Introducing lactide-based biodegradable tissue adhesives

Lactide-based low molecular weight copolymers were synthesized and investigated as tissue adhesives. The oligomers were composed of di or trifunctional central connecting segments and lateral PLA blocks. Copolymers with glass transition temperatures in the 20–25 °C range, were found to perform better. Strong connection was found between the length of the PLA blocks, the glass transition temperature (T _g) and the Adhesive Failure Strength of the different materials. Flexible -caprolactone (CL) molecules were inserted into the PLA blocks, to produce longer biodegradable chains and improve the adhesive strength of the oligomers, while keeping their T _g within the appropriate temperature interval. Branched oligomers consisting of a trimethylolpropane central molecule and three LA–CL segments, displayed enhanced in vitro adhesive properties.     

Calibrated single-plunge bipolar electrode array for mapping myocardial vector fields in three dimensions during high-voltage transthoracic defibrillation

Mapping of the myocardial scalar electric potential during defibrillation is normally performed with unipolar electrodes connected to voltage dividers and a global potential reference. Unfortunately, vector potential gradients that are calculated from these data tend to exhibit a high sensitivity to measurement errors. This paper presents a calibrated single-plunge bipolar electrode array (EA) that avoids the error sensitivity of unipolar electrodes. The EA is triaxial, uses a local potential reference, and simultaneously measures all three components of the myocardial electric field vector. An electrode spacing of approximately 500 microm allows the EA to be direct-coupled to high-input-impedance, isolated, differential amplifiers and eliminates the need for voltage dividers. Calibration is performed with an electrolytic tank in which an accurately measured, uniform electric field is produced. For each EA, unique calibration matrices are determined which transform potential difference readings from the EA to orthogonal components of the electric field vector. Elements of the matrices are evaluated by least squares multiple regression analysis of data recorded during rotation of the electric field. The design of the electrolytic tank and electrode holder allows the electric field vector to be rotated globally with respect to the electrode axes. The calibration technique corrects for both field perturbation by the plunge electrode body and deviations from orthogonality of the electrode axes. A unique feature of this technique is that it eliminates the need for mechanical measurement of the electrode spacing. During calibration, only angular settings and voltages are recorded. For this study, ten EAs were calibrated and their root-mean-square (rms) errors evaluated. The mean of the vector magnitude rms errors over the set of ten EAs was 0.40% and the standard deviation 0.07%. Calibrated EAs were also tested for multisite mapping in four dogs during high-voltage transthoracic shocks.     

Genetic testing: Psychological aspects and implications.

As the number of genes associated with inherited disease continues to grow, researchers and practitioners in behavioral medicine will encounter complex psychological issues faced by individuals at risk for these diseases. A review of the literature concerning prenatal, carrier, and predictive genetic testing suggests that the severity of psychological risks posed by research-based genetic testing is not great. However, subgroups of individuals with particular psychological traits may be more vulnerable to adverse effects. Available data do not provide evidence that genetic testing promotes changes in health-related behaviors. Thus, although there may be less of a role for mental health professionals in the psychological counseling of genetic testing participants, there is a need for research and practice to facilitate health protective behaviors in response to genetic risk information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biallelic mutations in the ATM gene in T-prolymphocytic leukemia

Ataxia-telangiectasia (AT) is an autosomal recessive disorder characterized by cerebellar ataxia, oculocutaneous telangiectasia, immune deficiency, genome instability and predisposition to malignancies, particularly T-cell neoplasms. The responsible gene, designated ataxia-telangiectasia mutated (ATM), was recently identified by positional cloning in the chromosomal region 11q22.3-23.1 (ref. 4, 5) ATM is 150 kb in length, consists of 66 exons and encodes a nuclear phosphoprotein of approximately 350 kDa (ref. 4-9). Although ATM is considered to be a tumorigenic factor in several human cancers, it has not yet been found mutated in tumors of non-AT patients. Given the marked predisposition of AT patients to develop neoplasms of the T-cell lineage, we analyzed a series of T-cell leukemias (T-prolymphocytic leukemia, or T-PLL) in non-AT patients in search of genomic changes associated with the development of this disease. Among the recurrent aberrations identified, deletion of the chromosome arm 11q was very frequent. Subsequent molecular cytogenetic analyses allowed us to define a small commonly deleted segment at 11q22.3-23.1 in 15 of 24 T-PLLs studied. Since this critical region contained ATM, we further analyzed the remaining copy of the gene in six cases showing deletions affecting one ATM allele. In all six cases, mutations of the second ATM allele were identified, leading to the absence, premature truncation or alteration of the ATM gene product. Thus, our study demonstrates disruption of both ATM alleles by deletion or point mutation in T-PLL, suggesting that ATM functions as a tumor-suppressor gene in tumors of non-AT individuals.     

