504 research outputs found
Hydrolysis and availability to plants of polyphosphates added to soils
The hydrolysis by plant roots and in soils of seven linear oligomers (P(,2), P(,3), P(,5), P(,15), P(,25), P(,35), and P(,65)) and one cyclic polyphosphate, trimetaphosphate (TMP), was investigated. Nonsterile intact corn roots showed greater rates of hydrolysis than sterile corn roots, with hydrolysis rates in the order: P(,2) \u3e P(,3) \u3e P(,5) \u3e TMP \u3e P(,15) \u3e P(,25) \u3e P(,35) \u3e P(,65). An experiment with sterile intact corn roots suggested that pyrophosphatase was induced in corn roots in the presence of its substrate. The amount of polyphosphate-P hydrolyzed in four Iowa surface soils at 25(DEGREES)C with incubation times ranging from 1 to 14 days decreased with increasing polyphosphate chain length, with 37 to 74% hydrolysis in 14 days. The relationship between the nonhydrolyzed polyphosphate and time of incubation showed that polyphosphate hydrolysis in soils was controlled by two first-order reactions. The initial faster rate (k(,1)) changed to a slower rate (k(,2)) at incubation times ranging from 2 to 7 days, depending on the polyphosphate, soil type, and soil moisture status. The k(,1) and k(,2) values for soils incubated aerobically ranged from 1.7 x 10(\u27-4) to 3.3 x 10(\u27-5)/min and from 4.5 x 10(\u27-5) to 7.4 x 10(\u27-6)/min, respectively. The corresponding values for soils incubated under waterlogging conditions ranged from 2.4 x 10(\u27-4) to 2.6 x 10(\u27-5)/min and from 5.2 x 10(\u27-5) to 1.0 x 10(\u27-5)/min. Hydrolysis of polyphosphates in 29 Iowa soils incubated for one week at 25(DEGREES)C showed that from 27 to 47% of the orthophosphate produced was due to chemical hydrolysis; the rest was due to biochemical hydrolysis. Multiple regression analysis showed that polyphosphate hydrolysis was significantly correlated with pH, water-soluble Ca(\u272+), and nonbuffered pyrophosphatase activity, and negatively correlated with clay content, water-soluble Mg(\u272+) (except for P35 and P(,65)), and dithionite-extractable Al(\u273+) (except for P(,3) and TMP);The uptake of P from four Iowa surface soils amended with four linear oligomers (P(,2), P(,3), P(,15), P(,45)), one cyclic polyphosphate (TMP), and orthophosphate in a greenhouse study using ryegrass and corn as indicator plants showed that all of these sources of P are equally available to plants. Tests indicated that the residual P levels were similar among the P compounds after a short cropping period with corn (35 days) and a long cropping period with ryegrass (120 days)
Application of 3D Laser Scanning to the Preservation of Fort Conger, a Historic Polar Research Base on Northern Ellesmere Island, Arctic Canada
Fort Conger, located in Quttinirpaaq National Park, Ellesmere Island, is a historic landmark of national and international significance. The site is associated with many important Arctic expeditions, including the ill-fated Lady Franklin Bay Expedition of the First International Polar Year and Robert Peary’s attempts to claim the North Pole. Although situated in one of the most remote locations on earth, Fort Conger is currently at risk because of the effects of climate change, weather, wildlife, and human activity. In this paper, we show how 3D laser scanning was used to record cultural features rapidly and accurately despite the harsh conditions present at the site. We discuss how the future impacts of natural processes and human activities can be managed using 3D scanning data as a baseline, how conservation and restoration work can be planned from the resulting models, and how 3D models created from laser scanning data can be used to excite public interest in cultural stewardship and Arctic history.Fort Conger, situé dans le parc national Quttinirpaaq, sur l’île d’Ellesmere, est un lieu historique d’importance nationale et internationale. Ce site est lié à de nombreuses expéditions arctiques importantes, dont l’infortunée expédition de la baie Lady Franklin relevant de la première année polaire internationale et les tentatives de revendication du pôle Nord par Robert Peary. Bien qu’il se trouve dans l’un des endroits les plus éloignés du globe, Fort Conger subit actuellement les risques découlant des effets du changement climatique, des conditions météorologiques, de la faune et de l’activité humaine. Dans cette communication, nous montrons comment un scanneur laser 3D a permis de répertorier les caractéristiques culturelles avec rapidité et précision malgré les conditions difficiles qui ont cours à ce site. Nous discutons de la manière dont les incidences futures des processus naturels et de l’activité humaine peuvent être gérées à l’aide des données 3D comme données de base, comment les travaux de conservation et de restauration peuvent être planifiés à partir des modèles qui en résultent et comment les modèles 3D créés à partir des données de scannage laser peuvent rehausser l’intérêt du grand public à l’égard de la gérance culturelle et de l’histoire de l’Arctique
