The transfer of fresh embryos is generally preferred over the transfer of frozen embryos for in vitro fertilization (IVF), but some evidence suggests that frozen-embryo transfer may improve the ...live-birth rate and lower the rates of the ovarian hyperstimulation syndrome and pregnancy complications in women with the polycystic ovary syndrome.
In this multicenter trial, we randomly assigned 1508 infertile women with the polycystic ovary syndrome who were undergoing their first IVF cycle to undergo either fresh-embryo transfer or embryo cryopreservation followed by frozen-embryo transfer. After 3 days of embryo development, women underwent the transfer of up to two fresh or frozen embryos. The primary outcome was a live birth after the first embryo transfer.
Frozen-embryo transfer resulted in a higher frequency of live birth after the first transfer than did fresh-embryo transfer (49.3% vs. 42.0%), for a rate ratio of 1.17 (95% confidence interval CI, 1.05 to 1.31; P=0.004). Women who underwent frozen-embryo transfer also had a lower frequency of pregnancy loss (22.0% vs. 32.7%), for a rate ratio of 0.67 (95% CI, 0.54 to 0.83; P<0.001), and of the ovarian hyperstimulation syndrome (1.3% vs. 7.1%), for a rate ratio of 0.19 (95% CI, 0.10 to 0.37; P<0.001), but a higher frequency of preeclampsia (4.4% vs. 1.4%), for a rate ratio of 3.12 (95% CI, 1.26 to 7.73; P=0.009). There were no significant between-group differences in rates of other pregnancy and neonatal complications. There were five neonatal deaths in the frozen-embryo group and none in the fresh-embryo group (P=0.06).
Among infertile women with the polycystic ovary syndrome, frozen-embryo transfer was associated with a higher rate of live birth, a lower risk of the ovarian hyperstimulation syndrome, and a higher risk of preeclampsia after the first transfer than was fresh-embryo transfer. (Funded by the National Basic Research Program of China and others; ClinicalTrials.gov number, NCT01841528.).
Viruses are infectious and abundant in the marine environment. Viral lysis of host cells releases organic matter and nutrients that affect the surrounding microbial community.
are important primary ...producers in the ocean and they are subject to frequent viral infection. In the laboratory,
cultures are often associated with bacteria and such a co-existence relationship appears to be important to the growth and stability of
. However, we know little about how viral lysis of
affects the co-existing bacteria in the culture. This study investigated the influence of viral infection of
on co-occurring bacterial community in the culture. We analyzed the community composition, diversity, predicted functions of the bacterial community, and its correlations with fluorescent dissolved organic matter (FDOM) components and nutrients after introducing a cyanophage to the
culture. Cyanophage infection altered the bacterial community structure and increased the bacterial diversity and richness. Increased bacterial groups such as
and
and decreased bacterial groups such as
were observed. Moreover, cyanophage infection reduced bacterial interactions but enhanced correlations between the dominant bacterial taxa and nutrients. Unique FDOM components were observed in the cyanophage-added culture. Fluorescence intensities of FDOM components varied across the cyanophage-infection process. Decreased nitrate and increased ammonium and phosphate in the cyanophage-added culture coupled with the viral progeny production and increased substance transport and metabolism potentials of the bacterial community. Furthermore, increased potentials in methane metabolism and aromatic compound degradation of the bacterial community were observed in the cyanophage-added culture, suggesting that cyanophage infections contribute to the production of methane-related compounds and refractory organic matter in a microcosm like environment. This study has the potential to deepen our understanding of the impact of viral lysis of cyanobacteria on microbial community in the surrounding water.
Unmanned combat aerial vehicles (UCAVs) are preferred for regional electronic reconnaissance due to their versatility and stealth. This paper proposes a deep reinforcement learning (DRL) method to ...enable UCAVs to complete regional multi-target electronic reconnaissance (MER) tasks with continuous autonomous maneuvers. Distinguishing from traditional heuristic search algorithms, we first derive the objective function of MER and elucidate sufficient conditions to improve the success rate of reconnaissance recognition. Then, using the original cognitive electronic warfare framework, a three-dimensional MER simulator named Scouer-N is created to satisfy the requirements of dynamic environment training for DRL-based agents. To enable the processing of sequential situation awareness, a generative network is constructed by introducing a partially observable Markov decision process (POMDP) model, which assists the UCAV in filtering the observations from the sensor and predicting the actual states. Finally, we propose a priority-driven state reward shaping method that provides normalized state representation and dense rewards to the agent during training to improve the agent's behavioral knowledge for MER. The experimental results demonstrate a considerable improvement in the task success rate of the trained UCAV relative to the benchmark, proving the efficacy of our approach in helping agents learn the optimal reconnaissance strategy from the potential state space.
