Percent Change In Area Research Articles

Incremental value of multidomain risk factors for dementia prediction: A machine learning approach

ObjectiveThe current evidence regarding how different predictor domains contribute to predicting incident dementia remains unclear. This study aims to assess the incremental value of five predictor domains when added to a simple dementia risk prediction model (DRPM) for predicting incident dementia in older adults. DesignPopulation-based, prospective cohort study SettingUK Biobank study ParticipantsIndividuals aged 60 or older without dementia. Measurements55 dementia-related predictors were gathered and categorized into clinical and medical history, questionnaire, cognition, polygenetic risk, and neuroimaging domains. Incident dementia (all-cause) and the subtypes, Alzheimer's disease (AD) and vascular dementia (VaD), were determined through hospital and death registries. Ensemble machine learning (ML) DRPMs were employed for prediction. The incremental values of risk predictors were assessed using the percent change in Area Under the Curve (∆AUC%) and the net reclassification index (NRI). ResultsThe simple DRPM which included age, body mass index, sex, education, diabetes, hyperlipidaemia, hypertension, depression, smoking, and alcohol consumption yielded an AUC of 0.711 (± 0.008 SD). The five predictor domains exhibited varying levels of incremental value over the basic model when predicting all-cause dementia and the two subtypes. Neuroimaging markers provided the highest incremental value in predicting all-cause dementia (∆AUC% +9.6%) and AD (∆AUC% +16.5%) while clinical and medical history data performed the best at predicting VaD (∆AUC% +12.2%). Combining clinical and medical history, and questionnaire data synergistically enhanced ML DRPM performance. ConclusionCombining predictors from different domains generally results in better predictive performance. Selecting predictors entails trade-offs, and while neuroimaging markers can significantly enhance predictive accuracy, they may pose challenges in terms of cost or accessibility.

Impact of Krishi Bhagya Yojana (KBY) Farm Pond Technology on Semi-Arid Farmers in North Eastern Transition Zone of Karnataka State in India

Efficient water management through farm pond technology is a great initiative by Krishi Bhagya Yojana scheme in 2015. Out of 240 sample farmers, about 180 farmers are adopters and 60 are non adopters of farm pond technology in Bidar and Gulbarga districts of Karnataka. Majority of farmers prefer farm pond of size 30 m × 30 m × 3 m as during Kharif season with storage capacity of 2700 cubic metric which is able to irrigate 1.5 ha land area .Through analysis, it is found that, the cropping intensity was increased to 225 per cent from 203.75 which accounts 9.47 per cent change to that of the base year. The percent change in area under rabicrops was relatively more when compared with farm ponds which directly increase their income by sale of crops in market. The number of migrating people decreased from six to three persons after adoption of KBY by the beneficiary farmers. The most influencing factors in adoption of farm pond technology by farmers are access to rural credit, diffusion of information and adoption of high value crops.

Communication Partner Engagement: A Relevant Factor for Functional Outcomes in Speech-Language Therapy for Aphasic Dementia.

Previous reports established the feasibility of a telehealth model for delivering speech-language therapy via Internet videoconferencing, which connects individuals with primary progressive aphasia (PPA) to an expert speech and language pathologist for treatment. This study reports feasibility of the same telehealth intervention in a larger set of progressive aphasia participants and explores factors potentially influencing functional intervention outcomes. Participants with PPA or progressive aphasia in the context of a neurodegenerative dementia syndrome and their communication partners were enrolled into an 8-session intervention, with 3 evaluations (baseline, 2 months, and 6 months postenrollment). Half of the participants were randomized into a "check-in" group and received 3-monthly half-hour sessions postintervention. Mixed linear models with post hoc testing and percent change in area under the curve were used to examine communication confidence over time, as well as the influence of check-in sessions and the role of communication partner engagement on communication confidence. Communication confidence improved at the 2-month evaluation and showed no significant decline at the 6-month evaluation. Item-level analysis revealed gains in communication confidence across multiple communication contexts. Gains and maintenance of communication confidence were only present for the engaged communication partner group and were not bolstered by randomization to the check-in group. Internet-based, person-centered interventions demonstrate promise as a model for delivering speech-language therapy to individuals living with PPA. Maintenance is possible for at least 6 months postenrollment and is better for those with engaged communication partners, which supports the use of dyadic interventions.

