Mutual regulation of novel transcription factors RsrD and RsrE positively modulates the production of raw-starch-degrading enzyme in Penicillium oxalicum.

Filamentous fungi can produce raw-starch-degrading enzyme, however, regulation of production of raw-starch-degrading enzyme remains poorly understood thus far. Here, two novel transcription factors raw-starch-degrading enzyme regulator D (RsrD) and raw-starch-degrading enzyme regulator E (RsrE) were identified to participate in the production of raw-starch-degrading enzyme in Penicillium oxalicum. Individual knockout of rsrD and rsrE in the parental strain Δku70 resulted in 31.1%-92.9% reduced activity of raw-starch-degrading enzyme when cultivated in the presence of commercial starch from corn. RsrD and RsrE contained a basic leucine zipper and a Zn2Cys6-type DNA-binding domain, respectively, but with unknown functions. RsrD and RsrE dynamically regulated the expression of genes encoding major amylases over time, including raw-starch-degrading glucoamylase gene PoxGA15A and α-amylase gene amy13A. Interestingly, RsrD and RsrE regulated each other at transcriptional level, through binding to their own promoter regions; nevertheless, both failed to bind to the promoter regions of PoxGA15A and amy13A, as well as the known regulatory genes for regulation of amylase gene expression. RsrD appears to play an epistatic role in the module RsrD-RsrE on regulation of amylase gene expression. This study reveals a novel regulatory pathway of fungal production of raw-starch-degrading enzyme.IMPORTANCETo survive via combating with complex extracellular environment, filamentous fungi can secrete plant polysaccharide-degrading enzymes that can efficiently hydrolyze plant polysaccharide into glucose or other mono- and disaccharides, for their nutrients. Among the plant polysaccharide-degrading enzymes, raw-starch-degrading enzymes directly degrade and convert hetero-polymeric starch into glucose and oligosaccharides below starch gelatinization temperature, which can be applied in industrial biorefinery to save cost. However, the regulatory mechanism of production of raw-starch-degrading enzyme in fungi remains unknown thus far. Here, we showed that two novel transcription factors raw-starch-degrading enzyme regulator D (RsrD) and raw-starch-degrading enzyme regulator E (RsrE) positively regulate the production of raw-starch-degrading enzyme by Penicillium oxalicum. RsrD and RsrE indirectly control the expression of genes encoding enzymes with amylase activity but directly regulate each other at transcriptional level. These findings expand diversity of gene expression regulation in fungi.

The Burden of Diagnostic Error in Dentistry: A Study on Periodontal Disease Misclassification.

BACKGROUND: Periodontal disease constitutes a widely prevalent category of non-communicable diseases and ranks among the top 10 causes of disability worldwide. Little however is known about diagnostic errors in dentistry. In this work, by retrospectively deploying an electronic health record (EHR)-based trigger tool, followed by gold standard manual review, we provide epidemiological estimates on the rate of diagnostic misclassification in dentistry through a periodontal use case. METHODS: An EHR-based trigger tool (a retrospective record review instrument that uses a list of triggers (or clues), i.e., data elements within the health record, to alert reviewers to the potential presence of a wrong diagnosis) was developed, tested and run against the EHR at the two participating sites to flag all cases having a potential misdiagnosis. All cases flagged as potentially misdiagnosed underwent extensive manual reviews by two calibrated domain experts. A subset of the non-flagged cases was also manually reviewed. RESULTS: A total of 2,262 patient charts met the study's inclusion criteria. Of these, the algorithm flagged 1,124 cases as potentially misclassified and 1,138 cases as potentially correctly diagnosed. When the algorithm identified a case as potentially misclassified, compared to the diagnosis assigned by the gold standard, the kappa statistic was 0.01. However, for cases the algorithm marked as potentially correctly diagnosed, the review against the gold standard showed a kappa statistic of 0.9, indicating near perfect agreement. The observed proportion of diagnostic misclassification was 32%. There was no significant difference by clinic or provider characteristics. CONCLUSION: Our work revealed that about a third of periodontal cases are misclassified. Diagnostic errors have been reported to happen more frequently than other types of errors, and to be more preventable. Benchmarking diagnostic quality is a first step. Subsequent research endeavor will delve into comprehending the factors that contribute to diagnostic errors in dentistry and instituting measures to prevent them. CLINICAL SIGNIFICANCE: This study sheds light on the significance of diagnostic excellence in the delivery of dental care, and highlights the potential role of technology in aiding diagnostic decision-making at the point of care.

