[Virtual reconstruction and clinical verification of maxillary defect based on deep learning]

Objective: To construct a virtual reconstruction method including midspan maxillary defects and provide clinical reference by training a generative adversarial network (GAN) model. Methods: The CT data of middle-aged Han patients with oral diseases who visited the Department of Radiology, West China Hospital of Stomatology, Sichuan University from June 2015 to June 2022 were collected, where the CT data of 100 healthy maxilla and 15 maxillary defects (5 simple unilateral defects, 5 unilateral defects involving zygomatic bone, 5 midspan defects) were selected. Mimics was used to create spherical phantom and simulate bone defects around the healthy maxillas, including simple unilateral defects, unilateral defects involving zygomatic bone and midspan defects. The original image was set as the correct reference for the reconstruction: artificial defects paired with the correct reference were divided into training set (n=70), validation set (n=20) and test set (n=10), where the first two were used to train the GAN model, and the test set was used to evaluate the GAN performance. Data from 15 clinical defects were imported into the trained GAN model for reconstruction, with mirroring and GAN-based virtual reconstruction for unilateral clinical defects, and only the latter method was adopted for midspan defects. The reconstruction results were divided into mirror reconstruction group (n=10), unilateral defect GAN reconstruction group (n=10) and midspan defect GAN reconstruction group (n=5). The test set, mirror reconstruction group, and unilateral defect GAN reconstruction group were quantitatively evaluated, whose quantitative indicators were Dice similarity coefficient (DSC) and 95% Hausdorff distance (HD95), and the group results were subjected to one-way ANOVA and Tukey test. The test set, mirror reconstruction group, unilateral defect GAN reconstruction group and midspan defect GAN reconstruction group were qualitatively scored, and Kruskal-Wallis test and Bonferroni correction were used for the total score of each group. Results: The total differences in the test set, mirror reconstruction group, unilateral defect GAN reconstruction group DCS (0.891±0.049, 0.721±0.047, 0.778±0.057, respectively) and HD95 [(3.58±1.51), (5.19±1.38), (4.51±1.10) mm, respectively] were statistically significant (F=28.08, P<0.001; F=3.62, P=0.041); among them, the test set DSC was significantly larger than the mirror reconstruction group (P<0.05), and the test set HD95 was significantly less than the mirror reconstruction group (P<0.05). Overall difference in qualitative total scores [8 (1), 6 (2), 6 (2), and 4 (2) points, respectively] in the test set, mirror reconstruction group, unilateral defect GAN reconstruction group, and midspan defect GAN reconstruction group were statistical significance (H=18.13, P<0.001); pairwise comparison showed that the total score of the test set was significantly higher than that of the mirror reconstruction group (P<0.05). Conclusions: The virtual reconstruction method based on GAN proposed in this study has better virtual reconstruction effect of unilateral defect than mirror technique, and can also realize virtual reconstruction of maxillary midspan defect.

Heart failure across the range of preserved ejection fraction in United States clinical practice

Introduction

Recent clinical trials of heart failure with preserved ejection fraction (HFpEF) have observed varying patient profiles by ejection fraction (EF), with attenuation of treatment benefits as EF increases. In routine clinical practice, the degree to which patients hospitalized for HF with EF≥60% may differ from those with lower EF is unknown.

Purpose

To compare patient characteristics, treatment patterns, and clinical outcomes across the range of EF among patients hospitalized for HFpEF.

Methods

Using the Humedica electronic medical records database between Jan 2010 and Dec 2020, patients hospitalized for a primary diagnosis of HF with EF&gt;40% and who were haemodynamically stable at admission, without concurrent acute coronary syndrome or end-stage renal disease, and treated with intravenous (IV) diuretic agents within 48 h of admission were identified. Patient characteristics, treatment patterns, and clinical outcomes were compared by EF ranges of 41–49%, 50–59%, and ≥60%.