Effect of the Mini-Nutritional Assessment-Short Form in Elderly Burn Patients.

Nutritional assessment can early identify patients who are malnourished and at risk of malnutrition. To examine the effect of nutritional status on wound healing in elderly burn patients, we used the Mini-Nutritional Assessment-Short Form (MNA-SF) to measure the nutritional status of elderly patients. This study aimed to examine the role of MNA-SF in elderly burn patients through the correlation analysis of wound healing indicators and MNA-SF score. This was a prospective observational and cross-sectional study. This study used the MNA-SF to investigate the elderly burn patients at the department of burn. According to the score, the patients fell into three groups: good nutritional status (more than 12 points), malnutrition risk (8-11 points), and malnutrition (0-7 points). At the same time, we measured and compared the wound healing indicators among the three groups of patients, and detected the correlation. The results showed gender had a slight influence on the score of nutritional status, while age was negatively correlated with the MNA-SF score and nutrition-related indicators. There was a low positive linear correlation between the wound healing percent area change or wound healing rate of patients and the score of the MNA-SF. This study finds malnutrition is common among hospitalized elderly burn patients. The application of the MNA-SF in elderly burn patients is efficient and accurate to identify malnutrition early and prevent further obstruction of the normal wound healing, which can provide reference points for early nutrition intervention programs.

Does the pediatric hemodynamic cliff exist in response to hemorrhagic shock?

BackgroundThe paradigm that children maintain normal blood pressure during hemorrhagic shock until 30%–45% hemorrhage is widely accepted. There are minimal data supporting when decompensation occurs and how a child's vasculature compensates up to that point. We aimed to observe the arterial response to hemorrhage and when mean arterial pressure (MAP) decreased from baseline in pediatric swine. MethodsPiglets were hemorrhaged in 20% increments of their total blood volume to 60%. MAP and angiograms of the thoracic aorta (TA) and abdominal arteries were obtained. Percent change in area of the vessels from baseline was calculated. ResultsPiglets (n = 8) had a differential vasoconstriction starting at 20% hemorrhage (celiac artery 36.3% [31.4–44.6] vs TA 16.7% [10.7–19.1] p = 0.0012). At 40% hemorrhage, the differential vasoconstriction favored shunting blood away from the abdominal visceral branches to the TA (celiac artery 54.7% [36.9–60.6] vs TA 29.5% [23.9–36.2] p = 0.0056 superior mesenteric artery 46.7% [43.9–68.6] vs TA 29.5% [23.9–36.2] p = 0.0100). This was exacerbated at 60% hemorrhage. MAP decreased from baseline at 20% hemorrhage (66.4 ± 6.0 mmHg vs 41.4 ± 10.4 mmHg, p < 0.0001), and worsened at 40% and 60% hemorrhage. ConclusionIn piglets, a differential vasocontriction shunting blood proximally occurred in response to hemorrhage. This did not maintain normal MAP at 20%, 40% or 60% hemorrhage. Level of evidenceLevel II.

Loss of Function in Dopamine Receptor‐3 (D3R) Attenuates Left Ventricular Cardiac Fibroblast Migration and Proliferation In Vitro

