Ultrafast laser parallel microdrilling using multiple annular beams generated by a spatial light modulator

Ultrafast laser parallel microdrilling using diffractive multiple annular beam patterns is demonstrated in this paper. The annular beam was generated by diffractive axicon computer generated holograms (CGHs) using a spatial light modulator. The diameter of the annular beam can be easily adjusted by varying the radius of the smallest ring in the axicon. Multiple annular beams with arbitrary arrangement and multiple annular beam arrays were generated by superimposing an axicon CGH onto a grating and lenses algorithm calculated multi-beam CGH and a binary Dammann grating CGH, respectively. Microholes were drilled through a 0.03 mm thick stainless steel foil using the multiple annular beams. By avoiding huge laser output attenuation and mechanical annular scanning, the processing is ~200 times faster than the normal single beam processing

First Measurement of Transferred Polarization in the Exclusive e p --> e' K+ Lambda Reaction

The first measurements of the transferred polarization for the exclusive ep --> e'K+ Lambda reaction have been performed in Hall B at the Thomas Jefferson National Accelerator Facility using the CLAS spectrometer. A 2.567 GeV electron beam was used to measure the hyperon polarization over a range of Q2 from 0.3 to 1.5 (GeV/c)2, W from 1.6 to 2.15 GeV, and over the full center-of-mass angular range of the K+ meson. Comparison with predictions of hadrodynamic models indicates strong sensitivity to the underlying resonance contributions. A non-relativistic quark model interpretation of our data suggests that the s-sbar quark pair is produced with spins predominantly anti-aligned. Implications for the validity of the widely used 3P0 quark-pair creation operator are discussed.Comment: 6 pages, 4 figure

Observation of an Exotic S=+1S=+1 Baryon in Exclusive Photoproduction from the Deuteron

In an exclusive measurement of the reaction $\gamma d \to K^+ K^- p n$, a narrow peak that can be attributed to an exotic baryon with strangeness $S=+1$ is seen in the $K^+n$ invariant mass spectrum. The peak is at $1.542\pm 0.005$ GeV/c$^2$ with a measured width of 0.021 GeV/c$^2$ FWHM, which is largely determined by experimental mass resolution. The statistical significance of the peak is $5.2 \pm 0.6 \sigma$. The mass and width of the observed peak are consistent with recent reports of a narrow $S=+1$ baryon by other experimental groups.Comment: 5 pages, 5 figure

Accelerated discovery of two crystal structure types in a complex inorganic phase field

The discovery of new materials is hampered by the lack of efficient approaches to the exploration of both the large number of possible elemental compositions for such materials, and of the candidate structures at each composition1. For example, the discovery of inorganic extended solid structures has relied on knowledge of crystal chemistry coupled with time-consuming materials synthesis with systematically varied elemental ratios2,3. Computational methods have been developed to guide synthesis by predicting structures at specific compositions4,5,6 and predicting compositions for known crystal structures7,8, with notable successes9,10. However, the challenge of finding qualitatively new, experimentally realizable compounds, with crystal structures where the unit cell and the atom positions within it differ from known structures, remains for compositionally complex systems. Many valuable properties arise from substitution into known crystal structures, but materials discovery using this approach alone risks both missing best-in-class performance and attempting design with incomplete knowledge8,11. Here we report the experimental discovery of two structure types by computational identification of the region of a complex inorganic phase field that contains them. This is achieved by computing probe structures that capture the chemical and structural diversity of the system and whose energies can be ranked against combinations of currently known materials. Subsequent experimental exploration of the lowest-energy regions of the computed phase diagram affords two materials with previously unreported crystal structures featuring unusual structural motifs. This approach will accelerate the systematic discovery of new materials in complex compositional spaces by efficiently guiding synthesis and enhancing the predictive power of the computational tools through expansion of the knowledge base underpinning them

Femtosecond laser internal structuring of materials using a spatial light modulator

