The atomic dispersing of metal atoms supported on an optimal substrate exhibits an ideal strategy for maximizing metal utilization for catalysis, which is particularly significant for exploiting new ...catalysts with low cost and high catalytic efficiency. The dramatic development of atomic metal catalysts, including single atom catalysts (SACs), double atoms catalysts (DACs), and triple atoms catalysts (TACs), has spawned two remarkable platforms: (1) bridging homogeneous catalysts and heterogeneous catalysts; (2) linking theoretical calculations and experimental results. In this review, recent syntheses, characterizations, and applications of SACs, DACs, and TACs are highlighted through a focus on various applied substrates. We extensively discuss the synthetic strategies of successfully achieving SACs, DACs, and TACs. Moreover, the opportunities and challenges in developing SACs, DACs, and TACs are pointed out, together with the prospects for the development of atomic catalysis.
SACs, DACs, and TACs, heterogeneous catalysts with the advantages of homogeneous catalysts, are ideal models for exploring catalytic mechanisms and further designing catalysts.
The ventromedial hypothalamus (VMH) was thought to be essential for coping with threat, although its circuit mechanism remains unclear. To investigate this, we optogenetically activated steroidogenic ...factor 1 (SF1)-expressing neurons in the dorsomedial and central parts of the VMH (VMHdm/c), and observed a range of context-dependent somatomotor and autonomic responses resembling animals’ natural defensive behaviors. By activating independent pathways emanating from the VMHdm/c, we demonstrated that VMHdm/c projection to the dorsolateral periaqueductal gray (dlPAG) induces inflexible immobility, while the VMHdm/c to anterior hypothalamic nucleus (AHN) pathway promotes avoidance. Consistent with the behavior changes induced by VMH to AHN pathway activation, direct activation of the AHN elicited avoidance and escape jumping, but not immobility. Retrograde tracing studies revealed that nearly 50% of PAG-projecting VMHdm/c neurons send collateral projection to the AHN and vice versa. Thus, VMHdm/c neurons employ a one-to-many wiring configuration to orchestrate multiple aspects of defensive behaviors.
•Activating VMHdm/c SF1 cells induces defensive-like motor and autonomic responses•The VMH→PAG and VMH→AHN pathways mediate immobility and avoidance, respectively•VMHdm/c neurons send collateral projections to the AHN and dlPAG•AHN activation elicits escape jumping and avoidance, but not immobility
Wang et al. show that SF1-expressing cells in the ventromedial hypothalamus (VMH) mediate complex defense-like somatomotor and autonomic responses. Collateral projections from the VMH to different downstream regions mediate distinct aspects of defense, suggesting a one-to-many and nonredundant circuit configuration.
CTONG0806 assessed the efficacy of pemetrexed versus gefitinib as second-line treatment in advanced nonsquamous nonsmall-cell lung cancer (NSCLC) harboring wild-type epidermal growth factor receptor ...(EGFR).
Patients with locally advanced or metastatic nonsquamous NSCLC harboring wild-type EGFR, detected by direct sequencing, and previously treated with platinum-based chemotherapy were randomized to receive gefitinib (250 mg/day) orally or pemetrexed (500 mg/m2) i.v. on day 1 of a 21-day cycle until disease progression or unacceptable toxicity. The primary end point was progression-free survival (PFS). The Independent Review Committee (IRC) evaluated all pictorial data.
From February 2009 to August 2012, 161 patients were enrolled, and 157 were assessable (81 in the gefitinib arm, 76 in the pemetrexed arm). Baseline characteristics were balanced between the two arms. The median PFSs were 4.8 versus 1.6 months in the pemetrexed and gefitinib arms, respectively hazard ratio (HR) 0.54, 95% confidence interval (CI) 0.40–0.75, P < 0.001 as confirmed by IRC evaluation (5.6versus 1.7 months, HR 0.53, 95% CI 0.38–0.75, P < 0.001). The median overall survival (OS) showed a trend of superiority in the pemetrexed arm (12.4 versus 9.6 months, HR 0.72, 95% CI 0.49–1.04, P = 0.077). Quality-of-life assessment showed no marked difference between the arms. No unexpected adverse events were found. Of 108 patients with sufficient DNA samples, EGFR mutation status was re-tested by Scorpion amplification refractory mutation system (ARMS); 32 (29.6%) tested positive (19 in the pemetrexed arm, 13 in the gefitinib arm; median PFS: 8.1 versus 7.0 months, HR 0.94, 95% CI 0.43–2.08, P = 0.877).
