806 research outputs found

    Non-invasive assessment of pulmonary vascular resistance in pulmonary hypertension: Current knowledge and future direction

    Get PDF
    Pulmonary Hypertension (PHT) is relatively common, dangerous and under-recognised. Pulmonary hypertension is not a diagnosis in itself; it is caused by a number of differing diseases each with different treatments and prognoses. Therefore, timely and accurate recognition of the underlying cause for PHT is essential for appropriate management. This is especially true for patients with Pulmonary Arterial Hypertension (PAH) in the current era of disease-specific drug therapy. Measurement of Pulmonary Vascular Resistance (PVR) helps separate pre-capillary from post-capillary PHT, and is measured with right heart catheterisation (RHC). Echocardiography has been used to derive a number of non-invasive surrogates for PVR, with varying accuracy. Ultimately, the goal of non-invasive assessment of PVR is to separate PHT due to left heart disease from PHT due to increased PVR, to help streamline investigation and subsequent treatment. In this review, we summarise the physiology and pathophysiology of pulmonary blood flow, the various causes of pulmonary hypertension, and non-invasive surrogates for PVR

    Solving YCS : final report 2014/049

    Get PDF
    Yellow canopy syndrome (YCS) is a sporadic condition presenting as golden-yellowing of the mid canopy in sugarcane during the peak growing period of December to March. The key driver of YCS is growth rate and symptoms usually exhibit after rainfall. YCS can be induced or mitigated by altering sink strength and sugarcane can recover from a YCS event. Abiotic or biotic stress has a serious effect on the photosystems and the physiological fitness of the crop. There is a strong correlation between YCS expression, leaf sucrose and sink strength, independent of crop age. YCS symptomatic leaves always have high leaf sucrose and ?-glucan content. Under experimental conditions the pyrethroid bifenthrin supresses insect stress, promotes increased sink growth and maintains low leaf sucrose and ?-glucan levels. Induced senescence causes YCS plants to have a lower number of attached leaves. Yield loss precedes YCS expression and there is no correlation between YCS severity and cane yield or CCS. Lamina starch staining is a useful tool to assist in YCS identification. There is no strong evidence of genetic predisposition for YCS susceptibility. Industry-wide incidence and severity of YCS is too difficult to accurately assess due to its episodic nature, no single causal agent and the link to climate change and severe weather events. The data does not support the cause of YCS being a pathogen, specific insect or mite, soil borne agent, poor root health, nutrient deficiency, or heavy metal toxicity. YCS is a physiological disorder visualised as the terminal expression of metabolic perturbances caused by growth disruption

    High-contrast imaging of 180{\deg} ferroelectric domains by optical microscopy using ferroelectric liquid crystals

    Full text link
    Ferroelectric liquid crystals (FLCs) couple the direction of their spontaneous electric polarization to the direction of tilt of their optic axis. Consequently, reversal of the electric polarization by an electric field gives rise to an immediate and lasting optical response when an appropriately aligned FLC is observed between crossed polarizers, with one field direction yielding a dark image, and the opposite direction yielding a bright image. Here this peculiar electro-optic response is used to image, with high optical contrast, 180{\deg} ferroelectric domains in a crystalline substrate of magnesium-doped lithium niobate. The lithium niobate substrate contains a few domains with upwards electric polarization surrounded by regions with downward electric polarization. In contrast to a reference non-chiral liquid crystal that is unable to show ferroelectric behavior due to its high symmetry, the FLC, which is used as a thin film confined between the lithium niobate substrate and an inert aligning substrate, reveals ferroelectric domains as well as their boundaries, with strong black and white contrast. The results show that FLCs can be used for non-destructive read-out of domains in underlying ferroelectrics, with potential applications in e.g. photonic devices and non-volatile ferroelectric memories.Comment: 12 pages, 3 figure

    In Reply: Rongeurs, neurosurgeons, and COVID-19: how do we protect health care personnel during neurosurgical operations in the midst of aerosol-generation from high-speed drills?

    Get PDF
    To the Editor: We appreciated the manuscript by Chan et al,“Rongeurs, Neurosurgeons, and COVID-19: How Do We Protect Health Care Personnel During Neurosurgical Operations in the Midst of Aerosol-Generation From High-Speed Drills?” published April 2020 in Neurosurgery. We are grateful to the authors of the letter1 for their precise analysis and useful recommendations to fellow neurosurgeons and trainees to uphold the traditional craft of using hand drills and rongeurs in order to minimize aerosol generation from the neurosurgical-powered instruments during the COVID-19 pandemic. Nevertheless, we write in reply to present our surgical experience during the COVID-19 pandemic

    Microstructural and morphological properties of homoepitaxial (001)ZnTe layers investigated by x-ray diffuse scattering

