Biochemical Characterization of the Axolemmal Mitogen for Cultured Schwann Cells

The molecule(s) involved at the axon plasma membrane (axolemma) which causes Schwann cells to proliferate has been investigated by three biochemical techniques: 1) Alkaline extraction of axolemma resulted in recovery of 95% of the mitogenic activity and 50% of the protein in the membrane-bound portion of the axolemma. 2) The axonal mitogen for Schwann cells may be associated with heparan sulfate proteoglycans at the axonal surface. Treatment of axolemma with heparitinase, which cleaves the glycosidic bonds of sulfated glycosaminoglycans, allowed mitogenic activity to be solubilized. 3) Treatment of axolemma with heparin, a highly sulfated glycosaminoglycan analogous to heparan sulfate, resulted in a soluble mitogenic extract which had a higher specific mitogenic activity than the starting material. The results of these biochemical treatments support the model of an axonal mitogen for Schwann cells which is positively charged and bound to the negatively charged portion of heparan sulfate proteoglycans. A monoclonal antibody (1A5-2G3) was raised against the soluble mitogenic heparin extract of axolemma. The monoclonal antibody inhibited the mitogenicity of heparin extract as well as the mitogenicity of the starting axolemmal membrane. Non-specific monoclonal antibodies did not inhibit mitogenicity to as great an extent as 1A5-2G3. Mitogenic heparin extract was incubated with 1A5-2G3-coupled or non-specific antibody-coupled Sepharose. Sepharose coupled with 1A5-2G3 removed significantly more mitogenic activity from the heparin extract than did nonspecific antibodies. Using immunoaffinity techniques with the monoclonal antibody and the soluble heparin extract should permit separation of the axolemmal mitogen from other components of the axon plasma membrane

Electrical and structural properties of In-implanted Si1−xGex alloys

We report on the effects of dopant concentration and substrate stoichiometry on the electrical and structural properties of In-implanted Si1−xGex alloys. Correlating the fraction of electrically active In atoms from Hall Effect measurements with the In atomic environment determined by X-ray absorption spectroscopy, we observed the transition from electrically active, substitutional In at low In concentration to electrically inactive metallic In at high In concentration. The In solid-solubility limit has been quantified and was dependent on the Si1−xGex alloy stoichiometry; the solid-solubility limit increased as the Ge fraction increased. This result was consistent with density functional theory calculations of two In atoms in a Si1−xGex supercell that demonstrated that In–In pairing was energetically favorable for x ≲ 0.7 and energetically unfavorable for x ≳ 0.7. Transmission electron microscopy imaging further complemented the results described earlier with the In concentration and Si1−xGex alloy stoichiometry dependencies readily visible. We have demonstrated that low resistivity values can be achieved with In implantation in Si1−xGex alloys, and this combination of dopant and substrate represents an effective doping protocol

Enhanced Electrical Activation in In-Implanted Si0.35Ge0.65 by C Co-Doping

In this report, we have achieved a significant increase in the electrically active dopant fraction in Indium (In)-implanted Si0.35Ge0.65, by co-doping with the isovalent element Carbon (C). Electrical measurements have been correlated with X-ray absorption spectroscopy to determine the electrical properties and the In atom lattice location. With C+ In co-doping, the solid solubility of In in Si0.35Ge0.65 was at least tripled from between 0.02 and 0.06 at% to between 0.2 and 0.6 at% as a result of C-In pair formation, which suppressed In metal precipitation. A dramatic improvement of electrical properties was thus attained in the co-doped samples.We also thank the Australian Research Council and Australian Synchrotron for support

The impact of a team-based intervention on the lifestyle risk factor management practices of community nurses: outcomes of the community nursing SNAP trial

BackgroundLifestyle risk factors like smoking, nutrition, alcohol consumption, and physical inactivity (SNAP) are the main behavioural risk factors for chronic disease. Primary health care is an appropriate setting to address these risk factors in individuals. Generalist community health nurses (GCHNs) are uniquely placed to provide lifestyle interventions as they see clients in their homes over a period of time. The aim of the paper is to examine the impact of a service-level intervention on the risk factor management practices of GCHNs.MethodsThe trial used a quasi-experimental design involving four generalist community nursing services in NSW, Australia. The services were randomly allocated to either an intervention group or control group. Nurses in the intervention group were provided with training and support in the provision of brief lifestyle assessments and interventions. The control group provided usual care. A sample of 129 GCHNs completed surveys at baseline, 6 and 12 months to examine changes in their practices and levels of confidence related to the management of SNAP risk factors. Six semi-structured interviews and four focus groups were conducted among the intervention group to explore the feasibility of incorporating the intervention into everyday practice.ResultsNurses in the intervention group became more confident in assessment and intervention over the three time points compared to their control group peers. Nurses in the intervention group reported assessing physical activity, weight and nutrition more frequently, as well as providing more brief interventions for physical activity, weight management and smoking cessation. There was little change in referral rates except for an improvement in weight management related referrals. Nurses’ perception of the importance of ‘client and system-related’ barriers to risk factor management diminished over time.ConclusionsThis study shows that the intervention was associated with positive changes in self-reported lifestyle risk factor management practices of GCHNs. Barriers to referral remained. The service model needs to be adapted to sustain these changes and enhance referral

An Open, Large-Scale, Collaborative Effort to Estimate the Reproducibility of Psychological Science

Reproducibility is a defining feature of science. However, because of strong incentives for innovation and weak incentives for confirmation, direct replication is rarely practiced or published. The Reproducibility Project is an open, large-scale, collaborative effort to systematically examine the rate and predictors of reproducibility in psychological science. So far, 72 volunteer researchers from 41 institutions have organized to openly and transparently replicate studies published in three prominent psychological journals in 2008. Multiple methods will be used to evaluate the findings, calculate an empirical rate of replication, and investigate factors that predict reproducibility. Whatever the result, a better understanding of reproducibility will ultimately improve confidence in scientific methodology and findings

Integration of a Copper-Containing Biohybrid (CuHARS) with Cellulose for Subsequent Degradation and Biomedical Control

We previously described the novel synthesis of a copper high-aspect ratio structure (CuHARS) biohybrid material using cystine. While extremely stable in water, CuHARS is completely (but slowly) degradable in cellular media. Here, integration of the CuHARS into cellulose matrices was carried out to provide added control for CuHARS degradation. Synthesized CuHARS was concentrated by centrifugation and then dried. The weighed mass was re-suspended in water. CuHARS was stable in water for months without degradation. In contrast, 25 μg/mL of the CuHARS in complete cell culture media was completely degraded (slowly) in 18 days under physiological conditions. Stable integration of CuHARS into cellulose matrices was achieved through assembly by mixing cellulose micro- and nano-fibers and CuHARS in an aqueous (pulp mixture) phase, followed by drying. Additional materials were integrated to make the hybrids magnetically susceptible. The cellulose-CuHARS composite films could be transferred, weighed, and cut into usable pieces; they maintained their form after rehydration in water for at least 7 days and were compatible with cell culture studies using brain tumor (glioma) cells. These studies demonstrate utility of a CuHARS-cellulose biohybrid for applied applications including: (1) a platform for biomedical tracking and (2) integration into a 2D/3D matrix using natural products (cellulose).This work was funded with the support of grant awards from the National Science Foundation (NSF #1547693 and NSF#1632891), and the MINECO (Spain) project MAT2015-71117-R. M. Darder acknowledges the joint sponsorship by the Fulbright Scholar Program and the Spanish Ministry of Education

Scalable High‐Aspect Ratio Bio‐ Metallic nanocomposites for cellular interactions

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