CTONG0806 is the first trial to show significant improvement in PFS and an improved OS trend with pemetrexed compared with gefitinib as second-line setting treatment of EGFR wild-type advanced nonsquamous NSCLC. ARMS is superior to direct sequencing in excluding false-negative patients.
NCT00891579.
Heterosis, also known as hybrid vigour, is widespread in plants and animals, but the molecular bases for this phenomenon remain elusive. Recent studies in hybrids and allopolyploids using ...transcriptomic, proteomic, metabolomic, epigenomic and systems biology approaches have provided new insights. Emerging genomic and epigenetic perspectives suggest that heterosis arises from allelic interactions between parental genomes, leading to altered programming of genes that promote the growth, stress tolerance and fitness of hybrids. For example, epigenetic modifications of key regulatory genes in hybrids and allopolyploids can alter complex regulatory networks of physiology and metabolism, thus modulating biomass and leading to heterosis. The conceptual advances could help to improve plant and animal productivity through the manipulation of heterosis.
Coronavirus disease 2019 (COVID-19) pandemic is a major public health concern all over the world. Little is known about the impact of COVID-19 pandemic on mental health in the general population. ...This study aimed to assess the mental health problems and associated factors among a large sample of college students during the COVID-19 outbreak in China.
This cross-sectional and nation-wide survey of college students was conducted in China from 3 to 10 February 2020. A self-administered questionnaire was used to assess psychosocial factors, COVID-19 epidemic related factors and mental health problems. Acute stress, depressive and anxiety symptoms were measured by the Chinese versions of the impact of event scale-6, Patient Health Questionnaire-9 and Generalized Anxiety Disorder-7, respectively. Univariate and hierarchical logistic regression analyses were performed to examine factors associated with mental health problems.
Among 821 218 students who participated in the survey, 746 217 (90.9%) were included for the analysis. In total, 414 604 (55.6%) of the students were female. About 45% of the participants had mental health problems. The prevalence rates of probable acute stress, depressive and anxiety symptoms were 34.9%, 21.1% and 11.0%, respectively. COVID-19 epidemic factors that were associated with increased risk of mental health problems were having relatives or friends being infected (adjusted odds ratio = 1.72-2.33). Students with exposure to media coverage of the COVID-19 ≥3 h/day were 2.13 times more likely than students with media exposure <1 h/day to have acute stress symptoms. Individuals with low perceived social support were 4.84-5.98 times more likely than individuals with high perceived social support to have anxiety and depressive symptoms. In addition, senior year and prior mental health problems were also significantly associated with anxiety or/and depressive symptoms.
In this large-scale survey of college students in China, acute stress, anxiety and depressive symptoms are prevalent during the COVID-19 pandemic. Multiple epidemic and psychosocial factors, such as family members being infected, massive media exposure, low social support, senior year and prior mental health problems were associated with increased risk of mental health problems. Psychosocial support and mental health services should be provided to those students at risk.
Hybrids such as maize (
Zea mays) or domestic dog (
Canis lupus familiaris) grow bigger and stronger than their parents. This is also true for allopolyploids such as wheat (
Triticum spp.) or frog ...(i.e.
Xenopus and
Silurana) that contain two or more sets of chromosomes from different species. The phenomenon, known as hybrid vigor or heterosis, was systematically characterized by Charles Darwin (1876). The rediscovery of heterosis in maize a century ago has revolutionized plant and animal breeding and production. Although genetic models for heterosis have been rigorously tested, the molecular bases remain elusive. Recent studies have determined the roles of nonadditive gene expression, small RNAs, and epigenetic regulation, including circadian-mediated metabolic pathways, in hybrid vigor, which could lead to better use and exploitation of the increased biomass and yield in hybrids and allopolyploids for food, feed, and biofuels.
Objective
To assess the current prevalence of and risk factors for infertility among couples of reproductive age in China.
Design
Population‐based cross‐sectional study.
Setting
We approached 25 270 ...couples in eight provinces/municipalities, of whom 18 571 (response rate 74%) were interviewed.
Population
Couples living together and married for more than 1 year, of whom the female spouse was 20–49 years old.