Dopamine is a neurotransmitter heavily involved in neural pathways regulating the reward response, body movement, mood, and cognitive function. As such, much of the research on dopamine and its five receptor subtypes has been conducted to observe the in vivo function of each receptor subtype in neurological disorders. However, recent studies by colleagues from our institution have suggested that D3Rs may play a role in cardiac‐related aging, as 2‐month old D3 receptor knock‐out (D3KO) mice show age‐related changes in cardiac function similar to 2‐year old wild‐type (WT) mice. Thus, it would be interesting to understand the role of D3R expression in LV cardiac fibroblast and its function. We isolated, cultured and characterized cardiac fibroblasts from the left ventricles (LV) of WT (23‐weeks old) and D3KO (5 and 31‐week‐old) mice. Immunohistochemistry was performed to determine the expression of D3R in LV cardiac fibroblasts, and cell culture experiments were performed to examine possible changes in WT and D3KO cell migration and proliferation. Proliferation was measured via total cell count over time points of 6, 12, 24, and 36 hours, while migration in response to scratch wound was examined as percent change in area at 3, 6, 12, 24 hours, and every 12 hours thereafter up to 86 hours. Staining with antibodies for D3R successfully showed expression of this receptor in WT fibroblasts, while cell culture experiments showed reduced proliferation and migration of D3KO fibroblasts compared to WT. Migration of D3KO fibroblasts from 5‐week old mice were significantly different (*p&lt;0.05) in response to an artificial wound when compared to 23‐week‐old mice. Additionally, upon isolation of LV cardiac fibroblasts from 5‐week‐old and 31‐week‐old D3KO and 23‐week‐old WT mice, cell volume from D3KO fibroblast isolation was markedly reduced compared to WT isolation under identical conditions (5‐fold and 10‐fold decrease in 5‐week and 31‐week D3KO, respectively). This data suggests that D3Rs play a role in LV cardiac fibroblast migration and proliferation and support previous observations of age‐related changes in cardiac function of D3KO mice.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effects of the Novel Dual GLP-1R/GCGR Agonist SAR425899 on Postprandial Glucose Metabolism in Overweight/Obese Subjects with Type 2 Diabetes

SAR425899 (SAR) is a novel dual glucagon-like peptide-1 receptor/glucagon receptor (GLP-1R/GCGR) agonist. A randomized, double-blind, phase I multiple-ascending-dose study (NCT02411825) in 27 overweight/obese subjects with type 2 diabetes receiving SAR demonstrated decreased body weight with a safety profile comparable with GLP-1R agonists. Here, we report additional analyses of the effect of SAR on key processes in glucose metabolism. Subjects were randomized to receive daily subcutaneous administrations of low-dose SAR (30, 60, 90 µg) or high-dose SAR (60, 120, 180 µg) for 28 days; dose escalation occurred after Days 7 and 14. Mixed meal tests were conducted before treatment (Day −1) and on Days 1 and 28. Oral glucose and C-peptide minimal models were used to quantify metabolic indices of glucose absorption, insulin sensitivity, and β-cell responsiveness. Percent change in area under the curve for rate of meal glucose appearance between 0 and 120 min from Day −1 to Day 28 was −14% and −19% with low- and high-dose SAR, respectively. Change in insulin sensitivity was 104% and 262%, respectively. Change in β-cell function was 127% and 145%, respectively (Table). After 28 days of treatment, SAR improved postprandial glucose control by significantly reducing glucose absorption rate, increasing insulin sensitivity, and enhancing β-cell function. Disclosure B. Goebel: Employee; Self; Sanofi. M. Schiavon: None. R. Visentin: None. M. Riz: Employee; Self; Sanofi-Aventis Deutschland GmbH. C. Dalla Man: None. C. Cobelli: Research Support; Self; Sanofi-Aventis. Advisory Panel; Self; Novo Nordisk Inc. T. Klabunde: Employee; Self; Sanofi.

Passive expansion of sub-maximally dilated transjugular intrahepatic portosystemic shunts and assessment of clinical outcomes