Esophageal cancer (EC) is a prevalent malignancy characterized by a low 5-year survival rate, primarily attributed to delayed diagnosis and limited therapeutic options. Currently, early detection of ...EC heavily relies on endoscopy and pathological examination, which pose challenges due to their invasiveness and high costs, leading to low patient compliance. The detection of DNA methylation offers a non-endoscopic, cost-effective, and secure approach that holds promising prospects for early EC detection.
To identify improved methylation markers for early EC detection, we conducted a comprehensive review of relevant literature, summarized the performance of DNA methylation markers based on different input samples and analytical methods in EC early detection and screening.
This review reveals that blood cell free DNA methylation-based method is an effective non-invasive method for early detection of EC, although there is still a need to improve its sensitivity and specificity. Another highly sensitive and specific non-endoscopic approach for early detection of EC is the esophageal exfoliated cells based-DNA methylation analysis. However, while there are substantial studies in esophageal adenocarcinoma, further more validation is required in esophageal squamous cell carcinoma.
In conclusion, DNA methylation detection holds significant potential as an early detection and screening technology for EC.
Cyanophages play important roles in regulating the population dynamics, community structure, metabolism, and evolution of cyanobacteria in aquatic ecosystems. Here, we report the genomic analysis of ...an estuarine cyanophage, S-CREM1, which represents a new genus of T4-like cyanomyovirus and exhibits new genetic characteristics. S-CREM1 is a lytic phage which infects estuarine
sp. CB0101. In contrast to many cyanomyoviruses that usually have a broad host range, S-CREM1 only infected the original host strain. In addition to cyanophage-featured auxiliary metabolic genes (AMGs), S-CREM1 also contains unique AMGs, including three antitoxin genes, a MoxR family ATPase gene, and a pyrimidine dimer DNA glycosylase gene. The finding of three antitoxin genes in S-CREM1 implies a possible phage control of host cells during infection. One small RNA (sRNA) gene and three
-regulatory RNA genes in the S-CREM1 genome suggest potential molecular regulations of host metabolism by the phage. In addition, S-CREM1 contains a large number of tRNA genes which may reflect a genomic adaption to the nutrient-rich environment. Our study suggests that we are still far from understanding the viral diversity in nature, and the complicated virus-host interactions remain to be discovered. The isolation and characterization of S-CREM1 further our understanding of the gene diversity of cyanophages and phage-host interactions in the estuarine environment.
Lytic and lysogenic infections are the main strategies used by viruses to interact with microbial hosts. The genetic information of prophages provides insights into the nature of phages and their ...potential influences on hosts. Here, the siphovirus vB_MoxS-R1 was induced from a
strain isolated from an estuarine
culture. vB_MoxS-R1 has a high replication capability, with an estimated burst size of 2000 virions per cell. vB_MoxS-R1 represents a novel phage genus-based genomic analysis. Six transcriptional regulator (TR) genes were predicted in the vB_MoxS-R1 genome. Four of these TR genes are involved in stress responses, virulence and amino acid transportation in bacteria, suggesting that they may play roles in regulating the host cell metabolism in response to external environmental changes. A glycerophosphodiester phosphodiesterase gene related to phosphorus acquisition was also identified in the vB_MoxS-R1 genome. The presence of six TR genes and the phosphorus-acquisition gene suggests that prophage vB_MoxS-R1 has the potential to influence survival and adaptation of its host during lysogeny. Possession of four endonuclease genes in the prophage genome suggests that vB_MoxS-R1 is likely involved in DNA recombination or gene conversion and further influences host evolution.
