•Catalytic mechanism of imidazolium ionic liquids was investigated by DFT.•Gibbs free energy was calculated to identify the rate-limiting step.•BmimHSO4 had the minimum energy barrier in ...esterification.•HSO3-BmimHSO4 had the minimum energy barrier in transesterification.•The catalytic mechanism was validated to be reasonable.
Imidazolium ionic liquid is a novel and efficient catalyst for biodiesel production from oleaginous yeast. However, the catalytic mechanism of how imidazolium ionic liquid works in the reaction is not clear. Herein, Density functional theory (DFT) was employed to investigate the catalytic mechanism of three imidazolium ionic liquids in esterification and transesterification reactions. Pathways containing three intermediates and two transition states were proposed for the two reactions. In the subsequent DFT calculation, PBE0-D3BJ functional and 6-31G* basis set were used to optimize the intermediates and transition states. Then the Gibbs free energy of the intermediates and transition states in each reaction step was calculated to obtain the energy barrier for each reaction. The calculation results showed that 1-butyl-3-methylimidazolium hydrogen sulfate (BmimHSO4) had the minimum energy barrier of 37.77 kcal/mol in esterification, and 1-sulfobutyl-3-methylimidazolium hydrosulfate (HSO3-BmimHSO4) had the minimum energy barrier of 20.80 kcal/mol in transesterification, which were consistent with previous experimental results. The catalytic mechanism validated in this study provides a new idea for subsequent optimization of imidazolium ionic liquid structure to improve their catalytic efficiency in biodiesel production from oleaginous yeast.
Density function theory calculations have been carried out to investigate the electronic structures of Cu-doped LiBH4 (Cu0, Cu1, Cu2 and Cu3), with the aim to provide new insights into the promoting ...dehydrogenation performances of LiBH4 modified by Cu. Our results show that Cu doping causes the hydrogen dissociation energy (Ed), the scaled bond order between Li-H (BOsLi-H) and the band gap (Eg) all decrease in the order of Cu0>Cu1>Cu2>Cu3. With Cu addition, the decreased B-H and Li-H interactions, coupled with the appearance of metal-like or metallic nature, may help to destabilize LiBH4, and subsequently improve the dehydrogenation performances of LiBH4.
•Cu-doped LiBH4 are introduced by Co partial substitutes for Li, B and interstitial site.•Dehydrogenation performances of LiBH4 are modified as Cu is added.•Cu doping destabilizes LiBH4 by decreasing B-H and Li-H interactions.
A semiconductor laser employed with two-external-cavity feedback structure for laser self-mixing interference (SMI) phenomenon is investigated and analyzed. The SMI model with two directions based on ...F–P cavity is deduced, and numerical simulation and experimental verification were conducted. Experimental results show that the SMI with the structure of two-external-cavity feedback under weak light feedback is similar to the sum of two SMIs.
•A semiconductor laser employed with two-external-cavity feedback structure for SMI phenomenon is studied.•The theoretical analysis of the detailed derivation through F–P cavity model is presented.•Under weak feedback, emitting power P was deduced, which simplifies the model.
Background Spinal muscular atrophy (SMA) is a rare autosomal recessive hereditary neuromuscular disease caused by survival motor neuron 1 (SMN1) gene deletion or mutation. Homozygous deletions of ...exon 7 in SMN1 result in 95% of SMA cases, while the remaining 5% are caused by other pathogenic variants of SMN1. Methods We analyzed two SMA-suspected cases that were collected, with no SMN1 gene deletion and point mutation in whole-exome sequencing. Exon 1 deletion of the SMN gene was detected using Multiplex ligation-dependent probe amplification (MLPA) P021. We used long-range polymerase chain reaction (PCR) to isolate the SMN1 template, optimized-MLPA P021 for copy number variation (CNV) analysis within SMN1 only, and validated the findings via third-generation sequencing. Results Two unrelated families shared a genotype with one copy of exon 7 and a novel variant, g.70919941_70927324del, in isolated exon 1 of the SMN1 gene. Case F1-II.1 demonstrated no exon 1 but retained other exons, whereas F2-II.1 had an exon 1 deletion in a single SMN1 gene. The read coverage in the third-generation sequencing results of both F1-II.1 and F2-II.1 revealed a deletion of approximately 7.3 kb in the 5' region of SMN1. The first nucleotide in the sequence data aligned to the 7385 bp of NG_008691.1. Conclusion Remarkably, two proband families demonstrated identical SMN1 exon 1 breakpoint sites, hinting at a potential novel mutation hotspot in Chinese SMA, expanding the variation spectrum of the SMN1 gene and corroborating the specificity of isolated exon 1 deletion in SMA pathogenesis. The optimized-MLPA P021 determined a novel variant (g.70919941_70927324del) in isolated exon 1 of the SMN1 gene based on long-range PCR, enabling efficient and affordable detection of SMN gene variations in patients with SMA, providing new insight into SMA diagnosis to SMN1 deficiency and an optimized workflow for single exon CNV testing of the SMN gene. Keywords: Spinal muscular atrophy, Exon 1, Isolated, g.70919941_70927324del, Diagnosis
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•A light-activated rolling circle amplification-triggered CRISPR/Cas12a method is developed.•The rolling circle amplification and Cas12a reactions can be separated in the time dimension.•This method ...shows higher sensitivity compared with the conventional one-pot assay.•Testing of 120 real samples demonstrates the good application capacity of this method.