AIMTo assess for passive expansion of sub-maximally dilated transjugular intrahepatic portosystemic shunts (TIPS) and compare outcomes with maximally dilated TIPS.METHODSPolytetrafluoroethylene covered TIPS (Viatorr) from July 2002 to December 2013 were retrospectively reviewed at two hospitals in a single institution. Two hundred and thirty patients had TIPS maximally dilated to 10 mm (mTIPS), while 43 patients who were at increased risk for hepatic encephalopathy (HE), based on clinical evaluation or low pre-TIPS portosystemic gradient (PSG), had 10 mm TIPS sub-maximally dilated to 8 mm (smTIPS). Group characteristics (age, gender, Model for End-Stage Liver Disease score, post-TIPS PSG and clinical outcomes were compared between groups, including clinical success (ascites or varices), primary patency, primary assisted patency, and severe post-TIPS HE. A subset of fourteen patients with smTIPS underwent follow-up computed tomography imaging after TIPS creation, and were grouped based on time of imaging (< 6 mo and > 6 mo). Change in diameter and cross-sectional area were measured with 3D imaging software to evaluate for passive expansion.RESULTSPatient characteristics were similar between the smTIPS and mTIPS groups, except for pre-TIPS portosystemic gradient, which was lower in the smTIPS group (19.4 mmHg ± 6.8 vs 22.4 mmHg ± 7.1, P = 0.01). Primary patency and primary assisted patency between smTIPS and mTIPS was not significantly different (P = 0.64 and 0.55, respectively). Four of the 55 patients (7%) with smTIPS required TIPS reduction for severe refractory HE, while this occurred in 6 of the 218 patients (3%) with mTIPS (P = 0.12). For the 14 patients with follow-up computed tomography (CT) imaging, the median imaging follow-up was 373 d. There was an increase in median TIPS diameter, median percent diameter change, median area, and median percent area change in patients with CT follow-up greater than 6 mo after TIPS placement compared to follow-up within 6 mo (8.45 mm, 5.58%, 56.04 mm2, and 11.48%, respectively, P = 0.01).CONCLUSIONPassive expansion of smTIPS does occur but clinical outcomes of smTIPS and mTIPS were similar. Sub-maximal dilation can prevent complications related to over-shunting in select patients.

Three-Dimensional Computed Tomography-Based Specimen-Specific Kinematic Model for Ex Vivo Assessment of Lumbar Neuroforaminal Space.

Cadaveric study to accurately measure lumbar neuroforaminal area and height throughout the flexion-extension range of motion (ROM). Create a new computed tomography (CT)-based specimen-specific model technique to provide insight on the effects of kinematics on lumbar neuroforamen morphology during flexion-extension ROM. Nerve root compression is a key factor in symptomatic progression of degenerative disc disease because these changes directly affect neuroforaminal area. Traditional techniques to evaluate the neuroforamen suffer from poor accuracy, have inherent limitations, and fail to provide data throughout the ROM. Six cadaveric specimens (L1-sacrum) were instrumented with radiopaque spheres and CT scanned. 3-Dimensional reconstructions were made of each vertebra and the sphere locations determined. During kinematic testing, the spheres were located in relation to optoelectronic targets attached to each vertebra. The result was a 3-dimensional representation of the specimen's CT reconstruction moving in response to experimental data. Bony contours of the L2-L3 and L4-L5 neuroforamen were digitized producing continuous neuroforaminal area and height data throughout the ROM. Neuroforaminal area and height linearly increased in flexion and decreased in extension. There was significant correlation between flexion-extension motion and percent change in area (L2-L3: 3.1%/deg, R = 0.94, L4-L5: 2.5%/deg, R = 0.90) and neuroforaminal height (L2-L3: 2.1%/deg, R = 0.95, L4-L5: 1.6%/deg, R = 0.93). Regression analysis showed that the ratio between neuroforaminal height and area is at least 1:1.5 such that a 100% increase in height is associated with an area increase of more than 150%. This is the first study to measure lumbar neuroforaminal area and height throughout flexion-extension ROM. The CT-based specimen-specific model technique can accurately evaluate the effect of kinematics on morphological features of the spine. The demonstrated increase in neuroforaminal dimension in flexion is consistent with treatment modalities used in clinical therapies to relieve radicular symptoms. N/A.

Assessing endothelial dysfunction in adolescents and young adults with type 1 diabetes mellitus using a non-invasive heat stimulus.

