The determinants of divalent/monovalent selectivity in anion exchangers

This research demonstrates that it is the distance of fixed-charge separation in the resin which is the primary determinant of divalent/monovalent selectivity. Anion resins, particularly acrylics and epoxies, with closely spaced N-containing (amine) functional groups are inherently divalent-ion selective. This is because the uptake of a divalent anion, e.g. sulfate, requires the presence of two closely-spaced positive charges.Results from this study of 30 commercially-available, strong- and weak-base, anion resins indicate that in order to bring positive charges into close proximity within a resin one can: (1) incorporate the amine functional groups into the polymer chains as opposed to having them pendant on the chains; (2) minimize the size and number of organic ("R") groups attached to the N atom, i.e., minimize the size of the amine; and (3) maximize the resin flexibility, i.e., its ability to reorient to satisfy divalent counterions, by minimizing the degree of crosslinking.The distance-of-charge-separation theory is not restricted to divalent anion exchangers but also applies to cation exchangers and to polyvalent ions in general.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25250/1/0000693.pd

The Ursinus Weekly, March 18, 1963

Future of the United Nations topic of speaker Bohmrich in April • Pre-medicals see childbirth films • Stayer & Campbell representatives to all-state band • Chemistry profs to gather at UC for convention • UC students invited to attend banquet of local businessmen • Pettit appears at Controversy chat • Sharon Robbins named editor-in-chief of Weekly; Hunter, Peek, Garner selected as staff editors • Campus Chest drive extended for week • Navy information team to visit campus soon • Gordon lectures on archaeology in Forum program • Junior Prom slated for April 5 • Social Security agent to interview students • Carlton Dingman plans to attend University of Sweden next year • Young Republicans see film on parties • Montgomery County science fair to be held at UC later this month • Helfferich plans to attend Navy orientation cruise • Editorial: This is it! • Progress on freshman term papers in various stages in Rimby\u27s dorm • Letters to the editor • Student-faculty show Saturday termed success of high quality • Freedom to learn topic of PSEA film • Intramural wrestling tournament produces 5 champions from 5 teams • Baseball prospects are encouraging • Trackmen optimistic about Spring season • IM basketball title game tomorrow pits Maples against Leber-South • Netwomen finish season with loss to West Chesterhttps://digitalcommons.ursinus.edu/weekly/1291/thumbnail.jp

Constraints on Large-Block Shareholders

Corporate managers who own a majority of the common stock in their company or who represent another firm owning such an interest appear to be less constrained than managers of diffusely held firms, yet their power to harm minority shareholders must be circumscribed by some organizational or legal arrangements. Empirical investigations reveal that boards of directors in majority-owned firms are little different from firms with diffuse stock ownership. Another source of constraints on a majority shareholders -- capital market activity -- also appears to be no different from firms with diffuse ownership. Finally, there is little evidence that new organizational mechanisms have evolved to constrain managers who own large blocks of stock. The frequency and associated wealth effects of reorganizations of majority shareholder firms, however, indicate that the law constrains managerial majority shareholders, both in their day-to-day management and when they redeem the ownership interest of minority shareholders.

Immunization with the C-domain of α-toxin prevents lethal infection, localizes tissue injury, and promotes host response to challenge with Clostridium perfringens

© 2004 by the Infectious Diseases Society of America. All rights reserved.Clostridium perfringens gas gangrene is characterized by rapid tissue destruction, impaired host response, and, often, death. Phospholipase C (α-toxin) is the virulence factor most responsible for these pathologies. The present study investigated the efficacy of active immunization with the C-terminal domain of α-toxin (Cpa247–370) in a murine model of gas gangrene. Primary end points of the study were survival, progression of infection, and tissue perfusion. Secondary end points, which were based on findings of histologic evaluation of tissues, included the extent of tissue destruction and microvascular thrombosis, as well as the magnitude of the tissue inflammatory response. Survival among C-domain–immunized animals was significantly greater than that among sham-immunized control animals. Furthermore, immunization with the C-domain localized the infection and prevented ischemia of the feet. Histopathologic findings demonstrated limited muscle necrosis, reduced microvascular thrombosis, and enhanced granulocytic influx in C-domain–immunized mice. We conclude that immunization with the C-domain of phospholipase C is a viable strategy for the prevention of morbidity and mortality associated with C. perfringens gas gangrene

Baseline Testosterone Predicts Body Composition and Metabolic Response to Testosterone Therapy

