1,612 research outputs found

    Heartwood Extractives of Maclura Pomifera and Their Role in Decay Resistance

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    A sample of ground heartwood of Maclura pomifera (Raf.) Schneid, was extracted sequentially with hexane, chloroform, and methanol. The dry methanol extract was partitioned between water and ether. The ether fraction was separated by liquid-liquid extraction with aqueous sodium bicarbonate and sodium carbonate solutions to differentiate the phenolics from organic acids and neutral materials. The phenolic components were separated by paper chromatography using benzene-acetic acid-water (125/72/3) as the developing solvent. The separated subfractions were examined quantitatively as well as qualitatively. The fungal toxicities of various extracts, fractions, and subfractions were determined by incorporating each material into nondurable ground wood or wood-base material and then inoculating the sample with one of several wood decay fungi. Fungal growth in wood was measured by respirometry or visual observation. The subfraction with the greatest inhibitory effect on wood decay fungi, as characterized by spectroscopic methods, appears to be a mixture of tetra and pentahydroxystilbenes

    Nasal septal perforation repair with an inferior turbinate flap and acellular dermal matrix

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    Nasal septal perforation is an uncommon disorder that can cause disturbance of nasal physiology. The perforations can vary widely in size, location, and symptomatology. Many different closure techniques have been described in the literature; however, no gold standard has been recognized. The choice of surgical technique usually depends on the characteristics of the perforation and surgeon experience. Due to the goal of perforation repair being restoration of normal nasal physiology, techniques with the best outcomes have been those resurfacing the septum with nasal respiratory mucosa. Here we present our novel surgical method for large (\u3e 2 cm) septal perforation closure using a modification of the inferior turbinate flap repair using a polydioxanone plate and the acellular dermal matrix allograft (Alloderm, Allergan Inc.)

    A novel landscape of nuclear human CDK2 substrates revealed by in situ phosphorylation.

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    Cyclin-dependent kinase 2 (CDK2) controls cell division and is central to oncogenic signaling. We used an in situ approach to identify CDK2 substrates within nuclei isolated from cells expressing CDK2 engineered to use adenosine 5\u27-triphosphate analogs. We identified 117 candidate substrates, ~40% of which are known CDK substrates. Previously unknown candidates were validated to be CDK2 substrates, including LSD1, DOT1L, and Rad54. The identification of many chromatin-associated proteins may have been facilitated by labeling conditions that preserved nuclear architecture and physiologic CDK2 regulation by endogenous cyclins. Candidate substrates include proteins that regulate histone modifications, chromatin, transcription, and RNA/DNA metabolism. Many of these proteins also coexist in multi-protein complexes, including epigenetic regulators, that may provide new links between cell division and other cellular processes mediated by CDK2. In situ phosphorylation thus revealed candidate substrates with a high validation rate and should be readily applicable to other nuclear kinases

    The chlorine isotope fingerprint of the lunar magma ocean

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    The Moon contains chlorine that is isotopically unlike that of any other body yet studied in the Solar System, an observation that has been interpreted to support traditional models of the formation of a nominally hydrogen-free (“dry”) Moon. We have analyzed abundances and isotopic compositions of Cl and H in lunar mare basalts, and find little evidence that anhydrous lava outgassing was important in generating chlorine isotope anomalies, because ^(37)Cl/^(35)Cl ratios are not related to Cl abundance, H abundance, or D/H ratios in a manner consistent with the lava-outgassing hypothesis. Instead, ^(37)Cl/^(35)Cl correlates positively with Cl abundance in apatite, as well as with whole-rock Th abundances and La/Lu ratios, suggesting that the high ^(37)Cl/^(35)Cl in lunar basalts is inherited from urKREEP, the last dregs of the lunar magma ocean. These new data suggest that the high chlorine isotope ratios of lunar basalts result not from the degassing of their lavas but from degassing of the lunar magma ocean early in the Moon’s history. Chlorine isotope variability is therefore an indicator of planetary magma ocean degassing, an important stage in the formation of terrestrial planets

    Ambient seismic noise tomography of Canada and adjacent regions: Part I. Crustal structures

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    This paper presents the first continental-scale study of the crust and upper mantle shear velocity (V_s) structure of Canada and adjacent regions using ambient noise tomography. Continuous waveform data recorded between 2003 and 2009 with 788 broadband seismograph stations in Canada and adjacent regions were used in the analysis. The higher primary frequency band of the ambient noise provides better resolution of crustal structures than previous tomographic models based on earthquake waveforms. Prominent low velocity anomalies are observed at shallow depths (<20 km) beneath the Gulf of St. Lawrence in east Canada, the sedimentary basins of west Canada, and the Cordillera. In contrast, the Canadian Shield exhibits high crustal velocities. We characterize the crust-mantle transition in terms of not only its depth and velocity but also its sharpness, defined by its thickness and the amount of velocity increase. Considerable variations in the physical properties of the crust-mantle transition are observed across Canada. Positive correlations between the crustal thickness, Moho velocity, and the thickness of the transition are evident throughout most of the craton except near Hudson Bay where the uppermost mantle V_s is relatively low. Prominent vertical V_s gradients are observed in the midcrust beneath the Cordillera and beneath most of the Canadian Shield. The midcrust velocity contrast beneath the Cordillera may correspond to a detachment zone associated with high temperatures immediately beneath, whereas the large midcrust velocity gradient beneath the Canadian Shield probably represents an ancient rheological boundary between the upper and lower crust