Developing robust methods that achieve simple and highly sensitive detection of Staphylococcus aureus (S. aureus) is still a challenge. Isothermal nucleic acid amplification reactions-triggered CRISPR/Cas12a strategies offer promising sensing tools for bacteria detection, but have several issues that need to be solved, such as incompatible reaction systems, compromised sensitivity, and multiple reaction steps. Here, we develop a light-activated one-pot method based on rolling circle amplification-triggered CRISPR/Cas12a (RCA-Cas12a) for analyzing S. aureus directly. In the one-pot assay, the Cas12a reaction is started under light irradiation only after the RCA reaction is completed, thus avoiding interference between the two systems. The light-activated method is simple to operate, and its sensitivity is two orders of magnitude higher than that of the traditional one-pot assay. Accurately identifying contaminated samples from 120 real samples (serum, milk, and broth) prepared in a double-blind way demonstrates the good application capacity of the light-activated one-pot method. The method has a shorter analysis time, fewer operation steps, and higher accuracy in identifying contaminated samples compared with bacterial culture. Thus, the light-activated one-pot RCA-Cas12a method represents a simple tool for sensitive and specific detection of S. aureus in food and clinical samples.
To overcome the low efficiency of single‐responsive smart surfaces, we have constructed a dual‐responsive smart surface – poly(spiropyran‐co‐N‐isopropylacrylamide) (poly(SP‐co‐NiPAAm))‐grafted ...silicon nanowire arrays – by combining photo‐responsive SP and thermo‐responsive NiPAAm units for enhancing the efficiencies of cancer‐cell capture and release. These enhanced efficiencies probably originate from the binary cooperative effect of two responsive building units: NiPAAm units can decrease the steric hindrance between SP units during the isomerization while SP units can facilitate phase transition of NiPAAm units. This study provides a new strategy for designing smart materials and surfaces with efficient responsiveness for biomedical applications.
Promoting each other: Photo and thermo dual‐responsive surfaces are successfully constructed using poly(spiropyran‐co‐N‐isopropylacrylamide) to achieve highly efficient cell capture and release. This study provides a new strategy for the design of smart surfaces with high responsiveness.
Psychrotrophic bacteria are the dominant organisms in refrigerated raw milk, which may have potentially adverse effects on the quality and shelf-life of dairy products. In this study, we investigated ...the concentration and microbial composition of psychrotrophic bacteria in raw milk from Heilongjiang Province (China) in winter and summer using traditional cultivation and single molecule real-time (SMRT) sequencing methods. The results showed that the mean counts of psychrotrophic bacteria were 3.73 log CFU/mL based on traditional cultivation method. The isolated psychrotrophic bacteria (45 genera, 120 species) showed high diversity. Pseudomonas, Lactococcus, Acinetobacter, Chryseobacterium and Staphylococcus were the most frequently isolated genera. Moreover, 2 potential novel genera and 3 unknown species were discovered. The SMRT sequencing method could accurately determine the relative abundance of psychrotrophic bacteria in raw milk. Brevundimonas (10.1%), Janthinobacterium (10.0%), Acinetobacter (8.9%), Sphingomonas (8.5%) and Enterococcus (8.1%), as the predominant genera, were present in all raw milk samples. The concentration and community structure of psychrotrophic bacteria varied significantly relying on the season. This work contributes to attracting dairy manufacturers' attention to the contamination of psychrotrophic bacteria in raw milk and providing support for the control of psychrotrophic bacteria.
•The traditional cultivation combined with SMRT sequencing method was used.•Psychrotrophic bacteria with high relative diversity were determined.•2 potential novel genera and 3 unknown species were detected in raw milk.•Concentration and community structure of psychrotrophic bacteria relied on seasons.•Provide support for controlling dominant psychrotrophic bacteria in raw milk.