Femtosecond laser pulses are of particular interest for internal modification of transperent materials as they enable nonlinear absorption due to the extremly high intensity in the focal volume. Since output from commercial laser sources currently exceeds single beam process requirements, parallel processing with multiple beams could provide a route to up-scaling processing speed and establish cost-effectiveness. The use of spatial light modulators, driven by fast computer-generated holograms for splitting a parent laser beam into a number of beamlets and digitally manipulate their positions and the laser intensity is demonstrated. With successful blocking of the zero order beam and subsequent focusing of the diffracted beams inside transperant materials, high throughput dynamic 2D/3D refractive index modification of polymer and glass substrates with a gain factor G > 20 has been achieved. Fundamental IR (775nm) femtosecond laser pulses were employed to produce optical components. For example, thick volume gratings written with more than 20 beams have 1st order diffraction efficiency η > 60%, indicating a refractive index change Δn ≈ 1.6x10-4. Characterization by microscopic examination and light coupling tests revealed the extent of resolution, process quality and assisted quantification of the process speed gain. The benefits and current limitations of this technique are discussed in detail

Development of a Surface Plasmon Resonance Biosensor for Real-Time Detection of Osteogenic Differentiation in Live Mesenchymal Stem Cells

Surface plasmon resonance (SPR) biosensors have been recognized as a useful tool and widely used for real-time dynamic analysis of molecular binding affinity because of its high sensitivity to the change of the refractive index of tested objects. The conventional methods in molecular biology to evaluate cell differentiation require cell lysis or fixation, which make investigation in live cells difficult. In addition, a certain amount of cells are needed in order to obtain adequate protein or messenger ribonucleic acid for various assays. To overcome this limitation, we developed a unique SPR-based biosensing apparatus for real-time detection of cell differentiation in live cells according to the differences of optical properties of the cell surface caused by specific antigen-antibody binding. In this study, we reported the application of this SPR-based system to evaluate the osteogenic differentiation of mesenchymal stem cells (MSCs). OB-cadherin expression, which is up-regulated during osteogenic differentiation, was targeted under our SPR system by conjugating antibodies against OB-cadherin on the surface of the object. A linear relationship between the duration of osteogenic induction and the difference in refractive angle shift with very high correlation coefficient was observed. To sum up, the SPR system and the protocol reported in this study can rapidly and accurately define osteogenic maturation of MSCs in a live cell and label-free manner with no need of cell breakage. This SPR biosensor will facilitate future advances in a vast array of fields in biomedical research and medical diagnosis

Cardiac Myosin Binding Protein C and MAP-Kinase Activating Death Domain-Containing Gene Polymorphisms and Diastolic Heart Failure

OBJECTIVE: Myosin binding protein C (MYBPC3) plays a role in ventricular relaxation. The aim of the study was to investigate the association between cardiac myosin binding protein C (MYBPC3) gene polymorphisms and diastolic heart failure (DHF) in a human case-control study. METHODS: A total of 352 participants of 1752 consecutive patients from the National Taiwan University Hospital and its affiliated hospital were enrolled. 176 patients diagnosed with DHF confirmed by echocardiography were recruited. Controls were matched 1-to-1 by age, sex, hypertension, diabetes, renal function and medication use. We genotyped 12 single nucleotide polymorphisms (SNPs) according to HapMap Han Chinese Beijing databank across a 40 kb genetic region containing the MYBPC3 gene and the neighboring DNA sequences to capture 100% of haplotype variance in all SNPs with minor allele frequencies ≥ 5%. We also analyzed associations of these tagging SNPs and haplotypes with DHF and linkage disequilibrium (LD) structure of the MYBPC3 gene. RESULTS: In a single locus analysis, SNP rs2290149 was associated with DHF (allele-specific p = 0.004; permuted p = 0.031). The SNP with a minor allele frequency of 9.4%, had an odds ratio 2.14 (95% CI 1.25-3.66; p = 0.004) for the additive model and 2.06 for the autosomal dominant model (GG+GA : AA, 95% CI 1.17-3.63; p = 0.013), corresponding to a population attributable risk fraction of 12.02%. The haplotypes in a LD block of rs2290149 (C-C-G-C) was also significantly associated with DHF (odds ratio 2.10 (1.53-2.89); permuted p = 0.029). CONCLUSIONS: We identified a SNP (rs2290149) among the tagging SNP set that was significantly associated with early DHF in a Chinese population

Diagnosing Hunter syndrome in pediatric practice: practical considerations and common pitfalls

