Flexible,Mechanically Stable,Porous Self-Standing Microfiber Network Membranes of Covalent Organic Frameworks: Preparation Method and Characterization

Covalent organic frameworks (COFs) show advantageous characteristics, such as an ordered pore structure and a large surface area for gas storage and separation, energy storage, catalysis, and molecular separation. However, COFs usually exist as difficult-to-process powders, and preparing continuous, robust, flexible, foldable, and rollable COF membranes is still a challenge. Herein, such COF membranes with fiber morphology for the first time prepared via a newly introduced template-assisted framework process are reported. This method uses electrospun porous polymer membranes as a sacrificial large dimension template for making self-standing COF membranes. The porous COF fiber membranes, besides having high crystallinity, also show a large surface area (1153 m² g⁻¹), good mechanical stability, excellent thermal stability, and flexibility. This study opens up the possibility of preparation of large dimension COF membranes and their derivatives in a simple way and hence shows promise in technical applications in separation, catalysis, and energy in the future.     

Vector coupled-mode theory of dielectric waveguides

A consistent derivation of a system of vector coupled-mode (VCM) equations for parallel dielectric waveguides is presented and compared with earlier versions of the improved coupled-mode theory (ICMT). As a validity test, it is shown that the effectively scalar transverse electric and transverse magnetic (TM) coupled-mode (CM) equations are direct limits of our full VCM formulation. In particular, our formulation does not lead to the fundamental error found with earlier coupled-mode theories (CMTs) in a case of TM fields. Functional equations of our VCMT are consistent with Maxwell's equations and lead to higher precision. They can be applied to complicated arrays of strongly coupled parallel dielectric waveguides with true vectorial behavior.     

Histochemical evaluation of placental dipeptidyl peptidase IV (CD26) in pre-eclampsia: enzyme activity in villous trophoblast indicates an enhanced likelihood of gestational hypertensive disorders

Nitric oxide (NO) acts as a modulator of neuronal transmission in mature neuronal systems, including the retina. Recently, NO has also been suggested to have a trophic function during development. We examined immunocytochemically the distribution of NO-producing cells in developing and transplanted rabbit retinas. An antibody detecting the neuronal isoform of its biosynthetic enzyme, nitric oxide synthase (NOS), was used on normal developing retinas [starting at embryonic day (E) 15] and on rabbit retinal transplants after various survival times (1-139 days after surgery). Weakly stained cell bodies were first observed in the proximal margin of the neuroblastic layer at E 29. Stained processes projecting towards a developing inner plexiform layer were also visible at this time point. Immunoreactive cells were located at later stages in the innermost part of the inner nuclear layer and in the ganglion cell layer, and are likely to correspond mainly to amacrine cells. NOS-labelled cells were also found in retinal transplants. The first NOS-labelled cells appeared, as in normal developing retinas, in ages corresponding to E 29 and were still detected in transplants corresponding to postnatal day 123. NOS-labelled cells were seen in areas between rosettes, where amacrine cells are located. NOS-labelled processes were at times seen to project for long distances, forming very distinct plexuses. NOS-containing amacrine cells thus appear both in the transplants and in developing retinas in the embryonic stages, long before synaptic function involving these cells can be expected, suggesting a role for NO not only in neuromodulation but also in retinal development.     

Olfactory discrimination of individual littermates in rats (Rattus norvegicus).

Tested the ability of 4 adult male Sprague-Dawley rats to use odors in discrimination among littermates living as a group. Ss were trained in a Y-maze to discriminate the presence of a littermate from its absence. Results from transfer of training in 3 subsequent testing periods indicated that the animals were capable of distinguishing among individuals when relatedness and familiarity were held constant, that this ability was not due to training, and that performance was based solely on odor cues. Results suggest that laboratory rats exhibit odor sensitivities conmensurate with very complex social processes. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What does the object decision task measure? Reflections on the basis of evidence from semantic dementia.

The authors investigated the impact of semantic knowledge on visual object analysis by assessing the performance of patients with semantic dementia on a different-views object matching test and on 2 object decision tests differing, for example, in whether the nonreal items were nonsense objects or chimeras of 2 real objects. On average, the patients scored normally on both the object matching and the object decision test including nonsense objects but were impaired on the object decision test including chimeras; this latter was also the only visual object test that correlated significantly with degree of semantic impairment. These findings demonstrate that object decision is not a single task or ability and that it is not necessarily independent of conceptual knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Short-term preoperative radiotherapy results in down-staging of rectal cancer: a study of 1316 patients

OBJECTIVE: The incidence of back pain in children in our country is unknown. Several causes can produce this symptom, but it is necessary to rule out pathologies that require specific treatments. The goal of this work was to study the incidence and the etiology of back pain in children in our country. PATIENTS AND METHODS: We present a prospective study done in our Orthopedic Department during a period of 7 months. Twenty-two patients were referred with back pain of at least two months duration. The incidence was 2.9% compared to the total number of patients. The average age ranged from 7 to 17 years. RESULTS: A careful history and a radiological examination diagnosed 50% (11 cases) of the causes of backache in the present study. An idiopathic etiology was the most frequent cause and represented 9 patients (41%). In the remaining 12 cases (59%) pathological causes that required special treatment were identified including 2 cases of Scheuermann disease, 4 cases of painful scoliosis, 3 spondylolysis with spondylolisthesis, 2 cases of discitis, 1 benign neoplasm and 1 psychogenic cause. CONCLUSIONS: We recommend conservative management with the use of medication for relief of pain and physical therapy in the idiopathic cases. In the remaining cases, the specific treatment of the disease can improve the back pain.     

Predicting future clinical adjustment from treatment outcome and process variables.

General issues relating to the use of outcome and process data from the treatment of antisocial children to predict future childhood adjustment are examined. For outcome measures, it was assumed that variables based on direct observation of child behavior would provide a better predictor of long-term adjustment than would ratings by participant adults. Long-term adjustment measures consisted of police arrest and out-of-home placement data collected 2 years after treatment termination. Observation data collected at termination predicted future police arrest, but parent and teacher ratings did not. It was also hypothesized that measures of the processes thought to produce the changes in child antisocial behavior would serve as predictors of future adjustment. The data supported this hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

“Technically Unavoidable” in Terms of Genetically Modified Organisms – an Approach for Food Control

In case of findings of authorized genetically modified (gm) plant ingredients below the 0.9 per cent threshold, exceptions from labelling requirements according to regulation (EC) No. 1829/2003 can only be made, “provided that this presence is adventitious or technically unavoidable”. The authors describe factors that should be considered regarding contaminations by gm plant ingredients as technically unavoidable or not. A practical approach for interpretation, taking into account quality control measures and documentation as well as present findings in comparable products is proposed. Received: February 23, 2007