Structural characterization of the virulence factor Sda1 nuclease from Streptococcus pyogenes
Abstract not provided
Moon, Andrea F.↗
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Results for “LU factorization”
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Systems Biology to Improve Camelina Seed and Oil Quality Traits (Final Report)
Camelina has great potential to become a sustainable high energy-yielding source of biofuel in the US. This project aims to address two critical needs for realizing this potential: to increase seed size and oil content for improved seedling establishment and oil yield, and to optimize oil quality for satisfactory fuel properties. Specifically, quantitative trait loci (QTL) and molecular markers associated with these important traits will be identified using high-density genome maps and repeated field trials in Montana and Washington states. Modern genomics and biotechnological approaches will be employed to uncover novel molecular mechanisms (including genes and gene networks regulated by microRNAs and transcription factors) regulating fatty acid modification, oil accumulation and seed size in Camelina.
59 BASIC BIOLOGICAL SCIENCES↗
Investigation of hydrometeorological influences on reservoir releases using explainable machine learning methods
Long short-term memory (LSTM) networks have demonstrated successful applications in accurately and efficiently predicting reservoir releases from hydrometeorological drivers including reservoir storage, inflow, precipitation, and temperature. However, due to its black-box nature and lack of process-based implementation, we are unsure whether LSTM makes good predictions for the right reasons. In this work, we use an explainable machine learning (ML) method, called SHapley Additive exPlanations (SHAP), to evaluate the variable importance and variable-wise temporal importance in the LSTM model prediction. In application to 30 reservoirs over the Upper Colorado River Basin, United States, we show that LSTM can accurately predict the reservoir releases with NSE ≥ 0.69 for all the considered reservoirs despite of their diverse storage sizes, functionality, elevations, etc. Additionally, SHAP indicates that storage and inflow are more influential than precipitation and temperature. Moreover, the storage and inflow show a relatively long-term influence on the release up to 7 days and this influence decreases as the lag time increases for most reservoirs. These findings from SHAP are consistent with our physical understanding. However, in a few reservoirs, SHAP gives some temporal importances that are difficult to interpret from a hydrological point of view, probably because of its ignorance of the variable interactions. SHAP is a useful tool for black-box ML model explanations, but the hydrological processes inferred from its results should be interpreted cautiously. More investigations of SHAP and its applications in hydrological modeling is needed and will be pursued in our future study.
54 ENVIRONMENTAL SCIENCES↗
High-fidelity quantum gates on quantum-dot-confined electron spins in low-Q optical microcavities
We propose some high-fidelity quantum circuits for quantum computing on electron spins of quantum dots (QD) embedded in low-Q optical microcavities, including the two-qubit controlled-NOT gate and the multiple-target-qubit controlled-NOT gate. The fidelities of both quantum gates can, in principle, be robust to imperfections involved in a practical input–output process of a single photon by converting the infidelity into a heralded error. Furthermore, the influence of two different decay channels is detailed. By decreasing the quality factor of the present microcavity, we can largely increase the efficiencies of these quantum gates while their high fidelities remain unaffected. This proposal also has another advantage regarding its experimental feasibility, in that both quantum gates can work faithfully even when the QD-cavity systems are non-identical, which is of particular importance in current semiconductor QD technology.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Modeling few-hole quantum dots in Ge/SiGe: 𝒈-factors and qubit properties
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Brickson, Mitchell Ian↗
Long non-coding RNA MALAT1 interacts with transcription factor Foxo1 to regulate SIRT1 transcription in high glucose-induced HK-2 cells injury
Tubular injury is considered as a crucial pathological feature of diabetic nephropathy. LncRNA MALAT1 is involved in diabetic complications. Hence the role of MALAT1 in high glucose-induced renal tubular epithelial cells (HK-2) injury deserves investigation.