Results

Of 47,026 patients hospitalized with HFpEF, 6,335 (13%) had EF 41–49%, 18,603 (40%) had EF 50–59%, and 22,088 (47%) had EF≥60%. Across all 3 groups, patients were similar with respect to age (median 77 years for each group), race (83–84% White, 12–13% Black), systolic blood pressure (137–138 mmHg at admission), and eGFR (63–64 mL/min/1.73 m2 at admission). With progressively higher EF group, the proportion of women increased (45% vs 54% vs 65%) and median NT-proBNP decreased (4,221 vs 2,945 vs 2,234 pg/mL). Patients with EF ≥60% had the lowest rates of coronary artery disease and atrial fibrillation, and the highest rates of chronic pulmonary disease (Figure 1, Panel A). Discharge medications were generally similar, with exception of less beta-blocker use and more calcium channel blocker use among those with EF ≥60% (Figure 1, Panel B). Discharge use of angiotensin receptor-neprilysin inhibitor and sodium glucose cotransporter-2 inhibitor therapies were each &lt;1% in all groups. Hospital length of stay (median 4 days for each group) and in-hospital mortality (1.1–1.3%) were similar across groups, but rates of in-hospital acute respiratory failure were higher among patients with EF ≥60% (27% vs 230-25% for lower EF groups). Rates of 30-day and 12-month post-discharge clinical events were high irrespective of EF, without meaningful differences between groups (Figure 2).

Conclusion

In a contemporary real-world population of US patients hospitalized for HF with EF &gt;40%, nearly half had an EF≥60%. While clinical profiles and discharge medications varied, post-discharge outcomes were similarly poor irrespective of EF. There remain important opportunities to improve the care and outcomes for patients with HF across the range of preserved ejection fraction.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): MyoKardia, Inc., a wholly owned subsidiary of Bristol Myers Squibb

Impact of weight loss on cardiac function: improvement in left ventricular global longitudinal strain following metabolic surgery

Introduction

Obesity leads to an increased risk of cardiovascular disease (CVD) morbidity and mortality and is associated with the metabolic risk factors such as hypertension, diabetes mellitus, hyperlipidemia [1]. Metabolic surgery has been proven to be the most effective long term weight management tool and has known benefits in CVD prevention [2]. Global longitudinal strain (GLS) is an effective quantitative measurement of left ventricular (LV) function that is also a powerful predictor of future CVD events and mortality [3]. The impact of metabolic surgery on LV structure and function is unknown.

Purpose

This study investigated the changes in cardiac structure and function after metabolic surgery, including GLS. To our knowledge there has not been a study investigating this relationship previously reported.

Methods

Consecutive patients undergoing metabolic surgery at our center between March 2005 and February 2019 were recruited. Patients with transthoracic echocardiographic imaging (TTE) pre and post metabolic surgery (May 2005 to January 2019) were included. Electronic medical records were searched to obtain demographic, surgical and clinical data. GLS was calculated with Velocity Vector Imaging (VVI, Siemens, v2.0, Pennsylvania, USA). Averaged GLS values were derived from 4 chamber, 2 chamber and 3 chamber calculations.

Results

398 patients with pre- and post-operative cardiac imaging were included. Please see Table 1 for the baseline demographics of our study population. The mean age was 60.0 years with 70% being female. There were significant rates of CVD risk factors such as: hypertension (76.4%), diabetes mellitus (58.8%) and hyperlipidemia (76.4%).

The clinical and echocardiographic changes noted post metabolic surgery are detailed in Table 2. Along with decreases in weight post operatively, there were significant improvements in the markers of CVD risk factors such as mean blood pressure (134/75 to 129/72 mmHg, p value &lt;0.001), mean gylcated hemoglobin levels (7.0 to 6.1%, p value &lt;0.001) and mean low density lipoprotein (LDL) levels (97.7 to 88.2 mg/dl, p value &lt;0.001).

There were a number of statistically significant positive changes in the left ventricular structure and function. The mean LV ejection fraction increased from 56.3% to 57.4% (p=0.008); left ventricular mass decreased from 238.2 g to 179.3 g (p value &lt;0.001), and both septal and posterior wall thicknesses decreased significantly (p value &lt;0.001). The LV mass indexed to body surface area (BSA) also decreased from 93.5 g/m2 to 83.1 g/m2.

