A surface spectroscopy study of a Pseudomonas fluorescens biofilm in the presence of an immobilized air bubble.

A linear spectral mapping technique was applied to monitor the growth of biomolecular absorption bands at the bio-interface of a nascent Pseudomonas fluorescens biofilm during and after interaction with a surface-adhered air bubble. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectra were obtained in different locations in a microchannel with adequate spatial and temporal resolution to study the effect of a static bubble on the evolution of protein and lipid signals at the ATR crystal surface. The results reveal that the presence of a bubble during the lag phase modified levels of extracellular lipids and affected a surface restructuring process, many hours after the bubble's disappearance.

Giant Quantum Hall Plateau in Graphene Coupled to an InSe van der Waals Crystal.

We report on a "giant" quantum Hall effect plateau in a graphene-based field-effect transistor where graphene is capped by a layer of the van der Waals crystal InSe. The giant quantum Hall effect plateau arises from the close alignment of the conduction band edge of InSe with the Dirac point of graphene. This feature enables the magnetic-field- and electric-field-effect-induced transfer of charge carriers between InSe and the degenerate Landau level states of the adjacent graphene layer, which is coupled by a van der Waals heterointerface to the InSe.

Hemodialysis Clinic Social Networks, Sex Differences, and Renal Transplantation.

This study describes patient social networks within a new hemodialysis clinic and models the association between social network participation and kidney transplantation. Survey and observational data collected between August 2012 and February 2015 were used to observe the formation of a social network of 46 hemodialysis patients in a newly opened clinic. Thirty-two (70%) patients formed a social network, discussing health (59%) and transplantation (44%) with other patients. While transplant-eligible women participated in the network less often than men (56% vs. 90%, p = 0.02), women who participated discussed their health more often than men (90% vs. 45.5%, p = 0.02). Patients in the social network completed a median of two steps toward transplantation compared with a median of 0 for socially isolated patients (p = 0.003). Patients also completed more steps if network members were closely connected (ß = 2.23, 95% confidence interval [CI] 0.16-4.29, p = 0.03) and if network members themselves completed more steps (ß = 2.84, 95% CI 0.11-5.57, p = 0.04). The hemodialysis clinic patient social network had a net positive effect on completion of transplant steps, and patients who interacted with each other completed a similar number of steps.

A microfluidic method and custom model for continuous, non-intrusive biofilm viscosity measurements under different nutrient conditions.

Straight, low-aspect ratio micro flow cells are used to support biofilm attachment and preferential accumulation at the short side-wall, which progressively reduces the effective channel width. The biofilm shifts downstream at measurable velocities under the imposed force from the constant laminar co-flowing nutrient stream. The dynamic behaviour of the biofilm viscosity is modeled semi-analytically, based on experimental measurements of biofilm dimensions and velocity as inputs. The technique advances the study of biofilm mechanical properties by strongly limiting biases related to non-Newtonian biofilm properties (e.g., shear dependent viscosity) with excellent time resolution. To demonstrate the proof of principle, young Pseudomonas sp. biofilms were analyzed under different nutrient concentrations and constant micro-flow conditions. The striking results show that large initial differences in biofilm viscosities grown under different nutrient concentrations become nearly identical in less than one day, followed by a continuous thickening process. The technique verifies that in 50 h from inoculation to early maturation stages, biofilm viscosity could grow by over 2 orders of magnitude. The approach opens the way for detailed studies of mechanical properties under a wide variety of physiochemical conditions, such as ionic strength, temperature, and shear stress.

Through thick and thin: a microfluidic approach for continuous measurements of biofilm viscosity and the effect of ionic strength.

Continuous, non-intrusive measurements of time-varying viscosity of Pseudomonas sp. biofilms are made using a microfluidic method that combines video tracking with a semi-empirical viscous flow model. The approach uses measured velocity and height of tracked biofilm segments, which move under the constant laminar flow of a nutrient solution. Following a low viscosity growth stage, rapid thickening was observed. During this stage, viscosity increased by over an order of magnitude in less than ten hours. The technique was also demonstrated as a promising platform for parallel experiments by subjecting multiple biofilm-laden microchannels to nutrient solutions containing NaCl in the range of 0 to 34 mM. Preliminary data suggest a strong relationship between ionic strength and biofilm properties, such as average viscosity and rapid thickening onset time. The technique opens the way for a combinatorial approach to study the response of biofilm viscosity under well-controlled physical, chemical and biological growth conditions.

A microfluidic platform with pH imaging for chemical and hydrodynamic stimulation of intact oral biofilms.