K-Doping Suppresses Oxygen Redox in P2-Na0.67Ni0.11Cu0.22Mn0.67O2 Cathode Materials for Sodium-Ion Batteries.

In P2-type layered oxide cathodes, Na site-regulation strategies are proposed to modulate the Na+ distribution and structural stability. However, their impact on the oxygen redox reactions remains poorly understood. Herein, the incorporation of K+ in the Na layer of Na0.67Ni0.11Cu0.22Mn0.67O2 is successfully applied. The effects of partial substitution of Na+ with K+ on electrochemical properties, structural stability, and oxygen redox reactions have been extensively studied. Improved Na+ diffusion kinetics of the cathode is observed from galvanostatic intermittent titration technique (GITT) and rate performance. The valence states and local structural environment of the transition metals (TMs) are elucidated via operando synchrotron X-ray absorption spectroscopy (XAS). It is revealed that the TMO2 slabs tend to be strengthened by K-doping, which efficiently facilitates reversible local structural change. Operando X-ray diffraction (XRD) further confirms more reversible phase changes during the charge/discharge for the cathode after K-doping. Density functional theory (DFT) calculations suggest that oxygen redox reaction in Na0.62K0.03Ni0.11Cu0.22Mn0.67O2 cathode has been remarkably suppressed as the nonbonding O 2p states shift down in the energy. This is further corroborated experimentally by resonant inelastic X-ray scattering (RIXS) spectroscopy, ultimately proving the role of K+ incorporated in the Na layer.

Covalent post-synthetic modification of MOFs as a fluorescent sensor for the efficient detection of the biomarker of cystinuria.

Cystinuria is a genetic disorder, and in severe cases, it might lead to kidney failure. As an important biomarker for cystinuria, the level of arginine (Arg) in urine is a vital indicator for cystinuria screening. Therefore, it is urgently needed to detect Arg with high selectivity and sensitivity. In this work, a boric acid functionalized Zr-based metal-organic framework UiO-PhbA is prepared by grafting phenylboronic acid on UiO-66-NH2 through a Schiff base reaction using a covalent post-synthesis modification (CPSM) strategy. The prepared UiO-PhbA exhibits a sensitive and specific fluorescence "turn-on" response to Arg and can be exploited to detect Arg in human serum and urine samples with a broad linear range of 0.6-350 µM and low limit of detection (LOD) of 18.45 nM. This study provides a new and reliable rapid screening protocol for sulfite oxidase deficiency-related diseases.

Defluorination of Organofluorine Compounds Using Dehalogenase Enzymes from Delftia acidovorans (D4B).

Organofluorine compounds have been widely used as pharmaceuticals, agricultural pesticides, and water-resistant coatings for decades; however, these compounds are recognized as environmental pollutants. The capability of microorganisms and enzymes to defluorinate organofluorine compounds is both rare and highly desirable to facilitate environmental remediation efforts. Recently, a strain of Delftia acidovorans (D4B) was identified with potential biodegradation activity toward perfluoroalkyl substances (PFAS) and other organofluorine compounds. Genomic analysis found haloacid and fluoroacetate dehalogenases as enzymes associated with Delftia acidovorans. Here, defluorination activity of these enzymes toward different fluorinated substrates was investigated after their recombinant expression and purification from E. coli. Using an electrochemical fluoride probe, 19F NMR, and mass spectrometry to monitor defluorination, we identified two dehalogenases, DeHa2 (a haloacid dehalogenase) and DeHa4 (a fluoroacetate dehalogenase), with activity toward mono- and difluoroacetate. Of the two dehalogenases, DeHa4 demonstrated a low pH optimum compared to DeHa2, which lost catalytic activity under acidic conditions. DeHa2 and DeHa4 are relatively small proteins, operate under aerobic conditions, and remain active for days in the presence of substrates. Significantly, while there have been many reports on dehalogenation of monofluoroacetate by dehalogenases, this study adds to the relatively small list of enzymes reported to carry out enzymatic defluorination of the more recalcitrant disubstituted carbon in an organofluorine compound. Thus, DeHa2 and DeHa4 represent organofluorine dehalogenases that may be used in the future to design and engineer robust defluorination agents for environmental remediation efforts.