Mucopolysaccharidosis II (MPS II), or Hunter syndrome, is an X-linked lysosomal storage disorder caused by a deficiency in the enzyme iduronate-2-sulfatase. Affected patients suffer progressive damage to multiple organ systems and early mortality. Two thirds of patients also manifest cognitive impairment and developmental delays. MPS II can be extremely difficult to diagnose before irreversible organ and tissue damage has occurred because of an insidious onset and the overlap in signs and symptoms with common childhood complaints. This is particularly true of patients without cognitive impairment (attenuated phenotype). Although not curative, early treatment with enzyme replacement therapy before irreversible organ damage has occurred may result in the greatest clinical benefit. Here, the signs, symptoms, and surgical history that should trigger suspicion of MPS II are described, and the diagnostic process is reviewed with a focus on practical considerations and the avoidance of common diagnostic pitfalls. Once a diagnosis is made, multidisciplinary management with an extended team of pediatric specialists is essential and should involve the pediatrician or family practice physician as facilitator and medical home for the patient and family. Conclusion: Because routine newborn screening is not yet available for MPS II, the involvement and awareness of pediatricians, family practice physicians, and pediatric specialists is critical for early identification, diagnosis, and referral in order to help optimize patient outcomes

Dlk1 Is Necessary for Proper Skeletal Muscle Development and Regeneration

Delta-like 1homolog (Dlk1) is an imprinted gene encoding a transmembrane protein whose increased expression has been associated with muscle hypertrophy in animal models. However, the mechanisms by which Dlk1 regulates skeletal muscle plasticity remain unknown. Here we combine conditional gene knockout and over-expression analyses to investigate the role of Dlk1 in mouse muscle development, regeneration and myogenic stem cells (satellite cells). Genetic ablation of Dlk1 in the myogenic lineage resulted in reduced body weight and skeletal muscle mass due to reductions in myofiber numbers and myosin heavy chain IIB gene expression. In addition, muscle-specific Dlk1 ablation led to postnatal growth retardation and impaired muscle regeneration, associated with augmented myogenic inhibitory signaling mediated by NF-κB and inflammatory cytokines. To examine the role of Dlk1 in satellite cells, we analyzed the proliferation, self-renewal and differentiation of satellite cells cultured on their native host myofibers. We showed that ablation of Dlk1 inhibits the expression of the myogenic regulatory transcription factor MyoD, and facilitated the self-renewal of activated satellite cells. Conversely, Dlk1 over-expression inhibited the proliferation and enhanced differentiation of cultured myoblasts. As Dlk1 is expressed at low levels in satellite cells but its expression rapidly increases upon myogenic differentiation in vitro and in regenerating muscles in vivo, our results suggest a model in which Dlk1 expressed by nascent or regenerating myofibers non-cell autonomously promotes the differentiation of their neighbor satellite cells and therefore leads to muscle hypertrophy

Scavenger Receptor CD36 Expression Contributes to Adipose Tissue Inflammation and Cell Death in Diet-Induced Obesity

The enlarged adipose tissue in obesity is characterized by inflammation, including the recruitment and infiltration of macrophages and lymphocytes. The objective of this study was to investigate the role of the scavenger receptor CD36 in high fat diet-induced obesity and adipose tissue inflammation and cell death.Obesity and adipose tissue inflammation was compared in CD36 deficient (CD36 KO) mice and wild type (WT) mice fed a high fat diet (60% kcal fat) for 16 weeks and the inflammatory response was studied in primary adipocytes and macrophages isolated from CD36 KO and WT mice.Compared to WT mice, CD36 KO mice fed a high fat diet exhibited reduced adiposity and adipose tissue inflammation, with decreased adipocyte cell death, pro-inflammatory cytokine expression and macrophage and T-cell accumulation. In primary cell culture, the absence of CD36 expression in macrophages decreased pro-inflammatory cytokine, pro-apoptotic and ER stress gene expression in response to lipopolysaccharide (LPS). Likewise, CD36 deficiency in primary adipocytes reduced pro-inflammatory cytokine and chemokine secretion in response to LPS. Primary macrophage and adipocyte co-culture experiments showed that these cell types act synergistically in their inflammatory response to LPS and that CD36 modulates such synergistic effects.CD36 enhances adipose tissue inflammation and cell death in diet-induced obesity through its expression in both macrophages and adipocytes