Stochastic population dynamics under regime switching II

This is a continuation of our paper [Q. Luo, X. Mao, Stochastic population dynamics under regime switching, J. Math. Anal. Appl. 334 (2007) 69-84] on stochastic population dynamics under regime switching. In this paper we still take both white and color environmental noise into account. We show that a sufficient large white noise may make the underlying population extinct while for a relatively small noise we give both asymptotically upper and lower bound for the underlying population. In some special but important situations we precisely describe the limit of the average in time of the population

Competitive Lotka-Volterra Population Dynamics with Jumps

This paper considers competitive Lotka-Volterra population dynamics with jumps. The contributions of this paper are as follows. (a) We show stochastic differential equation (SDE) with jumps associated with the model has a unique global positive solution; (b) We discuss the uniform boundedness of $p$th moment with $p>0$ and reveal the sample Lyapunov exponents; (c) Using a variation-of-constants formula for a class of SDEs with jumps, we provide explicit solution for 1-dimensional competitive Lotka-Volterra population dynamics with jumps, and investigate the sample Lyapunov exponent for each component and the extinction of our $n$-dimensional model.Comment: 25 page

Population dynamical behavior of Lotka-Volterra system under regime switching

In this paper, we investigate a Lotka-Volterra system under regime switching dx(t) = diag(x1(t); : : : ; xn(t))[(b(r(t)) + A(r(t))x(t))dt + (r(t))dB(t)]; where B(t) is a standard Brownian motion. The aim here is to find out what happens under regime switching. We first obtain the sufficient conditions for the existence of global positive solutions, stochastic permanence and extinction. We find out that both stochastic permanence and extinction have close relationships with the stationary probability distribution of the Markov chain. The limit of the average in time of the sample path of the solution is then estimated by two constants related to the stationary distribution and the coefficients. Finally, the main results are illustrated by several examples

Trends in illicit drug use and their association with HIV transmission risks from behavioural surveillance of Australian gay and bisexual men

Introduction. Investigating drug trends among Australian gay and bisexual men (GBM) is crucial for understanding levels of use and the potential for harm, including HIV transmission risk. Method. Using repeated, national, cross‐sectional survey data collected between 2012 and 2021 (69,567 surveys), trends of recent (previous 6 months) and frequent (weekly) drug use were analysed, using logistic regression models. The last round of data from each jurisdiction (6709 surveys) was used to compare GBM who reported no use, infrequent (less than weekly) use and frequent (at least weekly) use of party drugs to investigate the association between party drug use and HIV transmission risk, using multinomial logistic regression models. Results. There was a significant upward trend in any recent drug use (from 58.4% in 2012 to 64.1% in 2021; p<0.001). Frequent party drug use remained a minority practice over the period (consistently less than 3%). In cross‐sectional analysis, frequent party drug users were more likely to report behaviours with HIV transmission risks, such as condomless anal intercourse without biomedical prevention strategies (30.0% vs. 13.1%; adjusted relative risk ratio [aRRR], 2.08; 95% CI, 1.24–3.47), weekly group sex (16.3% vs. 0.6%; aRRR, 12.36; 95% CI, 5.75–26.56) and more than 20 recent sexual partners (42.5% vs. 5.0%; aRRR, 21.44; 95% CI, 5.82–78.89), compared with GBM who did not use party drugs. Discussion and Conclusion. Our findings suggest that the frequent use of party drugs remains a marker of HIV transmission risk among Australian GBM, despite the increased adoption of biomedical HIV prevention strategies over the past few years

HIP1–ALK, a Novel Fusion Protein Identified in Lung Adenocarcinoma

Introduction:The most common mechanism underlying overexpression and activation of anaplastic lymphoma kinase (ALK) in non–small-cell lung carcinoma could be attributed to the formation of a fusion protein. To date, five fusion partners of ALK have been reported, namely, echinoderm microtubule associated protein like 4, tropomyosin-related kinase-fused gene, kinesin family member 5B, kinesin light chain 1, and protein tyrosine phosphatase, nonreceptor type 3.Methods:In this article, we report a novel fusion gene huntingtin interacting protein 1 (HIP1)–ALK, which is conjoined between the huntingtin-interacting protein 1 gene HIP1 and ALK. Reverse-transcriptase polymerase chain reaction and immunohistochemical analysis were used to detect this fusion gene’s transcript and protein expression, respectively. We had amplified the full-length cDNA sequence of this novel fusion gene by using 5′-rapid amplification of cDNA ends. The causative genomic translocation t(2;7)(p23;q11.23) for generating this novel fusion gene was verified by using genomic sequencing.Results:The examined adenocarcinoma showed predominant acinar pattern, and ALK immunostaining was localized to the cytoplasm, with intense staining in the submembrane region. In break-apart, fluorescence in situ hybridization analysis for ALK, split of the 5′ and 3′ probe signals, and isolated 3′ signals were observed. Reverse-transcriptase polymerase chain reaction revealed that the tumor harbored a novel fusion transcript in which exon 21 of HIP1 was fused to exon 20 of ALK in-frame.Conclusion:The novel fusion gene and its protein HIP1–ALK harboring epsin N-terminal homology, coiled-coil, juxtamembrane, and kinase domains, which could play a role in carcinogenesis, could become diagnostic and therapeutic target of the lung adenocarcinoma and deserve a further study in the future