Alterations of resting-state network dynamics in Alzheimer's disease based on leading eigenvector dynamics analysis.

Alzheimer's disease (AD) is a neurodegenerative disease, and mild cognitive impairment (MCI) is considered a transitional stage between healthy aging and dementia. Early detection of MCI can help slow down the progression of AD. At present, there are few studies exploring the characteristics of abnormal dynamic brain activity in AD. This article uses a method called Leading Eigenvector Dynamics Analysis (LEiDA) to study resting-state functional magnetic resonance imaging (rs-fMRI) data of AD, MCI, and cognitively normal (CN) participants. By identifying repetitive states of phase coherence, inter group differences in brain dynamic activity indicators are examined. And the neurobehavioral scales were used to assess the relationship between abnormal dynamic activities and cognitive function. The results showed that in the indicators of occurrence probability and lifetime, the globally synchronized state of the patient group decreased. The activity state of the limbic regions significantly detected the difference between AD and the other two groups. Compared to CN, AD and MCI have varying degrees of increase in default and visual regions activity states. In addition, in the analysis related to the cognitive scales, it was found that individuals with poorer cognitive abilities were less active in the globally synchronized state, and more active in limbic regions activity state and visual regions activity state. Taken together, these findings reveal abnormal dynamic activity of resting-state networks in patients with AD and MCI, provide new insights into the dynamic analysis of brain networks, and contribute to a deeper understanding of abnormal spatial dynamic patterns in AD patients.

NIR-Remote Selectively Triggered Buprenorphine Hydrochloride Release from Microneedle Patches for the Treatment of Neuropathic Pain.

Neuropathic pain is a prevalent form of intermittent chronic pain, affecting approximately 7-10% of the global population. However, the current clinical administration methods, such as injection and oral administration, are mostly one-time administration, which cannot achieve accurate control of pain degree and drug dose. Herein, we developed near-infrared (NIR) light-responsive microneedle patches (MNPs) to spatiotemporally control the drug dose released to treat neuropathic pain according to the onset state. The mechanism of action utilizes upconversion nanoparticles to convert NIR light into visible and ultraviolet light. This conversion triggers the rapid rotation of the azobenzene molecular motor in the mesoporous material, enabling the on-demand controlled release of a drug dose. Additionally, MNs are used to overcome the barrier of the stratum corneum in a minimally invasive and painless manner, effectively promoting the transdermal penetration of drug molecules. The effectiveness of these patches has been demonstrated through significant results. Upon exposure to NIR light for five consecutive cycles, with each cycle lasting 30 s, the patches achieved a precise release of 318 µg of medication. In a mouse model, maximum pain relief was observed within 1 h of one cycle of NIR light exposure, with the effects lasting up to 6 h. The same level of precise treatment efficacy was maintained for subsequent pain episodes with similar light exposure. The NIR-controlled drugs precision-released MNPs provide a novel paradigm for the treatment of intermittent neuropathic pain.

The first two complete mitochondrial genomes for the genus Anagyrus (Hymenoptera, Encyrtidae) and their phylogenetic implications.