60 APPLIED LIFE SCIENCES↗
Facile and Efficient Decontamination of Thorium from Rare Earths Based on Selective Selenite Crystallization
The coexistence of radioactive contaminants (e.g., thorium, uranium, and their daughters) in rare earth minerals introduces significant environmental, economic, and technological hurdles in modern rare earth production. Capable, low cost, and green decontamination strategies are therefore desired to ameliorate this problem. In this work, we report a single-step and quantitative decontamination strategy of thorium from rare earths based on a unique periodic trend in the formation of crystalline selenite compounds across the lanthanide series, where Ce(III) is fully oxidized in situ to Ce(IV). This gives rise to a crystallization system that is highly selective to trap tetravalent f-blocks while all other trivalent lanthanides completely remain in solution when coexist. These findings are bolstered by first-principles calculations of lattice energies and an examination of bonding in these compounds. This system is contrasted with typical natural and synthetic systems, where trivalent and tetravalent f-block elements often cocrystallize. The separation factors after one round of crystallization were determined from binary systems of Th(IV)/La(III), Th(IV)/Eu(III), and Th(IV)/Yb(III) to reach 2.1 × 10 5 , 1.2 × 10 5 , and 9 × 10 4 , respectively. Selective crystallization of thorium from a simulated monazite composite yields a separation factor of 1.9 × 10 3 with nearly quantitative removal of thorium.
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
Multiscale Characterization of the Influence of the Organic–Inorganic Interface on the Dielectric Breakdown of Nanocomposites
Nanoscale engineered materials such as nanocomposites can display or be designed to enhance their material properties through control of the internal interfaces. In this report we unveil the nanoscale origin and important characteristics of the enhanced dielectric breakdown capabilities of gold nanoparticle/polymer nanocomposites. Our multiscale approach spans from the study of a single chemically designed organic/inorganic interface to micrometer-thick films. At the nanoscale, we relate the improved breakdown strength to the interfacial charge retention capability by combining scanning probe measurements and density functional theory calculations. At the meso- and macroscales, our findings highlight the relevance of the nanoparticle concentration and distribution in determining and enhancing the dielectric properties, as well as identifying this as a crucial limiting factor for the achievable sample size.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Local Recurrence of Benign, Borderline, and Malignant Phyllodes Tumors of the Breast: A Systematic Review and Meta-analysis
Background: This systematic review and meta-analysis aimed to investigate local recurrence (LR) rates among the three grades (benign, borderline, and malignant) of phyllodes tumors (PTs). The study also assessed various risk factors for LR. Methods: Electronic articles published between 1 January 1995 and 31 May 2018, were searched and critically appraised. The authors independently reviewed the abstracts and extracted data for LR rates and LR risk factors. Results: The review incorporated 54 studies with 9234 individual cases. The pooled LR rates were 8% for benign, 13% for borderline, and 18% for malignant PTs. The risk of LR was significantly increased by borderline versus benign PTs (odds ratio [OR] 2.00; 95% confidence interval [CI] 1.68–2.38) and malignant versus borderline PTs (OR 1.28; 95% CI 1.05–1.55). The significant risk factors for LR were mitoses, tumor border (infiltrating vs. pushing), stromal cellularity (moderate/severe vs. mild), stromal atypia (severe vs. mild/absent), stromal overgrowth (severe vs. mild/absent), and tumor necrosis (positive vs. negative). Age and tumor size were not associated with LR risk. The subgroup analysis showed that breast-conserving surgery versus mastectomy and positive versus negative surgical margins were significantly associated with an increased LR risk only in malignant PTs. Conclusions: The risk of LR was significantly increased from benign to borderline to malignant PTs. Mitoses, tumor border, stromal cellularity, stromal atypia, stromal overgrowth, tumor necrosis, type of surgery, and surgical margin status may be risk factors for LR. Different management strategies could be considered for different PT grades.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Influence of site and soil properties on the DRIFT spectra of northern cold-region soils [Influence of site and soil properties on the mid-infrared spectra of northern cold-region soils]