Objective
The purpose of this study was to investigate whether soy isoflavone supplementation is effective in preventing periodontal destruction exacerbated by estrogen deficiency (ED) and its ...potential mechanism.
Background
The progression of periodontitis is affected by host factors, such as smoking, diabetes mellitus, and steroid use. Bone loss in periodontitis can be aggravated by ED.
Methods
A rat model of experimental periodontitis (EP) with ED was established by silk ligature and inoculation with Porphyromonas gingivalis, and some EP rats were subjected to bilateral ovariectomy (OVX). The treatment groups received an intravenous injection of 17‐β‐estradiol (E2B) or soy isoflavones (SI) by gavage. The rats were euthanized, and the maxillary jaws, gingiva, and serum were harvested. Tight junction protein and interleukin (IL)‐17 expression, reactive oxygen species (ROS) level, and periodontal destruction were assessed. In addition, we determined whether grainyhead‐like 2 (GRHL2) is required for enhancing the epithelial barrier by SI in an in vitro P. gingivalis infection model.
Results
Estrogen deficiency impaired the expression of genes encoding tight junction proteins in the gingiva, increased IL‐17 level, and accelerated alveolar bone resorption. SI treatment alleviated tight junction protein expression, decreased IL‐17 and ROS levels, and prevented the absorption of alveolar bone. Furthermore, GRHL2 expression was significantly induced by SI in human oral keratinocytes‐1 (HOK‐1) cells; GRHL2 knockdown impaired the expression of OCLN and ZO‐1 induced by SI treatment.
Conclusion
Soy isoflavones alleviates periodontitis in OVX rats, as observed by the increased expression of tight junction proteins, and reduced IL‐17 level and alveolar bone loss. The in vitro studies suggested that the enhancement of oral epithelial barrier by SI treatment was partially dependent on GRHL2.
The safe operation of parallel pipelines has become a focus of attention. The jet flame generated by the initial pipe accident may cause adjacent pipe section failure. Therefore, it is necessary to ...study the thermal impact of jet flame on adjacent pipelines. In this paper, we design and establish a thermal effect test platform to determine the change in pipe wall temperature and mechanical properties under the horizontal jet flame. Firstly, the flame combustion characteristics, such as flame form, temperature, and heat flux, are tested and analyzed. Then, the quantitative variation law of the pipe wall and oil temperature under different flow rates, wall thicknesses, and heating lengths is obtained. Combined with the mechanical test results of experimental pipelines, a pipe-bearing capacity calculation model is established via the GA-BP machine learning algorithm. Finally, the safety evaluation method and classification of the stress margin are established. The results indicate that the temperature and heat flux of the fire-facing surface is significantly higher than other clock orientations, where the values are 1287.38 ℃ and 12.37 kW/m2, respectively. As the flow rate decreases and the wall thickness and heating length increase, the pipe wall temperature rises linearly, and the tensile strength and impact toughness reduce logarithmically. The average relative error of the pipe strength prediction model is less than 2.44 %. The established safety evaluation method can be applied to determine the thermal risk level of steel pipelines under the jet flame.
Obesity-related diseases such as diabetes, hypertension, dyslipidemia, and cardiovascular diseases have increased due to the obesity epidemic. Early intervention for obesity through lifestyle and ...nutrition plays an important role in preventing obesity-related diseases. Therefore, the purpose of this study is to explore the role of leucine and exercise in adiposity, systemic insulin resistance, and inflammation to provide theoretical and guiding basis for the early prevention and treatment of obesity.
C57BL/6J male mice were randomly divided into HFD or LFD-fed mice group. After 9 weeks, glucose tolerance test (GTT) was performed to detect their systemic insulin sensitivity. Starting from week 10, mice were divided into eight groups and treated with moderate exercise or/and 1.5% leucine. At week 13, systemic insulin sensitivity was detected by GTT. At week 14, mice were dissected to analyze adiposity and inflammation.
In LFD mice, exercise significantly increased systemic insulin sensitivity by increasing GLUT4 expression in the muscle and decreasing adiposity through increasing AMPK phosphorylation in adipose tissue. In HFD mice, the simultaneous intervention of exercise and leucine increases systemic insulin sensitivity by reducing liver and adipose tissue inflammation
decreasing NF-
B p65 phosphorylation, and increasing the expression of adiponectin in adipose tissue.
There are different mechanisms underlying the effects of exercise and leucine on insulin resistance and inflammation in LFD-fed mice or HFD-fed mice.
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