The optical properties of vertically aligned ZnO nanowires deposited using a dimethylzinc adduct

The optical properties of zinc oxide nanowires are critically influenced by the growth process. Herein, we describe a metal-organic chemical vapour deposition (MOCVD) process for the growth of ZnO nanowires with improved optical properties. A tetrahydrofuran adduct is used to control the reactivity of dimethylzinc to enable this. Vertically aligned zinc oxide nanowires have been grown on Si(111) substrates by liquid injection MOCVD, using a solution of [Me(2)Zn(tetrahydrofuran)] in the presence of oxygen. The ZnO morphology becomes nanowire-like in a narrow temperature range centred about 500 degrees C. Above and below this temperature range, the ZnO is deposited in the form of polycrystalline films. The ZnO nanowires grow from a polycrystalline nucleation layer, with the (0002) c-axis parallel to the Si[111] substrate orientation. High-resolution electron microscopy reveals a highly crystalline nanowire microstructure. Resonance enhanced ultraviolet Raman spectroscopy shows that the ratio of first- and second-order longitudinal optic modes is commensurate with electron-phonon coupling effects observed previously in ZnO nanostructures. Photoluminescence exhibits intense near band-edge emission with a full width at half-maximum of 110 meV at room temperature and shows negligible defect-related visible emission.

The social endocrinology of dominance: basal testosterone predicts cortisol changes and behavior following victory and defeat

Past research suggests that individuals high in basal testosterone are motivated to gain high status. The present research extends previous work by examining endocrinological and behavioral consequences of high and low status as a function of basal testosterone. The outcome of a competition--victory versus defeat--was used as a marker of status. In Study 1, high testosterone men who lost in a dog agility competition rose in cortisol, whereas high testosterone men who won dropped in cortisol. Low testosterone men's cortisol changes did not depend on whether they had won or lost. Study 2 replicated this pattern of cortisol changes in women who participated in an experimental laboratory competition, and Study 2 extended the cortisol findings to behavior. Specifically, high testosterone winners chose to repeat the competitive task, whereas high testosterone losers chose to avoid it. In contrast, low testosterone winners and losers did not differ in their task preferences. These results provide novel evidence in humans that basal testosterone predicts cortisol reactivity and behavior following changes in social status. Implications for the social endocrinology of dominance are discussed.

The placebo effect and its determinants in osteoarthritis: meta-analysis of randomised controlled trials

OBJECTIVE

To examine the placebo effect and its potential determinants in the treatment of osteoarthritis (OA) via a systematic literature search of Medline, EMBASE, Scientific Citation Index, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Cochrane Library.

METHODS

Randomised placebo controlled trials in OA were included. The placebo effect was defined as the overall change from baseline in the placebo group. It was estimated as the effect size (ES; the standard mean difference between baseline and endpoint) and this was compared with the ES obtained from untreated control. ES for pain was the primary outcome. Statistical pooling was undertaken as appropriate and 95% CIs were used for comparison. Quality of trials was assessed and potential determinants of placebo effect were examined using multiple regression analysis. The partial regression coefficient (beta) was used to present the adjusted size of the association.

RESULTS

We identified 198 trials with 193 placebo groups (16 364 patients) and 14 untreated control groups (1167 patients) that met our inclusion criteria. These included a range of therapies (non-pharmacological, pharmacological and surgical treatments). Placebo was effective at relieving pain (ES 0.51, 95% CI 0.46 to 0.55 for the placebo group and 0.03, 95% CI -0.13 to 0.18 for untreated control). Placebo was also effective at improving function and stiffness. The pain-relieving effect increased when the active treatment effect (beta=0.38, p<0.001), baseline pain (0.006, p=0.014) and sample size (0.001, p=0.004) increased, and when placebo was given through injections/needles (0.144, p=0.020).

CONCLUSION

Placebo is effective in the treatment of OA, especially for pain, stiffness and self-reported function. The size of this effect is influenced by the strength of the active treatment, the baseline disease severity, the route of delivery and the sample size of the study.