Here, we investigated the influence of site characteristics and soil properties on the chemical composition of organic matter in soils collected from a latitudinal transect across Alaska through analysis of diffuse reflectance Fourier transform mid infrared (MidIR) spectra of bulk soils. The study included 119 soil samples collected from 28 sites including tundra, boreal forest, and grassland ecosystems. Organic, mineral, and cryoturbated soil horizons, both seasonally and perennially frozen, from a variety of depths and edaphic conditions were examined. The amount and chemical composition of organic matter as well as site and soil properties exerted a strong influence on the MidIR spectra. The spectra were highly sensitive to the extent of organic matter decomposition, enabling the ordination of Oi, Oe and Oa organic horizons. Differences in absorbance intensity for several spectral bands indicated that Oi horizons contained greater abundance of relatively fresh residues, phenolic-OH compounds, aliphatic compounds (waxes, lipids and fats), and carbohydrates. In contrast, Oa horizons had a greater presence of amide groups (possibly from microbial residues), aromatics, C=C bonds, carboxylates and carboxylic acids. Another significant factor differentiating these horizons was the incorporation of clays and silicates into the decomposing organic matter of Oa horizons. Calculated height peak ratios showed a clear trend to greater decomposition among Oi, Oe and Oa. The MidIR spectra were related to many site/soil attributes including land cover type, parent material, and associated factors, such as permafrost presence/absence, soil drainage, horizon depth, bulk density, cation exchange capacity, and pH. Single MidIR spectral bands were identified that might be used in future studies to quickly estimate the organic and inorganic carbon, total nitrogen, and carbon:nitrogen ratios of soils from northern latitudes. Lastly, our results demonstrate that the information contained in MidIR spectra of bulk soil integrates the quantity and chemical composition of soil organic matter with soil forming factors and highlights the potential for using this information to assess the degradation state of organic matter stored in northern cold-region soils.
58 GEOSCIENCES↗
Monte Carlo simulations of time-of-flight PET with double-ended readout: calibration, coincidence resolving times and statistical lower bounds
Here, this paper demonstrates through Monte Carlo simulations that a practical positron emission tomograph with (1) deep scintillators for efficient detection, (2) double-ended readout for depth-of-interaction information, (3) fixed-level analog triggering, and (4) accurate calibration and timing data corrections can achieve a coincidence resolving time (CRT) that is not far above the statistical lower bound. One Monte Carlo algorithm simulates a calibration procedure that uses data from a positron point source. Annihilation events with an interaction near the entrance surface of one scintillator are selected, and data from the two photodetectors on the other scintillator provide depth-dependent timing corrections. Another Monte Carlo algorithm simulates normal operation using these corrections and determines the CRT. A third Monte Carlo algorithm determines the CRT statistical lower bound by generating a series of random interaction depths, and for each interaction a set of random photoelectron times for each of the two photodetectors. The most likely interaction times are determined by shifting the depth-dependent probability density function to maximize the joint likelihood for all the photoelectron times in each set. Example calculations are tabulated for different numbers of photoelectrons and photodetector time jitters for three 3 × 3 × 30 mm 3 scintillators: Lu 2 SiO 5 :Ce,Ca (LSO), LaBr 3 :Ce, and a hypothetical ultra-fast scintillator. To isolate the factors that depend on the scintillator length and the ability to estimate the DOI, CRT values are tabulated for perfect scintillator-photodetectors. For LSO with 4000 photoelectrons and single photoelectron time jitter of the photodetector J = 0.2 ns (FWHM), the CRT value using the statistically weighted average of corrected trigger times is 0.098 ns FWHM and the statistical lower bound is 0.091 ns FWHM. For LaBr 3 :Ce with 8000 photoelectrons and J = 0.2 ns FWHM, the CRT values are 0.070 and 0.063 ns FWHM, respectively. For the ultra-fast scintillator with 1 ns decay time, 4000 photoelectrons, and J = 0.2 ns FWHM, the CRT values are 0.021 and 0.017 ns FWHM, respectively. Lastly, the examples also show that calibration and correction for depth-dependent variations in pulse height and in annihilation and optical photon transit times are necessary to achieve these CRT values.