    Automated Long-Term Monitoring of Parallel Microfluidic Operations Applying a Machine Vision-Assisted Positioning Method

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    As microfluidics has been applied extensively in many cell and biochemical applications, monitoring the related processes is an important requirement. In this work, we design and fabricate a high-throughput microfluidic device which contains 32 microchambers to perform automated parallel microfluidic operations and monitoring on an automated stage of a microscope. Images are captured at multiple spots on the device during the operations for monitoring samples in microchambers in parallel; yet the device positions may vary at different time points throughout operations as the device moves back and forth on a motorized microscopic stage. Here, we report an image-based positioning strategy to realign the chamber position before every recording of microscopic image. We fabricate alignment marks at defined locations next to the chambers in the microfluidic device as reference positions. We also develop image processing algorithms to recognize the chamber positions in real-time, followed by realigning the chambers to their preset positions in the captured images. We perform experiments to validate and characterize the device functionality and the automated realignment operation. Together, this microfluidic realignment strategy can be a platform technology to achieve precise positioning of multiple chambers for general microfluidic applications requiring long-term parallel monitoring of cell and biochemical activities

    Epidemiology and risk factors for Carbapenemase-Producing Enterobacteriaceae carriage in the hospital: a population-based nested case-control study

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    Objective: This study aims to study the epidemiology of Carbapenemase-producing Enterobacteriaceae (CPE) in Hong Kong. / Methods: This is a longitudinal population-based study reporting monthly CPE incidence rate and a nested case-control study for identifying risk factors for CPE carriage. The cases were patients with at least one CPE positive genotypic test, while the controls were randomly selected from the cohort with negative tests. Up to four controls per case were matched by sex, age group, and admission year-month. The independent risk factors were identified from a conditional logistic regression with potential covariates. / Results: From 1st January 2008 to 31st December 2019, 8,588 patients received CPE genotyping tests, and 2,353 had at least one positive result. Class B carbapenemase was the predominant enzyme in the samples (78.6%). The incidence rate increased from 0.04 in 2015 to 1.62 in 2019 per 10,000 person-year. In the nested case-control study, 1709 cases and 6664 controls were matched. Previous use of any beta-lactam antibiotics [Odds ratio:1.37 (1.22-1.53), p<.001] was found as an independent risk factor for carriage of CPE. / Conclusion: The carriage of CPE was found with an increasing trend in Hong Kong. Previous use of any beta-lactam antibiotics is a risk factor for CPE. / Summary: The incidence rate of Carbapenemase-producing Enterobacteriaceae is increasing in Hong Kong, with the predominant enzyme of class B carbapenemase. With multivariable conditional logistic regression, the previous use of any beta-lactam antibiotics was found as an independent risk factor for CPE carriage

    Selective Serotonin Reuptake Inhibitors Are Associated with Increased Bleeding Related Complications Following Primary Total Hip and Total Knee Arthroplasty

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    Introduction: Approximately 10-22% of patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) are diagnosed with depression. Pre-operative depression is associated with poorer patient reported outcomes, costs and increased complications. Selective serotonin-reuptake inhibitors (SSRIs) are first-line treatment for depression due to their efficacy and low side effect profile. There are conflicting studies regarding SSRI-related bleeding complications. This study compares the rate of bleeding-related complications in THA and TKA patients taking SSRI’s to a control group of non-SSRI users. Methods: A retrospective single institution study of 16,407 primary THA and TKA’s from 2008 to 2018 was performed. Patients with THA for fracture, conversion arthroplasty with existing hardware, revision TJA, and uni-compartmental knee arthroplasty. Patients taking SSRIs (2,588) were compared to non-SSRI users (13,819). Patient demographics were reviewed and matched at a 3:1 ratio. Multivariate logistic regression analysis was performed and adjusted to control for potential confounders. Results: Patients on SSRI had a significant increase in transfusion, post-operative anemia, irrigation and debridement (I&D) and superficial infection. There was a trend towards increased hematoma and revision. There was a significantly higher rate of pulmonary embolism for SSRI users compared to non-SSRI. Rates of 1-year PJI, hematoma removal or calculated blood loss did not differ. Discussion: The rate of bleeding related complications is significantly greater in SSRI users undergoing TKA and THA. Poorer outcomes in depression may be due to the intrinsic nature of the disease; however, increased pain due to swelling and wound complications may be due to increased rates of bleeding in SSRI users
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