysis consists of 13 equations which are reduced to a single thirty-second order polynomial equation in one unknown variable. This new equation is numerically solved and validated by substituting the 32 roots into the 13 forward positional equations. The new analysis is also used to solve an example, with a set of known results from a previously published paper, in which a special case of the 4–6 in-parallel platform is considered; the results are in exact agreement. For a number of general platform and actuator inputs a maximum of 24 real solutions have been found. One example is illustrated.

Chemical induction of mammary tumors in mice requires usually a long latency period and is often complicated by high non-mammary tumor related mortality. Classically hormone stimulation has been used as the means to increase tumor incidence. The synthetic progestin medroxyprogesterone acetate (MPA) was postulated by some authors to increase mammary tumor incidence in various rodent models. However, controversy exists regarding the role of MPA in experimental and human carcinogenesis. In our study we tested the use of a protocol of combined MPA- and dimethylbenz[a]anthracene (DMBA) treatment for the obtention of mammary tumors with a short latency and with a lower toxicity than the classical multiple dose DMBA protocol. MPA was very effective in accelerating the development and increasing the incidence of mammary tumors induced by DMBA in CD2F1 mice. MPA by itself did not produce any mammary tumors. The mean latency for tumor development from the end of carcinogen treatment was 99 +/- 51 days in the group that received a combination of MPA and four DMBA doses. This group showed significantly earlier mammary tumor incidence (P < 0.0001) and higher tumor numbers than the groups that received only DMBA. Mammary tumors were also analyzed for effects on the mutation rate affecting the Ha-ras and Ki-ras genes. Our data is consistent with MPA probably increasing the number of target cells at risk for mutation by the chemical carcinogen DMBA and possibly promoting the faster development of tumors.

The global distribution and variations of the monthly mesopause temperature are presented during 2002–2019 covering the latitudes of 83°S to 83°N based on Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) observations. To investigate the long‐term trend and solar response of the mesopause temperature, a three‐component harmonic fit is first applied to remove the seasonal variation from the monthly temperature data series. Then a multiple linear regression model is performed to residual temperatures versus constant, linear trend, solar activity, and geomagnetic activity terms. In this study, the mesopause temperature shows a cooling trend through all latitudes ranging from ~0 to −0.14 K/year with a mean of −0.075 ± 0.043 K/year. The cooling trends in the Southern Hemisphere are stronger than those in the Northern Hemisphere. For high latitudes (60–80°), significant negative trends can be observed during nonsummertime, while no significant trends are found for summertime. The mesopause temperature shows apparent positive responses to solar activity through all latitudes ranging from 3.03 to 4.80 K per 100 solar flux units (sfu) with a mean of 3.99 ± 0.49 K per 100 sfu, which is more significant and stable in the Northern Hemisphere. There is a pronounced drop for mesopause height at polar latitudes, which reflects the shrinking effect at lower altitudes mainly caused by greenhouse gas cooling. We show that the length of the time interval analyzed strongly influences the results. Our results, obtained from 18‐year SABER observations, are expected to be a robust measure of the mesopause temperature variability. The mesopause temperature during 2002–2019 shows a cooling trend through all latitudes ranging from ~0 to −0.14 K/yearThe mesopause temperature shows a positive response to solar activity through all latitudes ranging from 3.03 to 4.80 K per 100 sfuA sufficiently long time interval is necessary for such analyses

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The use of MeLi instead fo BuLi in the first reaction step shifts the product ratio markedly to the epoxide (V); thus, the ratio of (IVa):(Va) with MeLi is 2:51.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Olefination of the ketones (IV) with the arsonium ylide, generated from the silylated propargylic arsonium bromide (III), yields the ω‐silyl enynes (V).

Phase‐transfer reaction of the arsonium ylide (II), obtained from the arsonium salt (I) and aqueous sodium hydroxide, with the chalcones (III) leads to the stereoselective formation of the (trimethylsilyl)‐(cyclopropyl)acetylenes (IV).