Synthesis of a Novel,Biodegradable Electrically Conducting Polymer for Biomedical Applications

We report the synthesis and characterization of a novel biomaterial that possesses the unique properties of being both electrically conducting and biodegradable; and thus capable of electronic interfacing with tissue. This polymer was synthesized from conducting oligomers of pyrrole and thiophene that are connected together via degradable ester linkages. We demonstrate that this polymer is conductive, degradable, and biocompatible.     

Photoconductivity in p-i-n Quantum Well Optical Modulators

Abstract

We have studied the temperature dependence of the current due to photoexcited carriers in p-i-n single quantum-well optical modulators, in order to ascertain the dominant transport mechanisms involved. A model describing the photocurrent is presented which includes the temperature and field dependence of the thermal emission, the tunnelling, the mobility and the recombination rate. A comparison between the experimental results and the model is also presented, outlining the probable transport processes.     

A technique revisited: hemodynamic comparison of closed- and open-chest cardiac massage during human cardiopulmonary resuscitation

OBJECTIVE: To compare the hemodynamics of closed-chest cardiac massage vs. open-chest cardiac massage in patients resuscitated from cardiac arrest that occurred outside of the hospital. DESIGN: Prospective, non-outcome, case series. SETTING: Large urban emergency department. PATIENTS: Ten adult, normothermic, nontraumatic, out-of-hospital, cardiac arrest patients who failed advanced cardiac life support (ACLS) therapy. INTERVENTIONS: Patients presenting to the hospital in cardiac arrest were managed according to the ACLS protocol at the clinician's discretion. Proximal aortic and central venous pressure catheters were placed to measure arteriovenous compression- and relaxation-phase pressure gradients. After 5 mins of baseline measurements during closed-chest cardiac massage, patients underwent a left lateral thoracotomy, and open-chest cardiac massage was performed for 5 mins. MEASUREMENTS AND MAIN RESULTS: The mean coronary perfusion pressure and compression-phase pressure gradients were 7.3 +/- 5.7 and 6.2 +/- 5.4 mm Hg, respectively, during closed-chest cardiac massage, while increasing to 32.6 +/- 17.8 and 32.6 +/- 29.9 mm Hg, respectively, during open-chest cardiac massage. The differences between both measurements were statistically significant (p < .05). CONCLUSIONS: Open-chest cardiac massage is superior to closed-chest cardiac massage in providing relaxation-phase and compression-phase pressure gradients during cardiac arrest in patients failing current ACLS protocols. During open-chest cardiac massage, all patients exceeded the minimum coronary perfusion pressure of 15 mm Hg, which is recommended to obtain a return of spontaneous circulation. Further outcome studies are needed to determine the timeliness and appropriate indications for open-chest cardiac massage.     

Passively mode-locked Er3+ fiber laser using asemiconductor nonlinear mirror

A nonlinear mirror consisting of an InGaAs/InP multiple-quantum-well saturable absorber integrated with a Bragg reflector stack has been used to passively mode-lock a fiber laser in an extremely simple and advantageous linear-cavity configuration. To date, pulses as short as 7.6 ps have been observed     

Density measurements of noncrystalline materials at high pressure with diamond anvil cell

We describe an x-ray absorption method for in situ density measurement of non-crystalline materials in the diamond anvil cell using a monochromatic synchrotron x-ray microbeam. Sample thickness, which is indispensable in the absorption method, can be determined precisely by extrapolating the thickness profile of the gasket obtained by x-ray absorption and diffraction measurements. Diamond deformation across the sample chamber becomes noticeable at high pressures above 10 GPa, which can be monitored with a precision better than 1%, as demonstrated by measurements on crystalline Ag. We have applied the developed method to measure densities of the classic network-forming GeO(2) glass in octahedral form at pressures up to 56 GPa. The fit to the pressure-volume data with the Birch-Murnaghan equation from 13 to 56 GPa gives parameters of V(0)=23.2+/-0.4 cm(3)mol and K=35.8+/-3.0 GPa, assuming that K(')=4. This method could be applicable for in situ determination of the density of liquids and other noncrystalline materials using a diamond anvil cell up to ultrahigh pressures.     