Development of specimen-specific finite element models of human vertebrae for the analysis of vertebroplasty

The aim of this study was to determine the accuracy of specimen-specific finite element models of untreated and cement-augmented vertebrae by direct comparison with experimental results. Eleven single cadaveric vertebrae were imaged using micro computed tomography (mCT) and tested to failure in axial compression in the laboratory. Four of the specimens were first augmented with PMMA cement to simulate a prophylactic vertebroplasty. Specimen-specific finite element models were then generated using semi-automated methods. An initial set of three untreated models was used to determine the optimum conversion factors from the image data to the bone material properties. Using these factors, the predicted stiffness and strength were determined for the remaining specimens (four untreated, four augmented). The model predictions were compared with the corresponding experimental data. Good agreement was found with the non-augmented specimens in terms of stiffness (root-mean-square (r.m.s.) error 12.9 per cent) and strength (r.m.s. error 14.4 per cent). With the augmented specimens, the models consistently overestimated both stiffness and strength (r.m.s. errors 65 and 68 per cent). The results indicate that this method has the potential to provide accurate predictions of vertebral behaviour prior to augmentation. However, modelling the augmented bone with bulk material properties is inadequate, and more detailed modelling of the cement region is required to capture the bone—cement interactions if the models are to be used to predict the behaviour following vertebroplasty.

Disparities in joint replacement utilization: a quality of care issue

Although total joint replacement is an effective treatment option for end-stage lower extremity osteoarthritis, racial disparities in joint replacement utilization have been well documented. These disparities may be due in part to patient-level factors such as willingness to consider joint replacement and worse expectations of joint replacement outcomes. In addition, African-Americans may have worse outcomes after total joint replacement and are more likely to have surgery performed by surgeons with lower volumes or in hospitals with lower volumes. All of these issues may be considered concerns with the quality of care delivered to African-Americans with osteoarthritis.

Interconversion of contact and separated ion pairs in silyl- and arylthio-substituted alkyllithium reagents

Ether-solvated contact and separated ion pairs (CIP and SIP) for two lithium reagents, tris(trimethylsilyl)methyllithium (1) and bis(3,5-bistrifluoromethylphenylthio)methyllithium (2), have been characterized and observed for the first time under conditions of slow exchange by NMR spectroscopy, and barriers to interconversion have been measured. A Saunders isotope perturbation experiment was used to support identification of the CIP and SIP species for 2.

Interspecies hormonal interactions between man and the domestic dog (Canis familiaris)

To date, hormonal influence in interspecies interaction has not been examined. In a study of a dog agility competition among human/dog teams, men's pre-competition basal testosterone (T) levels were positively related to changes in dogs' cortisol levels from pre- to post-competition, but only among losing teams. Furthermore, pre-competition basal T in men on losing teams predicted more than half of the variance in dogs' cortisol change. This relationship was mediated through men's punitive and affiliative behaviors towards their dogs immediately after competition. Men's T change was also a significant predictor of dogs' change in cortisol such that men who experienced greater decreases in T after a loss were associated with dogs that experienced greater increases in cortisol. In winning teams, men's pre-competition T and T changes were unrelated to dogs' cortisol changes. These results are discussed in light of T as a proxy for dominance motivation as well as T's relation to stress across the species boundary.

Induction of apoptosis with tobacco smoke and related products in A549 lung epithelial cells in vitro

Background

This study has investigated the ability of tobacco smoke, and ingredients of tobacco smoke, to induce apoptosis in the airway epithelial cell line A549.

Method

A549 cells were treated with 80 μg/ml Tobacco smoke condensate (TSC), 10 mM Nicotine, 10 μM paraldehyde, 10 μM hydrogen peroxide, 1 μM Taxol^® (Paclitaxel), 100%, 50% and 25% cigarette smoke extract (CSE). Following 4–48 h incubation apoptosis was measured morphologically following staining of cells with DAPI. TUNEL staining was also used to assess DNA damage after 24 and 48 h incubation. In addition, loss of mitochondrial cytochrome C and activation of Bax-α, early events in the apoptotic process, were measured after 4 h of incubation.

Results

Incubation of A549 cells with vehicle, Taxol, TSC, nicotine, paraldehyde, hydrogen peroxide and CSE caused a time-dependent detachment of the cells from the flask between 6 and 48 h. DAPI staining revealed that the cells remaining adhered to the flask appeared healthy whereas some of those that had detached appeared to be either apoptotic or indeterminate. Treatment with Taxol, TSC, nicotine, paraldehyde, hydrogen peroxide and CSE caused a significant increase in the number of apoptotic cells. Similarly, treatment with Taxol, TSC, nicotine, hydrogen peroxide and CSE caused a significant increase in the number of apoptotic cells among the cells that had detached from the culture plate. After 4 h of incubation, Taxol, TSC, hydrogen peroxide and CSE caused a significant reduction in mitochondrial cytochrome C and an increase in cytosolic cytochrome C. At the same time point, hydrogen peroxide and CSE significantly increased the concentration of Bax-α in the mitochondria.

