Long term laboratory column experiments to simulate bank filtration: Factors controlling removal of sulfamethoxazole

Microbial removal of the poorly degradable antibiotic sulfamethoxazole (SMX) from surface water was investigated in laboratory columns to identify critical factors for SMX removal during bank filtration, such as the substrate concentration, redox conditions and the availability of biodegradable DOC. About 60% of SMX at a start concentration of 0.25 μg/L in surface water were removed within 14 d of column passage under aerobic conditions while no removal occurred under anoxic conditions. The adaptation time was very long and was not completed after 2 years of operation. Adaptation was faster and SMX degradation was improved at an elevated concentration of SMX (4.5 μg/L) with 90% removal in 3.5 d under aerobic conditions. SMX removal was less effective under anoxic conditions (27% in 14 d) but increased again under anaerobic conditions (51% in 14 d). According to the half-lives for SMX determined from the column data (1-9 d aerobic, 49 d anoxic and 16 d anaerobic) it is essential to provide several weeks up to months of travel time in bank filtration to allow for the degradation of SMX, and likely, also for other poorly degradable compounds. Thus, the occurrence of SMX in groundwater samples does not indicate persistency of SMX but reflects insufficient residence time or unfavorable respective redox conditions. Adaptation times of years may also be required for new bank filtration sites to develop their full removal potential towards trace pollutants. Long operation time, a comparable concentration level and similar redox conditions as in the field appear to be essential to obtain realistic results with laboratory column experiments that can be transferred to real bank filtration sites.     

Nitric oxide synthase in skeletal muscle fibers: a signaling component of the dystrophin-glycoprotein complex

The present review deals with the anatomical distribution, physiological importance, and pathological implications of the neuronal-type nitric oxide synthase (nNOS) in skeletal muscle. Throughout the body, nNOS is located beneath the sarcolemma of skeletal muscle fibers. In rodents, nNOS is enriched in type IIb muscle fibers, but is more homogenously distributed among type II and type I fibers in humans and subhuman primates. It is accumulated on the postsynaptic membrane at the neuromuscular junction. An increased concentration of nNOS is noted at the sarcolemma of muscle spindle fibers, in particular nuclear bag fibers, which belong to type I fibers. The association of nNOS with the sarcolemma is mediated by the dystrophin-glycoprotein complex. Specifically, nNOS is linked to alpha 1-syntrophin through PDZ domain interactions. Possibly, it also directly binds to dystrophin. The activity and expression of nNOS are regulated by both myogenic and neurogenic factors. Besides acetylcholine, glutamate has also been shown to stimulate nNOS, probably acting through N-methyl-D-aspartate receptors, which are colocalized with nNOS at the junctional sarcolemma. Functional studies have implicated nitric oxide as a modulator of skeletal muscle contractility, mitochondrial respiration, carbohydrate metabolism, and neuromuscular transmission. A clinically relevant aspect of nNOS is its absence from the skeletal muscle sarcolemma of patients with Duchenne muscular dystrophy (DMD). A concept is presented which suggests that, as a consequence of the disruption of the dystrophin-glyoprotein complex in DMD, nNOS fails to become attached to the sarcolemma and is subject to downregulation in the cytosol.     

Bright Blue Solution Processed Triple‐Layer Polymer Light‐Emitting Diodes Realized by Thermal Layer Stabilization and Orthogonal Solvents

The realization of fully solution processed multilayer polymer light‐emitting diodes (PLEDs) constitutes the pivotal point to push PLED technology to its full potential. Herein, a fully solution processed triple‐layer PLED realized by combining two different deposition strategies is presented. The approach allows a successive deposition of more than two polymeric layers without extensively redissolving already present layers. For that purpose, a poly(9,9‐dioctyl‐fluorene‐co‐N‐(4‐butylphenyl)‐diphenylamine) (TFB) layer is stabilized by a hard‐bake process as hole transport layer on top of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). As emitting layer, a deep blue emitting pyrene‐triphenylamine copolymer is deposited from toluene solution. To complete the device assembly 9,9‐bis(3‐(5′,6′‐bis(4‐(polyethylene glycol)phenyl)‐[1,1′:4′,1″‐terphenyl]‐2′‐yl)propyl)‐9′,9′‐dioctyl‐2,7‐polyfluorene (PEGPF), a novel polyfluorene‐type polymer with polar sidechains, which acts as the electron transport layer, is deposited from methanol in an orthogonal solvent approach. Atomic force microscopy verifies that all deposited layers stay perfectly intact with respect to morphology and layer thickness upon multiple solvent treatments. Photoelectron spectroscopy reveals that the offsets of the respective frontier energy levels at the individual polymer interfaces lead to a charge carrier confinement in the emitting layer, thus enhancing the exciton formation probability in the device stack. The solution processed PLED‐stack exhibits bright blue light emission with a maximum luminance of 16 540 cd m^?2 and a maximum device efficiency of 1.42 cd A^?1, which denotes a five‐fold increase compared to corresponding single‐layer devices and demonstrates the potential of the presented concept.     

Aluminiumalkyle mit Heteroatomen. X. Elektronenstoßinduzierte Fragmentierung von Trimethylsilylalkanonen

Aluminium Alkyls with Heteroatoms. X. Electron Impact Fragmentation of Trimethylsilylalkanones It has been shown that the fragmentation of trimethylsilyl alkanones on electron impact proceeds with a uniform mechanism which differs from that of silicon-free ketones by the fact, that no α cleavage is observed. It consists of a McLafferty rearrangement at the silicon-free alkyl group, followed by a McLafferty-type cleavage involving migration of the silyl group to yield the radical ion of the respective trimethylsilyl enolether.     