The average global LV GLS was −15.7% pre-operatively, improving significantly to −17.9% post-operatively (p&lt;0.001).

Conclusion

Our study has shown for the first time the impact of metabolic surgery on ventricular structure and function, with reduction in LV mass and improvement in LV GLS. These novel findings lends further support to the cardiovascular benefits of metabolic surgery.

Funding Acknowledgement

Type of funding sources: None.

Multimodality imaging predictors of appropriate ICD shock and mortality in adults with cardiac sarcoidosis

Background

Identifying patients with cardiac sarcoidosis (CS) who are at increased risk of sudden cardiac death (SCD) is imperative. Current guideline recommendations for implantable cardioverter-defibrillator (ICD) implantation in patients with CS are based on small observational studies and have not been validated in contemporary cohorts using multimodality cardiac imaging.

Purpose

The aim of this study was to characterize a cohort of patients with tissue-proven cardiac sarcoidosis who underwent multimodality cardiac imaging and identify predictors of appropriate ICD shock and mortality.

Methods

We retrospectively identified subjects with a diagnosis of CS established by clinical/imaging criteria, and tissue biopsy (N=273) seen at our tertiary care center between 2001 and 2021. Clinical characteristics and outcomes were collected from electronic medical records. The primary endpoint of interest was a composite of appropriate ICD shock and all-cause mortality. Secondary endpoints were individual rates of appropriate ICD shock and all-cause mortality. Cox proportional hazard regression analysis was used to identify independent predictors of the outcomes.

Results

Mean age was 59±11 years and 40% were female. Isolated CS was found in 49 subjects (17.9%). The prevalence of traditional cardiovascular risk factors was low. Atrial fibrillation prevalence was high (41%). After a median follow-up of 7.9 years, the rate of appropriate ICD shock and all-cause mortality was 29% (N=79). The 5-year overall survival rate of 97.5%. Age, left ventricular ejection fraction (LVEF), and delayed gadolinium enhancement (DGE) in cardiac magnetic resonance (CMR) were independent predictors of the primary composite endpoint; LVEF and DGE in CMR were independent predictors of appropriate ICD-shock; and LVEF and baseline serum NT proBNP were independent predictors of overall mortality. An LVEF of 47% was identified as the optimal cutoff in predicting the primary composite endpoint. Presence of scar, inflammation or mismatch pattern in positron emission tomography were not significant predictors of the outcomes.

Conclusion

In this large cohort of subjects with CS, we found that the presence of DGE in CMR was the strongest independent predictor of the composite endpoint of appropriate ICD-shock and mortality and of appropriate ICD-shock individually; LVEF by echocardiogram was an independent predictor of the primary and secondary endpoints with an optimal LVEF cutoff for predicting the composite endpoint of 47%.

Funding Acknowledgement

Type of funding sources: None.

Evaluating the impact of Hartree-Fock exact exchange on the performance of global hybrid functionals for the vertical excited-state energies of fused-ring electron acceptors using TD-DFT

The acceptor-donor-acceptor structured fused-ring electron acceptors (FREAs) have piqued interest for organic solar cells. We herein employ time-dependent density functional theory to evaluate the effect of Hartree-Fock exact exchange (HFX) on the performance of 16 global hybrid functionals for computing the maximum absorption wavelengths (λ_ver-theo) and the vertical excitation energies (E_ver-theo) of 34 molecules. We customize the HFX ratio in the functionals used to perform an in-depth analysis of its impact on the E_ver-theo values. The computed λ_ver-theo values strictly follow an inverse proportionality to the HFX percentage. The performance of the methods with the same ratio of HFX is almost identical, such as B3LYP, B3PW91, and mPW3PBE containing 20% HFX. The performance enhances with a relatively higher HFX ratio of 21% in X3LYP, B971, B972, and 22% in B98 giving smaller deviations. APF and APFD containing 23% HFX provide the smallest deviations for all compounds, with a mean signed error limited to 0.02 eV and a mean absolute error (MAE) of 0.06 eV. The performance drops using M06 and M05 with comparatively higher HFX ratios providing MAE values of 0.07 eV and 0.1 eV, respectively. M06-2X with 54% HFX provides the largest MAE value of 0.35 eV. The lowest obtained MAE is 0.06 eV at 23 to 25% HFX in most of the functionals considered in this study, suggesting that these are the optimal values for the prediction of excitation energies of FREAs. It has also been found that global hybrids seem to be more efficient for larger-sized molecules with a smaller bandgap.