A microfluidic platform with a fluorescent nanoparticle-based sensor is demonstrated for real-time, ratiometric pH imaging of biofilms. Sensing is accomplished by a thin patterned layer of covalently bonded Ag@SiO2+FiTC nanoparticles on an embedded planar glass substrate. The system is designed to be sensitive, responsive and give sufficient spatial resolution to enable new micro-scale studies of the dynamic response of oral biofilms to well-controlled chemical and hydrodynamic stimulation. Performance under challenging operational conditions is demonstrated, which include long-duration exposure to sheer stresses, photoexcitation and pH sensor biofouling. After comprehensive validation, the device was used to monitor pH changes at the attachment surface of a biofilm of the oral bacteria, Streptococcus salivarius. By controlling flow and chemical concentration conditions in the microchannel, biochemical and mass transport contributions to the Stephan curve could be probed individually. This opens the way for the analysis of separate contributions to dental caries due to localized acidification directly at the biofilm tooth interface.

Systematic reviews in rehabilitation for stroke: issues and approaches to addressing them.

OBJECTIVES: To describe the problems encountered when undertaking systematic reviews of rehabilitation and to give advice to reviewers about ways of addressing these issues. BACKGROUND: Evidence-based practice has become established as a way of linking clinical practice with research evidence. The most robust evidence is usually considered to be that from randomized controlled trials, and from systematic reviews of these trials. However, most reviews have focused on drug and surgical interventions, and few reviews have been produced in the field of rehabilitation. This may be due to the unique difficulties that are posed by reviews in this area. EXPERIENCE OF SYSTEMATIC REVIEWS IN APHASIA: We describe the challenges that occurred when carrying out systematic reviews of speech and language therapy for aphasia following stroke, and of ways to deliver rehabilitation services to people who have suffered a stroke. Issues arose at all stages of the reviews and included: using expertise; planning the review; defining the health care problem, patients, outcomes and interventions of interest; searching for, interpreting and synthesizing the results of the studies identified; and deriving implications from the review. Suggestions made to address these challenges include: developing a suitable team of reviewers; using inclusive and broad criteria for inclusion of trials to a review; developing appropriate search strategies; and using caution in arriving at conclusions. It is important to be explicit about decisions made during the review process concerning how to handle the challenges. Practical advice about carrying out reviews in the field of stroke rehabilitation is likely to be helpful to reviewers of other rehabilitative interventions. There are likely to be relatively few studies available for such reviews, and limitations in drawing specific practical conclusions. Such undertakings are, however, useful in setting the agenda for further research.

Pharmacological treatment for aphasia following stroke.

BACKGROUND: Aphasia describes language impairment associated with a brain lesion. OBJECTIVES: The objective of this review was to assess the effects of drugs on language abilities when given to people with aphasia following stroke. SEARCH STRATEGY: We searched the Cochrane Stroke Group Register (last searched: May 2001), and reference lists of relevant articles to December 1998. We also contacted academic institutions and other researchers to identify further published and unpublished trials. MEDLINE was searched from 1966-1998, and CINAHL from 1982-1998. We searched the International Journal of Disorders of Communication by hand (known by other names in the past), from 1969 to 1998. SELECTION CRITERIA: Randomised controlled trials comparing: ~bullet~Any drug given to improve language, versus no treatment, or versus placebo ~bullet~Any drug given to improve language versus speech and language therapy ~bullet~One drug given to improve language versus another drug given with the same aim DATA COLLECTION AND ANALYSIS: The principal reviewer collected the data, and assessed the quality of the trials with independent data checking and methodological advice. If we could not perform a statistical combination of different studies, we sought missing data. Failing that we provided a description. We sought missing data from authors, or where appropriate, a drug company. MAIN RESULTS: We considered fifty two studies in detail, from which we identified ten trials suitable for the review. In most cases the methodological quality was unassessable, and only one trial reported sufficient detail for us to complete a description and analysis. This study did lose a large number of patients during its course. Drugs used in the trials identified were piracetam, bifemalane, piribedil, bromocriptine, idebenone, and Dextran 40. We found weak evidence that patients were more likely to have improved on any language measure at the end of the trial if they had received treatment with piracetam (odds ratio 0.46, 95% confidence interval 0.3 to 0.7). The evidence is considered weak because of the large numbers of drop outs from the trials identified, who were lost to follow up. Patients who were treated with piracetam were no more likely (considering statistical significance) than those who took a placebo to experience unwanted effects, including death (odds ratio 1.29, 95% confidence interval for difference 0.9 to 1.7). However, the differences in death rates between the two groups, even though not not statistically significant, do give rise to some concerns that there may be an increased risk of death from taking piracetam. We could not determine if drug treatment is more effective than speech and language therapy. We could not determine whether one drug is more effective than another. REVIEWER'S CONCLUSIONS: The main conclusion of this review is that drug treatment with piracetam may be effective in the treatment of aphasia after stroke. Further research is needed to explore the effects of drugs for aphasia, in particular piracetam. If a trial is done, this must be large enough to have adequate statistical power. The safety of the drug should be of primary interest. Researchers should examine the long term effects of this treatment, and whether it is more effective than speech and language therapy.