60 APPLIED LIFE SCIENCES↗
Temperature dependent thermoelectric properties of cuprous delafossite oxides
The use of nanostructured delafossite oxides in thermoelectric (TE) applications has attracted a great interest due to their high performance and long-term stability at elevated temperatures. Cuprous delafossites, CuMO 2 (M=Al, Cr, Fe, Ga, Mn), compared to conventional TE materials, such as Bi 2 Te 3 , PbTe and SiGe, are non-toxic and more earth abundant. In particular, CuAlO 2 compound shows a great potential for high performance thermoelectric materials. In this work, a systematic study of temperature dependent TE properties of cuprous delafossite materials, CuAlO 2 , is reported. The optimization of the TE properties has been realized by controlling nanostructure size around 80 nm CuAlO 2 powder was prepared using a solid-state synthesis method at ~1373 K in nitrogen/air atmosphere. The nanostructure size was controlled by a high energy ball milling process. Reducing the particle size of nanostructured bulk materials decouples interdependent electron and phonon transport and results in a lattice thermal conductivity decrease without deteriorating electrical conductivity. As a result, the high effective mass plays a dominant role in the high Seebeck coefficient and low electrical conductivity. The power factor reached ~0.78×10 -5 W/mK 2 at 780 K. Temperature dependent TE properties, including Seebeck coefficient, electrical conductivity, and thermal conductivity are analyzed. The processing-structure-property correlation of these materials are discussed.
36 MATERIALS SCIENCE↗
3-D AM prototyping and the geometric factor on mechanical behavior and property of 316L stainless steel.
Abstract not provided.
Yang, Nancy Y. C.↗
Study on aggregation and electric properties in the micro-region of functionalized dithieno[2, 3-b: 3′, 2′-d]thiophene (DTT) oligomers
Three kinds of 2,5,-diphenyl-dithienol[2, 3-b: 3′, 2′-d]thiophene (DP-DTT), 2,5,-distyryl-dithienol[2, 3-b: 3′, 2′-d]thiophene (DEP-DTT) and 2,5,-thienyl-dithienol[2, 3-b: 3′, 2′-d]thiophene (DET-DTT) micro-region structure and electronic properties were studied. Thin films of these functionalized DTT oligomers were prepared in a one-step drop-casting deposition onto highly oriented pyrolytic graphite substrates. The surface structure of these films was characterized by atomic force microscopy (AFM). Conducting probe atomic force microscope (C-AFM) and Kelvin probe force microscope (KFM) were both used to characterize the electronic transport behavior and surface potential distribution. The substituents of DTT oligomers can greatly affect their aggregation and the hopping conductance mechanism was used to explain the Au-DTTs-HOPG junctions. KFM investigation revealed that these oligomers with different substituents have different highest occupied molecular orbital energy levels. The corresponding theoretical analysis reveals similar result to KFM characterization. The I-V results indicated that the aggregates of molecules were the dominating factor to their micro-region electrical transport.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Lnc-SNHG1 may promote the progression of non-small cell lung cancer by acting as a sponge of miR-497
Highlights: • lnc-SNHG1 promotes the progression of non-small cell lung cancer(NSCLC). • lnc-SNHG1 might modulate cell proliferation, migration and invasion by sponging miR-497. • The effect of lnc-SNHG1 on NSCLC could be rescued by miR-497. • lnc-SNHG1 promotes cancer cell motility in a miR-497-dependent manner via IGF1-R. Lnc-SNHG1 (small nucleolar RNA host gene 1) is considered an important regulating factor in several types of cancers. However, the biological functions and underlying molecular mechanisms in which lnc-SNHG1 is involved in non-small cell lung cancer (NSCLC) still need to be explored. In this study, we investigated the detailed effects and possible molecular mechanisms. The transcript level of lnc-SNHG1 was higher in lung adenocarcinoma specimens and NSCLC cell lines than in noncancer tissue and cells. The level of expression was positively correlated with invasiveness and was negatively correlated with the level of miR-497 in vivo and in vitro. In exploring the regulatory mechanism, we found that lnc-SNHG1 might modulate tumor growth by sponging miR-497. The inhibitory effect of si-lnc-SNHG1 on NSCLC cell proliferation, migration and invasion could be rescued by miR-497 inhibition, while the overexpression of miR-497 could reverse the effect of lnc-SNHG1 overexpression. Furthermore, our study demonstrated that the lnc-SNHG1 regulated the expression of the insulin-like growth factor 1 receptor (IGF1-R) by acting as a sponge of miR-497 in NSCLC. lnc-SNHG1 could be a novel biomarker as well as a curative target.