Methods
Women were approached via telephone and face‐to‐face conversation to complete the standardised and structured questionnaire by trained interviewers.
Main outcome measures
Prevalence of and risk factors for infertility.
Results
Among women ‘at risk’ of pregnancy, the prevalence of infertility was 15.5% (2680/17 275). Among 10 742 women attempting to become pregnant, the prevalence of infertility was 25.0% (2680/10 742), which increased with age in the second population. Among women who failed to achieve pregnancy in the last 12 months, 3470 finished our questionnaire about fertility care, and 55.2% (1915/3470) of them had sought medical help. Sociodemographic risk factors for infertility included lower educational level adjusted odds ratio (aOR) 3.4, 95% CI 2.0–5.5 and employment (aOR 2.3, 95% CI 1.9–2.9). Clinical risk factors were irregular menstrual cycle (aOR 1.8, 95% CI 1.2–2.5), light menstrual blood volume (aOR 1.6, 95% CI 1.2–2.0), history of cervicitis (aOR 1.5, 95% CI 1.2–2.0) and endometriosis (aOR 3.1, 95% CI 1.1–9.3), previous stillbirth (aOR 2.1, 95% CI 1.3–3.3) and miscarriage (aOR 2.7, 95% CI 2.1–3.5). In addition, history of operation was a significant risk factor of infertility.
Conclusions
Among couples of reproductive age in China, the prevalence of infertility was 25%, and almost half of the couples experiencing infertility had not sought medical help.
Tweetable
In China, 25% of couples actively attempting to become pregnant suffered infertility.
Tweetable
In China, 25% of couples actively attempting to become pregnant suffered infertility.
Circadian clocks regulate growth and development in plants and animals, but the role of circadian regulation in crop production is poorly understood. Rice (
) grain yield is largely determined by ...tillering, which is mediated by physiological and genetic factors. Here we report a regulatory loop that involves the circadian clock, sugar, and strigolactone (SL) pathway to regulate rice tiller-bud and panicle development. Rice
(
) positively regulates expression of
(
, also known as
),
(
), and
(
, also known as
) to repress tiller-bud outgrowth. Downregulating and overexpressing
increases and reduces tiller numbers, respectively, whereas manipulating
(
) expression results in the opposite effects.
also regulates
expression to mediate panicle and grain development. Genetic analyses using double mutants and overexpression in the mutants show that
,
, and
act downstream of
Sugars repress
expression in roots and tiller buds to promote tiller-bud outgrowth. The circadian clock integrates sugar responses and the SL pathway to regulate tiller and panicle development, providing insights into improving plant architecture and yield in rice and other cereal crops.
Polyploidy or whole genome duplication (WGD) occurs throughout the evolutionary history of many plants and some animals, including crops such as wheat, cotton, and sugarcane. Recent studies have ...documented rapid and dynamic changes in genomic structure and gene expression in plant polyploids, which reflects genomic and functional plasticity of duplicate genes and genomes in plants. Common features of uniparental gene regulation and nonadditive gene expression in regulatory pathways responsive to growth, development, and stresses in many polyploids have led to the conclusion that epigenetic mechanisms including chromatin modifications and small RNAs play central roles in shaping molecular and phenotypic novelty that may be selected and domesticated in many polyploid plants and crops.
For the globalized world economy with intensive international trade, an overview of energy consumption is presented by an embodied energy analysis to track both direct and indirect energy uses based ...on a systems input–output simulation. In 2004, the total amounts of energy embodied in household consumption, government consumption, and investment are 7749, 874, and 2009
Mtoe (million tons of oil equivalent), respectively. The United States is shown as the world’s biggest embodied energy importer (683
Mtoe) and embodied energy surplus receiver (290
Mtoe), in contrast to China as the biggest exporter (662
Mtoe) and deficit receiver (274
Mtoe). Energy embodied in consumption per capita varies from 0.05 (Uganda) to 19.54
toe (Rest of North America). Based on a forecast for 2005–2035, China is to replace the United States as the world’s leading embodied energy consumer in 2027, when its per capita energy consumption will be one quarter of that of the United States.
► We present an overview of global energy profile in terms of embodied energy. ► The US and China are top embodied energy consumers as well as traders in 2004. ► Equality issue is studied by analyzing per capita embodied energy consumption. ► The US remains to be the leading energy consumer until replaced by China in 2027.
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