Anagyrus, a genus of Encyrtidae (Hymenoptera, Chalcidoidea), represents a successful group of parasitoid insects that attack various mealybug pests of agricultural and forestry plants. Until now, only 20 complete mitochondrial genomes have been sequenced, including those in this study. To enrich the diversity of mitochondrial genomes in Encyrtidae and to gain insights into their phylogenetic relationships, the mitochondrial genomes of two species of Anagyrus were sequenced, and the mitochondrial genomes of these species were compared and analyzed. Encyrtid mitochondrial genomes exhibit similarities in nucleotide composition, gene organization, and control region patterns. Comparative analysis of protein-coding genes revealed varying molecular evolutionary rates among different genes, with six genes (ATP8, ND2, ND4L, ND6, ND4 and ND5) showing higher rates than others. A phylogenetic analysis based on mitochondrial genome sequences supports the monophyly of Encyrtidae; however, the two subfamilies, Encyrtinae and Tetracneminae, are non-monophyletic. This study provides valuable insights into the phylogenetic relationships within the Encyrtidae and underscores the utility of mitochondrial genomes in the systematics of this family.

Bedside ultrasound-assisted puncture and drainage under local anesthesia: A novel approach for early post-operative space-occupying tumor bed cysts of glioma resection.

OBJECTIVES: To investigate the causes of space-occupying tumor bed cysts formed early after glioma resection by measuring the osmotic pressure gradient between cystic fluid, serum, and cerebrospinal fluid (CSF) and propose a new method of bedside ultrasound-assisted puncture and drainage (UAP&D) under local anesthesia for treatment. METHODS: Bedside UAP&D under local anesthesia was performed through a burr hole on the skull flap.Following a successful puncture, cystic fluid was collected, while blood and CSF were obtained through vein and lumbar puncture, respectively. The osmotic pressure of all fluids collected was measured. The appearance, biochemical composition, and results of microbial culture of cystic fluid and CSF were analyzed. Within 24 h after UAP&D, a CT examination and Glasgow coma scale (GCS) were assessed. RESULTS: The osmotic pressure of cystic fluid was higher than that of serum and CSF. White blood cell count and protein concentration were higher in the cystic fluid compared to the CSF. Conversely, the concentration of chloride ions and glucose were lower. CT scan confirmed the correct placement of the cysts' drainage tube and that the cysts' volume decreased significantly with continued drainage. Accompanied by a reduction in the volume of cysts, there were significant improvements in GCS score within 24 h after UAP&D. All drainage tubes were removed within 2-5 days, and no puncture tract hemorrhage or infection was observed. CONCLUSION: The osmotic pressure gradient between cystic fluid, serum, and CSF caused the formation of early post-operative space-occupying tumor bed cysts for glioma. UAP&D aligns with the concept that micro-invasive neurosurgery is an effective treatment method for such cysts.

Polar Solvent-Induced Spontaneous Nanofoaming for Synthesizing Ultra-High-Performance Polyamide Nanofiltration Membranes.

Nanofiltration membranes with both high water permeance and selectivity are perpetually studied because of their applications in water purification. However, these two critical attributes are considered to be mutually exclusive. Here, we introduce a polar solvent, dichloromethane, in place of the apolar hexane used for decades as the organic phase for membrane interfacial polymerization synthesis to solve this dilemma. When a polar solvent as the organic phase is combined with a solvent-resistant aramid nanofibrous hydrogel film as the water phase, monomer enrichment in the reaction zone leads to a polyamide nanofiltration membrane with densely distributed nanobubble features, enhanced nanoporosity, and a loosened backbone. Benefiting from these structural features, the resulting membrane exhibits superior properties with a combination of high water permeance (52.7 L m-2 h-1 bar-1) and selectivity (water/Na2SO4, 36 bar-1; NaCl/Na2SO4, 357 bar-1), outperforming traditional nanofiltration membranes. We envision that this novel technology involving polar solvent systems and the water phase of nanofibrous hydrogel would provide new opportunities for membrane development for environmental engineering.

Engineered AAV13 variants with enhanced transduction and confined spread.