EPICS based low-level radio frequency control system in LIPAc

The IFMIF–EVEDA (International Fusion Materials Irradiation Facility – Engineering Validation and Engineering Design Activity) linear accelerator, known as Linear IFMIF Prototype Accelerator (LIPAc), will be a 9 MeV, 125 mA continuous wave (CW) deuteron accelerator prototype to validate the technical options of the accelerator design for IFMIF. The primary mission of such facility is to test and verify materials performance when subjected to extensive neutron irradiation of the type encountered in a fusion reactor to prepare for the design, construction, licensing and safe operation of a fusion demonstration reactor (DEMO). The radio frequency (RF) power system of IFMIF–EVEDA consists of 18 RF chains working at 175 MHz with three amplification stages each. The low-level radio frequency (LLRF) controls the amplitude and phase of the signal to be synchronized with the beam and it also controls the resonance frequency of the cavities. The system is based on a commercial compact peripheral component interconnect (cPCI) field programmable gate array (FPGA) board, provided by Lyrtech and controlled by a Windows host PC. For this purpose, it is mandatory to communicate the cPCI FPGA board from EPICS Channel Access [1]. A software architecture on EPICS framework in order to control and monitor the LLRF system is presented.     

A model to predict outbreak periods of the pest blackfly Simulium chutteri Lewis (simuliidae,Diptera) in the Great Fish River,Eastern Cape province,South Africa

Elevated, more constant flows characterize the current flow regime of the Great Fish River (Eastern Cape province, South Africa) following the completion of an interbasin transfer scheme (IBT) in 1977, where prior to this the winter months were often characterized by zero flows. Changes in aquatic macroinvertebrate communities, and in particular outbreaks of the pest blackfly Simulium chutteri Lewis (Diptera: Simuliidae) have been documented in response to these altered flows. Integrated control measures of pest blackfly have been advocated based on flow reductions during the winter months. In this study, a site‐specific discharge threshold of 2 m³ s^?1 was identified as a flow reduction target based on the amount of hydraulic habitat available to S. chutteri larvae within a particular rapid. Hydrological analyses showed that flow conditions have created ideal blackfly larval habitat in this rapid, with prolonged uninterupted periods (>3 months) exceeding this threshold. A model was developed to predict probabilities and severities of blackfly outbreaks, based on flow periods and water temperatures, both of which determine the success and duration respectively of the aquatic phase of S. chutteri. July was identified as the critical month for flow restriction to 2 m³ s^?1 for a period of 38 days, in order to reduce the winter populations of S. chutteri in the Great Fish River at the study site and avoid the typical spring outbreaks of blackfly. Copyright © 2008 John Wiley & Sons, Ltd.     

Recommendations for mass spectrometry data quality metrics for open access data (corollary to the Amsterdam principles)

Policies supporting the rapid and open sharing of proteomic data are being implemented by the leading journals in the field. The proteomics community is taking steps to ensure that data are made publicly accessible and are of high quality, a challenging task that requires the development and deployment of methods for measuring and documenting data quality metrics. On September 18, 2010, the U.S. National Cancer Institute (NCI) convened the "International Workshop on Proteomic Data Quality Metrics" in Sydney, Australia, to identify and address issues facing the development and use of such methods for open access proteomics data. The stakeholders at the workshop enumerated the key principles underlying a framework for data quality assessment in mass spectrometry data that will meet the needs of the research community, journals, funding agencies, and data repositories. Attendees discussed and agreed up on two primary needs for the wide use of quality metrics: (i) an evolving list of comprehensive quality metrics and (ii) standards accompanied by software analytics. Attendees stressed the importance of increased education and training programs to promote reliable protocols in proteomics. This workshop report explores the historic precedents, key discussions, and necessary next steps to enhance the quality of open access data. By agreement, this article is published simultaneously in Proteomics, Proteomics Clinical Applications, Journal of Proteome Research, and Molecular and Cellular Proteomics, as a public service to the research community. The peer review process was a coordinated effort conducted by a panel of referees selected by the journals.