[Antibody levels of measles, rubella and mumps viruses in healthy population in Shanghai from 2010 to 2020]

Objective: To determine IgG antibody levels of measles, rubella, mumps in healthy population in Shanghai from 2010 to 2020 and analyze the trend of antibody changes in different age groups. Methods: 10 828 healthy people without measles, rubella and mumps in Shanghai were included in the study from 2010 to 2020. Serum samples were collected from 12 age groups, and the serum IgG antibody of measles, rubella and mumps were detected by ELISA. The difference of antibody positive rates and antibody levels were analyzed. Results: The median age M (Q₁, Q₃) of 10 828 objects were 8 years old (9 months old, 20 years old). Males accounted for 48.34% (5 234/10 828) and females accounted for 50.92% (5 514/10 828). Unknown gender information accounted for 0.74% (80/10 828), and 27.03% (2 927/10 828) of participants had unknown MMR immunization history. The total positive rates of measles, rubella and mumps IgG antibody were 76.78%, 64.46% and 64.29% and their GMCs were 541.45 mIU/ml, 31.76 IU/ml and 133.73 U/ml respectively. There were significant differences in serum IgG antibody GMC of measles, rubella and mumps in each year (F_measles=180.74, P<0.001; F_rubella=189.95, P<0.001; F_mumps=122.40, P<0.001). The positive rate of measles antibody was higher than that of rubella and mumps, and the difference was statistically significant (χ²=518.09, P<0.001). Conclusion: The level of measles IgG antibody in healthy people in Shanghai is higher, while the level of rubella and mumps IgG antibody is slightly lower.

Design Rules of the Mixing Phase and Impacts on Device Performance in High-Efficiency Organic Photovoltaics

In nonfullerene acceptor- (NFA-) based solar cells, the exciton splitting takes place at both domain interface and donor/acceptor mixture, which brings in the state of mixing phase into focus. The energetics and morphology are key parameters dictating the charge generation, diffusion, and recombination. It is revealed that tailoringthe electronic properties of the mixing region by doping with larger-bandgap components could reduce the density of state but elevate the filling state level, leading to improved open-circuit voltage (V_OC) and reduced recombination. The monomolecular and bimolecular recombinations are shown to be intercorrelated, which show a Gaussian-like relationship with V_OC and linear relationship with short-circuit current density (J_SC) and fill factor (FF). The kinetics of hole transfer and exciton diffusion scale with J_SC similarly, indicating the carrier generation in mixing region and crystalline domain are equally important. From the morphology perspective, the crystalline order could contribute to V_OC improvement, and the fibrillar structure strongly affects the FF. These observations highlight the importance of the mixing region and its connection with crystalline domains and point out the design rules to optimize the mixing phase structure, which is an effective approach to further improve device performance.

Search for an Excess of Electron Neutrino Interactions in MicroBooNE Using Multiple Final-State Topologies

We present a measurement of ν_{e} interactions from the Fermilab Booster Neutrino Beam using the MicroBooNE liquid argon time projection chamber to address the nature of the excess of low energy interactions observed by the MiniBooNE Collaboration. Three independent ν_{e} searches are performed across multiple single electron final states, including an exclusive search for two-body scattering events with a single proton, a semi-inclusive search for pionless events, and a fully inclusive search for events containing all hadronic final states. With differing signal topologies, statistics, backgrounds, reconstruction algorithms, and analysis approaches, the results are found to be either consistent with or modestly lower than the nominal ν_{e} rate expectations from the Booster Neutrino Beam and no excess of ν_{e} events is observed.

