812 research outputs found
Genotypic variation in phosphorus efficiency between wheat cultivars grown under greenhouse and field conditions
Phosphorus (P) efficiency (relative growth), which is described as the ratio of shoot dry matter or grain yield at deficient P supply to that obtained under adequate P supply, was compared in 25 winter wheat cultivars grown under greenhouse and field conditions with low and adequate P levels in a P-deficient calcareous soil. Adequate P supply resulted in significant increases in shoot dry weight and grain yield under both experimental conditions. In the greenhouse experiment, the increases in shoot dry weight under adequate P supply (80 mg kg(-1)) were from 0% (cv: C-1252) to 34% (cv: Dagdas). Under field conditions, the cultivars showed much greater variation in their response to adequate P supply (60 kg ha(-1)): the increases in shoot dry weight and grain yield with adequate P supply were between -2% (cv: Sivas-111/33) and 25% (cv: Kirac-66) for shoot dry matter production at the heading stage and between 0% (cv: Kirkpinar-79) and 76% (cv: Kate A-1) for grain yield at maturity. Almost all cultivars behaved totally different in their response to P deficiency under greenhouse and field conditions. Phosphorus efficiency ratios (relative growth) under greenhouse conditions did not correlate with the P efficiency ratios under field conditions. In general, durum wheat cultivars were found to be more P efficient compared with bread wheat cultivars. The results of this study indicated that there is wide variation in tolerance to P deficiency among wheat cultivars that can be exploited in breeding new wheat cultivars for high P deficiency tolerance. The results also demonstrated that P efficiency was expressed differently among the wheat cultivars when grown under greenhouse and field conditions and, therefore, special attention should be paid to growth conditions in screening wheat for P efficiency
Gastroesophageal reflux disease in 2006: The imperfect diagnosis
There continues to be significant controversy related to diagnostic testing for gastroesophageal reflux disease (GERD). Clearly, barium contrast fluoroscopy is superior to any other test in defining the anatomy of the upper gastrointestinal (UGI) tract. Although fluoroscopy can demonstrate gastroesophageal reflux (GER), this observation does not equate to GERD. Fluoroscopy time should not be prolonged to attempt to demonstrate GER during barium contrast radiography. There are no data to justify prolonging fluoroscopy time to perform provocative maneuvers to demonstrate reflux during barium contrast UGI series. Symptoms of GERD may be associated with physiologic esophageal acid exposure measured by intraesophageal pH monitoring, and a significant percentage of patients with abnormal esophageal acid exposure have no or minimal clinical symptoms of reflux. Abnormal acid exposure defined by pH monitoring over a 24-h period does not equate to GERD. In clinical practice presumptive diagnosis of GERD is reasonably assumed by substantial reduction or elimination of suspected reflux symptoms during therapeutic trial of acid reduction therapy
Isolation of a wide range of minerals from a thermally treated plant: Equisetum arvense, a Mare’s tale
Silica is the second most abundant biomineral being exceeded in nature only by biogenic CaCO3. Many land plants (such as rice, cereals, cucumber, etc.) deposit silica in significant amounts to reinforce their tissues and as a systematic response to pathogen attack. One of the most ancient species of living vascular plants, Equisetum arvense is also able to take up and accumulate silica in all parts of the plant. Numerous methods have been developed for elimination of the organic material and/or metal ions present in plant material to isolate biogenic silica. However, depending on the chemical and/or physical treatment applied to branch or stem from Equisetum arvense; other mineral forms such glass-type materials (i.e. CaSiO3), salts (i.e. KCl) or luminescent materials can also be isolated from the plant material. In the current contribution, we show the chemical and/or thermal routes that lead to the formation of a number of different mineral types in addition to biogenic silica
Impact of hiatal hernia on histological pattern of non-erosive reflux disease
