708 research outputs found
On the validity of the definition of angular momentum in general relativity
We exam the validity of the definition of the ADM angular momentum without
the parity assumption. Explicit examples of asymptotically flat hypersurfaces
in the Minkowski spacetime with zero ADM energy-momentum vector and finite
non-zero angular momentum vector are presented. We also discuss the Beig-\'O
Murchadha-Regge-Teitelboim center of mass and study analogous examples in the
Schwarzschild spacetime.Comment: References are updated, and typos and computational errors are
corrected. Accepted by Ann. Henri Poincar
Dydrogesterone has no effect on uterine fibroids when used to prevent miscarriage in pregnant women with uterine fibroids
Objectives: To analyse the effect of dydrogesterone use during pregnancy on uterine fibroids, pregnancy complications, and pregnancy outcome.
Material and methods: In all, 372 pregnant women with uterine fibroids who were treated at the Affiliated Provincial Hospital of Shandong University were included in this study. Thirty-three of these women received dydrogesterone and constituted the treatment group, and the 27 women who were found to have uterine fibroids during the first trimester but did not receive intervention to prevent miscarriage composed the control group. The changes in uterine fibroids before and after pregnancy and the pregnancy complications were recorded; immunohistochemistry was used to detect the expression of progesterone receptor (PR) and proliferation- and apoptosis-related proteins in the uterine fibroid tissue.
Results: No significant difference was observed in the change in uterine fibroid volume during pregnancy between the treatment group and the control group (p > 0.05). The percentage of uterine fibroids with red degeneration was lower in the treatment group than in the control group, but the difference was not statistically significant. No significant difference was observed in newborn weight, height, Apgar score, threatened miscarriage, or premature birth, among other characteristics, between the two groups (p > 0.05). Immunohistochemistry showed no significant difference in the expression of PR, cyclinD1, insulin-like growth factor (IGF1), or B-cell lymphoma 2 (Bcl2) between the two groups.
Conclusions: The use of dydrogesterone during pregnancy has no significant effect on uterine fibroids, pregnancy progression, or pregnancy outcomes in pregnant patients with uterine fibroids
Specifying angular momentum and center of mass for vacuum initial data sets
We show that it is possible to perturb arbitrary vacuum asymptotically flat
spacetimes to new ones having exactly the same energy and linear momentum, but
with center of mass and angular momentum equal to any preassigned values
measured with respect to a fixed affine frame at infinity. This is in contrast
to the axisymmetric situation where a bound on the angular momentum by the mass
has been shown to hold for black hole solutions. Our construction involves
changing the solution at the linear level in a shell near infinity, and
perturbing to impose the vacuum constraint equations. The procedure involves
the perturbation correction of an approximate solution which is given
explicitly.Comment: (v2) a minor change in the introduction and a remark added after
Theorem 2.1; (v3) final version, appeared in Comm. Math. Phy
Transcendocardinal Delivery of AAV6 Results in Highly Efficient and Global Cardiac Gene Transfer in Rhesus Macaques
Heart disease is the leading cause of morbidity and mortality, and cardiac gene transfer has potential as a novel therapeutic approach. We previously demonstrated safe and efficient gene transfer to the canine heart using a percutaneous transendocardial injection procedure to deliver self-complementary (sc) adeno-associated virus 6 (AAV6) vector. In the present study, we proceed with our vertical translation study to evaluate cardiac gene transfer in nonhuman primates (NHPs). We screened approximately 30 adult male rhesus macaques for the presence of neutralizing antibodies against AAV6, AAV8, and AAV9, and then selected seven monkeys whose antibody titers against these three serotypes were lower than 1/5. The animals were then randomized to receive either scAAV6 (n =3), scAAV8 (n =1), or scAAV9 (n =3) vector expressing the enhanced green fluorescent protein (EGFP) reporter gene at a dose of 5.4×1012 genome copies/kg, which was administered according to a modified version of our previously developed transendocardial injection procedure. One animal treated with scAAV6 died secondary to esophageal intubation. The remaining animals were euthanized 7 days after gene transfer, at which time tissue was collected for analysis of EGFP expression, histopathology, and biodistribution of the vector genome. We found that (i) transendocardial delivery of AAV is safe in the NHP, (ii) AAV6 and AAV8 provide efficient cardiac gene transfer at similar levels and are superior to AAV9, and (iii) AAV6 is more cardiac-specific than AAV8 and AAV9. The results of this NHP study may help guide the development AAV vectors for the treatment of cardiovascular disease in humans
The effective expression of xylanase gene in Candida utilis by 18S rDNA targeted homologous recombination in pGLR9K
In order to test whether 18S rDNA can influence positively xylanase gene effective expression in the yeast of Candida utilis, a targeting vector pGLR9K-XA was constructed by adding an interested gene xynA from Streptomyces olivaceoviridis into the vector pGLR9K which is constructed by ourselves. pGLR9K contains the 18S rDNA, GAP promoter and CYH resistance gene sequence, all of which is from C. utilis. Then the vector pGLR9K-XA was transformed into C. utilis. To test the vector and transformed system, PCR, Southern blot and DNS methods were used. The results showed that xylanase gene can be detected in the chromosome DNA of recombinant C. utilis and the enzyme activity of xylanase is up to 60 IU ml(-1) in the study. It is suggested that this system can be used to express exogenous genes in C. utilis as a bioreactors. This is the first report that xylanase gene was expressed in C. utilis