Unfused Acceptors Matching π-Bridge Blocks with Proper Frameworks Enable Over 12% As-Cast Organic Solar Cells

Emerging unfused-ring acceptors (UFAs) have been explored in pursuit of low-cost high-efficient organic solar cells (OSCs). Assembling unfused building blocks into proper frameworks are challenging for the molecular design of UFAs. The authors report herein four UFAs adopting either dithiophene cyclopentadiene (DTC) or dithieno[3,2-b:2',3'-d]pyrrole (DTP) as π-bridge units with different molecular frameworks for high-efficient as-cast OSCs. All these acceptors exhibit strong near-infrared absorption and narrow optical band gap (E_g ^opt  < 1.50 eV). DTC-bridged symmetric and DTP-bridged asymmetric UFAs exhibit higher planar conformation as well as suitable miscibility and homogeneous phase separation when blending with polymer donor PBDB-T to promote efficient charge transport in the blends. Their blends with PBDB-T contribute optimal PCE of 12.17% and 11.92% in as-cast OSCs, among the highest values for UFAs based as-cast devices in the literature. Experimental and theoretical simulations systematically reveal the impact of manipulating the molecular framework of UFAs on their conformation, optoelectronic, and photovoltaic performance. The results indicate the matching π-bridge units with molecular frameworks as an attractive approach to design UFAs for high-performance as-cast OSCs.

First Measurement of Energy-Dependent Inclusive Muon Neutrino Charged-Current Cross Sections on Argon with the MicroBooNE Detector

We report a measurement of the energy-dependent total charged-current cross section σ(E_{ν}) for inclusive muon neutrinos scattering on argon, as well as measurements of flux-averaged differential cross sections as a function of muon energy and hadronic energy transfer (ν). Data corresponding to 5.3×10^{19} protons on target of exposure were collected using the MicroBooNE liquid argon time projection chamber located in the Fermilab booster neutrino beam with a mean neutrino energy of approximately 0.8 GeV. The mapping between the true neutrino energy E_{ν} and reconstructed neutrino energy E_{ν}^{rec} and between the energy transfer ν and reconstructed hadronic energy E_{had}^{rec} are validated by comparing the data and Monte Carlo (MC) predictions. In particular, the modeling of the missing hadronic energy and its associated uncertainties are verified by a new method that compares the E_{had}^{rec} distributions between data and a MC prediction after constraining the reconstructed muon kinematic distributions, energy, and polar angle to those of data. The success of this validation gives confidence that the missing energy in the MicroBooNE detector is well modeled and underpins first-time measurements of both the total cross section σ(E_{ν}) and the differential cross section dσ/dν on argon.

Search for Neutrino-Induced Neutral-Current Δ Radiative Decay in MicroBooNE and a First Test of the MiniBooNE Low Energy Excess under a Single-Photon Hypothesis

We report results from a search for neutrino-induced neutral current (NC) resonant Δ(1232) baryon production followed by Δ radiative decay, with a ⟨0.8⟩  GeV neutrino beam. Data corresponding to MicroBooNE's first three years of operations (6.80×10^{20} protons on target) are used to select single-photon events with one or zero protons and without charged leptons in the final state (1γ1p and 1γ0p, respectively). The background is constrained via an in situ high-purity measurement of NC π^{0} events, made possible via dedicated 2γ1p and 2γ0p selections. A total of 16 and 153 events are observed for the 1γ1p and 1γ0p selections, respectively, compared to a constrained background prediction of 20.5±3.65(syst) and 145.1±13.8(syst) events. The data lead to a bound on an anomalous enhancement of the normalization of NC Δ radiative decay of less than 2.3 times the predicted nominal rate for this process at the 90% confidence level (C.L.). The measurement disfavors a candidate photon interpretation of the MiniBooNE low-energy excess as a factor of 3.18 times the nominal NC Δ radiative decay rate at the 94.8% C.L., in favor of the nominal prediction, and represents a greater than 50-fold improvement over the world's best limit on single-photon production in NC interactions in the sub-GeV neutrino energy range.

Preoperative MRI of breast squamous cell carcinoma: diagnostic value of distinguishing between two subtypes

AIM

To retrospectively analyse the clinical and MRI data of primary squamous cell carcinoma (SCC), particularly pure squamous cell carcinoma (PSCC) and mixed squamous cell carcinoma (MSCC).