A brief assessment of concerns associated with genetic testing for cancer: The multidimensional impact of cancer risk assessment (MICRA) questionnaire.

The Multidimensional Impact of Cancer Risk Assessment (MICRA) is a new tool to measure the specific impact of result disclosure after genetic testing. The authors compared its performance with that of questionnaires measuring general and cancer-specific distress. Participants (158 women) responded 1 month after they received genetic test results. The women were divided into 4 standard clinical test result groups: BRCA1/2 positive, BRCA1/2 negative, panel negative, and true negative. Factor analysis supported the formation of 3 subscales: Distress (6 items, α= .86), Uncertainty (9 items, α= .77), and Positive Experiences (4 items, α= .75). All 3 MICRA subscales differentiated participants who were BRCAI/2 positive from the other 3 groups. MICRA thus helps identify subgroups of vulnerable genetic testing participants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

GCI—A tool for developing interactive cad user interfaces

GCI is a Unix-based tool for developing interactive CAD programs. By separating command/ menu definitions from the progam, GCI makes it easier to change and extend the user interface. The language provided by GCI is used to define the syntax of commands, menus, messages, and help text. Generally, GCI supports a static hierarchical structure of commands and menus. However, through a program interface, an application program has the freedom to change environments, commands and menus. This flexibility of run-time control of the user interface is essential for developing highly responsive interfaces in a CAD environment. This paper presents the main concepts and definition language of GCI. It then discusses architectural and implementation issues, and finally presents a typical application's view of using the tool.     

Aerobic deterioration in maize silage stored in a bunker silo under farm conditions in a subtropical climate

Whole maize plants at the milk and dough maturation stages were ensiled in August and October 1984, for periods of 45 and 40 days, respectively. Thirteen net bags containing herbage samples were buried at different locations within the silo to determine changes and losses during the conservation period. Thermocouple wires and small-diameter plastic pipes were connected to every bag for temperature and gas measurements. Air penetration in the upper layer was much faster than in the inner parts. Losses in dry matter of 3.9-7.4% were found in well sealed sites in the bunkers, and of up to 36% at locations where air penetrated. The rate of air penetration into the silage and temperature at various sites in the bunker were recorded. Correlation between CO₂, and N₂, contents in the silage was very high (r² = 0.995) whereas oxygen levels were close to zero.     

Do small lapses predict relapse to smoking behavior under bupropion treatment?

Although bupropion is known to be an effective aid to smoking cessation, little is known about its mode of action. In the present study we tested the hypothesis that bupropion reduces the likelihood that a smoking lapse, or slip, leads to a subsequent relapse. This hypothesis was tested in the context of a clinical trial of bupropion as a smoking cessation aid, using Cox regression and representing lapse history as a discrete time-varying covariate. Bupropion treatment reduced the probability of relapse during the treatment phase (hazard ratio, or HR=.421, p< or =.000) but not during the follow-up phase (end of treatment to 6 months, HR=.896, p< or=.67). As anticipated, having small lapses during treatment contributed to or predicted subsequent relapse, both during treatment (HR=2.897, p< or =.000) and during follow-up (HR=2.320, p< or=.008). Although an interaction was found between drug treatment and lapse history in predicting subsequent failure during the treatment phase, the finding suggested that drug slightly increased the effect of lapse on eventual failure during treatment (HR=1.706, p相似文献