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Endogenous hydrogen sulfide (H2S) produced by cystathionine β-synthase (CBS) and cystathionine-γ lyase (CSE) has emerged as a novel uterine vasodilator contributing to pregnancy-associated increases in uterine blood flow, which safeguard pregnancy health. Uterine artery (UA) H2S production is stimulated via exogenous estrogen replacement and is associated with elevated endogenous estrogens during pregnancy through the selective upregulation of CBS without altering CSE. However, how endogenous estrogens regulate uterine artery CBS expression in pregnancy is unknown. This study was conducted to test a hypothesis that endogenous estrogens selectively stimulate UA CBS expression via specific estrogen receptors (ER). Treatment with E2β (0.01 to 100 nM) stimulated CBS but not CSE mRNA in organ cultures of fresh UA rings from both NP and P (gestational day 20, GD20) rats, with greater responses to all doses of E2β tested in P vs. NP UA. ER antagonist ICI 182,780 (ICI, 1 µM) completely attenuated E2β-stimulated CBS mRNA in both NP and P rat UA. Subcutaneous injection with ICI 182,780 (0.3 mg/rat) of GD19 P rats for 24 h significantly inhibited UA CBS but not mRNA expression, consistent with reduced endothelial and smooth muscle cell CBS (but not CSE) protein. ICI did not alter mesenteric and renal artery CBS and CSE mRNA. In addition, ICI decreased endothelial nitric oxide synthase mRNA in UA but not in mesenteric or renal arteries. Thus, pregnancy-augmented UA CBS/H2S production is mediated by the actions of endogenous estrogens via specific ER in pregnant rats.

Objective Establish an animal model of preeclampsia in goats, collect data on various physiological indicators and maternal biological characteristics of the disease model to compare with clinical feature of the disease in humans, provide reference for the prevention and treatment of preeclampsia in humans. Methods Twenty-three goats bred in Chongming district were divided into three groups: Control group, no surgical procedure was performed on animals of this group; sham group, ewes in this group underwent the sham operation on the 100±5th day of gestation, and only the uterine artery was exposed and dissociated; surgical group, a silver vascular clamp was clipped on one side of the uterine body artery of the ewe to narrow the inner diameter of the artery at the same gestation period (100±5) days. Heart rate and hindlimb blood pressure were continuously monitored in control and surgical ewes from 100 to 140 d of gestation, and blood flow data within the lateral branches of the uterine arteries of ewes in the sham group were collected using a hemodynamometer in combination with a hemodynamic probe and an animal physiological signal collector, as well as changes in blood flow within the uterine arteries in the lateral branches of the uterine arteries of the surgical group before and after placement of vascular clips in the surgical ewes. At the expected date of delivery, jugular vein blood was taken from ewes for routine blood test, creatinine, urea nitrogen, and blood ion analysis; urine was also collected from ewes in each group for analysis of urinary protein and urinary creatinine. All experimental groups were subjected to cesarean section on the 140±5th day of gestation in ewes, and then liver, kidney, uterus and placenta tissues were taken from ewes in each group and stained with HE for pathological observation.Results After 15 minutes of preeclampsia modeling surgery, blood flow volume remained stable in the vessel stenosis segment and the volume differential was relatively reduced in comparison to the control group and sham group (P＜0.05，P＜0.01). Compared with the control group, the ewes in the surgical group showed prenatal changes such as increased serum osmolality, decreased hemoglobin, increased blood glucose and urea nitrogen values, as well as increased levels of calcium, sodium, and chloride ions (all P