Speech and language therapy for aphasia following stroke.

BACKGROUND: Aphasia describes language impairment associated with a brain lesion. OBJECTIVES: The objective of this review was to assess the effects of formal speech and language therapy and non-professional types of support from untrained providers for people with aphasia after stroke. SEARCH STRATEGY: We searched the Cochrane Stroke Group Trials Register (last searched: March 1999), and reference lists of relevant articles to December 1998. We also contacted academic institutions and other researchers to identify further published and unpublished trials. We searched The International Journal of Disorders of Communication by hand (known by other names in the past), from 1969 to 1998. Date of most recent searches: January 1999. SELECTION CRITERIA: Randomised controlled trials comparing: 1. Any type of formal speech and language therapy in any setting administered by trained speech and language therapists versus no treatment. 2. Any type of formal speech and language therapy in any setting administered by trained speech and language therapists versus any type of informal support for aphasia, given by speech and language therapists or volunteers, whether these were trained or untrained. 3. One type of speech and language therapy versus another type. Outcome measures included measures of any type of communication, other measures of functioning, numbers of drop-outs, and other non-clinical outcomes. DATA COLLECTION AND ANALYSIS: The principal reviewer collected the data, and assessed the quality of the trials with independent data checking and methodological advice. If we could not perform a statistical combination of different studies, we sought missing data. Failing that we provided a description. MAIN RESULTS: We considered sixty studies in detail, from which we identified twelve trials suitable for the review. Most of these trials were relatively old with poor or unassessable methodological quality. None of the trials was detailed enough for us to complete description and analysis. We could not determine whether formal speech and language therapy is more effective than informal support. REVIEWER'S CONCLUSIONS: The main conclusion of this review is that speech and language therapy treatment for people with aphasia after a stroke has not been shown either to be clearly effective or clearly ineffective within a RCT. Decisions about the management of patients must therefore be based on other forms of evidence. Further research is required to find out if effectiveness of speech and language therapy for aphasic patients is effective. If researchers choose to do a trial, this must be large enough to have adequate statistical power, and be clearly reported.

Modeling year 1 outcomes with treatment process and post-treatment social influences.

Follow-up studies of drug user treatment generally find significant improvements in client functioning, but information about the therapeutic components associated with client behavioral changes over time is limited. An integrative model developed previously to predict treatment retention was expanded and applied to post-treatment outcomes. This study is based on 321 daily opioid users treated in three methadone treatment clinics. Effects of pre-treatment motivation, treatment process measures representing therapeutic relationship, counseling session attendance, and length of treatment are examined in relation to measures of family relations, peer deviancy, return to treatment, drug use, and criminality in the year after treatment. Models were tested in two stages. The first was built on a during-treatment process model for predicting time in treatment to include post-treatment outcomes. The second model was expanded further to include the effects of intervening social support variables as predictors of post-treatment drug and criminality outcomes. The results supported both models and emphasize the importance of considering social influences and related community contextual factors that affect recovery dynamics.

Integrative modeling of client engagement and outcomes during the first 6 months of methadone treatment.

Integrative models containing client and treatment components were tested in a sample of 396 daily opioid users from three methadone maintenance treatment sites. Measures included client motivation at intake as well as repeated assessments of therapeutic engagement (relationships between clients and their counselors, session attendance, and results of urine testing) during the first 6 months of treatment. There was a positive effect of pretreatment motivation on greater engagement and a reciprocal positive relationship between components of engagement and their effects on lowering drug use throughout treatment. Further analyses addressed differential effects of group versus individual counseling and showed that group session attendance was associated with higher rates of drug-negative urines.

Treatment for aphasia following stroke: evidence for effectiveness.

A systematic review of SLT for aphasia following stroke, for the Cochrane Collaboration Stroke Group. Twelve randomised controlled trials were identified, however there was no standard comparison group amongst the trials. Based on this review, it is not possible to reach a conclusion about the effectiveness of the treatments evaluated in these trials. Further research is therefore indicated, and SLTs must base decisions about treatment for aphasia on other forms of evidence.

Beliefs about effectiveness of treatment for aphasia after stroke.

A postal survey of SLTs in Scotland was conducted. 598 SLTs responded, 194 worked with people aphasic after stroke. A number of obstacles to the provision of the SLT service to aphasic people were identified. SLTs expressed concern about the effectiveness of the treatments they offered, and about factors which may influence effectiveness. A number of suggestions are made for further research into this area including into the problems of competing client groups.