Microvascular dysfunction is a key event in the development of atherosclerosis, which predates the clinical manifestations of vascular disease including stroke and myocardial infarction. Dysfunction of the microvasculature can be measured as a decreased microperfusion in response to heat. We sought to evaluate the microvasculature using heat among adolescents and young adults with type 1 diabetes (T1D) compared to healthy non-diabetic controls. We hypothesized that youth with T1D would have impaired microvascular function measured as decreased perfusion. We studied 181 adolescents and young adults with T1D and 96 age-, race-, and sex-matched healthy controls (mean age 19 yr). Patients were seen at an in-person study visit where demographics, anthropometrics, and laboratory data was obtained. Skin microvascular perfusion was measured on the volvar surface of the right forearm using a standard laser flow Doppler. Measurements were taken at baseline and after heating to 44° C. Youth with T1D had decreased microvascular perfusion as measured by lower percent change of perfusion units (1870 ± 945 vs. 2539 ± 1255, p < 0.01) and percent change in area under the curve (1870 ± 945 vs. 2539 ± 1255, p < 0.01) compared to controls. Glycosylated hemoglobin A1c (HbA1c) was found to be an independent determinant of microvascular function (p < 0.05). Adolescents and young adults with T1D have evidence of microvascular dysfunction that can be detected using heat, a non-invasive physiologic stimulus. HbA1c appears to play an independent role in determining microvascular perfusion suggesting tight glycemic control is probably important for the development of vascular disease.

Granulation Response and Partial Wound Closure Predict Healing in Clinical Trials on Advanced Diabetes Foot Ulcers Treated With Recombinant Human Epidermal Growth Factor

OBJECTIVETo determine if partial wound closure surrogate markers proposed for neuropathic, small diabetic foot ulcers (DFUs) can be extended to advanced lesions and if the development of granulation tissue can be used to predict complete healing.RESEARCH DESIGN AND METHODSData from two multicenter, double-blind, randomized clinical trials (one of them placebo controlled) that used intralesional recombinant human epidermal growth factor (rhEGF) to promote granulation and healing were used. For confirmation in a larger sample from common clinical practice, the results of an active postmarketing surveillance of rhEGF treatment of DFUs in 60 healthcare units was included. The surrogates evaluated were percent area change, log healing rate, ratio of log areas, and percent of granulation tissue covering the wound area. The tests used were surrogate final end point correlation, receiver operating characteristic curves to discriminate healers from nonhealers, validation tests using logistic regression models, and the proportion-mediated estimation.RESULTSTwo weeks >50% granulation, end of treatment >75% granulation, and 16.1% area change showed significant predictive value (>70% correct classification) for final wound closure. The granulation-based variables fulfilled the criterion that the effect of rhEGF treatment on wound closure was mediated by the surrogate.CONCLUSIONSThis work provides the first evidence for the use of granulation tissue development as a predictor of wound healing in advanced DFUs. These results can be useful for clinical trial design, particularly during the exploratory phase of new products.

Ultraviolet-C Irradiation in the Management of Pressure Ulcers in People With Spinal Cord Injury: A Randomized, Placebo-Controlled Trial

ObjectiveTo compare the effects of ultraviolet-C (UVC) with placebo-UVC on pressure ulcer healing in individuals with spinal cord injury (SCI). DesignDouble-blind randomized trial with stratification for ulcer location to buttock or lower extremity. Subjects were followed up for 1 year postintervention. SettingRehabilitation institution. ParticipantsAdult inpatients and outpatients (N=43) with SCI and stage 2 to 4 pressure ulcers (n=58). InterventionsUlcers and periwound skin were irradiated 3 times per week using UVC or placebo-UVC. The endpoint was wound closure or hospital discharge without closure. Main Outcome MeasuresPrimary outcome was weekly percent area relative to baseline. Secondary outcomes were mean percent area change between consecutive weeks, surface appearance, weeks to closure, and impact on quality of life and wound status postintervention. ResultsGroups were similar at baseline for all demographic characteristics except ulcer duration (P=.02). Groups were similar when healing was compared overall. Subgroup analysis showed that the percent area relative to baseline for stage 2 buttock ulcers was significantly smaller in the group receiving UVC compared with placebo at weeks 3, 5, and 7. During weeks 1 through 8, these ulcers were 26% to 76% of baseline area using UVC versus 111% to 180% for placebo (achieved significant level [ASL], .03–.08; effect size, 0.5–0.8). Groups were similar in the percent area relative to baseline for stage 2 lower extremity ulcers. Group mean percent area change between consecutive weeks for all stage 2 ulcers was 36.6% with the use of UVC and 5.8% for placebo (ASL=.09). There were no group differences in the percent area relative to baseline and the mean percent area change between consecutive weeks for stage 3 to 4 ulcers. Groups were similar for all other secondary outcomes. ConclusionsUVC is beneficial for stage 2 buttock ulcers. Further studies are warranted using a larger sample size, carefully considered exclusion criteria, and strategies to ensure homogeneity of the groups that are being compared.