The existing research on the spontaneous combustion characteristics of oxidized coal is mostly based on the coal samples prepared under the conditions of lower oxidation temperature and air. It lacks the analysis of the kinetic characteristics during the oxidation process of oxidized coal. In order to solve the above problems, the C80 microcalorimeter is used to study the exothermic and kinetic characteristics of low-temperature oxidation reaction of preoxidized coal prepared under different oxidation temperatures (100, 200, 300 ℃) and oxygen volume fraction (21%, 15%, 5%). The effects of oxidation temperature and oxygen concentration on the activation energy of low-temperature oxidation reaction of preoxidized coal are discussed. The analysis results of low-temperature oxidation exothermic characteristics of preoxidized coal are shown as follows. ① The low-temperature oxidation process of preoxidized coal lags behind that of raw coal. The degree of lag increases with the increase of oxidation temperature and oxygen concentration. ② The heat release of low-temperature oxidation reaction of preoxidized coal is lower than that of raw coal. The heat release gradually decreases with the increase of oxidation temperature and oxygen concentration. When the oxidation temperature is 100 ℃, t1 (the temperature at which the heat flow value starts ＞0), t2 (the temperature corresponding to the maximum growth rate of heat flow value) and the reaction heat of low-temperature oxidation of preoxidized coals with different oxygen concentrations are basically equal. ③ With the increase of oxidation temperature, the effect of oxygen concentration on t1, t2 and the reaction heat of low-temperature oxidation is gradually obvious. The results show that the effect of oxygen concentration on the low-temperature oxidation reaction of preoxidized coal is only reflected at higher oxidation temperatures. However, too high oxidation temperature will lead to a serious lag of the low-temperature oxidation reaction process of pre-oxidized coal and the reaction heat release is less than 0. The analysis results of kinetic parameters (activation energy and pre-exponential factor) of low-temperature oxidation of pre-oxidized coal are shown as follows. ① The activation energy of the low-temperature oxidation reaction of pre-oxidized coal in the accelerated oxidation stage is higher than that of raw coal. The activation energy of the rapid oxidation stage is lower than that of raw coal. The results show that the threshold of the oxidation reaction of pre-oxidized coal entering the accelerated oxidation stage is increased, but it is easier to enter the rapid oxidation stage. ② The pre-exponential factor data show that the low-temperature oxidation reaction of pre-oxidized coal is more rapid than that of raw coal. ③ The changes of oxidation temperature and oxygen concentration have no obvious regularity with the activation energy of the low-temperature oxidation process of preoxidized coal. In the accelerated oxidation stage, the activation energy increases with the increase of oxidation temperature. The activation energy first decreases and then increases with the increase of oxygen concentration. In the rapid oxidation stage, when the oxidation temperature is 100 ℃, the activation energy first decreases and then increases with the increase of oxygen concentration, while 200 ℃ is the opposite.

Network function virtualization (NFV) has been proposed to enable flexible management and deployment of the network service in cloud. In NFV architecture, a network service needs to invoke several service functions (SFs) in a particular order following the service chain function. The placement of SFs has significant impact on the performance of network services. However, stochastic nature of the network service arrivals and departures as well as meeting the end-to-end Quality of Service(QoS) makes the SFs placement problem even more challenging. In this paper, we firstly provide a system architecture for the SFs placement of cloud service with end-to-end QoS deadline. We then formulate the end-to-end service placement as a Markov decision process (MDP) which aims to minimize the placement cost and the end-to-end delay. In our MDP, the end-to-end delay of active services in the network is considered to be the state of the system, and the placement (nonplacement or placement) of SF is considered as the action. Also, we discuss the rationality of our analytical model by analyzing the Markov stochastic property of the end-to-end service placement. To obtain the optimal placement policy, we then propose an algorithm (Algorithm 1) for dynamic SFs placement based on our model and use successive approximations, i.e. |$\epsilon $| -iteration algorithm (Algorithm 2) to obtain action distribution. Finally, we evaluate the proposed MDP by comparing our optimal method with DDQP, DRL-QOR, MinPath and MinDelay for QoS optimization, including acceptance probability, average delay, resource utilization, load-balancing and reliability. [ABSTRACT FROM AUTHOR]

The emergence of optical communications has opened up new perspectives for high‐capacity data transmission and signal processing, to meet the demand of the increasing data traffic. Despite significant progress in multi‐dimensional multiplexing for capacity scaling in fiber–optic communications or photonic networks‐on‐chip, achieving high‐capacity data transmission and signal processing in an entire fiber–chip–fiber system remains a great challenge. This challenge is attributed to the lack of effective multi‐dimensional coupling between fiber and chip. Here, the 3D (de)multiplexing SiO2 chip inscribed by femtosecond laser direct writing is proposed to achieve the multi‐dimensional coupling between the few‐mode fiber (FMF) transmission link and the silicon processing network. Combined with the 2D silicon chip fabricated by a standard lithography process, a multi‐dimensional fiber–chip–fiber communication system designed to transmit and process the hybrid wavelength‐, mode‐ and polarization‐division multiplexing signals in FMF is constructed. The silicon chip integrates Mach–Zehnder interferometer (MZI) switches and arrayed‐waveguide gratings (AWGs) to serve as a reconfigurable optical add/drop multiplexer (ROADM). As a proof‐of‐concept demonstration, a 96‐channel FMF–chip–FMF communication system with a data transmission capacity of 4.032 Tbit s−1, achieving a bit‐error ratio (BER) of less than 3.8 × 10−3, is successfully implemented. [ABSTRACT FROM AUTHOR]