Conclusion

Tobacco smoke initiates apoptosis in A549 airway epithelial cells as a result of mitochondrial damage and that this results in a cell detachment and full apoptosis. This effect appears to result from factors in tobacco smoke other than nicotine and may result from free radical activity. However, additional stable factors may also be involved since the free radical content of TSC is likely to be low.

Elimination of transmissible spongiform encephalopathy infectivity and decontamination of surgical instruments by using radio-frequency gas-plasma treatment

It has now been established that transmissible spongiform encephalopathy (TSE) infectivity, which is highly resistant to conventional methods of deactivation, can be transmitted iatrogenically by contaminated stainless steel. It is important that new methods are evaluated for effective removal of protein residues from surgical instruments. Here, radio-frequency (RF) gas-plasma treatment was investigated as a method of removing both the protein debris and TSE infectivity. Stainless-steel spheres contaminated with the 263K strain of scrapie and a variety of used surgical instruments, which had been cleaned by a hospital sterile-services department, were examined both before and after treatment by RF gas plasma, using scanning electron microscopy and energy-dispersive X-ray spectroscopic analysis. Transmission of scrapie from the contaminated spheres was examined in hamsters by the peripheral route of infection. RF gas-plasma treatment effectively removed residual organic residues on reprocessed surgical instruments and gross contamination both from orthopaedic blades and from the experimentally contaminated spheres. In vivo testing showed that RF gas-plasma treatment of scrapie-infected spheres eliminated transmission of infectivity. The infectivity of the TSE agent adsorbed on metal spheres could be removed effectively by gas-plasma cleaning with argon/oxygen mixtures. This treatment can effectively remove 'stubborn' residual contamination on surgical instruments.

Cost effectiveness of a two-year home exercise program for the treatment of knee pain

OBJECTIVE

To assess the cost effectiveness of a 2-year home exercise program for the treatment of knee pain.

METHODS

A total of 759 adults aged > or = 45 years were randomized to receive exercise therapy, monthly telephone contact, exercise therapy and telephone contact, or no intervention. Efficacy was measured using self-reported knee pain at 2 years. Costs to both the National Health Service and to the patient were included.

RESULTS

Exercise therapy was associated with higher costs and better effectiveness. Direct costs for the interventions were pound 112 for the exercise program and pound 61 for the monthly telephone support. Participants allocated to receive exercise therapy were significantly more likely to incur higher medical costs than those in the no-exercise groups (mean difference pound 225; 95% confidence interval pound 218, pound 232; P < 0.001).

CONCLUSION

Exercise therapy is associated with improvements in knee pain, but the cost of delivering the exercise program is unlikely to be offset by any reduction in medical resource use.

Preoperative chemoradiotherapy and total mesorectal excision surgery for locally advanced rectal cancer: correlation with rectal cancer regression grade

PURPOSE

Preoperative long-course chemoradiotherapy is recommended for rectal carcinoma when there is concern that surgery alone may not be curative. Downstaging of the tumor can be measured as rectal cancer regression grade (1-3) and may be of importance when estimating the prognosis. The aim of this study was to look at the long-term results of tumor regression in patients receiving long-course chemotherapy before surgical resection of rectal cancer.

METHODS

We reviewed those patients who received preoperative chemoradiotherapy followed by surgical resection for carcinoma of the mid rectum or distal rectum found to be stage T3/4 between January 1995 and November 1999. Patients received 45 to 50 Gy irradiation in 2-Gy fractions and an infusion of 5-fluorouracil. Surgical specimens were assessed for rectal cancer regression grade. Patients were followed up routinely with clinical examination, computed tomography, and colonoscopy.

RESULTS

Sixty-five patients with a mean age 65 (range, 32-83) years underwent chemoradiotherapy before surgical resection. Thirty patients (46 percent) were classified as rectal cancer regression Grade 1, with 9 patients (14 percent) having complete sterilization of the tumor. Fifty-three patients (82 percent) underwent a curative resection. Overall survival, with a median follow-up of 39 (range, 24-83) months, was 67 percent and was associated with tumor downstaging. The local recurrence rate was 5.8 percent in those patients who underwent a curative resection and was significantly lower with rectal cancer regression Grade 1 tumors (P = 0.03). Eight of nine patients (89 percent) whose tumor had been sterilized were alive and well with no recurrence of tumor at a median follow-up of 41 (range, 24-70) months.