Replacing Traditional Plastics with Biodegradable Plastics:Impact on Carbon Emissions
In recent years, a great deal of attention has been focused on the environmental impact of plastics, including the carbon emissions related to plastics, which has promoted the application of biodegradable plastics. Countries worldwide have shown high interest in replacing traditional plastics with biodegradable plastics. However, no systematic comparison has been conducted on the carbon emissions of biodegradable versus traditional plastic products. This study evaluates the carbon emissions of traditional and biodegradable plastic products (BPPs) over four stages and briefly discusses environmental and economic perspectives. Four scenarios—namely, the traditional method, chemical recycling, industrial composting, and anaerobic digestion—are considered for the disposal of waste biodegradable plastic product (WBBPs). The analysis takes China as a case study. The results show that the carbon emissions of 1000 traditional plastic products (plastic bags, lunch boxes, cups, etc.) were 52.09–150.36 carbon emissions equivalent of per kilogram (kg CO2eq), with the stage of plastic production contributing 50.71%–50.77%. In comparison, 1000 similar BPPs topped out at 21.06–56.86 kg CO2eq, approximately 13.53%–62.19% lower than traditional plastic products. The difference was mainly at the stages of plastic production and waste disposal, and the BPPs showed significant carbon reduction potential at the raw material acquisition stage. Waste disposal plays an important role in environmental impact, and composting and anaerobic digestion are considered to be preferable disposal methods for WBBPs. However, the high cost of biodegradable plastics is a challenge for their widespread use. This study has important reference significance for the sustainable development of the biodegradable plastics industry.</p
Porous polydimethylsiloxane films with specific surface wettability but distinct regular physical structures fabricated by 3D printing
Porous polydimethylsiloxane (PDMS) films with special surface wettability have potential applications in the biomedical, environmental, and structural mechanical fields. However, preparing porous PDMS films with a regular surface pattern using conventional methods, such as chemical foaming or physical pore formation, is challenging. In this study, porous PDMS films with a regular surface pattern are designed and prepared using 3D printing to ensure the formation of controllable and regular physical structures. First, the effect of the surface wettability of glass substrates with different surface energies (commercial hydrophilic glass and hydrophobic glass (F-glass) obtained by treating regular glass with 1H,1H,2H,2H-perfluorooctyl-trichlorosilane) on the structural characteristics of the 3D printed PDMS filaments is investigated systematically. Additionally, the effect of the printing speed and the surface wettability of the glass substrate on the PDMS filament morphology is investigated synchronously. Next, using the F-glass substrate and an optimized printing speed, the effects of the number of printed layers on both the morphologies of the individual PDMS filaments and porous PDMS films, and the surface wettability of the films are studied. This study reveals that regularly patterned porous PDMS films with distinct structural designs but the same controllable surface wettability, such as anisotropic surface wettability and superhydrophobicity, can be easily fabricated through 3D printing. This study provides a new method for fabricating porous PDMS films with a specific surface wettability, which can potentially expand the application of porous PDMS films
Synthesis, biological evaluation, and physicochemical property assessment of 4-substituted 2-phenylaminoquinazolines as Mer tyrosine kinase inhibitors
Current results identified 4-substituted 2-phenylaminoquinazoline compounds as novel Mer tyrosine kinase (Mer TK) inhibitors with a new scaffold. Twenty-one 2,4-disubstituted quinazolines (series 4-7) were designed, synthesized, and evaluated against Mer TK and a panel of human tumor cell lines aimed at exploring new Mer TK inhibitors as novel potential antitumor agents. A new lead, 4b, was discovered with a good balance between high potency (IC50 0.68μM) in the Mer TK assay and antiproliferative activity against MV4-11 (GI50 8.54μM), as well as other human tumor cell lines (GI50<20μM), and a desirable druglike property profile with low logP value (2.54) and high aqueous solubility (95.6μg/mL). Molecular modeling elucidated an expected binding mode of 4b with Mer TK and necessary interactions between them, thus supporting the hypothesis that Mer TK might be a biologic target of this kind of new active compound
The HIF/PHF8/AR axis promotes prostate cancer progression.
Recent studies provide strong evidence that the androgen receptor (AR) signaling pathway remains active in castration-resistant prostate cancer (CRPC). However, the underlying mechanisms are not well understood. In this study, we demonstrate that plant homeo domain finger protein 8 (PHF8 )interacts with and functions as an essential histone demethylase activity-dependent AR coactivator. Furthermore, we demonstrate that the expression of PHF8 is induced by hypoxia in various prostate cancer cell lines. Knockdown of either hypoxia-inducible factor HIF2α or HIF1α almost completely abolished hypoxia-induced PHF8 expression. Importantly, we observed that PHF8 is highly expressed in clinical androgen deprived prostate cancer samples and expression of PHF8 correlates with increased levels of HIF1α and HIF2α. Moreover, elevated PHF8 is associated with higher grade prostate cancers and unfavorable outcomes. Our findings support a working model in which hypoxia in castrated prostate cancer activates HIF transcription factors which then induces PHF8 expression. The elevated PHF8 in turn promotes the AR signaling pathway and prostate cancer progression. Therefore, the HIF/PHF8/AR axis could serve as a potential biomarker for CRPC and is also a promising therapeutic target in combating CRPC
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