314 research outputs found

    Microstructure of chemically modified wood using X-ray computed tomography in relation to wetting properties

    Get PDF
    X-ray computed tomography (XCT) was utilized to visualize and quantify the 2D and 3D microstructure of acetylated southern yellow pine (pine) and maple, as well as furfurylated pine samples. The total porosity and the porosity of different cell types, as well as cell wall thickness and maximum opening of tracheid lumens were evaluated. The wetting properties (swelling and capillary uptake) were related to these microstructural characteristics. The data show significant changes in the wood structure for furfurylated pine sapwood samples, including a change in tracheid shape and filling of tracheids by furan polymer. In contrast, no such changes were noted for the acetylated pine samples at the high resolution of 0.8 mu m. The XCT images obtained for the furfurylated maple samples demonstrated that all ray cells and some vessel elements were filled with furan polymer while the fibers largely remained unchanged. Furfurylation significantly decreased the total porosity of both the maple and pine samples. Furthermore, this was observed in both earlywood (EW) and latewood (LW) regions in the pine samples. In contrast, the total porosity of pine samples was hardly affected by acetylation. These findings are in line with wetting results demonstrating that furfurylation reduces both swelling and capillary uptake in contrast to acetylation which reduces mostly swelling. Furfurylation significantly increased the cell wall thickness of both the maple and pine samples, especially at higher levels of furfurylation

    Overcoming detection loss and noise in squeezing-based optical sensing

    Get PDF
    Among the known resources of quantum metrology, one of the most practical and efficient is squeezing. Squeezed states of atoms and light improve the sensing of the phase, magnetic field, polarization, mechanical displacement. They promise to considerably increase signal-to-noise ratio in imaging and spectroscopy, and are already used in real-life gravitational-wave detectors. But despite being more robust than other states, they are still very fragile, which narrows the scope of their application. In particular, squeezed states are useless in measurements where the detection is inefficient or the noise is high. Here, we experimentally demonstrate a remedy against loss and noise: strong noiseless amplification before detection. This way, we achieve loss-tolerant operation of an interferometer fed with squeezed and coherent light. With only 50% detection efficiency and with noise exceeding the level of squeezed light more than 50 times, we overcome the shot-noise limit by 6 dB. Sub-shot-noise phase sensitivity survives up to 87% loss. Application of this technique to other types of optical sensing and imaging promises a full use of quantum resources in these fields

    Elastic properties, thermal stability, and thermodynamic parameters of MoAlB

    Get PDF
    MoAlB is the first and, so far, the only transition-metal boride that forms alumina when heated in air and is thus potentially useful for high-temperature applications. Herein, the thermal stability in argon and vacuum atmospheres and the thermodynamic parameters of bulk polycrystalline MoAlB were investigated experimentally. At temperatures above 1708 K, in vacuum and inert atmospheres, this compound incongruently melts into the binary MoB and liquid aluminum metal as confirmed by differential thermal analysis, quenching experiments, x-ray diffraction, and scanning electron microscopy. Making use of that information together with heat-capacity measurements in the 4–1000-K temperature range—successfully modeled as the sum of lattice, electronic, and dilation contributions—the standard enthalpy, entropy, and free energy of formation are computed and reported for the full temperature range. The standard enthalpy of formation of MoAlB at 298 K was found to be −132±3.2 kJ/mol. Lastly, the thermal conductivity values are computed and modeled using a variation of the Slack model in the 300–1600-K temperature range

    Gestational diabetes and endothelial function: impact of gestational insulin resistance on reactive hyperhemia index

    Get PDF
    Our aim was to characterize endothelial function in gestational diabetes by evaluating the reactive hyperemia index (RHI, LnRHI). A prospective, descriptive and comparative study was conducted on a population of pregnant women aged over 20 and under 36, located in the gestational age group 24-38th week of amenorrhea. They were divided into two groups. Group 1 (G1): group of pregnancies without diabetes, consists of pregnant women with no risk factor for gestational diabetes and with normal fasting blood glucose. Group 2 (G2): group of pregnancies with diabetes, includes pregnancies whose oral glucose tolerance tests (OGTT) came back positive. Anthropo-physiological parameters (age, weight, height, blood pressure (PA) and biochemical parameters (glycemia, insulinemia, HOMA-IR, cholesterol, triglycerides) were measured. RHI and LnRHI were determined at Endopat 2000. The two groups were matched for age, weight, heart rate (HR) and blood pressure (BP). Levels of glucose (G1:0.76±0.11; G2:1.11±0.11; p˂0.0001), insulin (G1:7.67±4.35; G2:22.9±3.75; p˂0.0001), HOMA-IR (G1:1.51±0.97; G2:6.29±1.23; p˂0.0001), total cholesterol (G1:1±0.81; G2:2.49±0.74; p=0.002), HDL cholesterol (G1:0.45±0.23; G2: 0.8±0.19; p=0.004, LDL cholesterol (G1:0.42±0.54; G2:1.39±0.6; p=0.004), triglycerides (G1:0.65±0.49; G2:1.48±0.27; p=0.0018), were significantly higher in the diabetic group. Both RHI and LnRHI were negatively correlated with HOMA-IR (respectively, r=-0.8931, p<0.0001; r=-0.8938; p<0.0001). HOMA-IR index was independently associated with levels of RHI and LnRHI (respectively r²=0.797; p<0.0001); (r²=0.804; p<0.0001)). Thus, gestational insulin resistance would be associated with a change in endothelial function such as a decrease in endothelium-dependent vasodilatation reflecting endothelial dysfunction, hence an increase in cardiovascular risk