Precise targeting of specific regions within the central nervous system (CNS) is crucial for both scientific research and gene therapy in the context of brain diseases. Adeno-associated virus 13 (AAV13) is known for its restricted diffusion range within the CNS, making it an ideal choice for precise labeling and administration within small brain regions. However, AAV13 mediates relatively low expression of target genes. Here, we introduced specifically engineered modifications to the AAV13 capsid protein to enhance its transduction efficiency. We first constructed AAV13-YF by mutating tyrosine to phenylalanine on the surface of the AAV13 capsid. We then inserted the 7m8 peptide, known to enhance cell transduction, into positions 587/588 and 585/586 of the AAV13 capsid, resulting in two distinct variants named AAV13-587-7m8 and AAV13-585-7m8, respectively. We found that AAV13-YF exhibited superior in vitro infectivity in HEK293T cells compared to AAV13, while AAV13-587-7m8 and AAV13-585-7m8 showed enhanced CNS infection capabilities in C57BL/6 mice, with AAV13-587-7m8 infection retaining a limited spread range. These modified AAV13 variants hold promising potential for applications in gene therapy and neuroscience research.

7D High-Dynamic Spin-Multiplexing.

Multiplexing technology creates several orthogonal data channels and dimensions for high-density information encoding and is irreplaceable in large-capacity information storage, and communication, etc. The multiplexing dimensions are constructed by light attributes and spatial dimensions. However, limited by the degree of freedom of interaction between light and material structure parameters, the multiplexing dimension exploitation method is still confused. Herein, a 7D Spin-multiplexing technique is proposed. Spin structures with four independent attributes (color center type, spin axis, spatial distribution, and dipole direction) are constructed as coding basic units. Based on the four independent spin physical effects, the corresponding photoluminescence wavelength, magnetic field, microwave, and polarization are created into four orthogonal multiplexing dimensions. Combined with the 3D of space, a 7D multiplexing method is established, which possesses the highest dimension number compared with 6 dimensions in the previous study. The basic spin unit is prepared by a self-developed laser-induced manufacturing process. The free state information of spin is read out by four physical quantities. Based on the multiple dimensions, the information is highly dynamically multiplexed to enhance information storage efficiency. Moreover, the high-dynamic in situ image encryption/marking is demonstrated. It implies a new paradigm for ultra-high-capacity storage and real-time encryption.

S-ketamine Infusion on Chronic Postoperative Pain Following Breast Cancer Surgery: A Randomized Double-Blind Placebo-Controlled Trial.

BACKGROUND: Chronic postoperative surgical pain (CPSP) is a frequent complication following breast surgery and poses a challenge in terms of treatment. We hypothesized that the incidence of CPSP would be reduced at 3 months post-breast surgery with the administration of S-ketamine compared to a placebo. PATIENTS AND METHODS: Participants were recruited and randomly assigned to either the S-ketamine group (S) or the control group (C). In group S, S-ketamine was administered as a 1.5 mg kg-1 bolus followed by 2 mg kg-1h-1 infusion, while in group C, a placebo of 0.9% saline was administered in the same volume and rate as S-ketamine. The primary outcome was the incidence of CPSP, measured using a 0-10 numeric rating scale (NRS), at 3 months postsurgery. RESULTS: A total of 72 patients scheduled for mastectomy were enrolled (group S, n = 33; group C, n = 32). The incidence of CPSP at 3 months postsurgery was significantly lower in group S compared to group C (18.2% vs. 48.3%, P < .05). There was no statistical difference between the 2 groups in terms of the incidence of moderate to severe pain. NRS scores for postoperative pain at rest and during movement were significantly lower at 4 h and 24 h post-surgery (P < .05, respectively). Patients in Group S had lower Patient Health Questionnaire-9 (PHQ-9) scores at one week and 3 months post-surgery compared to Group C (P < .05, respectively). CONCLUSION: S-ketamine infusion reduces the incidence of CPSP 3 months after breast surgery.

Discovery of a Novel and Potent LCK Inhibitor for Leukemia Treatment via Deep Learning and Molecular Docking.