CONCLUSIONS

Preoperative chemoradiotherapy resulted in significant regression of tumor. Overall survival was high and was associated with downstaging of tumor. The local recurrence rate was significantly lower with rectal cancer regression Grade 1 tumors and was not seen in patients with sterilized tumors.

Investigation of microstructural features in regenerating bone using micro computed tomography

We illustrate some of the uses of micro-computed tomography (micro-CT) to study tissue-engineered bone using a micro-CT facility for imaging and visualizing biomaterials in three dimensions (3-D). The micro-CT is capable of acquiring 3D X-ray CT images made up of 2000(3) voxels on specimens up to 5 cm in extent with resolutions down to 2 microm. This allows the 3-D structure of tissue-engineered materials to be imaged across orders of magnitude in resolution. This capability is used to examine an explanted, tissue-engineered bone material based on a polycaprolactone scaffold and autologous bone marrow cells. Imaging of the tissue-engineered bone at a scale of 1 cm and resolutions of 10 microm allows one to visualize the complex ingrowth of bone into the polymer scaffold. From a theoretical viewpoint the voxel data may also be used to calculate expected mechanical properties of the tissue-engineered implant. These observations illustrate the benefits of tomography over traditional techniques for the characterization of bone morphology and interconnectivity. As the method is nondestructive it can perform a complimentary role to current histomorphometric techniques.

Plasma cleaning of dental instruments

The theoretical risk of prion transmission via surgical instruments is of current public and professional concern. These concerns are further heightened by reports of the strong surface affinity of the prion protein, and that the removal of organic material by conventional sterilization is often inadequate. Recent reports of contamination on sterilized endodontic files are of particular relevance given the close contact that these instruments may make with peripheral nerve tissue. In this paper, we report the effective use of a commercial gas plasma etcher in the cleaning of endodontic files. A representative sample of cleaned, sterilized, files was screened, using scanning electron microscopy and energy-dispersive X-ray analysis, to determine the level of contamination before plasma cleaning. The files were then exposed for a short-term to a low-pressure oxygen-argon plasma, before being re-examined. In all cases, the amount of organic material (in particular that which may have comprised protein) was reduced to a level below the detection limit of the instrument. This work suggests that plasma cleaning offers a safe and effective method for decontamination of dental instruments, thus reducing the risk of iatrogenic transmission of disease during dental procedures. Furthermore, whilst this study focuses on dental files, the findings indicate that the method may be readily extended to the decontamination of general surgical instruments.

Home based exercise programme for knee pain and knee osteoarthritis: randomised controlled trial

OBJECTIVES

To determine whether a home based exercise programme can improve outcomes in patients with knee pain.

DESIGN

Pragmatic, factorial randomised controlled trial of two years' duration.

SETTING

Two general practices in Nottingham.

PARTICIPANTS

786 men and women aged >/=45 years with self reported knee pain.

INTERVENTIONS

Participants were randomised to four groups to receive exercise therapy, monthly telephone contact, exercise therapy plus telephone contact, or no intervention. Patients in the no intervention and combined exercise and telephone groups were randomised to receive or not receive a placebo health food tablet.

MAIN OUTCOME MEASURES

Primary outcome was self reported score for knee pain on the Western Ontario and McMaster universities (WOMAC) osteoarthritis index at two years. Secondary outcomes included knee specific physical function and stiffness (scored on WOMAC index), general physical function (scored on SF-36 questionnaire), psychological outlook (scored on hospital anxiety and depression scale), and isometric muscle strength.

RESULTS

600 (76.3%) participants completed the study. At 24 months, highly significant reductions in knee pain were apparent for the pooled exercise groups compared with the non-exercise groups (mean difference -0.82, 95% confidence interval -1.3 to -0.3). Similar improvements were observed at 6, 12, and 18 months. Regular telephone contact alone did not reduce pain. The reduction in pain was greater the closer patients adhered to the exercise plan.

CONCLUSIONS

A simple home based exercise programme can significantly reduce knee pain. The lack of improvement in patients who received only telephone contact suggests that improvements are not just due to psychosocial effects because of contact with the therapist.

