Stability of narrow beams in bulk Kerr-type nonlinear media

We consider (2+1)-dimensional beams, whose transverse size may be comparable to or smaller than the carrier wavelength, on the basis of an extended version of the nonlinear Schr\"{o}dinger equation derived from the Maxwell`s equations. As this equation is very cumbersome, we also study, in parallel to it, its simplified version which keeps the most essential term: the term which accounts for the {\it nonlinear diffraction}. The full equation additionally includes terms generated by a deviation from the paraxial approximation and by a longitudinal electric-field component in the beam. Solitary-wave stationary solutions to both the full and simplified equations are found, treating the terms which modify the nonlinear Schr\"{o}dinger equation as perturbations. Within the framework of the perturbative approach, a conserved power of the beam is obtained in an explicit form. It is found that the nonlinear diffraction affects stationary beams much stronger than nonparaxiality and longitudinal field. Stability of the beams is directly tested by simulating the simplified equation, with initial configurations taken as predicted by the perturbation theory. The numerically generated solitary beams are always stable and never start to collapse, although they display periodic internal vibrations, whose amplitude decreases with the increase of the beam power.Comment: 7 pages, 6 figures Accepted for publication in PR

Utilization patterns of Chinese medicine and Western medicine under the National Health Insurance Program in Taiwan, a population-based study from 1997 to 2003

<p>Abstract</p> <p>Background</p> <p>In 1995, Taiwan has launched a national health-care system (the National Health Insurance Program, NHI) covering the use of both Western medicine (WM) and Chinese medicine (CM). This population-based study was conducted to understand the role of CM in this dual medical system by determining the utilization patterns of CM and WM and to analyze the demographic characteristics and primary indications influencing the choice of the medical services for the development of strategies to enhance the appropriate use and reduce unnecessary use of CM.</p> <p>Methods</p> <p>This study used the NHI sample files from 1997 to 2003 consisting of comprehensive utilization and enrolment information for a random sample of 200,432 NHI beneficiaries of the total enrolees from 1995 to 2000. A total of 136,720 subjects with valid and complete enrolment and utilization data were included in this study. The logistic regression method was employed to estimate the odds ratios (ORs) for utilization of CM and WM. The usage, frequency of services, and primary indications for CM and WM were evaluated. A significance level of α = 0.05 was selected.</p> <p>Results</p> <p>Compared with WM, the odds of CM increased from 1997 to 2003. The odds of using CM (OR = 1.48; 95% CI: 1.45–1.50; p < 0.001) and WM (OR = 1.74; 95% CI: 1.72–1.77; p < 0.001) were higher in females and that of CM increased with age to a peak in the 45–54-year-group (OR = 1.75; 95% CI: 1.68–1.82; p < 0.001) and WM (OR = 1.09; 95% CI: 1.05–1.13; p < 0.001) in the elderly subjects (≥ 65 years). The odds of CM and WM were similar in all income groups. However, those of CM were higher in Central (OR = 1.65; 95% CI: 1.56–1.74; p < 0.001) and Southern Taiwan (OR = 1.18; 95% CI: 1.12–1.25; p < 0.001) and lower in the remote areas (OR = 0.57; 95% CI: 0.52–0.63; p < 0.001). Most of the patients had one ambulatory visit of both medical services annually. However, the utilization of WM predominated over CM. Over 90% of CM service was provided by clinics, whereas over 60% of WM service by hospitals. Diseases of the respiratory system was the most frequent primary indication in CM and WM. Herbal medication was the most commonly used form of CM (68.4–72.7%).</p> <p>Conclusion</p> <p>In recent years, there is an increasing trend in the utilization of CM in Taiwan. This increasing trend may be due to the covering of CM in the national health insurance system.</p

Use frequency of traditional Chinese medicine in Taiwan

BACKGROUND: Use of Traditional Chinese medicine (TCM), an important category of complementary and alternative medicine (CAM), has increased substantially in Western countries during the past decade. Use of TCM is also widespread in the Chinese population. However, few informative data have been obtained to date by large-scale investigations of TCM use in the Chinese population. This study was aimed at elucidating the demographics and patterns of TCM use in Taiwan. METHODS: We employed the complete datasets of TCM outpatient reimbursement claims from 1996 to 2001, including the use of Chinese herbal remedies, acupuncture and traumatology manipulative therapy, to analyse use frequencies, the characteristics of TCM users, and the disease categories that were treated by TCM in Taiwan. RESULTS: At the end of 2001, 6,142,829 (28.4%) among the 21,653,555 valid beneficiaries of the National Health Insurance in Taiwan had used TCM during the year. However, 13,536,266 subjects (62.5%) had used TCM at least once during the whole 6-year period from 1996 to 2001, with a total of 156,224,266 visits (mean 11.5 visits per user). The mean number of TCM users per annum was 5,733,602, with a mean increment of 1,671,476 (29.2%) of new users yearly. Among TCM users, female was higher than male (female:male = 1.13:1), and the age distribution displayed a peak at around the 30s, followed by the 20s and 40s. Chinese herbal remedies (85.9%) were the most common TCM modality used by this population, followed by acupuncture (11.0%) and traumatology manipulative therapies (3.1%). Private TCM clinics provided most of the TCM care (82.6%), followed by private TCM hospitals (12.0%). The top ten major disease categories for TCM visits were diseases of the respiratory system, musculoskeletal system and connective tissue; symptoms, signs and ill-defined conditions; injury and poisoning; diseases of the digestive system, genitourinary system, skin and subcutaneous tissue, nervous system and sense organs, circulatory and endocrine system; nutritional and metabolic diseases; and immunological disorders. CONCLUSION: TCM was popular among the Chinese population in Taiwan during the period studied. More than 60% of all subjects had used TCM during the 6-year interval. TCM was widely used by the Chinese population to treat problems and diseases of major human organ systems recognised by western medicine. This study provides information about the use frequencies of TCM and the disease categories treated by TCM, which should be useful for health policy makers and for those considering the integration of TCM and Western medicine

