In-orbit dark count rate performance and radiation damage high-temperature annealing of silicon avalanche photodiode single-photon detectors of the Micius satellite

Silicon avalanche photodiode (APD) single-photon detectors in space are continuously affected by radiation, which gradually degrades their dark count performance. From August 2016 to June 2023, we conducted approximately seven years (2507 days) of in-orbit monitoring of the dark count performance of APD single-photon detectors on the Micius Quantum Science Experimental Satellite. The results showed that due to radiation effects, the dark count growth rate was approximately 6.79 cps/day @ -24 °C and 0.37 cps/day @ -55 °C, with a significant suppression effect on radiation-induced dark counts at lower operating temperature. Based on the proposed radiation damage induced dark count annealing model, simulations were conducted for the in-orbit dark counts of the detector, the simulation results are consistent with in-orbit test data. In May 2022, four of these detectors underwent a cumulative 5.7 hours high-temperature annealing test at 76 °C, dark count rate shows no measurable changes, consistent with annealing model. As of now, these ten APD single-photon detectors on the Micius Quantum Science Experimental Satellite have been in operation for approximately 2507 days and are still functioning properly, providing valuable experience for the future long-term space applications of silicon APD single-photon detectors.

Time transfer over 113 km free space laser communication channel

The space time frequency transfer plays a crucial role in applications such as space optical clock networks, navigation, satellite ranging, and space quantum communication. Here, we propose a high-precision space time frequency transfer and time synchronization scheme based on a simple intensity modulation/direct detection (IM/DD) laser communication system, which occupies a communication bandwidth of approximately 0.2%. Furthermore, utilizing an optical-frequency comb time frequency transfer system as an out-of-loop reference, experimental verification was conducted on a 113 km horizontal atmospheric link, with a long-term stability approximately 8.3 × 10-16 over a duration of 7800 seconds. Over an 11-hour period, the peak-to-peak wander is approximately 100 ps. Our work establishes the foundation of the time frequency transfer, based on the space laser communication channel, for future ground-to-space and inter-satellite links.

Surplus fatty acid synthesis increases oxidative stress in adipocytes and lnduces lipodystrophy

Adipocytes are the primary sites for fatty acid storage, but the synthesis rate of fatty acids is very low. The physiological significance of this phenomenon remains unclear. Here, we show that surplus fatty acid synthesis in adipocytes induces necroptosis and lipodystrophy. Transcriptional activation of FASN elevates fatty acid synthesis, but decreases NADPH level and increases ROS production, which ultimately leads to adipocyte necroptosis. We identify MED20, a subunit of the Mediator complex, as a negative regulator of FASN transcription. Adipocyte-specific male Med20 knockout mice progressively develop lipodystrophy, which is reversed by scavenging ROS. Further, in a murine model of HIV-associated lipodystrophy and a human patient with acquired lipodystrophy, ROS neutralization significantly improves metabolic disorders, indicating a causal role of ROS in disease onset. Our study well explains the low fatty acid synthesis rate in adipocytes, and sheds light on the management of acquired lipodystrophy.

TRiC/CCT chaperonin is required for the folding and inhibitory effect of WDTC1 on adipogenesis

Obesity has become a global pandemic. WDTC1 is a WD40-containing protein that functions as an anti-obesity factor. WDTC1 inhibits adipogenesis by working as an adaptor of the CUL4-DDB1 E3 ligase complex. It remains unclear about how WDTC1 is regulated. Here, we show that the TRiC/CCT functions as a chaperone to facilitate the protein folding of WDTC1 and proper function in adipogenesis. Through tandem purification, we identified the molecular chaperone TRiC/CCT as WDTC1-interacting proteins. WDTC1 bound the TRiC/CCT through its ADP domain, and the TRiC/CCT recognized WDTC1 through the CCT5 subunit. Disruption of the TRiC/CCT by knocking down CCT1 or CCT5 led to misfolding and lysosomal degradation of WDTC1. Furthermore, the knockdown of CCT1 or CCT5 eliminated the inhibitory effect of WDTC1 on adipogenesis. Our studies uncovered a critical role of the TRiC/CCT in the folding of WDTC1 and expanded our knowledge on the regulation of adipogenesis.