Left ventricular dimensions in pulmonary arterial hypertension: haemodynamic and exercise correlations

ABSTRACTBackground: Remodelling of the heart in patients with pulmonary arterial hypertension (PAH) involves both the right and left ventricles. The objective of the present study was to analyse the dimensions of the right and left ventricles as assessed by echocardiography, and to compare this with haemodynamics and exercise capacity in patients with PAH.Materials and methods: Transthoracic echocardiogram, exercise capacity as assessed by the 6-minute walk test and right-heart catheterization were performed within 1 week in 66 consecutive patients with PAH. Univariate correlation and multiple regression analyses were performed to relate echocardiographic and clinical variables.Results: Left ventricular end-diastolic area index had the best correlation with cardiac index (r = 0.62; p < 0.001) and 6-minute walk distance (r = 0.56; p < 0.001). The ratio of the right to left ventricular area correlated with right atrial pressure (r = 0.62; p < 0.001). Right ventricular percent change in area correlated with cardiac index (r = 0.51; p < 0.001). No correlations were observed between the right and left ventricular dimensions.Conclusions: Left ventricular dimensions and the ratio of the right to left ventricular area correlated with resting haemodynamics and exercise capacity in patients with pulmonary arterial hypertension. These correlations were stronger than those observed with right ventricular dimensions alone. Left ventricular dimensions are important for the non-invasive evaluation of severity of patients with pulmonary arterial hypertension.

Functional Magnetic Resonance Imaging in Conscious Animals: A New Tool in Behavioural Neuroscience Research

Functional magnetic resonance imaging (fMRI) is a unique window to the brain, enabling scientists to follow changes in brain activity in response to hormones, ageing, environment, drugs of abuse and other stimuli. There are two features that make fMRI unique when compared with other imaging modalities used in behavioural neuroscience. First, it can be entirely noninvasive: each animal can serve as its own control over the natural course of its life, vital for following neuroadaptation and other developmental processes critical to understanding behaviour. Second, fMRI has the spatial and temporal resolution to observe patterns of neuronal activity across the entire brain in less than a minute. Although fMRI does not have the cellular spatial resolution of immunostaining, nor the millisecond temporal resolution of electrophysiology, synchronised changes in neuronal activity across multiple brain areas seen with functional MRI can be viewed as functional neuroanatomical circuits coordinating the thoughts, memories and emotions for particular behaviours. Thus, fMRI affords a systems approach to the study of the brain, complementing and building from other neurobiological techniques to understand how behaviour is organised across multiple brain regions. In this review, we present a general background to fMRI and the different imaging modalities that can be used in fMRI studies. Included are examples of the application of fMRI in behavioural neuroscience research, along with discussion of the advantages and disadvantages of this technology.

Echocardiographic analysis of ventricular geometry and function during repair of congenital septal defects

Background This study investigated changes in left ventricular (LV) geometry and systolic function after corrective surgery for atrial (ASD) and ventricular septal defects (VSD). Methods Transesophageal LV short-axis echocardiograms were recorded before and after operative repair of ASD (n = 11) and VSD (n = 7). Preload was measured using LV end-diastolic area indexed for body surface area. Measurements of septal-freewall (D1) and anterior-posterior (D2) endocardial diameters were used to assess LV symmetry from D1/D2. Systolic indices included stroke area, area ejection fraction, and fractional shortening. Results Preload, stroke area, area ejection fraction, and fractional shortening of D1 increased after ASD repair but decreased after VSD repair ( p < 0.05). End-diastolic symmetry increased after ASD closure and decreased after VSD closure ( p < 0.05). Increases in stroke area and ejection fraction after ASD correction primarily reflected increased shortening of D1. A positive correlation was found overall between percent change in end-diastolic area (EDA) and percent change in area ejection fraction (r 2 = 0.80, p < 0.0001, n = 18). Conclusions Preload was the primary determinant of changes in LV function in this series of ASD and VSD repairs. Intraoperative changes in position of the interventricular septum affected systolic and diastolic LV symmetry and septal free wall shortening. Additional studies are needed to define changes in afterload and contractility as well as diastolic compliance and systolic mechanics.