Pharmacology of INS37217 [P(1)-(uridine 5')-P(4)- (2'-deoxycytidine 5')tetraphosphate, tetrasodium salt], a next-generation P2Y(2) receptor agonist for the treatment of cystic fibrosis

INS37217 [P(1)-(uridine 5')-P(4)-(2'-deoxycytidine 5')tetraphosphate, tetrasodium salt] is a deoxycytidine-uridine dinucleotide with agonist activity at the P2Y(2) receptor. In primate lung tissues, the P2Y(2) receptor mRNA was located by in situ hybridization predominantly in epithelial cells and not in smooth muscle or stromal tissue. The pharmacologic profile of INS37217 parallels that of UTP, leading to increased chloride and water secretion, increased cilia beat frequency, and increased mucin release. The combined effect of these actions was confirmed in an animal model of tracheal mucus velocity that showed that a single administration of INS37217 significantly enhanced mucus transport for at least 8 h after dosing. This extended duration of action is consistent with the ability of INS37217 to resist metabolism by airway cells and sputum enzymes. The enhanced metabolic stability and resultant increased duration of improved mucociliary clearance may confer significant advantages to INS37217 over other P2Y(2) agonists in the treatment of diseases such as cystic fibrosis.

Quantification of histologic regression of rectal cancer after irradiation: a proposal for a modified staging system

PURPOSE

Long-course preoperative radiotherapy has been recommended for rectal carcinoma when there is concern about the ability to perform a curative resection, for example, in larger tethered tumors or those sited anteriorly or near the anal sphincter. "Downstaging" of the tumor may occur, and this is of importance when estimating the prognosis and selecting postoperative therapy for patients. We studied the effects of preoperative chemoradiotherapy on the pathology of rectal cancer, and we propose a simplified measurement of tumor regression, the Rectal Cancer Regression Grade.

METHODS

We have reviewed those patients who received preoperative chemoradiotherapy followed by surgical resection for carcinomas of the mid or distal third of the rectum found to be Stage T3/4 on transrectal ultrasound or CT between January 1995 and December 1998. Patients received 45 to 50 Gy irradiation and an infusion of 5-fluorouracil. The surgical specimens were examined by one pathologist, and the Rectal Cancer Regression Grade was quantified.

RESULTS

Forty-two patients, mean age 60 (range, 42-86) years, underwent chemoradiotherapy before surgery for rectal carcinoma. There were 28 anterior resections (67 percent; 9 with a colonic pouch), 12 abdominoperineal resections (27 percent), and 2 Hartmann's procedures (5 percent). Comparison of preoperative and pathologic staging revealed that the depth of invasion was downstaged in 17 patients (38 percent), and the status of involved lymph nodes was downstaged in 13 (50 percent) of 26 patients. Tumor regression was more than 50 percent (Rectal Cancer Regression Grades 1 and 2) in 36 patients (86 percent), with 7 patients (17 percent) having complete regression with absence of residual cancer cells.

CONCLUSION

Significant tumor regression was seen in 86 percent of cases after chemoradiotherapy, with 19 patients showing a "good" responsiveness. We propose a modified pathologic staging system for irradiated rectal cancer, the Rectal Cancer Regression Grade, which includes a measurement of tumor regression. The utility of the proposed Rectal Cancer Regression Grade must be tested against long-term outcomes before its value in predicting prognosis and survival can be determined.

A nurse-delivered advice intervention can reduce chronic non-steroidal anti-inflammatory drug use in general practice: a randomized controlled trial

OBJECTIVE

To find out whether a nurse-delivered educational package can reduce chronic oral non-steroidal anti-inflammatory drug (NSAID) usage in general practice.

METHOD

A prospective randomized controlled trial with assessment of economic cost/benefits was carried out in five general practices in Nottinghamshire with computerized prescribing systems, representing a mix of rural/urban and fundholding/non-fundholding practices. Patients suffering from non-malignant, non-inflammatory musculoskeletal pain received repeat prescriptions for oral NSAIDs. Two hundred and twenty-two patients were randomized to a control group (simple advice regarding NSAID use) or an intervention group (asked to withdraw their NSAIDs and employ appropriate alternative drug and non-drug therapies). All advice was supported by patient literature and delivered by a nurse practitioner trained in musculoskeletal assessment. The primary outcome measure was change in NSAID use 6 months after the intervention. Secondary outcome measures were changes in health and quality of life (SF-36 and EQ-5D questionnaires) and drug, health service and patient costs.

RESULTS

An extra 28% of patients in the intervention group either stopped taking oral NSAIDs or reduced dosage by > or =50% at 6 months compared with controls. There was no detrimental effect on health and well-being. Oral NSAID prescription costs were significantly lowered in the intervention group but not in the control group. A non-significant increase in total drug prescription costs occurred in both groups.

CONCLUSIONS

Nurse-based intervention can reduce chronic NSAID usage and costs in primary care and would be cost-effective if maintained in the long term. This intervention package would be readily applicable in primary care.