Biotinylated Photocleavable Semiconductor Colloidal Quantum Dot Supraparticle Microlaser.

Luminescent supraparticles of colloidal semiconductor nanocrystals can act as microscopic lasers and are hugely attractive for biosensing, imaging, and drug delivery. However, biointerfacing these to increase functionality while retaining their main optical properties remains an unresolved challenge. Here, we propose and demonstrate red-emitting, silica-coated CdSxSe1-x/ZnS colloidal quantum dot supraparticles functionalized with a biotinylated photocleavable ligand. The success of each step of the synthesis is confirmed by scanning electron microscopy, energy dispersive X-ray and Fourier transform infrared spectroscopy, ζ-potential, and optical pumping measurements. The capture and release functionality of the supraparticle system is proven by binding to a neutravidin functionalized glass slide and subsequently cleaving off after UV-A irradiation. The biotinylated supraparticles still function as microlasers; e.g., a 9 µm diameter supraparticle has oscillating modes around 625 nm at a threshold of 58 mJ/cm2. This work is a first step toward using supraparticle lasers as enhanced labels for bionano applications.

MicroLED biosensor with colloidal quantum dots and smartphone detection.

A fluorescence sensor with the capability for spatially multiplexed measurements utilizing smartphone detection is presented. Bioconjugated quantum dots are used as the fluorescent tag and are excited using a blue-emitting microLED (µLED). The 1-dimensional GaN µLED array is butt-coupled to one edge of the glass slide to take advantage of total internal reflection fluorescence (TIRF) principles. The bioassays on the top surface of the glass waveguide are excited and the resultant fluorescence is detected with the smartphone. The red, green, and blue channels of the digital image are utilized to spectrally separate the excitation light from the fluorescence for analysis. Using a biotin-functionalized glass slide as proof of principle, we have shown that streptavidin conjugated quantum dots can be detected down to a concentration of 8 nM.

Pneumocystis pneumonia outbreak among renal transplant recipients at a North American transplant center: Risk factors and implications for infection control.

BACKGROUND: Pneumocystis pneumonia is a severe opportunistic fungal infection. Outbreaks among renal transplant recipients have been reported in Europe and Japan, but never in North America. METHODS: We conducted a retrospective case-control study among adult renal transplant recipients at a Canadian center, using a 3:1 matching scheme. Ten cases and 30 controls were matched based on initial transplantation date, and all patients received prophylaxis with trimethoprim-sulfamethoxazole for 1 year posttransplantation. RESULTS: The median time between transplantation and infection was 10.2 years, and all patients survived. Compared with controls, case patients had statistically lower estimated glomerular filtration rate (29.3 mL/min vs 66.3 mL/min; P = .028) and lymphopenia (0.51 × 10(9)/L vs 1.25 × 10(9)/L; P = .002). Transmission mapping revealed significant overlap in the clinic and laboratory visits among case vs control patients (P = .0002). One hundred percent of patients (4 out of 4) successfully genotyped had the same strain of Pneumocystis jirovecii. CONCLUSIONS: Our study demonstrated an outbreak of pneumocystis more than 10 years following initial transplantation, despite using recommended initial prophylaxis. We identified low estimated glomerular filtration rate and lymphopenia as risk factors for infection. Overlapping ambulatory care visits were identified as important potential sources of infection transmission, suggesting that institutions should re-evaluate policy and infrastructure strategies to interrupt transmission of respiratory pathogens.

Engaging Direct Care Providers in Improving Infection Prevention and Control Practices Using Participatory Visual Methods.

The purpose of this quality improvement project was to determine the feasibility of using provider-led participatory visual methods to scrutinize 4 hospital units' infection prevention and control practices. Methods included provider-led photo walkabouts, photo elicitation sessions, and postimprovement photo walkabouts. Nurses readily engaged in using the methods to examine and improve their units' practices and reorganize their work environment.

Understanding practice: factors that influence physician hand hygiene compliance.

OBJECTIVE: To identify the behavioral determinants--both barriers and enablers--that may impact physician hand hygiene compliance. DESIGN: A qualitative study involving semistructured key informant interviews with staff physicians and residents. SETTING: An urban, 1,100-bed multisite tertiary care Canadian hospital. PARTICIPANTS: A total of 42 staff physicians and residents in internal medicine and surgery. METHODS: Semistructured interviews were conducted using an interview guide that was based on the theoretical domains framework (TDF), a behavior change framework comprised of 14 theoretical domains that explain health-related behavior change. Interview transcripts were analyzed using thematic content analysis involving a systematic 3-step approach: coding, generation of specific beliefs, and identification of relevant TDF domains. RESULTS: Similar determinants were reported by staff physicians and residents and between medicine and surgery. A total of 53 specific beliefs from 9 theoretical domains were identified as relevant to physician hand hygiene compliance. The 9 relevant domains were knowledge; skills; beliefs about capabilities; beliefs about consequences; goals; memory, attention, and decision processes; environmental context and resources; social professional role and identity; and social influences. CONCLUSIONS: We identified several key determinants that physicians believe influence whether and when they practice hand hygiene at work. These beliefs identify potential individual, team, and organization targets for behavior change interventions to improve physician hand hygiene compliance.

Evaluating and operationalizing an environmental auditing program: a pilot study.