BACKGROUND: Hiatus hernia (HH) has major pathophysiological effects favoring gastroesophageal reflux and hence contributing to esophageal mucosa injury, especially in patients with severe gastroesophageal disease. However, prospective studies investigating the impact of HH on the esophageal mucosa in non-erosive reflux disease (NERD) are lacking. This study evaluated the association between the presence of (HH) and the histological findings in symptomatic patients with NERD. METHODS: Fifty consecutive patients with gastroesophageal reflux disease (GERD) were enrolled. After conventional endoscopy, Lugol solution was applied and biopsy specimens were obtained. Histological parameters including basal zone hyperplasia, papillary length and cellular infiltration were evaluated. The chi-square test with Yates' correlation was used for comparing discrete parameters between groups. However, Fisher's exact probability test was used where the expected frequencies were lower than 5. Wilcoxon's test for unpaired samples was preferred in cases of semi-quantitative parameters. RESULTS: The presence of HH along with more severe findings (0.01 <P < 0.05) was confirmed in 18 patients. NERD was observed in 29 (58%) patients. Basal zone hyperplasia and loss of glycogen accompanied HH in all cases, and the correlation was significant in NERD (P < 0.001). The remaining histological patterns were similar between erosive reflux disease and NERD in the presence of HH. CONCLUSION: The presence of HH is correlated with more severe endoscopy findings, and predisposes for severe histological abnormality in cases of NERD
Contribution of HOGG1 Ser326Cys Polymorphism to the Development of Prostate Cancer in Smokers: Meta-Analysis of 2779 Cases and 3484 Controls
The HOGG1 gene catalyzes the excision of modified bases and removal of DNA damage adducts. It may play an important role in the prevention of carcinogenesis. Ser326Cys polymorphism localizes in exon 7 of the hOGG1 gene. It takes the form of an amino acid substitution, from serine to cysteine, in codon 326. Several epidemiological association studies have been conducted on this polymorphism and its relationship with the risk of prostate cancer. However, results have been conflicting. To resolve this conflict, we conducted a meta-analysis on the association between this polymorphism and prostate cancer, taking into account race, country, sources of controls, and smoking status. A total of nine studies covering 2779 cases and 3484 controls were included in the current meta-analysis. Although no significant association was found between hOGG1 Ser326Cys polymorphism and prostate cancer susceptibility in the pooled analysis, individuals with Ser/Cys+Cys/Cys genotypes were found to have greater risk of prostate cancer if they were also smokers (OR = 2.66, 95% CI = 1.58−4.47) rather than non-smokers (OR = 2.18, 95% CI = 1.13−4.19), compared with those with Ser/Ser genotype. In conclusion, our meta-analysis demonstrates that hOGG1 Ser326Cys polymorphism is a risk factor for prostate cancer in smokers. Further studies are needed to confirm this relationship
Gastroesophageal reflux symptoms in infants in a rural population: longitudinal data over the first six months
<p>Abstract</p> <p>Background</p> <p>Increasing numbers of infants are receiving prescription medications for symptoms associated with gastroesophageal reflux. Our aim was to prospectively measure reported gastroesophageal reflux symptoms in healthy term infants for the first six months of life.</p> <p>Methods</p> <p>In a prospective cohort study in the rural Upper Peninsula of Michigan, 128 consecutive maternal-infant pairs were followed for six months and administered the Infant Gastroesophageal Reflux Questionnaire Revised (I-GERQ-R) at the one-month, two-month, four-month, and six-month well-child visits.</p> <p>Results</p> <p>The I-GERQ-R scores decreased with age. Average scores were 11.74 (SE = 5.97) at one-month, 9.97(4.92) at two-months, 8.44(4.39) at four-months, and 6.97(4.05) at six months. Symptoms associated with colic were greatest at one month of age.</p> <p>Conclusion</p> <p>Symptoms of gastroesophageal reflux as measured by the I-GERQ-R decrease with age in the first six months of life in otherwise healthy infants; however the I-GERQ-R may have difficulty differentiating gastroesophageal reflux disease from colic in those under 3 months of age.</p
Photonic gas sensors exploiting directly the optical properties of hybrid carbon nanotube localized surface plasmon structures
We investigate the modification of the optical properties of carbon nanotubes (CNTs) resulting from a chemical reaction triggered by the presence of a specific compound (gaseous carbon dioxide (CO2)) and show this mechanism has important consequences for chemical sensing. CNTs have attracted significant research interest because they can be functionalized for a particular chemical, yielding a specific physical response which suggests many potential applications in the fields of nanotechnology and sensing. So far, however, utilizing their optical properties for this purpose has proven to be challenging. We demonstrate the use of localized surface plasmons generated on a nanostructured thin film, resembling a large array of nano-wires, to detect changes in the optical properties of the CNTs. Chemical selectivity is demonstrated using CO2 in gaseous form at room temperature. The demonstrated methodology results additionally in a new, electrically passive, optical sensing configuration that opens up the possibilities of using CNTs as sensors in hazardous/explosive environments
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