Revision of Solar Spicule Classification

Solar spicules are the fundamental magnetic structures in the chromosphere and considered to play a key role in channelling the chromosphere and corona. Recently, it was suggested by De Pontieu et al. that there were two types of spicules with very different dynamic properties, which were detected by space- time plot technique in the Ca ii H line (3968 A) wavelength from Hinode/SOT observations. 'Type I' spicule, with a 3-7 minute lifetime, undergoes a cycle of upward and downward motion; in contrast, 'Type II' spicule fades away within dozens of seconds, without descending phase. We are motivated by the fact that for a spicule with complicated 3D motion, the space-time plot, which is made through a slit on a fixed position, could not match the spicule behavior all the time and might lose its real life story. By revisiting the same data sets, we identify and trace 105 and 102 spicules in quiet sun (QS) and coronal hole (CH), respectively, and obtain their statistical dynamic properties. First, we have not found a single convincing example of 'Type II' spicules. Secondly, more than 60% of the identified spicules in each region show a complete cycle, i.e., majority spicules are 'Type I'. Thirdly, the lifetime of spicules in QS and CH are 148 s and 112 s, respectively, but there is no fundamental lifetime difference between the spicules in QS and CH reported earlier. Therefore, the suggestion of coronal heating by 'Type II' spicules should be taken with cautions. Subject headings: Sun: chromosphere Sun:transition region Sun:coronaComment: accepted by Ap

内視鏡超音波ガイド下穿刺吸引の液状検体の残余を用いたK-ras 遺伝子検査は正診率を高める

Background: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) technology is widely used for the diagnosis of pancreatic masses. However, in some cases, inadequate tissue volume or difficulty of morphological diagnosis are constraining factors for adequate cytopathological evaluation. K-ras mutation is the most frequently acquired genetic abnormality, occurring in approximately 90% of all patients with pancreatic ductal adenocarcinoma (PDAC). In the present study, the clinical utility of residual liquid-based cytology (LBC) specimens obtained using EUS-FNA for K-ras mutation analysis was evaluated. Methods: In this study, 81 patients with pancreatic lesions were examined. The cell block (CB) specimens separated from EUS-FNA samples were morphologically evaluated by hematoxylin-eosin (HE) staining. Final diagnoses were confirmed by CB specimens, surgical resection specimens, diagnostic imaging, and clinical follow-up. Genomic DNA of residual LBC specimens stored at 4°C for several months were extracted and assessed for K-ras mutations using a fluorescence resonance energy transfer-based preferential homoduplex formation assay. Results: K-ras mutation analysis using residual LBC samples was successful in all cases. The sensitivity, specificity, and accuracy of CB examination alone were 77.4%, 100%, and 81.3%, respectively, and those of the combination of CB examination and K-ras mutation analysis were 90.3%, 92.3%, and 90.7%, respectively. Furthermore, K-ras mutations were detected in 8 (57.1%) of 14 PDAC samples for which the CB results were inconclusive. Conclusion: These findings suggest that K-ras mutation analysis using residual LBC specimens improves the diagnostic accuracy of EUS-FNA.博士（医学）・乙第1492号・令和2年12月24日Copyright: © 2018 Sekita-Hatakeyama et al. This is an open access article distributed under the terms of the Creative Commons Attribution License(https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

The Ubiquitous Conserved Glycopeptidase Gcp Prevents Accumulation of Toxic Glycated Proteins

