University of Liverpool

About: University of Liverpool is a education organization based out in Liverpool, United Kingdom. It is known for research contribution in the topics: Population & Context (language use). The organization has 40406 authors who have published 94388 publications receiving 3188970 citations. The organization is also known as: Liverpool University & The University of Liverpool.

Selective Laser Melting: a regular unit cell approach for the manufacture of porous, titanium, bone in-growth constructs, suitable for orthopedic applications.

Abstract: In this study, a novel porous titanium structure for the purpose of bone in-growth has been designed, manufactured and evaluated. The structure was produced by Selective Laser Melting (SLM); a rapid manufacturing process capable of producing highly intricate, functionally graded parts. The technique described utilizes an approach based on a defined regular unit cell to design and produce structures with a large range of both physical and mechanical properties. These properties can be tailored to suit specific requirements; in particular, functionally graded structures with bone in-growth surfaces exhibiting properties comparable to those of human bone have been manufactured. The structures were manufactured and characterized by unit cell size, strand diameter, porosity, and compression strength. They exhibited a porosity (10-95%) dependant compression strength (0.5-350 Mpa) comparable to the typical naturally occurring range. It is also demonstrated that optimized structures have been produced that possesses ideal qualities for bone in-growth applications and that these structures can be applied in the production of orthopedic devices.

Concomitant chemotherapy and radiation therapy for cancer of the uterine cervix

Abstract: Background The National Cancer Institute (USA) alert in February 1999 stated that concomitant chemoradiotherapy should be considered for all patients with cervical cancer, based on evidence from five randomised controlled trials (RCTs). Objectives To review all known RCTs comparing concomitant chemotherapy and radiation therapy with radiotherapy for locally advanced cervical cancer. Search methods We searched electronic databases, trials registers and reference lists of published trial reports and review articles were also searched. Selection criteria This review includes RCTs in cervical cancer comparing concomitant chemoradiation with radiotherapy in the experimental arm. Trials allowing further adjuvant chemotherapy or hydroxyurea were included. Trials using radiosensitisers or radioprotectors in the experimental arm were excluded. Data collection and analysis Two authors reviewed trials for inclusion and extracted data. For meta-analyses of time-to-event outcomes (survival, progression-free survival), a hazard ratio (HR) was extracted or estimated from trial reports, where possible. Only overall rates of local and distant recurrence were presented in many reports so only odds ratios (OR) of recurrence rates could be calculated, which takes no account of time to recurrence or censoring. Few trials reported acute toxicity adequately, but where possible ORs were calculated for the main types and severities of acute toxicity. The HRs and ORs for individual trials were combined across all trials, using the fixed effect model. Late toxicity was rarely described in sufficient detail so could only be reviewed qualitatively. Main results The original review was based on nineteen trials (17 published and two unpublished) including 4580 patients. This update includes twenty four trials (21 published, 3 unpublished) and 4921 patients, although due to patient exclusion and differential reporting 61% to 75% were available for the analyses. The review strongly suggests chemoradiation improves overall survival and progression free survival, whether or not platinum was used with absolute benefits of 10% and 13% respectively. There was, however, statistical heterogeneity for these outcomes. There was some evidence that the effect was greater in trials including a high proportion of stage I and II patients. Chemoradiation also showed significant benefit for local recurrence and a suggestion of a benefit for distant recurrence. Acute haematological and gastrointestinal toxicity was significantly greater in the concomitant chemoradiation group. Late effects of treatment were not well reported and so the impact of chemoradiation on these effects could not be determined adequately. Treatment-related deaths were rare. Authors' conclusions Concomitant chemoradiation appears to improve overall survival and progression-free survival in locally advanced cervical cancer. It also appears to reduce local and distant recurrence suggesting concomitant chemotherapy may afford radiosensitisation and systemic cytotoxic effects. Some acute toxicity is increased, but the long-term side effects are still not clear.

Redox state dependence of single molecule conductivity

Abstract: Spontaneous formation of stable molecular wires between a gold scanning tunneling microscopy (STM) tip and substrate is observed when the sample has a low coverage of alpha,omega-dithiol molecules and the tunneling resistance is made sufficiently small. Current-distance curves taken under these conditions exhibit characteristic current plateaux at large tip-substrate separations from which the conductivity of a single molecule can be obtained. The versatility of this technique is demonstrated using redox-active molecules under potential control, where substantial reversible conductivity changes from 0.5 to 2.8 nS were observed when the molecule was electrochemically switched from the oxidized to the reduced state.

Do we all mean the same thing by “problem-based learning”? A review of the concepts and a formulation of the ground rules

Abstract: Problem-based learning (PBL) has emerged as a useful tool of epistemological reform in higher education, particularly in medical schools. Indeed, PBL has spent most of its career inducing revolutionary undergraduate medical reform. Nevertheless, obtaining informed agreement on the characteristics of the PBL "genus" is a challenge when the label is vulnerable to being borrowed for prestige or subversion. Many "PBL" single-subject courses within traditional curricula do not use PBL at all. Such semantic uncertainty compromises the evidence-base on the added value of problem-based versus traditional approaches and the main messages for good practice. This literature review explores what is meant by the term PBL by aiming to answer the following questions: What difficulties are inherent in the "problem-based" tag? What does the term "problem-based curriculum" imply? How has PBL been characterized and validated by focusing on its purpose? How else has PBL been characterized? How does PBL relate to problem solving? How does PBL relate to epistemological reform? In conclusion, what ground rules can be formulated for PBL? Despite much conceptual fog lingering over the PBL literature, useful ground rules can be formulated.