Soil enzyme activities under long-term tillage and crop rotation systems in subtropical agro-ecosystems
Genetics of Perceived Family Interaction From 12 to 17 Years of Age
Correction: Volume: 49 Issue: 5 Pages: 484-484 DOI: 10.1007/s10519-019-09963-w Published: SEP 2019We analyzed how the effects of genetic and environmental factors on the perceptions of family interaction change from early to late adolescence. The data were collected by postal surveys on Finnish twins (N=4808) at 12, 14 and 17years of age and analyzed using genetic twin modeling. Additive genetic factors explained a modest share of the variation in perceived relational support (a(2)=0.30 in boys and 0.18 in girls) and relational tensions (a(2)=0.13 and 0.14, respectively) at 12years of age, with the proportions becoming larger through 17years of age (a(2)=0.53 in boys and 0.49 in girls for relational support; a(2)=0.35 in boys and 0.33 in girls for relational tensions). Simultaneously, the role of environment shared by co-twins decreased. These findings suggest that the associations between perceived family interaction and other factors in adulthood should be interpreted with caution, because they partly reflect genetic background, whereas in childhood, they may provide more reliable information on parental characteristics.Peer reviewe
Possible function of the protein bound to nuclear complementary RNA
It was demonstrated that individual renal endothelial dilatory function of the healthy rat predicts susceptibility to subsequent renal damage induced by 5/6 nephrectomy. In addition, it is reported that myocardial infarction (MI) that was performed upon unilateral nephrectomy (UNx) induced highly variable renal damage. Therefore, whether the variability in renal damage after MI could be explained by the variation in individual renal endothelial function before the induction of injury was studied. Endothelium-dependent relaxation to acetylcholine was investigated in vitro in small arteries that were isolated from the extirpated kidney at UNx. MI was induced 1 wk after UNx by ligation of the left coronary artery. Proteinuria and systolic BP were evaluated weekly for 16 wk thereafter using metabolic cages and the tail-cuff method, respectively. Upon termination of the study, focal glomerulosclerosis was evaluated by histology as an additional marker of renal damage. After MI, nephrectomized male Wistar rats (n = 15) gradually developed variable proteinuria, ranging from 20 to 507 mg/24 h at week 16, with an average systolic BP of 131 +/- 7 mmHg. The individual renal endothelial function of the healthy rats predicted the extent of renal damage in terms of proteinuria (r = -0.62, P = 0.008) and focal glomerulosclerosis (r = -0.70, P = 0.003). The individual level of renal endothelial function in the healthy rat is able to predict the severity of renal damage that is induced by MI. Further exploration of the underlying mechanisms may lead to discovery of preventive renoprotective therapies
Which adolescent factors predict alcohol misuse in young adulthood? A co-twin comparisons study
Background and aims Research on adolescent predictors of later alcohol misuse is typically conducted on samples of singletons, and associations may be confounded by between-family differences. To address potential confounding, we applied a co-twin comparison design to evaluate whether differences between co-twins in a wide array of adolescent risk factors predicted differences in young adult alcohol misuse. Design Longitudinal study in which associations between characteristics of the sample as adolescents were used to predict young adult alcohol misuse in individual-level analyses and co-twin comparisons. Setting Finland. Participants A total of 3402 individuals (1435 complete twin pairs; 36% monozygotic; 57% female) from the FinnTwin12 study. Measurements The young adult alcohol misuse outcome was a composite score of alcohol use and intoxication frequency. Adolescent predictors included factor scores representing academic performance, substance use, externalizing problems, internalizing problems, peer environment, physical health and relationship with parents; and single measures tapping alcohol expectancies, life events and pubertal development. Findings In individual-level analyses, individuals with higher adolescent substance use, externalizing problems, time with friends, peer deviance, sports involvement, sleeping