Cyanate is a nitrogen and energy source for diverse marine microorganisms, playing important roles in the nitrogen cycle. Despite the extensive research on cyanate utilization, the sources of this ...nitrogen compound remain largely enigmatic. To unravel the sources of cyanate, distributions and production of cyanate during photochemical degradation of natural dissolved organic matter (DOM) were investigated across various environments, including freshwater, estuarine, coastal areas in Florida, and the continental and slope regions of the North American mid-Atlantic Ocean (NATL). Cyanate production was also examined during the photochemical degradation of exudates from a typical strain of
Synechococcus
, an important phytoplankton component. To deepen our understanding of the sources and production mechanisms of cyanate, its production was assessed during the photochemical degradation of a natural seawater DOM supplemented with five nitrogen–containing compounds with distinguishing structures and functional groups. Generally, cyanate exhibited higher concentrations in the Florida coastal, estuarine, and freshwater environments than the NATL. However, cyanate distribution did not consistently align with its production rates. Despite significantly low concentrations in the NATL, DOM from this region exhibited cyanate production rates comparable to estuarine and Florida coastal environments. Although relatively high cyanate concentrations were observed in the freshwaters, DOM in this environment exhibited very low cyanate production rates. A highly significant correlation was observed between cyanate and chlorophyll
a
(Chl
a
) concentrations in these areas. Moreover, in most estuarine and NATL stations, cyanate concentration and production rate in the Chl
a
maximum layer were significantly higher than in other layers. Cyanate was produced during the photochemical degradation of the
Synechococcus
exudates. The cyanate production was significantly enhanced when the natural seawater DOM was supplemented with GlycylGlycine, 4-(methylamino) benzoic acid, 4-ethyl(methyl)amino benzaldehyde or methyl 2-aminobenzoate. Our study implies that photochemical degradation of marine DOM, especially phytoplankton-derived DOM, is a substantial source of cyanate in the ocean. Additionally, cyanate may form during the degradation of peptides and small aromatic compounds in DOM, providing novel insights into the nitrogen cycle.
A novel Gram-stain-negative, aerobic, yellow-pigmented bacterium was isolated from seawater of Aoshan Bay, and designated as strain ASW18
. Strain ASW18
was a long-rod-shaped bacterium without ...flagellum and lacked gliding ability. Based on 16S rRNA gene phylogeny, strain ASW18
showed the closest relationship to
MCCC 1A06690
, with a sequence similarity of 97.0 %. Strain ASW18
was able to grow at 25-40 °C, at pH 5.5-9.5 and with 0.5-9 % (w/v) NaCl. The genomic DNA G+C content of strain ASW18
was 37.3 %. The predominant cellular fatty acids of strain ASW18
were iso-C
, iso-C
3-OH and iso-C
G. The major polar lipids were phosphatidylethanolamine, phosphatidyldimethylethanolamine, an aminolipid and three unidentified lipids. The respiratory quinone of strain ASW18
was menaquinone with six isoprene units (MK-6). Based on the present polyphasic analysis, strain ASW18
represents a novel species of the genus
, for which the name
sp. nov. is proposed; the type strain is ASW18
(=MCCC 1K04203
=KCTC 72852
). In addition, it is also proposed that
should be reclassified as
comb. nov.; the type strain is CSW06
(=CGMCC 1.15761
=JCM 31455
=KCTC 52375
=MCCC 1K03195
).
Picocyanobacteria are major primary producers in the ocean, especially in the tropical or subtropical oceans or during warm seasons. Many “warm” picocyanobacterial species have been isolated and ...characterized. However, picocyanobacteria in cold environments or cold seasons are much less studied. In general, little is known about the taxonomy and ecophysiology of picocyanobacteria living in the winter. In this study, 17 strains of picocyanobacteria were isolated from Chesapeake Bay, a temperate estuarine ecosystem, during the winter months. These winter isolates belong to five distinct phylogenetic lineages, and are distinct from the picocyanobacteria previously isolated from the warm seasons. The vast majority of the winter isolates were closely related to picocyanobacteria isolated from other cold environments like Arctic or subalpine waters. The winter picocyanobacterial isolates were able to maintain slow growth or prolonged dormancy at 4°C. Interestingly, the phycoerythrin‐rich strains outperformed the phycocyanin‐rich strains at cold temperature. In addition, winter picocyanobacteria changed their morphology when cultivated at 4°C. The close phylogenetic relationship between the winter picocyanobacteria and the picocyanobacteria living in high latitude cold regions indicates that low temperature locations select specific ecotypes of picocyanobacteria.
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