Gene expression during normal and FSHD myogenesis

<p>Abstract</p> <p>Background</p> <p>Facioscapulohumeral muscular dystrophy (FSHD) is a dominant disease linked to contraction of an array of tandem 3.3-kb repeats (D4Z4) at 4q35. Within each repeat unit is a gene, <it>DUX4</it>, that can encode a protein containing two homeodomains. A <it>DUX4 </it>transcript derived from the last repeat unit in a contracted array is associated with pathogenesis but it is unclear how.</p> <p>Methods</p> <p>Using exon-based microarrays, the expression profiles of myogenic precursor cells were determined. Both undifferentiated myoblasts and myoblasts differentiated to myotubes derived from FSHD patients and controls were studied after immunocytochemical verification of the quality of the cultures. To further our understanding of FSHD and normal myogenesis, the expression profiles obtained were compared to those of 19 non-muscle cell types analyzed by identical methods.</p> <p>Results</p> <p>Many of the ~17,000 examined genes were differentially expressed (> 2-fold, <it>p </it>< 0.01) in control myoblasts or myotubes vs. non-muscle cells (2185 and 3006, respectively) or in FSHD vs. control myoblasts or myotubes (295 and 797, respectively). Surprisingly, despite the morphologically normal differentiation of FSHD myoblasts to myotubes, most of the disease-related dysregulation was seen as dampening of normal myogenesis-specific expression changes, including in genes for muscle structure, mitochondrial function, stress responses, and signal transduction. Other classes of genes, including those encoding extracellular matrix or pro-inflammatory proteins, were upregulated in FSHD myogenic cells independent of an inverse myogenesis association. Importantly, the disease-linked <it>DUX4 </it>RNA isoform was detected by RT-PCR in FSHD myoblast and myotube preparations only at extremely low levels. Unique insights into myogenesis-specific gene expression were also obtained. For example, all four Argonaute genes involved in RNA-silencing were significantly upregulated during normal (but not FSHD) myogenesis relative to non-muscle cell types.</p> <p>Conclusions</p> <p><it>DUX4</it>'s pathogenic effect in FSHD may occur transiently at or before the stage of myoblast formation to establish a cascade of gene dysregulation. This contrasts with the current emphasis on toxic effects of experimentally upregulated <it>DUX4 </it>expression at the myoblast or myotube stages. Our model could explain why <it>DUX4</it>'s inappropriate expression was barely detectable in myoblasts and myotubes but nonetheless linked to FSHD.</p

Unfolding Simulations of Holomyoglobin from Four Mammals: Identification of Intermediates and β-Sheet Formation from Partially Unfolded States

Myoglobin (Mb) is a centrally important, widely studied mammalian protein. While much work has investigated multi-step unfolding of apoMb using acid or denaturant, holomyoglobin unfolding is poorly understood despite its biological relevance. We present here the first systematic unfolding simulations of holoMb and the first comparative study of unfolding of protein orthologs from different species (sperm whale, pig, horse, and harbor seal). We also provide new interpretations of experimental mean molecular ellipticities of myoglobin intermediates, notably correcting for random coil and number of helices in intermediates. The simulated holoproteins at 310 K displayed structures and dynamics in agreement with crystal structures (R g ~1.48-1.51 nm, helicity ~75%). At 400 K, heme was not lost, but some helix loss was observed in pig and horse, suggesting that these helices are less stable in terrestrial species. At 500 K, heme was lost within 1.0-3.7 ns. All four proteins displayed exponentially decaying helix structure within 20 ns. The C- and F-helices were lost quickly in all cases. Heme delayed helix loss, and sperm whale myoglobin exhibited highest retention of heme and D/E helices. Persistence of conformation (RMSD), secondary structure, and ellipticity between 2-11 ns was interpreted as intermediates of holoMb unfolding in all four species. The intermediates resemble those of apoMb notably in A and H helices, but differ substantially in the D-, E- and F-helices, which interact with heme. The identified mechanisms cast light on the role of metal/cofactor in poorly understood holoMb unfolding. We also observed β-sheet formation of several myoglobins at 500 K as seen experimentally, occurring after disruption of helices to a partially unfolded, globally disordered state; heme reduced this tendency and sperm-whale did not display any sheet propensity during the simulations

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field

Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.

Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field