University at Buffalo

About: University at Buffalo is a education organization based out in Buffalo, New York, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 33773 authors who have published 63840 publications receiving 2278954 citations. The organization is also known as: UB & State University of New York at Buffalo.

Suppression of the periodontopathic microflora in localized juvenile periodontitis by systemic tetracycline

Abstract: Since recent studies have implicated Actinobacillus actinomycetemcomitans in the etiology of localized juvenile periodontitis, this investigation determined the effectiveness of subgingival debridement, topical Betadine Solution, and systemic tetracycline in suppressing subgingival A. actinomycetemcomitans and other microorganisms. A total of 20 deep periodontal pockets and 10 normal periodontal sites of 6 localized juvenile periodontitis patients was included in the study. Each patient was treated in 3 stages over a period of 22 weeks, and the result of treatment was monitored for an additional 38 weeks. The first stage of treatment included plaque control, as well as thorough scaling and root planing, composed of at least 6 h of debridement. No concomitant periodontal surgery was performed. In the second stage, Betadine saturated cotton gauze was inserted into the periodontal pockets for 10 min. Stage 3 involved systemic tetracycline therapy (1 g/day) for 14 days. The subgingival microflora was determined at frequent intervals by selective culturing of A. actinomycetemcomitans and Capnocytophaga and by direct microscopic examination. The clinical effect was assessed by measuring changes in probing periodontal attachment level, probing periodontal pocket depth, radiographic alveolar bone mass, and other relevant clinical parameters. Scaling and root planing reduced the total subgingival bacterial counts and the proportions of certain Gram-negative bacteria, but no periodontal pocket became free of A. actinomycetemcomitans. Betadine application had little or no effect on the subgingival microflora. In contrast, tetracycline administered via the systemic route suppressed A. actinomycetemcomitans, Capnocytophaga, and spirochetes to low or undetectable levels in all test periodontal pockets. A. actinomycetemcomitans reappeared in 9 of the deep periodontal pockets after the administration of tetracycline. Most of these 9 pockets became free of detectable A. actinomycetemcomitans during the second week of tetracycline administration, whereas pockets which yielded no A. actinomycetemcomitans after tetracycline therapy became free of the organisms during the first week of tetracycline treatment. This data suggests that systemic tetracycline therapy of localized juvenile periodontitis should, as a practical rule, be continued for 3 weeks. Periodontal destruction continued in 4 deep pockets which all showed high posttetracycline A. actinomycetemcomitans counts. All 6 pockets which demonstrated a marked gain in periodontal attachment yielded no cultivable A. actinomycetemcomitans. No association was found between periodontal disease status and subgingival Capnocytophaga, spirochetes or motile rods. The present study indicates that A. actinomycetemcomitans is an important etiologic agent in localized juvenile periodontitis.(ABSTRACT TRUNCATED AT 400 WORDS)

Tumor necrosis factor/cachectin stimulates peritoneal macrophages, polymorphonuclear neutrophils, and vascular endothelial cells to synthesize and release platelet-activating factor.

Abstract: Murine tumor necrosis factor (mTNF) stimulates production of platelet-activating factor (PAF) by cultured rat peritoneal macrophages in amounts comparable to those formed during treatment with the calcium ionophore A23187 or phagocytosis of zymosan. The cell-associated PAF that was released into the medium was identical to synthetic PAF, as determined with physicochemical, chromatographic, and enzymatic assays. Furthermore, de novo synthesis of PAF by macrophages was demonstrated by the incorporation of radioactive precursors such as [3H]acetyl-coenzyme A or [3H]2-lyso-PAF. Macrophages incubated with mTNF for 4 h synthesized PAF only during the first h of treatment. At this time, the amount of cell-associated PAF was approximately equal to that released into the medium. The cell-associated PAF decreased afterwards, whereas that in the medium did not correspondingly increase, suggesting that some PAF was being degraded. The response of rat macrophages to different doses of mTNF and human TNF (hTNF) was examined. Maximal synthesis of PAF was obtained with 10 ng/ml of mTNF and 50 ng/ml of hTNF. This finding may be explained by a lower affinity of hTNF for TNF receptors of rat cells. The hTNF stimulated production of PAF by human vascular endothelial cells cultured from the umbilical cord vein. The time course of PAF synthesis was slower than that observed with macrophages, with maximal production between 4 and 6 h of treatment. Optimal synthesis of PAF was obtained with 10 ng/ml of hTNF. Only 20-30% of the PAF synthesized by endothelial cells was released into the medium, even after several hours of incubation. Synthesis of PAF in response to TNF was also detected in rat polymorphonuclear neutrophils, but not in human tumor cells and dermal fibroblasts. Therefore, production of PAF is a specialized response that is transient in macrophages continuously treated with TNF, and that appears to be controlled by unidentified regulatory mechanisms.

Behavioural biometrics: a survey and classification

Abstract: This study is a survey and classification of the state-of-the-art in behavioural biometrics which is based on skills, style, preference, knowledge, motor-skills or strategy used by people while accomplishing different everyday tasks such as driving an automobile, talking on the phone or using a computer. The authors examine current research in the field and analyse the types of features used to describe different types of behaviour. After comparing accuracy rates for verification of users using different behavioural biometric approaches, researchers address privacy issues which arise or might arise in the future with the use of behavioural biometrics.

Enhanced valley splitting in monolayer WSe2 due to magnetic exchange field

Abstract: Exploiting the valley degree of freedom to store and manipulate information provides a novel paradigm for future electronics. A monolayer transition-metal dichalcogenide (TMDC) with a broken inversion symmetry possesses two degenerate yet inequivalent valleys, which offers unique opportunities for valley control through the helicity of light. Lifting the valley degeneracy by Zeeman splitting has been demonstrated recently, which may enable valley control by a magnetic field. However, the realized valley splitting is modest (∼0.2 meV T-1). Here we show greatly enhanced valley spitting in monolayer WSe2, utilizing the interfacial magnetic exchange field (MEF) from a ferromagnetic EuS substrate. A valley splitting of 2.5 meV is demonstrated at 1 T by magnetoreflectance measurements and corresponds to an effective exchange field of ∼12 T. Moreover, the splitting follows the magnetization of EuS, a hallmark of the MEF. Utilizing the MEF of a magnetic insulator can induce magnetic order and valley and spin polarization in TMDCs, which may enable valleytronic and quantum-computing applications.