The lymphocyte-specific protein tyrosine kinase (LCK) plays a crucial role in both T-cell development and activation. Dysregulation of LCK signaling has been demonstrated to drive the oncogenesis of T-cell acute lymphoblastic leukemia (T-ALL), thus providing a therapeutic target for leukemia treatment. In this study, we introduced a sophisticated virtual screening strategy combined with biological evaluations to discover potent LCK inhibitors. Our initial approach involved utilizing the PLANET algorithm to assess and contrast various scoring methodologies suitable for LCK inhibitor screening. After effectively evaluating PLANET, we progressed to devise a virtual screening workflow that synergistically combines the strengths of PLANET with the capabilities of Schrödinger's suite. This integrative strategy led to the efficient identification of four potential LCK inhibitors. Among them, compound 1232030-35-1 stood out as the most promising candidate with an IC50 of 0.43 nM. Further in vitro bioassays revealed that 1232030-35-1 exhibited robust antiproliferative effects on T-ALL cells, which was attributed to its ability to suppress the phosphorylations of key molecules in the LCK signaling pathway. More importantly, 1232030-35-1 treatment demonstrated profound in vivo antileukemia efficacy in a human T-ALL xenograft model. In addition, complementary molecular dynamics simulations provided deeper insight into the binding kinetics between 1232030-35-1 and LCK, highlighting the formation of a hydrogen bond with Met319. Collectively, our study established a robust and effective screening strategy that integrates AI-driven and conventional methodologies for the identification of LCK inhibitors, positioning 1232030-35-1 as a highly promising and novel drug-like candidate for potential applications in treating T-ALL.

Surface nanocoating-based universal platform for programmed delivery of microorganisms in complicated digestive tract.

Microbial therapies have promising applications in the treatment of a broad range of diseases. However, effective colonization of the target region by therapeutic microorganisms remains a significant challenge owing to the complexity of the intestinal system. Here, we developed surface nanocoating-based universal platform (SNUP), which enabled the manipulation of controlled release and targeted colonization of therapeutic microbes in the digestive tract without the utilization of any targeting molecules. The system controlled the decomposition time of SNUP in the gut by regulating different modification layers and modification sequences on the microorganism's surface, so that the microorganism was released at a predetermined time and space. With the SNUP nanomodification technology, we could effectively deliver therapeutic microorganisms to specific complex intestinal regions such as the small intestine and colon, and protect the bioactivity of therapeutic microorganisms from destruction by both strong acids and digestive enzymes. In this study, we found that two layers SNUP-encapsulated Liiliilactobacillus salivarius (LS@CCMC) could efficiently colonize the small intestine and significantly improve the symptoms of a mouse model of Parkinson's disease through sustained secretion of γ-aminobutyric acid (GABA). This surface nanocoating-based universal platform system does not require the design of specific targeting molecules, providing a simple and universal method for colonized microbial therapy, target theranostics, precision medicine, and personalized medicine.

Near-Field Microwave Imaging Method of Monopole Antennas Based on Nitrogen-Vacancy Centers in Diamond.

Visualizing the near-field distribution of microwave field in a monopole antenna is very important for antenna design and manufacture. However, the traditional method of measuring antenna microwave near field distribution by mechanical scanning has some problems, such as long measurement time, low measurement accuracy and large system volume, which seriously limits the measurement effect of antenna microwave near field distribution. In this paper, a method of microwave near-field imaging of a monopole antenna using a nitrogen-vacancy center diamond is presented. We use the whole diamond as a probe and camera to achieve wide-field microwave imaging. Because there is no displacement structure in the system, the method has high time efficiency and good stability. Compared with the traditional measurement methods, the diamond probe has almost no effect on the measured microwave field, which realizes the accurate near-field imaging of the microwave field of the monopole antenna. This method achieves microwave near-field imaging of a monopole antenna with a diameter of 100 µm and a length of 15 mm at a field of view of 5 × 5 mm, with a spatial resolution of 3 µm and an imaging bandwidth of 2.7~3.2 GHz, and an optimal input microwave phase resolution of 0.52° at a microwave power of 0.8494 W. The results provide a new method for microwave near-field imaging and measurement of monopole antennas.

Optimization of "vehicle-UAV" joint distribution routing for cold chain logistics considering risk of epidemic spreading and green cost.

