LMA fibers with increased higher-order mode loss for high average power, pulsed, diffraction-limited lasers.

We demonstrate new, large-mode area (LMA) gain fibers with ∼25 µm mode-field diameter, and increased higher-order mode loss that enable diffraction limited, pulsed fiber lasers operating at high average power with high pulse energy. We achieved 1.6 mJ, ns pulses, with 1.2 kW average power and 370 kW peak power in one of the new Yb-doped gain fibers. In a second, higher absorption fiber, we demonstrate 2 mJ pulse energy with peak power of >420 kW at an average power of 660 W. To the best of our knowledge these are the highest demonstrated energies, powers and peak powers for any nanosecond diffraction-limited, all-fiber laser. The TMI thresholds of two of these fibers were measured to be 1.8 kW and 1 kW respectively.

The use of novel electronic nose technology to locate missing persons for criminal investigations.

The search for missing persons is a major challenge for investigations involving presumed deceased individuals. Currently, the most effective tool is the use of cadaver-detection dogs; however, they are limited by their cost, limited operation times, and lack of granular information reported to the handler. Thus, there is a need for discrete, real-time detection methods that provide searchers explicit information as to whether human-decomposition volatiles are present. A novel e-nose (NOS.E) developed in-house was investigated as a tool to detect a surface-deposited individual over time. The NOS.E was able to detect the victim throughout most stages of decomposition and was influenced by wind parameters. The sensor responses from different chemical classes were compared to chemical class abundance confirmed by two-dimensional gas chromatography - time-of-flight mass spectrometry. The NOS.E demonstrated its ability to detect surface-deposited individuals days and weeks since death, demonstrating its utility as a detection tool.

Health Humanities: A Baseline Survey of Baccalaureate and Graduate Programs in North America.

The authors conducted a baseline survey of baccalaureate and graduate degree health humanities programs in the United States and Canada. The object of the survey was to formally assess the current state of the field, to gauge what kind of resources individual programs are receiving, and to assess their self-identified needs to become or remain programmatically sustainable, including their views on the potential benefits of program accreditation. A 56-question baseline survey was sent to 111 institutions with baccalaureate programs and 20 institutions with graduate programs. Respondents were asked about three areas: (1) program administration (managing unit, paid director, faculty lines, paid staff, funding sources); (2) educational program (curricular structure, CIP code usage, completion rates); and (3) views on accreditation for the field. A clear majority of respondents agreed that some form of accreditation or consultation service could address resource and sustainability issues. Overall, the survey responses to staffing, curricular structure, and support suggest the need for developing a sustainable infrastructure for health humanities.

Content development of the Child Community Health Inclusion Index: An evaluation tool for measuring inclusion of children with disabilities in the community.

BACKGROUND: Addressing barriers in the environment can contribute to health and quality of life for children with disabilities and their families. The Community Health Inclusion Index (CHII) is a measurement tool developed in the United States to identify environmental barriers and facilitators to community health inclusion. The CHII adopts an adult viewpoint and aspects crucial for children may have been omitted. AIMS: This study aimed to develop a comprehensive list of items that are relevant for the community inclusion of children with disabilities in the Canadian context. METHODS: The relevance and priority of items generated from a review of existing guidelines and best practice recommendations for community inclusion were rated as a dichotomous response and discussed by an expert panel in relevant fields related to children with disabilities. RESULTS: A total of 189 items from 12 instruments and best practice guidelines were identified. Expert consensus contributed to a relevant and comprehensive list of items. Expert suggestions were considered to refine and reduce the item list. CONCLUSION: This study highlights the importance of a child version of a community inclusion tool, as the needs of children with disabilities differ from those of adults. It can help communities improve inclusion of children with disabilities and inform health promotion initiatives for this population.

Evolution in Health and Medical Humanities education: a proposal for accreditation.