    Group rehabilitation of patients with acquired hearing impairment and their close relatives: Evaluation of short- and long-term effects

    Get PDF
    The aim of this study was to evaluate the effects of a two-weeks full-time group-rehabilitation program designed for hearing-impaired patients and their close relatives. Seventy-six consecutive patients in employment age (mean = 51 years; SD = 9 years, R = 22–64 years) with subjective need for audiological rehabilitation were included in the program. Pure tone averages were 46 dB HL and 58 dB HL at the low and high frequencies in the best ear, respectively. The patients responded to visual analogue scales (VAS) and questionnaires, intended to measure “perceived handicap”, “social support”, “perceived negative attitudes”, “acceptance of hearing loss” and “communication strategies”, before and after the last group session. The forms were also sent to the study group by post four and six months after the program was terminated. No significant short-term effects were found after the last group session, except that self-rated handicap in family life (VAS) was increased (p = 0.028), probably due to the participants’ increased awareness of hearing-related problems. Four months later, perceived negative attitudes from others were significantly reduced (p = 0.025), but self-rated handicap in family life was still increased (p = 0.023). Six months later (long-term effects), maladaptive strategies (e.g. guessing, pretending to hear and avoiding interactions) were significantly less often used (p = 0.036) and verbal strategies more frequently adopted (p = 0.018). This change of communication strategies might facilitate social participation and should therefore be seen as positive outcomes of a rehabilitation program

    On the phase space structure of IP3 induced Ca2+ signalling and concepts for predictive modeling

    Get PDF
    The correspondence between mathematical structures and experimental systems is the basis of the generalizability of results found with specific systems, and is the basis of the predictive power of theoretical physics. While physicists have confidence in this correspondence, it is less recognized in cellular biophysics. On the one hand, the complex organization of cellular dynamics involving a plethora of interacting molecules and the basic observation of cell variability seem to question its possibility. The practical difficulties of deriving the equations describing cellular behaviour from first principles support these doubts. On the other hand, ignoring such a correspondence would severely limit the possibility of predictive quantitative theory in biophysics. Additionally, the existence of functional modules (like pathways) across cell types suggests also the existence of mathematical structures with comparable universality. Only a few cellular systems have been sufficiently investigated in a variety of cell types to follow up these basic questions. IP3 induced Ca2+ signalling is one of them, and the mathematical structure corresponding to it is subject of ongoing discussion. We review the system’s general properties observed in a variety of cell types. They are captured by a reaction diffusion system. We discuss the phase space structure of its local dynamics. The spiking regime corresponds to noisy excitability. Models focussing on different aspects can be derived starting from this phase space structure. We discuss how the initial assumptions on the set of stochastic variables and phase space structure shape the predictions of parameter dependencies of the mathematical models resulting from the derivation

    Rapid determination of the acidity, alkalinity and carboxyl content of aqueous samples by 1H NMR with minimal sample quantity

    Get PDF
    The titratable acidity, alkalinity, and carboxylate content are fundamental properties required for the understanding of aqueous chemical systems. Here, we present a set of new methods that allow these properties to be determined directly by 1H NMR without the labor, cost, and sample quantity associated with running separate potentiometric or conductometric titrations. Our methods require only the measurement of the pH-sensitive 1H chemical shifts of indicator molecules and do not require the tedious titration of reagents into a sample. To determine the titratable acidity, an excess of 2-methylimidazole (2MI) is added to a sample and the quantity of protons absorbed by 2MI is determined from its 1H chemical shifts. The titratable alkalinity of a sample can be similarly determined using acetic acid. To determine the concentration of deprotonated carboxylates, a sample is acidified with HCl, and the quantity of H+ absorbed is determined from the 1H chemical shift of methylphosphonic acid. We validate our methods by demonstrating the measurement of the acidity of fruit-flavored drinks, the alkalinity of tap water, and the carboxylate content of nanocellulose dispersions

    Endometrial receptivity revisited: endometrial transcriptome adjusted for tissue cellular heterogeneity