The Mediator subunit MED20 organizes the early adipogenic complex to promote development of adipose tissues and diet-induced obesity

MED20 is a non-essential subunit of the transcriptional coactivator Mediator complex, but its physiological function remains largely unknown. Here, we identify MED20 as a substrate of the anti-obesity CRL4-WDTC1 E3 ubiquitin ligase complex through affinity purification and candidate screening. Overexpression of WDTC1 leads to degradation of MED20, whereas depletion of WDTC1 or CUL4A/B causes accumulation of MED20. Depleting MED20 inhibits adipogenesis, and a non-degradable MED20 mutant restores adipogenesis in WDTC1-overexpressing cells. Furthermore, knockout of Med20 in preadipocytes abolishes development of brown adipose tissues. Removing one allele of Med20 in preadipocytes protects mice from diet-induced obesity and reverses weight gain in Cul4a- or Cul4b-depleted mice. Chromatin immunoprecipitation sequencing (ChIP-seq) analysis reveals that MED20 organizes the early adipogenic complex by bridging C/EBPβ and RNA polymerase II to promote transcription of the central adipogenic factor, PPARγ. Our findings have thus uncovered a critical role of MED20 in promoting adipogenesis, development of adipose tissue and diet-induced obesity.

DDB1 binds histone reader BRWD3 to activate the transcriptional cascade in adipogenesis and promote onset of obesity

Obesity has become a global pandemic. Identification of key factors in adipogenesis helps to tackle obesity and related metabolic diseases. Here, we show that DDB1 binds the histone reader BRWD3 to promote adipogenesis and diet-induced obesity. Although typically recognized as a component of the CUL4-RING E3 ubiquitin ligase complex, DDB1 stimulates adipogenesis independently of CUL4. A DDB1 mutant that does not bind CUL4A or CUL4B fully restores adipogenesis in DDB1-deficient cells. Ddb1+/- mice show delayed postnatal development of white adipose tissues and are protected from diet-induced obesity. Mechanistically, by interacting with BRWD3, DDB1 is recruited to acetylated histones in the proximal promoters of ELK1 downstream immediate early response genes and facilitates the release of paused RNA polymerase II, thereby activating the transcriptional cascade in adipogenesis. Our findings have uncovered a CUL4-independent function of DDB1 in promoting the transcriptional cascade of adipogenesis, development of adipose tissues, and onset of obesity.

Patient perception of pre-pregnancy care and family planning among reproductive-age female diabetes mellitus patients in a primary care clinic in Penang, Malaysia

INTRODUCTION

Pre-pregnancy care (PPC) is an important part of diabetic care among females in the reproductive age group, as it improves feto-maternal outcomes.

OBJECTIVE

We aimed to assess female diabetic patients' perception of PPC and family planning prior to PPC care.

METHODS

This was an observational, cross-sectional survey performed from June 2019 to September 2019, using universal sampling of registered female diabetic patients who fit the inclusion criteria prior to integrated PPC care. A self-administered questionnaire was used to assess patients' perception of PPC.

RESULTS

A total of 67 patients were recruited for the study. Only 39.4% (n=26) of the patients had heard of PPC. In our study, Code 1 contraception included those methods with a Pearl index of ≤9. Code 2 & 3 contraception included those methods with a Pearl index of >9. Only one-third of patients, 29.9% (n=20), were using Code 1 contraception, although the majority, 79.1% (n=53), felt that they had completed their family. 45 patients (68.2%) felt that they were at risk of developing complications if they were to become pregnant, and 46 patients (69.7%) felt that their health condition was not suitable for another pregnancy. However, only 31.1% (n=14) and 34.8% (n=16) of these patients were using Code 1 contraception, respectively. There were 30 patients (65.2%) who perceived that their health was not suitable for another pregnancy but were only using Code 2 or 3 contraception.

CONCLUSION

The patients' perception of PPC was poor. Patients had an inadequate knowledge of the effectiveness of their current contraceptive practice in relation to their intentions for further pregnancy and their self-perceived risk in case of future conception. We suggest that integration of PPC into routine follow-ups for other high-risk medical diseases, such as hypertension, heart disease, and epilepsy, be considered in future practice.

Angina after anaphylaxis treatment

Anaphylaxis is a life-threatening emergency, and adrenaline is the mainstay treatment for this condition. However, there have been a few reported cases of patients experiencing cardiovascular complications, such as myocardial infarction and coronary vasospasm, after its use. We highlight such a case in a young, healthy patient and the important differentials to consider.

[Interpretation of clinical practice guideline for anorectal day surgery 2019 edition]

As the rapid development of minimally invasive techniques, anesthesia, and enhanced recovery after surgery (ERAS), anorectal day surgery receiving more and more attention by improving efficiency of medical care while reducing cost and hospitalized infection. However, day surgery also faces the challenge of completing the whole process from patient admission to discharge within 24 hours. Therefore, establishing a reasonable and detailed day surgery process is the cornerstone to guarantee safe medical practice and patients satisfaction. National Clinical Research Center for Geriatric Disorders (Xiangya), together with China Ambulatory Surgery Alliance formulates the clinical practice guideline for anorectal day surgery 2019 edition. Here we make some interpretations of the guidelines on the detailed process of anorectal day surgery, including indication, preoperative examination, preoperative risk evaluation, health education, assessment of day surgery anesthesia and before leaving postanesthesia care unit (PACU), postoperative management, assessment of discharge and follow-up, for the convenience of various medical centers.

