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Concept: Focus


This mixed-methods study examined barriers to and facilitators of street children’s drug use cessation in Eldoret, Kenya utilizing a cross-sectional survey and focus group discussions with a community-based sample of street-involved children and youth. The primary objective of this study was to describe factors that may assist or impede cessation of drug use that can be utilized in developing substance use interventions for this marginalized population. In 2011, 146 children and youth ages 10-19 years, classified as either children on the street or children of the street were recruited to participate in the cross-sectional survey. Of the 146 children that participated in the survey 40 were invited to participate in focus group discussion; 30 returned voluntarily to participate in the discussions. Several themes were derived from children’s narratives that described the barriers to and facilitators of drug cessation. Specifically, our findings reveal the strength of the addiction to inhalants, the dual role that peers and family play in substance use, and how the social, cultural, and economic context influence or impede cessation. Our findings demonstrate the need to integrate community, family and peers into any intervention in addition to traditional medical and psychological models for treatment of substance use dependence.

Concepts: Psychology, Focus group, Cross-sectional study, Drug addiction, Addiction, Youth, Focus, Substance abuse


Immunotherapies include various approaches, ranging from stimulating effector mechanisms to counteracting inhibitory and suppressive mechanisms, and creating a forum for discussing the most effective means of advancing these therapies through imaging is the focus of the newly formed Imaging in Cellular and Immune Therapies (ICIT) interest group within the World Molecular Imaging Society. Efforts are being made in the identification and validation of predictive biomarkers for a number of immunotherapies. Without predictive biomarkers, a considerable number of patients may receive treatments that have no chance of offering a benefit. This will reflect poorly on the field of immunotherapy and will yield false hopes in patients while at the same time contributing to significant cost to the healthcare system. This review summarizes the main strategies in cancer immune and cell-based therapies and discusses recent advances in imaging strategies aimed to improve cancer immunotherapy outcomes.

Concepts: Immune system, Medicine, Focus, Imaging, Immunotherapy, Cancer immunotherapy, Molecular imaging


We exploit the inherent dispersion in diffractive optics to demonstrate planar chromatic-aberration-corrected lenses. Specifically, we designed, fabricated and characterized cylindrical diffractive lenses that efficiently focus the entire visible band (450 nm to 700 nm) onto a single line. These devices are essentially pixelated, multi-level microstructures. Experiments confirm an average optical efficiency of 25% for a three-wavelength apochromatic lens whose chromatic focus shift is only 1.3 μm and 25 μm in the lateral and axial directions, respectively. Super-achromatic performance over the continuous visible band is also demonstrated with averaged lateral and axial focus shifts of only 1.65 μm and 73.6 μm, respectively. These lenses are easy to fabricate using single-step grayscale lithography and can be inexpensively replicated. Furthermore, these devices are thin (<3 μm), error tolerant, has low aspect ratio (<1:1) and offer polarization-insensitive focusing, all significant advantages compared to alternatives that rely on metasurfaces. Our design methodology offers high design flexibility in numerical aperture and focal length, and is readily extended to 2D.

Concepts: Optics, Magnification, Lens, Focus, Focal length, Photographic lens, F-number, Depth of field


Over the past decade, it has been convincingly shown that regularly performing repeated brief supramaximal cycle sprints (sprint interval training [SIT]) is associated with aerobic adaptations and health benefits similar to or greater than with moderate-intensity continuous training (MICT). SIT is often promoted as a time-efficient exercise strategy, but the most commonly studied SIT protocol (4-6 repeated 30-s Wingate sprints with 4 min recovery, here referred to as ‘classic’ SIT) takes up to approximately 30 min per session. Combined with high associated perceived exertion, this makes classic SIT unsuitable as an alternative/adjunct to current exercise recommendations involving MICT. However, there are no indications that the design of the classic SIT protocol has been based on considerations regarding the lowest number or shortest duration of sprints to optimise time efficiency while retaining the associated health benefits. In recent years, studies have shown that novel SIT protocols with both fewer and shorter sprints are efficacious at improving important risk factors of noncommunicable diseases in sedentary individuals, and provide health benefits that are no worse than those associated with classic SIT. These shorter/easier protocols have the potential to remove many of the common barriers to exercise in the general population. Thus, based on the evidence summarised in this current opinion paper, we propose that there is a need for a fundamental change in focus in SIT research in order to move away from further characterising the classic SIT protocol and towards establishing acceptable and effective protocols that involve minimal sprint durations and repetitions.