Context: Male hypogonadism adversely affects body composition, bone mineral density (BMD), and metabolic health. A previous report showed that pre-treatment testosterone (T) levels of = 264 ng/dl (N = 57). T and estradiol (E2) were measured by liquid chromatography/mass spectrometry; serum bone turnover markers (C-telopeptide [CTX], osteocalcin, and sclerostin), adiponectin, and leptin were measured by enzyme-linked immunosorbent assay; glycated hemoglobin (HbA1c) was measured by high-performance liquid chromatography; and areal BMD and body composition was measured by dual-energy x-ray absorptiometry (DXA). ResultsMen with T = 264 ng/dl (4.2 +/- 4.1 vs. 2.7 +/- 3.8%; p = 0.047) and unadjusted appendicular FFM at 6 and 18 months (8.7 +/- 11.5 vs. 4.4 +/- 4.3%, 7.3 +/- 11.6 vs. 2.4 +/- 6.8%; p = 0.033 and p = 0.043, respectively). Men with T >= 264 ng/dl showed significant decreases in HbA1c at 12 months (-3.1 +/- 9.2 vs. 3.2 +/- 13.9%; p = 0.005), fasting glucose at 18 months (-4.2 +/- 31.9 vs. 13.0 +/- 57.3%; p = 0.040), LDL at 6 months (-6.4 +/- 27.5 vs. 12.8 +/- 44.1%; p = 0.034), and leptin at 18 months (-40.2 +/- 35.1 vs. -27.6 +/- 31.0%; p = 0.034) compared to those with T = 264 ng/dl favors improvement in metabolic profile

Outer membrane β-barrel protein folding is physically controlled by periplasmic lipid head groups and BamA.

Outer membrane β-barrel proteins (OMPs) are crucial for numerous cellular processes in prokaryotes and eukaryotes. Despite extensive studies on OMP biogenesis, it is unclear why OMPs require assembly machineries to fold into their native outer membranes, as they are capable of folding quickly and efficiently through an intrinsic folding pathway in vitro. By investigating the folding of several bacterial OMPs using membranes with naturally occurring Escherichia coli lipids, we show that phosphoethanolamine and phosphoglycerol head groups impose a kinetic barrier to OMP folding. The kinetic retardation of OMP folding places a strong negative pressure against spontaneous incorporation of OMPs into inner bacterial membranes, which would dissipate the proton motive force and undoubtedly kill bacteria. We further show that prefolded β-barrel assembly machinery subunit A (BamA), the evolutionarily conserved, central subunit of the BAM complex, accelerates OMP folding by lowering the kinetic barrier imposed by phosphoethanolamine head groups. Our results suggest that OMP assembly machineries are required in vivo to enable physical control over the spontaneously occurring OMP folding reaction in the periplasm. Mechanistic studies further allowed us to derive a model for BamA function, which explains how OMP assembly can be conserved between prokaryotes and eukaryotes.This is the author accepted manuscript. The final version is available from the National Academy of Sciences via http://dx.doi.org/10.1073/pnas.132247311

Weight loss, exercise, or both and physical function in obese older adults

BACKGROUND: Obesity exacerbates the age-related decline in physical function and causes frailty in older adults; however, the appropriate treatment for obese older adults is controversial. METHODS: In this 1-year, randomized, controlled trial, we evaluated the independent and combined effects of weight loss and exercise in 107 adults who were 65 years of age or older and obese. Participants were randomly assigned to a control group, a weightmanagement (diet) group, an exercise group, or a weight-management-plus-exercise (diet–exercise) group. The primary outcome was the change in score on the modified Physical Performance Test. Secondary outcomes included other measures of frailty, body composition, bone mineral density, specific physical functions, and quality of life. RESULTS: A total of 93 participants (87%) completed the study. In the intention-to-treat analysis, the score on the Physical Performance Test, in which higher scores indicate better physical status, increased more in the diet–exercise group than in the diet group or the exercise group (increases from baseline of 21% vs. 12% and 15%, respectively); the scores in all three of those groups increased more than the scores in the control group (in which the score increased by 1%) (P<0.001 for the between-group differences). Moreover, the peak oxygen consumption improved more in the diet–exercise group than in the diet group or the exercise group (increases of 17% vs. 10% and 8%, respectively; P<0.001); the score on the Functional Status Questionnaire, in which higher scores indicate better physical function, increased more in the diet–exercise group than in the diet group (increase of 10% vs. 4%, P<0.001). Body weight decreased by 10% in the diet group and by 9% in the diet–exercise group, but did not decrease in the exercise group or the control group (P<0.001). Lean body mass and bone mineral density at the hip decreased less in the diet–exercise group than in the diet group (reductions of 3% and 1%, respectively, in the diet–exercise group vs. reductions of 5% and 3%, respectively, in the diet group; P<0.05 for both comparisons). Strength, balance, and gait improved consistently in the diet–exercise group (P<0.05 for all comparisons). Adverse events included a small number of exercise-associated musculoskeletal injuries. CONCLUSIONS: These findings suggest that a combination of weight loss and exercise provides greater improvement in physical function than either intervention alone