MATERIALS AND METHODS

The MRI data and clinicopathological characteristics of 20 patients with histopathologically confirmed SCC of the breast, including eight PSCC patients and 12 MSCC patients, from multiple centres between January 2013 and December 2020 were analysed retrospectively.

RESULTS

Nine of 12 patients in the MSCC group showed hyperintensity on T1-weighted imaging (WI), while this feature was not observed in the PSCC group (p=0.001). Most of the PSCC group showed rim enhancement, whereas most of the MSCC group showed heterogeneous enhancement (p=0.007). In addition, there was no significant difference in the thickness of the rim enhancement and the percentage of necrotic components in the tumours between the two types of SCCs of the breast (p=0.545 and p=0.662, respectively). Four patients (4/12) in the MSCC group had sentinel lymph node metastasis, while only one patient (1/8) in the PSCC group showed lymph node metastasis (p=0.603). Metastatic disease occurred in 25% of patients with PSCC and in approximately 41.7% of patients with MSCC.

CONCLUSION

The signal on T1WI and internal enhancement characteristics were the key features for differentiating PSCC and MSCC. Therefore, MRI phenotypes may provide additional information for the pathological classification of breast SCC.

Quasi-Epitaxial Growth of β-Ga2O3-Coated Wide Band Gap Semiconductor Tape for Flexible UV Photodetectors

The epitaxial growth of technically important β-Ga₂O₃ semiconductor thin films has not been realized on flexible substrates due to the limitations of high-temperature crystallization conditions and lattice-matching requirements. We demonstrate the epitaxial growth of β-Ga₂O₃(-201) thin films on flexible CeO₂(001)-buffered Hastelloy tape. The results indicate that CeO₂(001) has a small bi-axial lattice mismatch with β-Ga₂O₃(-201), inducing simultaneous double-domain epitaxial growth. Flexible photodetectors are fabricated on the epitaxial β-Ga₂O₃-coated tape. Measurements reveal that the photodetectors have a responsivity of 4 × 10⁴ mA/W, with an on/off ratio reaching 1000 under 254 nm incident light and 5 V bias voltage. Such a photoelectrical performance is within the mainstream level of β-Ga₂O₃-based photodetectors using conventional rigid single-crystal substrates. More importantly, it remained robust against more than 20,000 bending test cycles. Moreover, the technique paves the way for the direct in situ epitaxial growth of other flexible oxide semiconductor devices in the future.

Prediction of Static Characteristic Parameters of an Insulated Gate Bipolar Transistor Using Artificial Neural Network

Breakdown voltage (BV), on-state voltage (V_on), static latch-up voltage (V_lu), static latch-up current density (J_lu), and threshold voltage (V_th), etc., are critical static characteristic parameters of an IGBT for researchers. V_on and V_th can characterize the conduction capability of the device, while BV, V_lu, and J_lu can help designers analyze the safe operating area (SOA) of the device and its reliability. In this paper, we propose a multi-layer artificial neural network (ANN) framework to predict these characteristic parameters. The proposed scheme can accurately fit the relationship between structural parameters and static characteristic parameters. Given the structural parameters of the device, characteristic parameters can be generated accurately and efficiently. Compared with technology computer-aided design (TCAD) simulation, the average errors of our scheme for each characteristic parameter are within 8%, especially for BV and V_th, while the errors are controlled within 1%, and the evaluation speed is improved more than 10⁷ times. In addition, since the prediction process is mathematically a matrix operation process, there is no convergence problem, which there is in a TCAD simulation.