Concepts: Health insurance, Exercise, Running, Protocol, Focus, Common cold, Sprint Nextel, Interval training


BACKGROUND: The increasing fragmentation of healthcare has resulted in more patient handoffs. Many professional groups, including the Accreditation Council on Graduate Medical Education and the Society of Hospital Medicine, have made recommendations for safe and effective handoffs. Despite the two-way nature of handoff communication, the focus of these efforts has largely been on the person giving information. OBJECTIVE: To observe and characterise the listening behaviours of handoff receivers during hospitalist handoffs. DESIGN: Prospective observational study of shift change and service change handoffs on a non-teaching hospitalist service at a single academic tertiary care institution. MEASUREMENTS: The ‘HEAR Checklist’, a novel tool created based on review of effective listening behaviours, was used by third party observers to characterise active and passive listening behaviours and interruptions during handoffs. RESULTS: In 48 handoffs (25 shift change, 23 service change), active listening behaviours (eg, read-back (17%), note-taking (23%) and reading own copy of the written signout (27%)) occurred less frequently than passive listening behaviours (eg, affirmatory statements (56%) nodding (50%) and eye contact (58%)) (p<0.01). Read-back occurred only eight times (17%). In 11 handoffs (23%) receivers took notes. Almost all (98%) handoffs were interrupted at least once, most often by side conversations, pagers going off, or clinicians arriving. Handoffs with more patients, such as service change, were associated with more interruptions (r=0.46, p<0.01). CONCLUSIONS: Using the 'HEAR Checklist', we can characterise hospitalist handoff listening behaviours. While passive listening behaviours are common, active listening behaviours that promote memory retention are rare. Handoffs are often interrupted, most commonly by side conversations. Future handoff improvement efforts should focus on augmenting listening and minimising interruptions.

Concepts: Psychology, Medicine, Observational study, Observation, Hearing, Focus, Active listening


In the wide area of polyoxometalate (POM) chemistry, diphosphate/diphosphonate-based POMs represent a more recent area of study. However, in this short time it has emerged to become very dynamic, as shown by the wide variety of compounds reported. Ever since the discovery of the first polyoxotungstate framework constructed from diphosph(on)ate ligands, a widespread investigation on the preparative chemistry and properties of such compounds has followed. The main focus of such a study is based on factors such as the oxidation state of the metal, the effect of pH and temperature during synthesis, and the presence of different functional groups on the diphosphonate. In this review we discuss in detail all diphosphate/diphosphonate-based POMs, beginning with early developments, subsequent growth in interest, and finally focusing on the very latest developments.

Concepts: Amine, Chemical reaction, Functional group, Electrochemistry, Carbon, Organic chemistry, Oxidation state, Focus


The time course of blood lactate levels could be helpful to assess a patient’s response to therapy. Although the focus of published studies has been largely on septic patients, many other studies have reported serial blood lactate levels in different groups of acutely ill patients.

Concepts: Medicine, Medical terms, Patient, Illness, Focus


Light fields (LFs) have been shown to enable photorealistic visualization of complex scenes. In practice, however, an LF tends to have a relatively small angular range or spatial resolution, which limits the scope of virtual navigation. In this paper, we show how seamless virtual navigation can be enhanced by stitching multiple LFs. Our technique consists of two key components: LF registration and LF stitching. To register LFs, we use what we call the ray-space motion matrix (RSMM) to establish pairwise ray-ray correspondences. Using Pl ¨ucker coordinates, we show that the RSMM is a 5 6 matrix, which reduces to a 5 5 matrix under pure translation and/or in-plane rotation. The final LF stitching is done using multi-resolution, high-dimensional graph-cut in order to account for possible scene motion, imperfect RSMM estimation, and/or undersampling. We show how our technique allows us to create LFs with various enhanced features: extended horizontal and/or vertical field-of-view, larger synthetic aperture and defocus blur, and larger parallax.

Concepts: Optics, Virtual, The Final, Focus, SQL, Astronomical interferometer, Aperture synthesis, Angular resolution


Controlling size, shape and uniformity of porous constructs remains a major focus of the development of porous materials. Over the past two decades, we have seen significant developments in the fabrication of new, porous-ordered structures using a wide range of materials, resulting in properties well beyond their traditional use. Porous materials have been considered appealing, due to attractive properties such as pore size length, morphology and surface chemistry. Furthermore, their utilization within the life sciences and medicine has resulted in significant developments in pharmaceutics and medical diagnosis. This article focuses on various classes of porous materials, providing an overview of principle concepts with regard to design and fabrication, surface chemistry and loading and release kinetics. Furthermore, predictions from a multiscale mathematical model revealed the role pore length and diameter could have on payload release kinetics.

Concepts: Medicine, Mathematics, Physics, Materials science, Control, Focus, Micromeritics, Chemical physics


We have developed a powerful general spectroscopic method for rapidly screening liquid milk for adulterants by combining reflective focusing wells simply fabricated in aluminum with a small, portable Raman spectrometer with a focusing fiber optic probe. Hemispherical aluminum sample wells were specially designed to optimize internal reflection and sampling volume by matching the focal length of the mirror to the depth of focus of the laser probe. The technique was tested on milk adulterated with 4 different nitrogen-rich compounds (melamine, urea, dicyandiamide, and ammonium sulfate) and sucrose. No sample preparation of the milk was needed, and the total analysis time was 4 min. Reliable sample presentation enabled average reproducibility of 8% residual standard deviation. The limit of detection interval measured from partial least squares calibrations ranged between 140 and 520 mg/L for the 4 N-rich compounds and between 7,000 and 36,000 mg/L (0.7-3.6%) for sucrose. The portability of the system and the reliability and reproducibility of this technique open opportunities for general, reagentless screening of milk for adulterants at the point of collection.

Concepts: Scientific method, Spectroscopy, Regression analysis, Laser, Reflection, Geometrical optics, Focus, Depth of field