The growth of Health and Medical Humanities baccalaureate and master's degrees in recent decades makes the present moment ideal for initiating field-defining conversations among health humanities constituents about the boundaries of this transdisciplinary field. Focusing on accreditation at the programme level rather than the individual level, we explore four models with different advantages for Health and Medical Humanities: a certification for practice; a network (umbrella organisation); a programme of merit (POM) model; and consultancy. We conclude that for a young field like health humanities that is transdisciplinary, does not have an established canon and does not lead to entry to a specific professional path (ie, gatekeeping), the POM model is the best fit. In contrast to a full accreditation model, POM credentialling leaves room for creativity, expansiveness, and diversity of approaches and will not restrict programmes from calling themselves health humanities programmes; POM enhances visibility rather than decides who can teach in the field and what they must teach. To implement this model, we suggest the creation of a semi-independent Health and Medical Humanities Program Accreditation Commission (HMHPAC) that would be administered by the Health Humanities Consortium. The HMHPAC should have three goals: ensure that health humanities educational programmes are of the highest quality, assist programmes in acquiring the resources they need from their institutions and help programmes attract potential students.

Association of the Family Nutrition and Physical Activity Screening Tool with Weight Status, Percent Body Fat, and Acanthosis Nigricans in Children from a Low Socioeconomic, Urban Community.

OBJECTIVE: To examine the association of the Family Nutrition and Physical Activity (FNPA) screening tool with weight status, percent body fat, and acanthosis nigricans (AN) in 6- to 13-year-old children from a low socioeconomic, urban community. METHODS: Children (n=415) from four elementary schools located around Flint, Michigan were assessed for body mass index, percent body fat, and AN. The FNPA screening tool was completed by parents. Mann-Whitney U tests were used to assess differences in FNPA score by sex and presence of AN. Logistic regression was used to evaluate the association of the FNPA (tertiles) with weight status and AN. RESULTS: Children with AN (13.7%) had a significantly lower FNPA score (56.3 + 7.1) compared with children without AN (61.0 + 7.1; P<.05). Children with FNPA scores in the lowest tertile (high-risk) had odds ratios of 1.74 (95% CI =1.05 - 2.91) and 2.77 (95% CI =1.22 - 6.27) compared with children with FNPA scores in the highest tertile (low-risk) for being overfat and having AN, respectively. CONCLUSION: Although the FNPA screening tool did not predict risk for being overweight or obese, it was significantly associated with an increased odds of children at risk for being overfat or having AN.

Octave-spanning coherent supercontinuum generation in a silicon nitride waveguide.

We demonstrate the generation of a supercontinuum spanning more than 1.4 octaves in a silicon nitride waveguide using sub-100-fs pulses at 1 µm generated by either a 53-MHz, diode-pumped ytterbium (Yb) fiber laser or a 1-GHz, Yb:CaAlGdO(4) (Yb:CALGO) laser. Our numerical simulations show that the broadband supercontinuum is fully coherent, and a spectral interference measurement is used to verify that the supercontinuum generated with the Yb:CALGO laser possesses a high degree of coherence over the majority of its spectral bandwidth. This coherent spectrum may be utilized for optical coherence tomography, spectroscopy, and frequency metrology.

Multimodal fiber source for nonlinear microscopy based on a dissipative soliton laser.

Recent developments in high energy femtosecond fiber lasers have enabled robust and lower-cost sources for multiphoton-fluorescence and harmonic-generation imaging. However, picosecond pulses are better suited for Raman scattering microscopy, so the ideal multimodal source for nonlinear microcopy needs to provide both durations. Here we present spectral compression of a high-power femtosecond fiber laser as a route to producing transform-limited picosecond pulses. These pulses pump a fiber optical parametric oscillator to yield a robust fiber source capable of providing the synchronized picosecond pulse trains needed for Raman scattering microscopy. Thus, this system can be used as a multimodal platform for nonlinear microscopy techniques.

Divided-pulse lasers.