A Spiro-MeOTAD/Ga2O3/Si p-i-n Junction Featuring Enhanced Self-Powered Solar-Blind Sensing via Balancing Absorption of Photons and Separation of Photogenerated Carriers

Solar blind ultraviolet (SBUV) self-powered photodetectors (PDs) have a great number of applications in civil and military exploration. Ga₂O₃ is a prospective candidate for SBUV detection owing to its reasonable bandgap corresponding to the SBUV waveband. Nevertheless, the previously reported Ga₂O₃ photovoltaic devices had low photoresponse performance and were still far from the demands of practical application. Herein, we propose an idea of using spiro-MeOTAD (spiro) as the SBUV transparent conductive layer to construct p-i-n PDs (p-spiro/Ga₂O₃/n-Si). With the aid of double built-in electric fields, the designed p-i-n PDs could operate without any external power source. Furtherly, the influence of spiro thickness on improving the photoelectric performance of devices is investigated in detail and the optimum device is achieved, translating to a peak responsivity of 192 mA/W upon a weak 254 nm light illumination of 2 μW/cm² at zero bias. In addition, the I-t curve of our PD shows binary response characteristics and a four-stage current response behavior under a small forward bias, and also, its underlying working mechanism is analyzed. In sum, this newly developed device presents great potential for booming the high energy-efficient optoelectronic devices in the short run.

Biosynthesis of a New Fusaoctaxin Virulence Factor in Fusarium graminearum Relies on a Distinct Path To Form a Guanidinoacetyl Starter Unit Priming Nonribosomal Octapeptidyl Assembly

Fusarium graminearum is a pathogenic fungus causing huge economic losses worldwide via crop infection leading to yield reduction and grain contamination. The process through which the fungal invasion occurs remains poorly understood. We recently characterized fusaoctaxin A in F. graminearum, where this octapeptide virulence factor results from an assembly line encoded in fg3_54, a gene cluster proved to be involved in fungal pathogenicity and host adaptation. Focusing on genes in this cluster that are related to fungal invasiveness but not to the biosynthesis of fusaoctaxin A, we here report the identification and characterization of fusaoctaxin B, a new octapeptide virulence factor with comparable activity in wheat infection. Fusaoctaxin B differs from fusaoctaxin A at the N-terminus by possessing a guanidinoacetic acid (GAA) unit, formation of which depends on the combined activities of the protein products of fgm1-3. Fgm1 is a cytochrome P450 protein that oxygenates l-Arg to 4(R)-hydroxyl-l-Arg in a regio- and stereoselective manner. Then, C_β-C_γ bond cleavage proceeds in the presence of Fgm3, a pyridoxal-5'-phosphate-dependent lyase, giving guanidinoacetaldehyde and l-Ala. Rather than being directly oxidized to GAA, the guanidine-containing aldehyde undergoes spontaneous cyclization and subsequent enzymatic dehydrogenation to provide glycociamidine, which is linearized by Fgm2, a metallo-dependent amidohydrolase. The GAA path in F. graminearum is distinct from that previously known to involve l-Arg:l-Gly aminidotransferase activity. To provide this nonproteinogenic starter unit that primes nonribosomal octapeptidyl assembly, F. graminearum employs new chemistry to process l-Arg through inert C-H bond activation, selective C-C bond cleavage, cyclization-based alcohol dehydrogenation, and amidohydrolysis-associated linearization.

Study on the regulation mechanism of lipopolysaccharide on oxidative stress and lipid metabolism of bovine mammary epithelial cells