    Get PDF
    STUDY QUESTION Does cellular composition of the endometrial biopsy affect the gene expression profile of endometrial whole-tissue samples? SUMMARY ANSWER The differences in epithelial and stromal cell proportions in endometrial biopsies modify the whole-tissue gene expression profiles and affect the results of differential expression analyses. WHAT IS ALREADY KNOWN Each cell type has its unique gene expression profile. The proportions of epithelial and stromal cells vary in endometrial tissue during the menstrual cycle, along with individual and technical variation due to the method and tools used to obtain the tissue biopsy. STUDY DESIGN, SIZE, DURATION Using cell-population specific transcriptome data and computational deconvolution approach, we estimated the epithelial and stromal cell proportions in whole-tissue biopsies taken during early secretory and mid-secretory phases. The estimated cellular proportions were used as covariates in whole-tissue differential gene expression analysis. Endometrial transcriptomes before and after deconvolution were compared and analysed in biological context. PARTICIPANTS/MATERIAL, SETTING, METHODS Paired early- and mid-secretory endometrial biopsies were obtained from 35 healthy, regularly cycling, fertile volunteers, aged 23–36 years, and analysed by RNA sequencing. Differential gene expression analysis was performed using two approaches. In one of them, computational deconvolution was applied as an intermediate step to adjust for the proportions of epithelial and stromal cells in the endometrial biopsy. The results were then compared to conventional differential expression analysis. Ten paired endometrial samples were analysed with qPCR to validate the results. MAIN RESULTS AND THE ROLE OF CHANCE The estimated average proportions of stromal and epithelial cells in early secretory phase were 65% and 35%, and during mid-secretory phase, 46% and 54%, respectively, correlating well with the results of histological evaluation (r = 0.88, P = 1.1 × 10−6). Endometrial tissue transcriptomic analysis showed that approximately 26% of transcripts (n = 946) differentially expressed in receptive endometrium in cell-type unadjusted analysis also remain differentially expressed after adjustment for biopsy cellular composition. However, the other 74% (n = 2645) become statistically non-significant after adjustment for biopsy cellular composition, underlining the impact of tissue heterogeneity on differential expression analysis. The results suggest new mechanisms involved in endometrial maturation, involving genes like LINC01320, SLC8A1 and GGTA1P, described for the first time in context of endometrial receptivity. LARGE-SCALE DATA The RNA-seq data presented in this study is deposited in the Gene Expression Omnibus database with accession number GSE98386. LIMITATIONS REASONS FOR CAUTION Only dominant endometrial cell types were considered in gene expression profile deconvolution; however, other less frequent endometrial cell types also contribute to the whole-tissue gene expression profile. WIDER IMPLICATIONS OF THE FINDINGS The better understanding of molecular processes during transition from pre-receptive to receptive endometrium serves to improve the effectiveness and personalization of assisted reproduction protocols. Biopsy cellular composition should be taken into account in future endometrial ‘omics’ studies, where tissue heterogeneity could potentially influence the results. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by: Estonian Ministry of Education and Research (grant IUT34-16); Enterprise Estonia (EU48695); the EU-FP7 Eurostars program (NOTED, EU41564); the EU-FP7 Marie Curie Industry-Academia Partnerships and Pathways (SARM, EU324509); Horizon 2020 innovation program (WIDENLIFE, EU692065); MSCA-RISE-2015 project MOMENDO (No 691058) and the Miguel Servet Program Type I of Instituto de Salud Carlos III (CP13/00038); Spanish Ministry of Economy, Industry and Competitiveness (MINECO) and European Regional Development Fund (FEDER): grants RYC-2016-21199 and ENDORE SAF2017-87526. Authors confirm no competing interests

    Development of A Tool to Assess Resident Physicians’ Perceived Competence for Patient-centered Obesity Counseling

    Get PDF
    Physicians report a number of barriers to obesity counseling, among them low perceived competence in the ability to counsel. While there is increasing recognition of the need for resident training on counseling, implementation requires residency programs to have the necessary curricula and tools to evaluate training effectiveness. This study’s objective was to describe the development and psychometric testing of the Perceived Competence for Obesity Counseling (PCOC) scale. Items were generated based on constructs from the 5A’s counseling framework, review of the obesity literature, and expert opinion. The 20-item scale was piloted among 74 resident physicians. Exploratory factor analysis was conducted to identify the number and nature of factors in the scale.  Pearson's correlation was used to assess scale validity of the total scores and sub-scale scores association with residents’ overall confidence in counseling and outcome expectancy for obesity counseling. Analyses suggested a 3-factor solution. After the removal of cross loading items, eighteen items were retained; eleven items loaded on the first factor, four items on the second factor, and three on the third factor. Cronbach's alpha for the 18-item PCOC scale was 0.95 indicating internal consistency. The PCOC scale was significantly correlated with resident’s overall confidence in counseling (r = 0.60, p < 0.01) and outcome expectancy for obesity counseling (r = 0.41, p < 0.01). This pilot study suggests PCOC is holds promise as a valid and reliable measure of resident’s perceived competence for obesity counseling. Future studies are needed to assess the scale’s association with counseling skills
    corecore