We demonstrate the use of coherent division and recombination of the pulse within an ultrafast laser cavity to manage the nonlinear phase accumulation and scale the output pulse energy. We implement the divided-pulse technique in an ytterbium-doped fiber laser and achieve 16 times scaling of the pulse energy, to generate 6 nJ and 1.4 ps solitons in single-mode fiber. Potential extensions of this concept are discussed.

Self-similar erbium-doped fiber laser with large normal dispersion.

We report a large normal dispersion erbium-doped fiber laser with self-similar pulse evolution in the gain fiber. The cavity is stabilized by the local nonlinear attractor in the gain fiber through the use of a narrow filter. Experimental results are accounted for by numerical simulations. This laser produces 3.5 nJ pulses, which can be dechirped to 70 fs with an external grating pair.

Fiber optical parametric oscillator for coherent anti-Stokes Raman scattering microscopy.

We present a synchronously pumped fiber optical parametric oscillator for coherent anti-Stokes Raman scattering microscopy. Pulses from a 1 µm Yb-doped fiber laser are amplified and frequency converted to 779-808 nm through normal dispersion four-wave mixing in a photonic crystal fiber. The idler frequency is resonant in the oscillator cavity, and we find that bandpass filtering the feedback is essential for stable, narrow-bandwidth output. Experimental results agree quite well with numerical simulations of the device. Transform-limited 2 ps pulses with energy up to 4 nJ can be generated at the signal wavelength. The average power is 180 mW, and the relative-intensity noise is much lower than that of a similar parametric amplifier. High-quality coherent Raman images of mouse tissues recorded with this source are presented.

Quantification of naturally occurring pyrrole acids in melanosomes.

Three naturally occurring pyrrole acids were found in Sepia, human black hair, and bovine choroid and iris melanosomes using high-performance liquid chromatography and mass spectrometry--pyrrole-2,3-dicarboxylic acid (PDCA), pyrrole-2,3,5-tricarboxylic acid (PTCA) and pyrrole-2,3,4,5-tetracarboxylic acid (PTeCA). PDCA and PTCA are common markers quantified from oxidative degradation of eumelanins. Using standards, the amounts of naturally occurring PDCA and PTCA were determined and compared to those obtained following peroxide oxidation of the same samples. Because the naturally occurring acids are water soluble, these results indicate that care must be exercised when comparing PDCA and PTCA yields from the degradation analyses of melanins isolated and prepared by different methods. This work also establishes that PTeCA is a naturally occurring pyrrole acid in melanosomes.

Mutagenesis studies of substrate recognition and catalysis in the sortase A transpeptidase from Staphylococcus aureus.

The Staphylococcus aureus transpeptidase sortase A (SrtA) is responsible for anchoring a range of virulence- and colonization-associated proteins to the cell wall. SrtA recognizes substrates that contain a C-terminal LPXTG motif. This sequence is cleaved following the threonine, and an amide bond is formed between the threonine and the pentaglycine cross-bridge of branched lipid II. Previous studies have implicated the beta6/beta7 loop region of SrtA in LPXTG recognition but have not systematically characterized this domain. To better understand the individual roles of the residues within this loop, we performed alanine-scanning mutagenesis. Val-168 and Leu-169 were found to be important for substrate recognition, and Glu-171 was also found to be important, consistent with its hypothesized role as a Ca(2+)-binding residue. Gly-167 and Asp-170 were dispensable for catalysis, as was Gln-172. The role of Arg-197 in SrtA has been the subject of much debate. To explore its role in catalysis, we used native chemical ligation to generate semi-synthetic SrtA in which we replaced Arg-197 with citrulline, a non-ionizable analog. This change resulted in a decrease of <3-fold in k(cat)/K(m), indicating that Arg-197 utilizes a hydrogen bond, rather than an electrostatic interaction. Our results are consistent with a model for LPXTG recognition wherein the Leu-Pro sequence is recognized primarily by hydrophobic contacts with SrtA Val-168 and Leu-169, as well as a hydrogen bond from Arg-197. This model contradicts the previously proposed mechanism of binding predicted by the x-ray crystal structure of SrtA.