difficulties, parental discipline, positive alcohol expectancies and difficulty of life events reported higher alcohol misuse in young adulthood (Ps <0.019, R-2 = 0.0003-0.0310%). Conversely, those with higher adolescent internalizing problems, parent-child relationship quality and time with parents reported lower alcohol misuse (Ps <0021, R-2 = 0.0018-0.0093%). The associations with adolescent substance use and alcohol expectancies remained significant in co-twin comparisons (Ps <0.049, R-2 = 0.0019-0.0314%). Further, academic performance emerged as a significant predictor, such that individuals with higher grades compared with their co-twin reported higher young adult alcohol misuse (Ps <0.029, R-2 = 0.0449-0.0533%). Conclusions Adolescent substance use, positive alcohol expectancies and higher academic performance appear to be robust predictors of later alcohol misuse.Peer reviewe
A Systematic Review with Meta-Analysis of Randomized Controlled Trials
Objective Epidemiological evidence has linked consumption of black tea,
produced from Camellia sinensis, with a reduced risk of cardiovascular
diseases. However, intervention studies on the effects of tea consumption on
blood pressure (BP) have reported inconsistent results. Our objective was to
conduct a systematic literature review with meta-analysis of controlled human
intervention studies examining the effect of tea consumption on BP. Methods We
systematically searched Medline, Biosis, Chemical Abstracts and EMBASE
databases through July 2013. For inclusion, studies had to meet the following
pre-defined criteria: 1) placebo controlled design in human adults, 2) minimum
of 1 week black tea consumption as the sole intervention, 3) reported effects
on systolic BP (SBP) or diastolic BP (DBP) or both. A random effects model was
used to calculate the pooled overall effect of black tea on BP. Results Eleven
studies (12 intervention arms, 378 subjects, dose of 4–5 cups of tea) met our
inclusion criteria. The pooled mean effect of regular tea ingestion was −1.8
mmHg (95% CI: −2.8, −0.7; P = 0.0013) for SBP and −1.3 mmHg (95% CI: −1.8,
−0.8; P<0.0001) for DBP. In covariate analyses, we found that the method of
tea preparation (tea extract powders versus leaf tea), baseline SBP and DBP,
and the quality score of the study affected the effect size of the tea
intervention (all P<0.05). No evidence of publication bias could be detected.
Conclusions Our meta-analysis indicates that regular consumption of black tea
can reduce BP. Although the effect is small, such effects could be important
for cardiovascular health at population level
Predicting Alcohol Dependence Symptoms by Young Adulthood : A Co-Twin Comparisons Study
Co-twin comparisons address familial confounding by controlling for genetic and environmental influences that twin siblings share. We applied the co-twin comparison design to investigate associations of adolescent factors with alcohol dependence (AD) symptoms. Participants were 1286 individuals (581 complete twin pairs; 42% monozygotic; and 54% female) from the FinnTwin12 study. Predictors included adolescent academic achievement, substance use, externalizing problems, internalizing problems, executive functioning, peer environment, physical health, relationship with parents, alcohol expectancies, life events, and pubertal development. The outcome was lifetime AD clinical criterion count, as measured in young adulthood. We examined associations of each adolescent domain with AD symptoms in individual-level and co-twin comparison analyses. In individual-level analyses, adolescents with higher levels of substance use, teacher-reported externalizing problems at age 12, externalizing problems at age 14, self- and co-twin-reported internalizing problems, peer deviance, and perceived difficulty of life events reported more symptoms of AD in young adulthood (ps < .044). Conversely, individuals with higher academic achievement, social adjustment, self-rated health, and parent-child relationship quality met fewer AD clinical criteria (ps < .024). Associations between adolescent substance use, teacher-reported externalizing problems, co-twin-reported internalizing problems, peer deviance, self-rated health, and AD symptoms were of a similar magnitude in co-twin comparisons. We replicated many well-known adolescent correlates of later alcohol problems, including academic achievement, substance use, externalizing and internalizing problems, self-rated health, and features of the peer environment and parent-child relationship. Furthermore, we demonstrate the utility of co-twin comparisons for understanding pathways to AD. Effect sizes corresponding to the associations between adolescent substance use, teacher-reported externalizing problems, co-twin-reported internalizing problems, peer deviance, and self-rated health were not significantly attenuated (p value threshold = .05) after controlling for genetic and environmental influences that twin siblings share, highlighting these factors as candidates for further research.Peer reviewe