Response of mid-water common reed stands to water level variations and winter conditions in Lake Poygan, Wisconsin, USA

Because of wetland recession, common reed ( Phragmites australis) stands in the Upper Winnebago Pool Lakes, Wisconsin, now mark the former outer margins of destroyed cattail ( Typha spp.) marshes, occurring off shore in water up to 1.5 m deep. These mid-water common reed stands have experienced fragmentation and losses in area. This study examined the relation between changes in characteristics of common reed stands and some key environmental factors that may affect their success, especially those related to seasonal patterns in water level management and exposure to wind and severe winter temperatures. Individual patches (28–26,598 m 2) within each common reed stand (6740–43,048 m 2) were characterized with regard to stem densities (1–245 m −2) and water depths around the perimeter (0.10–1.52 m) and in the interior (0.22–1.30 m). Water-level cumulative frequency duration curves were used to quantify duration and continuity of exposure of common reed stands to various extreme water levels during 1986–1996, and we correlated these with annual percent changes in area derived from aerial photographs. Higher stem densities corresponded to larger patch size, greater historical stability, and less fragmentation. In addition, larger patches tended to be deeper, and covered a greater range of water depths. Conversely, more “ragged” patches tended to have lower maximum depths, both in the interior and on the perimeter, as well as smaller water level ranges. Overall, higher stem densities were associated with shallower water, though intermediate depths have experienced the greatest decline. Although combinations of extreme water levels and winter temperatures did not significantly predict annual changes in area of all common reed stands, these factors explained up to 75% of the variance in stands with the greatest loss. This indicates recent losses were caused by combined effects of extreme water levels and winter temperatures.

Echocardiographic Evaluation of Patients with Primary Pulmonary Hypertension Before and After Atrial Septostomy.

OBJECTIVES: To characterize the early changes in right ventricular [right ventricle (RV)] geometry and function, as assessed by two-dimensional (2-D) and Doppler echocardiography, after balloon-dilation atrial septostomy (BDAS) in patients with severe primary pulmonary hypertension (PPH). BACKGROUND: Survival in PPH is to a great extent dependent on the functional status of the RV. BDAS recently has been shown to improve functional class and hemodynamics in patients with PPH nonresponsive to conventional vasodilator treatment. METHODS: Ten patients with severe PPH who underwent BDAS were studied with transthoracic and transesophageal 2-D and Doppler echocardiography. RV dimensions were measured in the apical four-chamber view. Continuous-wave Doppler echocardiography was used to obtain peak velocity of tricuspid regurgitation. Transesophageal echocardiography (TEE) primarily was used for the follow-up of the atrial septal defects (ASDs). RESULTS: In the early post-BDAS studies, right atrial and ventricular dimensions significantly decreased in all patients (P < 0.05). Global right ventricular wall motion (RVWM) also improved. RV percent change in area after septostomy inversely correlated with the changes in RV systolic area (r = -0.75; P < 0.05) and also with the baseline (preprocedure) values of RV percent change in area (r = -0.77; P < 0.05). Neither RV wall thickness nor the degree of tricuspid regurgitation were modified significantly after the procedure. CONCLUSIONS: BDAS in the setting of severe PPH results in moderate and salutary changes in geometry and function of the RV as assessed by 2-D echocardiography. These changes mainly appear to be the result of the decompression effect of atrial septostomy.