To address the epidemic, such as COVID-19, the government may implement the home quarantine policy for the infected residents. The logistics company is required to control the risk of epidemic spreading while delivering goods to residents. In this case, the logistics company often uses vehicles and unmanned aerial vehicles (UAVs) for delivery. This paper studies the distribution issue of cold chain logistics by integrating UAV logistics with epidemic risk management innovatively. At first, a "vehicle-UAV" joint distribution mode including vehicles, small UAVs and large UAVs, is proposed. The green cost for vehicles and UAVs is calculated, respectively. The formula for infection risk due to large numbers of residents gathering at distribution centers to pick up goods is then derived. Furthermore, based on the control of infection risk, an optimization model is developed to minimize the total logistics cost. A modified ant colony algorithm is designed to solve the model. The numerical results show that the maximum acceptable risk and the crowd management level of distribution centers both have significant effects on the distribution network, logistics cost and number of new infections. Our study provides a new management method and technical idea for ensuring the needs of residents during the epidemic.

Theoretical and kinetic study of the H-atom abstraction reactions by H atom from alkyl cyclohexanes.

Reaction kinetics of hydrogen atom abstraction from six alkyl cyclohexanes, methyl cyclohexane (MCH), ethyl cyclohexane (ECH), n-propyl cyclohexane (nPCH), iso-propyl cyclohexane (iPCH), sec-butyl cyclohexane (sBCH) and iso-butyl cyclohexane (iBCH), by the H atom are systematically studied in this work. The M06-2X method combined with the 6-311++G(d,p) basis set is used to perform geometry optimization, frequency analysis and zero-point energy calculations for all species. The intrinsic reaction coordinate (IRC) calculations are performed to confirm the transition states connecting the reactants and products correctly. One-dimensional hindered rotors are used to treat the low frequency torsional models with potentials scanned at the M06-2X/6-31G level of theory. Electronic single-point energy calculations for all reactants, transition states, and products are performed at the QCISD(T)/CBS level of theory. High-pressure limiting rate constants of 39 reaction channels are obtained using conventional transition state theory with asymmetric Eckart tunneling corrections in the temperature range 298.15-2000 K. Reaction rate rules for H-atom abstraction by the H atom from alkyl cyclohexanes on primary, secondary and tertiary carbon sites on both the side chain and ring are provided. The obtained rate constants are given by the Arrhenius expression in the temperature range 500-2000 K, which can be used for the combustion kinetics model development for alkyl cyclohexanes.

First-Principles Study of the Schottky Contact, Tunneling Probability, and Optical Properties of MX/TiB4 Heterojunctions (M = Ge, Sn; X = S, Se, Te): Strain Engineering Tunability.

Designing two-dimensional (2D) heterojunctions with rapid response and minimal energy consumption holds immense significance for the advancement of the next generation of electronic devices. Here, we construct a series of Schottky heterojunctions based on TiB4 monolayer and group-IV monochalcogenide monolayers MX (M = Ge, Sn; X = S, Se, Te). Using first-principles calculations, we investigate the structural stability, Schottky contact barrier, tunneling probability, and optical properties of MX/TiB4 heterojunctions. The calculated binding energies reveal that X-type MX/TiB4 heterojunctions exhibit more stable structures than M- and C-type stacking modes. Schottky barrier heights (SBHs) indicate that X-type GeSe/TiB4 and GeTe/TiB4 form n-type Schottky contacts with SBHs of 0.497 and 0.132 eV, respectively, while SnS/TiB4 and SnSe/TiB4 form p-type Schottky contacts with SBHs of 0.557 and 0.418 eV, respectively. Moreover, X-type MX/TiB4 heterojunctions exhibit high susceptibility to interlayer electron tunneling due to their large tunneling probability and strong interlayer interaction. Meanwhile, enhanced optical absorption capacity in MX/TiB4 heterojunctions is also observed compared with individual TiB4 and MX monolayers. By applying in-plane biaxial strain, the transformation of MX/TiB4 heterojunctions from a Schottky contact to an Ohmic contact can also be realized. Our findings could offer valuable candidate materials and guidance for the design of the next generation of nanodevices with high electronic and optical performances.