Dystrophinopathy in a boy with Chediak-Higashi syndrome

OBJECTIVE: To evaluate the effect of surgery on muscular strength and endurance in patients with primary hyperparathyroidism (HPT). DESIGN: Prospective open study. SETTING: University hospital, Sweden. SUBJECTS: Nine patients undergoing HPT surgery and nine matched patients undergoing thyroid resection who acted as controls. INTERVENTIONS: Concentric and eccentric endurance was evaluated with a test comprising 100 repeatedly executed muscle action at 90 degrees.s-1. Blood samples obtained before and after operation were analysed for calcium, phosphate, thyroid stimulating hormone (TSH), and parathyroid hormone (PTH) concentrations. MAIN OUTCOME MEASURES: Peak torque during maximum voluntary concentric and eccentric muscle actions at 90 degrees.s-1 before, three months and one year after operation. RESULTS: There were no differences in concentric and eccentric peak torque before and after operation either within or between groups. Concentric and eccentric endurance were similar in the HPT group and controls before as well as after operation. The return of calcium and PTH concentrations to their reference ranges after parathyroidectomy did not correlate with changes in concentric and eccentric peak torque. CONCLUSIONS: The subjective improvement in muscle endurance which is often encountered in patients with HPT after operation is not associated with an objective increase in muscle strength or endurance as measured by isokinetic muscle performance.     

Flanking proline residues identify the L-type Ca2+ channel binding site of calciseptine and FS2

Calciseptine and FS2 are 60-amino acid polypeptides, isolated from venom of the black mamba (Dendroaspis polylepis polylepis), that block voltage-dependent L-type Ca2+ channels. We predicted that these polypeptides contain an identical functional site between residues 43 and 46 by searching for proline residues that mark the flanks of protein-protein interaction sites [Kini, R. M., and Evans, H. J. (1966) FEBS Lett. 385, 81-86]. The predicted Ca2+ channel binding site also occurs in closely related toxins, C10S2C2 and S4C8. Therefore, it is likely that these toxins also will block L-type Ca2+ channels. To test the proposed binding site on calciseptine and FS2, an eight-residue peptide, named L-calchin (L-type calcium channel inhibitor), was synthesized and examined for biological activity. As expected for an L-type Ca2+ channel blocker, L-calchin reduced peak systolic and developed pressure in isolated rat heart Langendorff preparations without affecting diastolic pressure or heart rate. Furthermore, L-calchin caused a voltage-independent block of L-type Ca2+ channel currents in whole-cell patch-clamped rabbit ventricular myocytes. Thus the synthetic peptide exhibits the L-type Ca2+ channel blocking properties of the parent molecules, calciseptine and FS2, but with a lower potency. These results strongly support the identification of a site in calciseptine and FS2 that is important for binding to L-type Ca2+ channels and reinforce the importance of proline brackets flanking protein-protein interaction sites.     

Effects of a restraint reduction intervention and OBRA '87 regulations on psychoactive drug use in nursing homes

OBJECTIVES: To describe the changes in psychoactive drug use in nursing homes after implementation of physical restraint reduction interventions and mandates of the Omnibus Budget Reconciliation Act of 1987 (OBRA '87). METHODS: A secondary analysis was conducted using data from a controlled clinical trial that took place in three nursing homes: a control home, one that received an educational intervention, and one that received an educational/consultation intervention. All three homes were influenced by the OBRA mandates. Complete pre- and 6 months' post-intervention data on use of psychoactive drugs and physical restraints were available for 446 resident subjects. Changes were first analyzed with the resident subjects as the unit of analysis and then using the nursing home ward (n = 16) as the unit of analysis. RESULTS: While physical restraint use declined in the home that received the educational/consultation intervention, neither neuroleptic nor benzodiazepine use increased in any of the homes after the interventions. The percentage of residents taking neuroleptics declined in the control home (18.6% to 11.3%, P = .014). Benzodiazepine use, which was more prevalent than described previously in the literature, declined in all three homes (P < .001). Of those residents whose physical restraints were discontinued, only 2% were started on neuroleptics. When the effect of OBRA mandates on appropriateness of neuroleptic use was examined, the percentage of residents on neuroleptics who lacked an OBRA-approved indication declined from 21.3% to 14.6% in the total sample, and from 39.9% to 8% in the control home. CONCLUSIONS: Interventions to reduce physical restraint did not lead to an increase in psychoactive drug use; further, reduction in both can occur simultaneously. OBRA mandates regarding psychoactive drug use were not uniformly effective, but appear, at minimum, to have increased awareness of the indications for neuroleptics.     

Prostaglandins compared with oxytocin for induction of labour at term (author's transl)

12 cases of induction of labour with prostaglandin F2 alpha and 8 with prostaglandin E2 were compared with 14 cases in which induction was undertaken with oxytocin. All inductions were successful, the induction--delivery intervals being slightly shorter in the prostaglandin groups than in the oxytocin group. Both with prostaglandin F2 alpha and with prostaglandin E2 the cardiotocogram showed uterine hyperactivity in most of the cases with an unexpected, episodically-occurring increase in basal uterine tone and remarkable tachysystoly. Uterine hyper-activity led to fetal heart rate alterations of the "dip 2" type in about 50% of the cases. According to these results prostaglandins cannot be considered superior to oxytocin for the induction of labour at term.