Drug abuse treatment process components that improve retention.

BACKGROUND: Longer retention has been the most consistent predictor of favorable drug abuse treatment outcomes, but key therapeutic and patient engagement indicators of treatment process need to be more clearly established. METHODS: An integrative model representing treatment dynamics was tested for explaining long-term program retention. It was based on a multisite sample of 527 daily opioid users who remained in methadone maintenance a minimum of 3 months. All had been assigned randomly to a counseling condition at admission (i.e., cognitively enhanced or standard), and information obtained from patient files, as well as periodic assessments completed by patients and their counselors in the first 90 days after admission were the sources of predictors. RESULTS: Counseling enhancements (using node-link mapping, a visual representation tool for improving communication and problem solving) contributed to stronger therapeutic relationships between counselor and patient, which in turn had a positive reciprocal relationship with patient engagement (session attendance). Pretreatment motivation measured at intake was also related to higher engagement. More positive therapeutic relationships (in months 1 and 2) led to lower levels of during-treatment drug use (defined from urinalysis results in months 2 and 3), and better session attendance and therapeutic relationships both predicted longer retention. In addition, lower drug use during treatment was related to longer retention. CONCLUSIONS: Major conceptual domains of drug abuse treatment process were identified in community-based programs and their interrelationships with retention specified. As intermediate (during treatment) criteria, they can help guide functional improvements in program effectiveness as illustrated with our counseling enhancements.

Client engagement and change during drug abuse treatment.

Previous work has shown length of time in drug abuse treatment is associated with better outcomes, but the role of therapeutic engagement and process needs further examination. In this study, the total number of counseling sessions attended by 557 clients in their first 90 days of community-based outpatient treatment was examined in relation to indicators of treatment delivery and progress. Significant client improvements were found on behavioral criteria and psychosocial functioning during the first 3 months of treatment, and session attendance was positively related to favorable behavioral changes as well as to positive perceptions by clients and counselors of their therapeutic interactions. Client background, treatment motivation, and therapeutic focus of counseling in Month 1 were significant predictors of session attendance in the first 3 months following admission to methadone treatment.

A double blind cross-over study of high-frequency emphasis hearing aids in individuals with noise-induced hearing loss.

This study compared the benefits of a high-frequency emphasis hearing aid and a more conventional, flatter response aid. Subjects with moderate noise-induced hearing loss were fitted binaurally within a double blind procedure. Each aid type was worn for 1 month, during which the subjects completed diaries concerning their problems in various listening situations. At the end of each month, a satisfaction questionnaire was completed and free field assessment, consisting of speech in noise discrimination measurement and warble tone threshold determinations, was performed. Results indicated that although there were few significant differences found between the aids using any of the assessment techniques, the subjects generally preferred the aid with the high-frequency emphasis.

The inhibiting effect of soft paraffin on the Köbner response in psoriasis.

White soft paraffin has been shown to inhibit the development of the isomorphic response (Kobner phenomenon) in psoriasis. The possible reasons for this are discussed and it is suggested that this finding has implications which should lead to a greater understanding of the nature of psoriasis.

Effects of ouabain on sodium uptake by frog heart and skeletal muscle.

Effects of ouabain (10(-3)-10(-12) M) on frog heart and skeletal muscle net uptake of Na from a K-free Conway-Ringer solution at 0-2 degrees C were investigated. Under these circumstances Na pumps are inactive and fibers are gaining Na even without ouabain. Changes in K, H2O, and solids were also measured. Na gains and K losses were increased by ouabain at greater than 10(-6) and greater than 10(-7) M, respectively, and decreased in heart muscle at less than or equal to 10(-8) M. It is suggested that these effects are due to actions on membrane permeability. Implications for mechanisms of positive inotropic effect of glycosides and for treatment are discussed.

Effect of added elastances on the first loaded breath in man.

Tidal volume together with end-inspiratory pressure was measured in four seated healthy men, during normal breathing and during single inspirations taken from a series of rigid containers which provided added elastances (range: 5-70 cmH2O/l). Experiments were performed both during quiet breathing and during ventilation increased by added dead space. Added elastic loads always resulted in a decreased tidal volume. This decrease was partly compensated by increased pressure developed by the inspiratory muscles; being more so with greater added elastance, control ventilation, or both. Analysis of our results indicates that the load-compensatory response may be attributed to changes in mechanical impedance of the ventilatory pump, due to the mechanical arrangement and the intrinsic properties of the inspiratory muscles (force-length and force-velocity relationships), changes in respiratory frequency with increasing ventilation, and to vagally mediated load compensation.