Dose estimation by chromosome aberration analysis and micronucleus assays in victims accidentally exposed to (60)Co radiation

The objective of this study was to assess the radiation exposure levels in victims of a (60)Co radiation accident using chromosome aberration analysis and the micronucleus assay. Peripheral blood samples were collected from three victims exposed to (60)Co 10 days after the accident and were used for the chromosome aberration and micronucleus assays. After in vitro culture of the lymphocytes, the frequencies of dicentric chromosomes and rings (dic+r) and the numbers of cytokinesis blocking micronuclei (CBMN) in the first mitotic division were determined and used to estimate radiation dosimetry. The Poisson distribution of the frequency of dic+r in lymphocytes was used to assess the uniformity of the exposure to (60)Co radiation. Based on the frequency of dic+r in lymphocytes, estimates of radiation exposure of the three victims were 5.61 Gy (A), 2.48 Gy (B) and 2.68 Gy (C). The values were estimated based on the frequencies of CBMN, which were 5.45 Gy (A), 2.78 Gy (B) and 2.84 Gy (C). The estimated radiation dosimetry demonstrated a critical role in estimating the radiation dose and facilitating an accurate clinical diagnosis. Furthermore, the frequencies of dir+r in victims A and B deviated significantly from a normal Poisson distribution. Chromosome aberration analysis offers a reliable means for estimating biological exposure to radiation. In the present study, the micronucleus assay demonstrated a high correlation with the chromosome aberration analysis in determining the radiation dosimetry 10 days after radiation exposure.

Two recurrent neural networks for local joint torque optimization of kinematically redundant manipulators

This paper presents two neural network approaches to real-time joint torque optimization for kinematically redundant manipulators. Two recurrent neural networks are proposed for determining the minimum driving joint torques of redundant manipulators for the eases without and with taking the joint torque limits into consideration, respectively. The first neural network is called the Lagrangian network and the second one is called the primal-dual network. In both neural-network-based computation schemes, while the desired accelerations of the end-effector for a specific task are given to the neural networks as their inputs, the signals of the minimum driving joint torques are generated as their outputs to drive the manipulator arm. Both proposed recurrent neural networks are shown to be capable of generating minimum stable driving joint torques. In addition, the driving joint torques computed by the primal-dual network are shown never exceeding the joint torque limits.

The internet and suicide: A double-edged tool

Many physicians are unaware of the power of the internet. In an era of an empowered public and patients, the internet may be a more powerful determinant of health-seeking behaviour than medical opinion. In the same way, it may provide more information for self-harm than was ever available to the public domain in the past. The internet is effective across cultural and geographical boundaries. In addition to reporting and romanticising suicide, it has a significant impact in assisting and promoting suicide. It provides services and information ranging from general information to online orders of prescription drugs or other poisons that bypass government regulations and custom controls. This bridges the gaps of locality and accessibility, which previously formed a natural divide in selecting the means of suicide. In addition to these negative effects, there is a vast potential to harness these properties to a beneficial effect. The wide acceptance of the internet makes it a powerful tool for recognition of the at-risk individual, for preventing suicide and supporting survivors, with chat rooms taking the place of telephone help lines. In an information age, it is vital for physicians to use all available means of informing and empowering the public and patients. The internet also has a role in training, providing accessible self-help sites for suicidal persons and web-based prevention services, all of which remain sadly under-utilised. The challenge to physicians of the 21st century is to harvest the internet in a beneficial manner.

A discrete-time Lagrangian network for solving constrained quadratic programs

A discrete-time recurrent neural network which is called the discrete-time Lagrangian network is proposed in this letter for solving convex quadratic programs. It is developed based on the classical Lagrange optimization method and solves quadratic programs without using any penalty parameter. The condition for the neural network to globally converge to the optimal solution of the quadratic program is given. Simulation results are presented to illustrate its performance.

Urbanisation in China: a review of its causal mechanisms and spatial relations

This article reviews "the forces underpinning Chinese urbanization.... This paper is divided into two main parts. The first addresses the (non-spatial) causal mechanisms between 1949 and 1977. Neither the ideological, the class, nor the economic formulation has touched on the more systemic mechanisms related to the socialist state and the shortage economy. This paper attempts to redress the imbalance by examining the advantages of combining Kornai's shortage model with Foucault's concept of governmentality. By drawing on concepts of spatial contingency, spatial boundary and locality effects, the second part of the paper argues that spatial relations do play significant roles in revealing Chinese urbanisation policies and patterns."