Synthesis and characterization of grafted polyethylenes for use as membranes in water desalination

Polyethylene, although known to have very poor permeability behaviour towards electrolyte solution, functionalization through grafting is found to improve upon this property. Grafting of vinyl monomers containing polar pendant groups such as - CN of pyridine, - CN of methacrylonitrile, -COOR of esters of acrylic acid, can impart desirable properties to the hydrophobic backbone. In the present work, grafting of 4-vinyl pyridine (4-VP) and a binary mixture of 4-VP and methacrylonitrile (4-VP + MAN) onto PE film has been carried out by radiochemical method. Optimum conditions for affording maximum percentage of grafting have been evaluated. The grafted polyethylene membranes have been characterized by IR spectroscopy, scanning electron microscopy, thermogravimetric analysis, swelling behaviour, percent area change and permeability behaviour. Thermal stability of the grafted PE film was found to decrease upon grafting. However, at higher temperature ranges corresponding to the weight loss above 80%, thermal stability of PE film and PE grafted with mixed monomer becomes almost equal. Percent area change upon grafting and percent swelling in different solvents were found to increase in grafted films. The grafted membranes showed significant permeability towards electrolyte solution and were capable of effecting desalination of brine solution.

Functionalization of polyethylene film by radiochemical grafting for use as membranes in seawater desalination

Functionalization of polyethylene (PE) film with vinyl monomers containing polar groups can impart certain important additional properties to polyethylene membranes. With this idea in mind, attempts have been made to incorporate functional groups such as nitrile and ester groups onto polyethylene film by grafting methacrylonitrile (MAN) and a binary mixture of MAN and methylacrylate (MA) by radiochemical method. Optimum conditions for affording maximum percentage of grafting (Pg) have been evaluated. The grafted membranes have been characterized by IR spectroscopy and by thermogravimetric analysis. Thermal stability of the grafted PE films was found to decrease to some extent upon grafting. Percent area change and percent swelling of the grafted films in polar and nonpolar solvents have been determined. The dimension of the grafted films enhanced with increasing level of grafting indicating that grafting is not only confined to surface of the film but also proceeds into the interior of the film. Desalination of a model brine solution has been qualitatively studied using PE-g-poly(MAN) and PE-g-poly(MAndashco-MA) membranes. The grafted films were capable of effecting desalination of model brine solutions with enhanced permeability as compared to ungrafted PE film.

Evaluation of the nasal cavity by acoustic rhinometry in normal and allergic subjects

With acoustic rhinometry, one can detect a difference in response to a topical decongestant between normal and allergic subjects at the minimal cross-sectional area. The minimal cross-sectional area corresponds in most cases to the anterior end of the inferior turbinate or the first valley, which occurs after the nose piece of the acoustic rhinometer on the acoustic rhinometry graph. Allergic patients typically have an increase in nasal mucosal swelling, which leads to a decrease in the nasal volume and area and, subsequently, to an increase in congestion. In this study acoustic rhinometry was used to test normal and allergic subjects before and after the application of a topical decongestant (1% phenylephrine [Neo-Synephrine]). Symptoms were measured by a five-point scale. Results showed that increasing symptom scores demonstrated a trend toward being related to decreasing area as measured at the minimal cross-sectional area or nasal valve. The average total percent change at the minimal cross-sectional area was calculated for both groups and compared. The normal subjects had an average total percent area change at the minimal cross-sectional area of 15.6% ± 14.8%, and the allergic subjects had a percent change of 24.6% ± 20.8%. This represents a significant difference between the normal and allergic subjects in response to the topical decongestant at the minimal cross-sectional area ( p = 0.04). However, the average total percent change was not significantly different between the two groups at the second and third valleys. At the second valley, the normal subjects had a percent change of 40% ± 17.5%, and the allergic subjects had a percent change of 36% ± 18.5%. At the third valley, the normal subjects had a percent change of 35% ± 15.4%, and the allergic subjects had a percent change of 32% ± 20.6% ( p = 0.4 and 0.5, respectively). The total area was calculated by adding measurements from both right and left nasal cavities for each subject in an attempt to control the effect of the nasal cycle. Acoustic rhinometry makes it possible to detect a trend in the relationship between either a decrease in area at the minimal cross-sectional area or a decrease in the total volume from 0 to 7 cm into the nasal cavity and congestion. A statistically significant difference between normal and allergic subjects in their response to a topical decongestant at the minimal cross-sectional area was detected by acoustic rhinometry at the nasal valve. (Otolaryngol Head Neck Surg 1997;117:22-8.)