An empirical method to compensate the NMR calibrated porosity of the tight volcanic rocks based on comprehensive laboratory studies

The nuclear magnetic resonance (NMR) response is known to deviate from the true value for the volcanic reservoirs, particularly when the pore throat size is ultralow. Consequently, the related petrophysical parameters such as porosity, permeability, and pore size distribution from NMR measurements are greatly influenced. An empirical method to correct the NMR calibrated porosity for the tight volcanic rocks is proposed after comprehensive investigations of influential factors combined with mineralogical and petrophysical analyses. The laboratory result indicates that the relative porosity deviation is negatively correlated with the geometric mean of the transversal relaxation time (T2) but positively correlated with the clay content. Moreover, both the paramagnetic materials, such as the manganese (Mn) content, and the diamagnetic materials, such as the magnesium (Mg) content, contribute to the NMR relaxation intensity reduction but with different mechanisms. The NMR calibrated porosity can be compensated through multiple regressions with these controlling factors, which can be generalized to other tight volcanic reservoirs

The Correlation between Chemical Composition, as Determined by UPLC-TOF-MS, and Acute Toxicity of Veratrum nigrum

The eighteen incompatible medicaments is an important theory in traditional Chinese medicine. The theory suggests that drugs in the eighteen incompatible medicaments can be toxic when used together. Veratrum nigrum L. and Radix paeoniae alba belong to the eighteen incompatible medicaments and have been prohibited for thousands of years. This study offers preliminary insight into the mechanism and chemical constituents responsible for the incompatibility and toxicity of these two agents. Specifically, we performed toxicology studies to identify and quantify the constituent substances of the two agents. Experiments revealed that acute toxicity increases when the dose of V. nigrum L. is higher than, or equal to, RPA. UPLC-TOF-MS analysis showed that, although the volumes of V. nigrum L. were the same, the content of some veratrum alkaloids changed significantly and had a trend toward a highly positive correlation r≥0.8 with toxicity. This suggests that the increased toxicity of the V. nigrum L. and RPA combination was due mainly to increased content of the special veratrum alkaloids. The cytotoxicity of veratridine in SH-SY5Y cells was decreased with increasing paeoniflorin concentrations. This study provides insight into the mechanism behind the incompatibility theory of TCM

Tetramethylpyrazine exerts neuroprotective effects in a mouse model of acute hypobaric hypoxia

IntroductionCognitive impairment is a common issue for individuals ascending to high-altitude regions, and there is currently a lack of effective preventive or therapeutic medications. Tetramethylpyrazine (TMP), a small-molecule compound with blood-brain barrier permeability, has shown neuroprotective effects in various neurological disorders. This study aimed to investigate its potential protective role against hypoxia-induced cognitive deficits.MethodsThe neuroprotective effects of TMP were evaluated both in vivo and in vitro. A simulated high-altitude hypobaric hypoxia mouse model was used to assess survival, cognitive function, cerebral ATP levels, and hippocampal histopathology. In vitro studies were conducted to examine hypoxia-induced neuronal death using primary neurons and HT22 cells. Furthermore, mechanistic investigations were performed to identify the molecular target of TMP and its functional impact.ResultsTMP treatment significantly prolonged survival and alleviated cognitive impairment in mice exposed to hypobaric hypoxia. It also elevated cerebral ATP levels and reduced hippocampal cellular edema. In vitro, TMP reduced hypoxia-induced neuronal death. Mechanistically, TMP was identified to potentially bind to the ion channel protein KCNK2 (TREK-1) and inhibit TREK-1-mediated current.DiscussionOur findings demonstrate that TMP provides significant neuroprotection under hypobaric hypoxia conditions. The mechanism is linked, at least in part, to the inhibition of the TREK-1 channel. These results position TMP as a promising therapeutic candidate for preventing or treating high-altitude-induced cognitive dysfunction

Iodine-induced synthetic method and pharmacokinetic study of cis- and trans-crocetin