BACKGROUND: Environmental auditing is an important tool to ensure consistent and effective cleaning. Our pilot study compared an alcohol-based fluorescent marking product and an adenosine-5'-triphosphate bioluminescence product for use in an environmental auditing program to determine which product was more practical and acceptable to users. METHODS: Both products were tested on 15 preselected high touch objects in randomly selected patient rooms, following regular daily cleaning. A room was considered a "pass" if ≥80% of surfaces were adequately cleaned as defined by manufacturers' guidelines. A qualitative survey assessed user preference and operational considerations. RESULTS: Using fluorescent marking, 9 of 37 patient rooms evaluated (24%) were considered a "pass" after daily cleaning. Using adenosine-5'-triphosphate bioluminescence, 21 of 37 patient rooms passed (57%). There was great variability in results between different high touch objects. Eighty percent of users preferred the alcohol-based fluorescent marking product because it provided an effective visual aid to coach staff on proper cleaning techniques and allowed simple and consistent application. CONCLUSIONS: Environmental auditing using translucent, alcohol-based fluorescent marking best met the requirements of our organization. Our results reinforce the importance of involving a multidisciplinary team in evaluating and operationalizing an environmental auditing program.

Improving physician hand hygiene compliance using behavioural theories: a study protocol.

BACKGROUND: Healthcare-associated infections affect 10% of patients in Canadian acute-care hospitals and are significant and preventable causes of morbidity and mortality among hospitalized patients. Hand hygiene is among the simplest and most effective preventive measures to reduce these infections. However, compliance with hand hygiene among healthcare workers, specifically among physicians, is consistently suboptimal. We aim to first identify the barriers and enablers to physician hand hygiene compliance, and then to develop and pilot a theory-based knowledge translation intervention to increase physicians' compliance with best hand hygiene practice. DESIGN: The study consists of three phases. In Phase 1, we will identify barriers and enablers to hand hygiene compliance by physicians. This will include: key informant interviews with physicians and residents using a structured interview guide, informed by the Theoretical Domains Framework; nonparticipant observation of physician/resident hand hygiene audit sessions; and focus groups with hand hygiene experts. In Phase 2, we will conduct intervention mapping to develop a theory-based knowledge translation intervention to improve physician hand hygiene compliance. Finally, in Phase 3, we will pilot the knowledge translation intervention in four patient care units. DISCUSSION: In this study, we will use a behavioural theory approach to obtain a better understanding of the barriers and enablers to physician hand hygiene compliance. This will provide a comprehensive framework on which to develop knowledge translation interventions that may be more successful in improving hand hygiene practice. Upon completion of this study, we will refine the piloted knowledge translation intervention so it can be tested in a multi-site cluster randomized controlled trial.

The effects of visual degradation on face discrimination.

PURPOSE: People with reduced visual acuity (VA) and/or contrast sensitivity have difficulty recognizing faces and facial expressions. We have quantified these difficulties, using a synthetic face discrimination task employing both normal and artificially degraded vision. METHODS: VA and contrast thresholds were measured using an optimised staircase procedure [Freiburg acuity Test (FrACT)] in 25 young adults (aged 18-24 years) with corrected visual acuity of 0.0 logMAR or better and with four levels of vision degraded with Bangerter occlusion foils. For face discrimination, male face images were synthesised from 37 cardinal points (position of eyes, width of nose, head shape etc) derived from frontal face photographs and manipulated by altering the points as a fraction of the mean head radius. Face discrimination thresholds (% difference) were measured from a simultaneous four-alternative forced choice of 'odd one out' from three identical faces and one that differed. Psychometric functions were measured for four participants with normal and degraded vision. Subsequently, the difference between faces was fixed at twice the discrimination thresholds and the size of the faces manipulated using the FrACT threshold procedure in 25 participants. Data were converted to equivalent face discrimination distances for realistic face dimensions. RESULTS: With normal vision, face discrimination thresholds ranged from 2.7% to 5.6%; these increased systematically and were more variable with visual degradation. When manipulating face size, face discrimination distance was highly correlated with both acuity and contrast sensitivity (r(2) = 0.77 and 0.80 respectively, p < 0.01). The mean distance with normal vision was 15.3 m (14.5-16.2 ± S.E.M.). With vision degraded to 0.6 logMAR (6/24 Snellen, contrast threshold 15%) the mean face discrimination distance was reduced to 3.9 m (3.7-4.1, ±S.E.M.). CONCLUSIONS: Poor face discrimination has a profound impact on real-life social communication. Here we report that artificial visual degradation also adversely impacts a synthetic face recognition task. As a rule of thumb, reduction in VA of 0.3 logMAR (halving the decimal VA) reduces the face recognition distance by a factor of 0.6 times. The FrACT-based face discrimination task provides an efficient new tool to quantify and monitor face discrimination ability.

Knowledge and attitudes regarding preconception care in a predominantly low-income Mexican American population.

OBJECTIVE: The objective of the study was to determine knowledge and attitudes regarding preconception care in a low-income Mexican American population. STUDY DESIGN: This was a cross-sectional survey of 305 reproductive-age women at an urban public hospital. RESULTS: The sample was mostly Hispanic (88%) and pregnant (68%); 35% had not completed high school. Eighty-nine percent agreed that improving preconception health benefits pregnancy. Seventy-seven percent expressed some interest in preconception health care with the obstetrics gynecology office at the preferred location. The average knowledge of preconception care score was 76% (higher score more favorable). Areas of higher knowledge included the effects on pregnancy of folic acid; alcohol use; substance use; and verbal, physical, and sexual abuse; lower knowledge was found for the effects of cat litter and fish products. CONCLUSION: There was interest in preconception education and agreement that preconception health has a positive effect on pregnancy. Fewer respondents agreed that it had a good effect than a suburban sample in the same region (89% vs 98%).