The long-term feeding of a high-concentrate diet (the concentrate ratio is greater than 60 %) leads to mammary gland inflammatory response in ruminants and decreased quality in dairy cows and affects the robust development of the dairy industry. The main reason is closely related to elevated lipopolysaccharide (LPS) in the body. In this experiment, a bovine mammary epithelial cell line (MAC-T) was used as a model, and LPS at different concentrations (0 ng/ml, 1 ng/ml, 10 ng/ml, 100 ng/ml, 1000 ng/ml, 10000 ng/ml) was added to the cells. The cell survival rate, oxidative stress indicators, total lipid droplet area, triglyceride content and key genes regulating lipid metabolism were detected by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT), assay kit, microscope observation and RT-PCR methods to explore the regulatory mechanism of mammary health and milk fat synthesis. The results showed that compared with those of the control group, the survival rates of cells were significantly decreased after 9 h of stimulation with 1000 ng/ml and 10000 ng/ml LPS (P<0.01). The contents of superoxide dismutase (SOD), catalase (CAT) and total antioxidant capacity (T-AOC) in cells were significantly decreased (P<0.05). Compared with that of the control group, the content of malondialdehyde (MDA) in cells was significantly increased (P<0.05) after stimulation with 10000 ng/ml LPS for 9 h. After 9 h of stimulation with 100 ng/ml, 1000 ng/ml and 10000 ng/ml LPS, the total lipid drop area and triglyceride (TG) content of MAC-T cells were significantly decreased (P<0.05). The expression levels of fatty acid synthesis-related genes Acetyl-CoA carboxylase (ACC) and Stearoyl-CoA desaturase 1 (SCD-1) were significantly decreased after 9 h of stimulation with 100 ng/ml, 1000 ng/ml and 10000 ng/ml LPS (P<0.05), while the expression levels of Fatty Acid synthetase (FAS) were significantly decreased after stimulation with 1000 ng/ml and 10000 ng/ml LPS (P<0.05). TG synthesis by the related gene Diacylglycerol acyltransferase-1 (DGAT1) was significantly lower than that of the control group after stimulation with 1000 ng/ml and 10000 ng/ml LPS for 9 h (P<0.05), and Diacylglycerol acyltransferase-2 (DGAT2) also showed a significant decrease after 10000 ng/ml LPS stimulation (P<0.05). In conclusion, adding different concentrations of LPS to MAC-T cells not only led to a decrease in cell activity, resulting in oxidative damage, but also affected fatty acid and TG synthesis, which may ultimately be closely related to the decrease in milk fat synthesis.

Ultrahigh Gain Solar Blind Avalanche Photodetector Using an Amorphous Ga2O3-Based Heterojunction

Solar blind photodetectors with a cutoff wavelength within the 200-280 nm region is attracting much attention due to their potential civilian and military applications. The avalanche photodetectors (APDs) formed based on wide-bandgap semiconductor Ga₂O₃ are expected to meet emerging technological demands. These devices, however, suffer from limitations associated with the quality of as-grown Ga₂O₃ or the difficulty in alleviating the defects and dislocations. Herein, high-performance APDs incorporating amorphous Ga₂O₃ (a-Ga₂O₃)/ITO heterojunction as the central element have been reliably fabricated at room temperature. The a-Ga₂O₃-based APDs exhibits an ultrahigh responsivity of 5.9 × 10⁴ A/W, specific detectivity of 1.8 × 10¹⁴ Jones, and an external quantum efficiency up to 2.9 × 10⁷% under 254 nm light irradiation at 40 V reverse bias. Notably, the gain could reach 6.8 × 10⁴, indicating the outstanding capability for ultraweak signals detection. The comprehensive superior capabilities of the a-Ga₂O₃-based APDs can be ascribed to the intrinsic carrier transport manners in a-Ga₂O₃ as well as the modified band alignment at the heterojunctions. The trade-off between low processing temperature and superior characteristics of a-Ga₂O₃ promises greater design freedom for realization of wide applications of emerging semiconductor Ga₂O₃ with even better performance since relieving the burden on the integration progress.

Search for a Higgs Portal Scalar Decaying to Electron-Positron Pairs in the MicroBooNE Detector

We present a search for the decays of a neutral scalar boson produced by kaons decaying at rest, in the context of the Higgs portal model, using the MicroBooNE detector. We analyze data triggered in time with the Fermilab NuMI neutrino beam spill, with an exposure of 1.93×10^{20} protons on target. We look for monoenergetic scalars that come from the direction of the NuMI hadron absorber, at a distance of 100 m from the detector, and decay to electron-positron pairs. We observe one candidate event, with a standard model background prediction of 1.9±0.8. We set an upper limit on the scalar-Higgs mixing angle of θ<(3.3-4.6)×10^{-4} at the 95% confidence level for scalar boson masses in the range (100-200)  MeV/c^{2}. We exclude, at the 95% confidence level, the remaining model parameters required to explain the central value of a possible excess of K_{L}^{0}→π^{0}νν[over ¯] decays reported by the KOTO collaboration. We also provide a model-independent limit on a new boson X produced in K→πX decays and decaying to e^{+}e^{-}.