    Full text link
    The microstructural and morphological properties of homoepitaxial (001)ZnTe layers are investigated by x-ray diffuse scattering. High resolution reciprocal space maps recorded close to the ZnTe (004) Bragg peak show different diffuse scattering features. One kind of cross-shaped diffuse scattering streaks along directions can be attributed to stacking faults within the epilayers. Another kind of cross-shaped streaks inclined at an angle of about 80deg with respect to the in-plane direction arises from the morphology of the epilayers. (abridged version

    In Reply: neurosurgery and coronavirus (COVID-19) epidemic: doing our part

    Get PDF
    To the Editor: We appreciated the Letter, “Letter: Neurosurgery and Coronavirus (COVID-19) Epidemic: Doing Our Part” by Pesce et al, published in April 2020 in Neurosurgery. We are grateful to the authors of the Letter for their clear analysis of some neurosurgical procedures in the COVID-19 era. Everyone in the neurosurgical community and in the whole medical community is doing their own part to face this terrible pandemic. Specifically, we would like to present our experience with patients needing a lumbar function or a neuroimaging. We already described our strategy for all emergency patients in an article published in Neurosurgery in April 2020 entitled “In Reply: Rongeurs, Neurosurgeons, and COVID-19: How Do We Protect Health Care Personnel During Neurosurgical Operations in the Midst of Aerosol-Generation From High-Speed Drills?

    Selection of novel geopolymeric mortars for sustainable construction applications using fuzzy topsis approach

    Get PDF
    Construction is recognized as one of the most polluting and energy consuming industries worldwide, especially in developing countries. Therefore, Research and Development (R&D) of novel manufacturing technologies and green construction materials is becoming extremely compelling. This study aims at evaluating the reuse of various wastes, originated in the Kraft pulp-paper industry, as raw materials in the manufacture of novel geopolymeric (GP) mortars whose properties fundamentally depend on the target application (e.g., insulating panel, partition wall, structural element, furnishing, etc.). Five different wastes were reused as filler: Two typologies of Biomass Fly Ash, calcareous sludge, grits, and dregs. The produced samples were characterized and a multi criteria analysis, able to take into account not only the engineering properties, but also the environmental and economic aspects, has been implemented. The criteria weights were evaluated using the Delphi methodology. The fuzzy Topsis approach has been used to consider the intrinsic uncertainty related to unconventional materials, as the produced GP-mortars. The computational analysis showed that adding the considered industrial wastes as filler is strongly recommended to improve the performance of materials intended for structural applications in construction. The results revealed that the formulations containing 5 wt.% of calcareous sludge, grits, and dregs and the one containing 7.5 wt.% of calcareous sludge, grits, dregs, and Biomass Fly Ash-1 have emerged as the best alternatives. Furthermore, it resulted that the Biomass Fly Ash-2 negatively influences the structural performance and relative rank of the material. Finally, this case study clearly shows that the fuzzy Topsis multi-criteria analysis represents a valuable and easy tool to investigate construction materials (either traditional and unconventional) when an intrinsic uncertainty is related to the measurement of the quantitative and qualitative characteristics

    Pelvic floor function after third and fourth degree perineal lacerations: a case-control study on quality of life

    Get PDF
    Background: The primary aim of this study was to compare the quality of life between women with obstetric anal sphincter injury (OASI) and women with intact perineum or minor vaginal tears following their first vaginal birth through a validated urogynaecological questionnaire. As a secondary aim, we wanted to identify the specific symptoms for pelvic floor dysfunction after a vaginal birth. Methods: One hundred thirty-three cases (III- and IV-degree vaginal tears) and 133 controls (intact perineum or I- and II-degree vaginal tear) were asked to fill the PFDI-20 condition-specific and quality of life survey at three and 12 months after vaginal delivery. The survey evaluates pelvic floor dysfunction symptoms through three subsections: the Pelvic Organ Prolapse Distress Inventory (POPDI), the Colorectal-Anal Distress Inventory (CRADI), and Urinary Distress Inventory, (UDI). The scoring system ranges from 0 (no distress) to 100 (maximum distress) for each subsection, subsequently summed up to obtain the summary score (0 to 300). The patients recruited were asked to complete the survey at 3- and 12-months follow-up visit. Accordingly, data collection started. Categorical variables were subjected to Chi-square test or Fisher’s Exact test. Quantitative variables were compared through Student’s t-test or Mann-Whitney test. Results: All surveys have shown statistically significant differences when comparing the cases to the control group. Consequently, PFDI-20 has shown a strong correlation between III- and IV-grade lacerations and pelvic floor dysfunction persistence at 12 months after delivery. Intestinal symptoms were the most reported disturbances among women with previous OASI. Conclusions: Major vaginal tears have demonstrated to have a strong impact on women’s quality of life up to a follow-up of 12 months. The use of PFDI-20 questionnaire is a useful and valid tool in the diagnosis and follow-up of genital prolapse, fecal and urinary incontinence in primiparous women with a history of OASI. Thus, its application in clinical practice can help offering the most adequate rehabilitative treatment
    • …
    corecore