Objective:This experiment aimed to obtain the relatively rare cis-crocetin isomer from natural plants, which predominantly exist in the more stable all-trans configuration. This was achieved through iodine-induced isomerization, followed by purification and structural identification. The study also aimed to compare the pharmacokinetic differences between cis- and trans-crocetin in vivo.Methods:Trans-crocetin of high purity was extracted by hydrolysis from gardenia yellow pigment. Cis-crocetin was then synthesized through an optimized electrophilic addition reaction induced by elemental iodine, and subsequently separated and purified via silica gel column chromatography. Structural identification of cis-crocetin was determined using IR, UV, and NMR techniques. In vivo pharmacokinetic studies were conducted for both cis- and trans-crocetin. In addition to this, we have conducted a comparative study on the in vivo anti-hypoxic activity of trans- and cis-crocetin.Results:Under the selected reaction conditions using DMF as the solvent, with a concentration of 2.5 mg/mL for both trans-crocetin and the iodine solution, and adjusting the illumination time according to the amount of trans-crocetin, the rate of iodine-induced isomerization was the fastest. Cis-crocetin was successfully obtained and, after purification, its structure was identified and found to be consistent with reported data. Cis-crocetin exhibited a faster absorption rate and higher bioavailability, and despite its shorter half-life, it could partially convert to trans-crocetin in the body, thereby extending the duration of the drug’s action within the body to some extent.Conclusion:This study accomplished the successful preparation and structural identification of cis-crocetin. Additionally, through pharmacokinetic studies, it uncovered notable variations in bioavailability between cis- and trans-crocetin. These findings serve as a solid scientific foundation for future functional research and practical applications in this field

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Establishment and evaluation of a competitive performance evaluation system for blood centers

Objective To investigate the establishment of a competitive performance evaluation management program for blood centers to ensure the blood supply. Methods A competitive performance evaluation system for Blood Donor Service Department of blood centers in eastern Shenzhen was established. The data concerning blood collection after (May to October 2021, the experiment group) and before (the corresponding period in 2020, the control) the launch of evaluation system was compared, including the proportion of total/novel blood donors in fixed donation sites, the donation rate of 400 mL and pre-collection deferral rate; collected units per shift, the average collection volume of staff, and the growth rate of per capita donation; the proportion of first-time/repeated/double-dose platelet apheresis donors; the proportion of transfer-in/transfer-out of red blood cells; the ratio of group to street blood donors. Results The proportion of total/novel blood donors in fixed donation sites(81.13% vs 75.87%), the donation rate of 400 mL(58.14% vs 57.91%) and pre-collection deferral rate(76.55% vs 65.92%) in the experimental group was higher than that of the control, while the proportion of pre-collection deferral was lower(18.87% vs 24.13%) (P<0.05). Compared by the control, the units collected per shift, the average collection volume of staff and the blood donation per capita at fixed sites in the experiment group increased by 54.29%, 52.21%, and 3.36% (P<0.05). The proportion of first-time platelet donors was greater than that in the control(43.90% vs 19.61%), while the proportion of repeated platelet donors was lower (56.10% vs 80.39%). The proportion of double-dose platelet donors was lower than that in the control(12.62% vs 22.19%) (P<0.05). The amount of red blood cells transfer-in was 0%, lower than 2.38% in the control group(P<0.05), while the amount of red blood cell transfer-out was 1.86%, higher than 0% in the control group (P<0.05). The proportion of group blood donors decreased from 24% to 15.19%, while street blood donors increased from 76% to 84.81% (P<0.05). Conclusion Proper competitive performance evaluation system can effectively mobilize employee motivation, improve the efficacy of blood collection and internal management, and ensure clinical blood supply

Synthesis and characterization of bridged bis(amidato) rare earth metal amides and their applications in C–N bond formation reactions

Eight bis(amidato) rare-earth metal amides were successfully synthesized and well characterized, which exhibited high catalytic activities in both the direct amidation of aldehydes and the addition of amines with carbodiimine.</p