Amadori-modified proteins (AMPs) are the products of nonenzymatic glycation formed by reaction of reducing sugars with primary amine-containing amino acids and can develop into advanced glycated end products (AGEs), highly stable toxic compounds. AGEs are known to participate in many age-related human diseases, including cardiovascular, neurological, and liver diseases. The metabolism of these glycated proteins is not yet understood, and the mechanisms that reduce their accumulation are not known so far. Here, we show for Escherichia coli that a conserved glycopeptidase (Gcp, also called Kae1), which is encoded by nearly every sequenced genome in the three domains of life, prevents the accumulation of Amadori products and AGEs. Using mutants, we show that Gcp depletion results in accumulation of AMPs and eventually leads to the accumulation of AGEs. We demonstrate that Gcp binds to glycated proteins, including pyruvate dehydrogenase, previously shown to be a glycation-prone enzyme. Our experiments also show that the severe phenotype of Gcp depletion can be relieved under conditions of low intracellular glycation. As glycated proteins are ubiquitous, the involvement of Gcp in the metabolism of AMPs and AGEs is likely to have been conserved in evolution, suggesting a universal involvement of Gcp in cellular aging and explaining the essentiality of Gcp in many organisms

Evolution of Nuchal Glands, Unusual Defensive Organs of Asian Natricine Snakes (Serpentes: Colubridae), Inferred From a Molecular Phylogeny

A large body of evidence indicates that evolutionary innovations of novel organs have facilitated the subsequent diversification of species. Investigation of the evolutionary history of such organs should provide important clues for understanding the basis for species diversification. An Asian natricine snake, Rhabdophis tigrinus, possesses a series of unusual organs, called nuchal glands, which contain cardiotonic steroid toxins known as bufadienolides. Rhabdophis tigrinus sequesters bufadienolides from its toad prey and stores them in the nuchal glands as a defensive mechanism. Among more than 3,500 species of snakes, only 17 Asian natricine species are known to possess nuchal glands or their homologues. These 17 species belong to three nominal genera, Balanophis, Macropisthodon, and Rhabdophis. In Macropisthodon and Rhabdophis, however, species without nuchal glands also exist. To infer the evolutionary history of the nuchal glands, we investigated the molecular phylogenetic relationships among Asian natricine species with and without nuchal glands, based on variations in partial sequences of Mt‐CYB, Cmos, and RAG1 (total 2,767 bp). Results show that all species with nuchal glands belong to a single clade (NGC). Therefore, we infer that the common ancestor of this clade possessed nuchal glands with no independent origins of the glands within the members. Our results also imply that some species have secondarily lost the glands. Given the estimated divergence time of related species, the ancestor of the nuchal gland clade emerged 19.18 mya. Our study shows that nuchal glands are fruitful subjects for exploring the evolution of novel organs. In addition, our analysis indicates that reevaluation of the taxonomic status of the genera Balanophis and Macropisthodon is required. We propose to assign all species belonging to the NGC to the genus Rhabdophis, pending further study

Soluble LR11/SorLA represses thermogenesis in adipose tissue and correlates with BMI in humans.

Thermogenesis in brown adipose tissue (BAT) is an important component of energy expenditure in mammals. Recent studies have confirmed its presence and metabolic role in humans. Defining the physiological regulation of BAT is therefore of great importance for developing strategies to treat metabolic diseases. Here we show that the soluble form of the low-density lipoprotein receptor relative, LR11/SorLA (sLR11), suppresses thermogenesis in adipose tissue in a cell-autonomous manner. Mice lacking LR11 are protected from diet-induced obesity associated with an increased browning of white adipose tissue and hypermetabolism. Treatment of adipocytes with sLR11 inhibits thermogenesis via the bone morphogenetic protein/TGFβ signalling pathway and reduces Smad phosphorylation. In addition, sLR11 levels in humans are shown to positively correlate with body mass index and adiposity. Given the need for tight regulation of a tissue with a high capacity for energy wastage, we propose that LR11 plays an energy conserving role that is exaggerated in states of obesity.AW and AVP were supported by FP7 – BetaBAT, BBSRC (BB/J009865/1), the British Heart Foundation (PG/12/53/29714) and MDU MRC. MJ and HB were supported by Japan Health and Labour Sciences Research grant (H22-rinkensui-ippan-001) and Grants-in–aid for Scientific Research from Japanese Ministry of Education, Culture, Sports, Science and Technology (24390231 and 24790907). VP was supported by Wellcome Trust and the Cambridge Overseas Trust. JR was supported by Ministerio de Educación, through “Programa Nacional de Movilidad de Recursos Humanos del Plan Nacional de I-D+i 2008-2011 (Subprograma de Estancias de Movilidad en el Extranjero “José Castillejo” para jóvenes Doctores, ref: JC2011-0248). SV was supported by MRC. WJS was supported by the Austrian Science Fund (FWF P-20218 and P-20455). Animal work was performed at the MDU DMC Core facilities.This is the final version of the article. It first appeared from NPG via http://dx.doi.org/10.1038/ncomms995