Polygenic risk for alcohol misuse is moderated by romantic partnerships
Background and Aims Previous twin research suggests relationship status can moderate underlying genetic liability towards alcohol misuse. This paper examined: (1) whether genome-wide polygenic scores (GPS) for alcohol consumption are associated with alcohol misuse; (2) whether these GPS are moderated by romantic relationships (gene-environment interaction; G x E) and (3) whether G x E results are consistent across sex. Design Linear mixed-effects models were used to test associations between genome-wide polygenic scores, relationship status and alcohol use/misuse. Setting Finnish twins born between 1983 and 1987 identified through Finland's central population registry. Participants An intensively studied subset of Finnish Twin Study (FinnTwin12) during the young adult phase (aged 20-26 years). The analytical sample includes those with complete interview and genetic data (n = 1201). Measurements Key measurements included involvement in a romantic partnership, drinking frequency, intoxication frequency and DSM-IV alcohol dependence (AD) symptoms. Genome-wide polygenic scores (GPS) were created from available summary statistics from a large genome-wide association study (GWAS) of drinks per week. Results GPS predicted drinking frequency [b = 0.109; 95% confidence interval (CI) = 0.050, 0.168], intoxication frequency (b = 0.111; 95% CI = 0.054, 0.168) and AD symptoms (b = 0.123; 95% CI = 0.064, 0.182). Having a romantic relationship negatively influenced the association between GPS and drinking frequency (b = -0.105; 95% CI = -0.211, -0.001), intoxication frequency (b = -0.118; 95% CI = -0.220, -0.016) and AD symptoms (b = -0.119; 95% CI = -0.229, -0.009). There was a three-way interaction between sex, relationship status and GPS for intoxication frequency (b = 0.223; 95% CI = 0.013, 0.433), such that the reduced association between GPS and intoxication frequency for those in a relationship was only apparent in males. We found no evidence of three-way interactions for drinking frequency or AD symptoms. Conclusions Being in a romantic relationship reduced the association between genetic predisposition and drinking, high-risk drinking and alcohol problems. However, for high-risk drinking the protective effect was limited to males, mapping onto earlier findings suggesting that males benefit more from romantic partnerships.Peer reviewe
The Realm and Frontiers of Mycosis Fungoides
Objectives Chronic renal failure (CRF) is associated with altered systemic arterial tone and hypertension. Myogenic constriction and endothelium-derived hyperpolarizing factor (EDHF)-dependent relaxation represent major vasoregulatory mechanisms in small systemic arteries. Elevated myogenic response and impaired EDHF might participate in the development of essential hypertension; however, their role in CRF-related hypertension is unknown. We investigated whether myogenic response and EDHF are altered in subtotally nephrectornized (sNX) rats and whether these changes are modifiable by chronic treatment with angiotensin-converting enzyme (ACE) inhibitor. Methods In a pressure arteriograph, myogenic constriction and EDHF-mediated relaxation were evaluated in small mesenteric arteries isolated from male Wistar rats 15 weeks after either sham operation (n = 7) (SHAM), sNX (n = 12) or sNX followed by 9 weeks of treatment with lisinopril (sNX + LIS, 2.5 mg/kg, n = 13). Results Surprisingly, myogenic response was reduced in hypertensive CRF rats (maximal myogenic tone: 37 +/- 2 and 18 +/- 4%, P <0.01; peak myogenic index: -0.80 +/- 0.08 and -0.40 +/- 0.12%/mmHg, P <0.05 in SHAM and sNX respectively). At the same time EDHF-mediated relaxation was also impaired (maximal response: 92 +/- 2 and 77 +/- 5%, P <0.01; pD(2): 6.5 +/- 0.1 and 5.9 +/- 0.1, P <0.05). Both myogenic response and EDHF were inversely related to the severity of renal failure and restored by treatment with lisinopril to levels found in SHAM animals. Conclusion Major constrictive (myogenic) and dilatory (EDHF) mechanisms of small systemic arteries are impaired in hypertensive CRF rats. These alterations do not seem to participate in the development of hypertension, being rather directly related to the severity of renal impairment. Both systemic vascular changes might be restored by renoprotective treatment with ACE inhibitor
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