60 APPLIED LIFE SCIENCES↗
N-oleoylethanolamide suppresses intimal hyperplasia after balloon injury in rats through AMPK/PPARα pathway
Highlights: • OEA alleviates intimal hyperplasia induced by balloon injury. • OEA suppresses VSMC proliferation and migration. • OEA modulats VSMC proliferation and migration partly through AMPK- PPARα pathway. Vascular smooth muscle cell (VSMC) proliferation and migration are crucial events in the pathological course of restenosis after percutaneous coronary intervention (PCI). N-oleoylethanolamide (OEA) is a bioactive lipid amide released upon dietary fat digestion with many reported actions. However, the effect of OEA on restenosis after vascular injury remains unknown. Here, we investigated the effects of OEA on intimal hyperplasia after balloon injury in vivo, its effect on VSMC proliferation and migration induced by platelet-derived growth factor (PDGF) stimulation in vitro, and the underlying mechanism underlying these effects. The results showed that OEA-treated rats displayed a significant reduction in neointima formation after balloon injury. In cultured VSMCs, treatment with OEA decreased cell proliferation and migration induced by PDGF. OEA treatment both in vivo and in vitro led to an increase in adenosine monophosphate-activated protein kinase (AMPK) phosphorylation and peroxisome proliferator-activated receptor alpha (PPARα), and a decrease in proliferating cell nuclear antigen (PCNA) and cyclinD1 expression. Pharmacological inhibition of AMPK and PPARα reversed the suppressive effects of OEA on VSMC proliferation and migration, suggesting that the suppressive effect of OEA on VSMC proliferation and migration is mediated through the activation of AMPK and PPARα. In conclusion, our present study demonstrated that OEA attenuated neointima formation in response to balloon injury by suppressing SMC proliferation and migration through an AMPK and PPARα-dependent mechanism. Our data suggests that OEA may be a potential therapeutic agent for restenosis after PCI.
60 APPLIED LIFE SCIENCES↗
Low expression level of HMBOX1 in high-grade serous ovarian cancer accelerates cell proliferation by inhibiting cell apoptosis
Highlights: • HMBOX1 was significantly downregulated in HGSOC tissues and ovarian cancer cell lines. • There was a negative correlation between the expression of HMBOX1 and cell proliferation of ovarian cancer cell lines. • HMBOX1 inhibited the cell proliferation and promoted the cell apoptosis. • HMBOX1 downregulated the expression of Bcl-2, Bcl-xL and upregulated that of Bad, Bax and Caspase3. Homeobox-containing 1 (HMBOX1) has been described as a transcription factor involved in the occurrence of some tumors, but its roles in ovarian cancer have never been reported. Here we aimed to investigate the roles of HMBOX1 on high-grade serous ovarian carcinoma (HGSOC). In this present study, HMBOX1 expression was decreased in HGSOC tissues and ovarian cancer cell lines (HO8910 and A2780) compared with ovarian surface epithelial tissues or normal human ovarian surface epithelial cell line (HOSEpiC). The cell proliferation of HOSEpiC was weaker than ovarian cancer cell lines. By altering the expression of HMBOX1 in A2780 and HOSEpiC, we demonstrated that HMBOX1 inhibited the cell proliferation and promoted the cell apoptosis. Furthermore, our study revealed that HMBOX1 downregulated the expression of anti-apoptotic proteins (Bcl-2, Bcl-xL), raised the expression of pro-apoptotic-regulated proteins (Bad, Bax), apoptotic executionior (Caspase3), and P53. In conclusion, HMBOX1 played important roles in occurrence of HGSOC through regulation of proliferation and apoptosis, which implied that HMBOX1 might serve as a new therapeutic target for HGSOC.
60 APPLIED LIFE SCIENCES↗
Radiologic Response and Disease Control of Recurrent Intracranial Meningiomas Treated With Reirradiation
To evaluate the clinical outcomes of reirradiation of recurrent meningiomas and factors related to patient selection and treatment modality.
62 RADIOLOGY AND NUCLEAR MEDICINE↗