Phase transition in phase transition lines of quantum XY model

Phase transitions in quantum systems, including symmetry breaking and topological types, always associate with gap closing and opening. We analyze the topological features of the quantum phase boundary of the XY model in a transverse magnetic field. Based on the results from graphs in the auxiliary space, we find that gapless ground states at boundary have different topological characters. On the other hand, in the framework of Majorana representation, the Majorana lattice is shown to be two coupled SSH chains. The analysis of the quantum fidelity for the Majorana eigen vector, which is shown to be identical to the square of that for ground states of the XY model, indicates the signature of the gapless phase transition (GPT). Furthermore analytical and numerical results for second-order derivative of groundstate energy density show that such a GPT obeys scaling behavior.

Abundance and molecular diversity of thraustochytrids in coastal waters of southern China

Thraustochytrids are unicellular fungi-like (heterotrophic) marine protists that have long been considered to play an important role in the biogeochemical cycles of the coastal oceans. However, the significance of their ecological functions and their diversity in marine ecosystems remain largely unknown. In this report, we examined the spatial and temporal variations of planktonic thraustochytrids, their relationship with other environmental factors, and their diversity in the subtropical coastal waters of China. The abundance of planktonic thraustochytrids ranged from 2.56 × 105 to 17.57 × 105 cells L-1 with highest abundance detected in polluted coastal water in the Spring (March) season. The thraustochytrid biomass was greater than the bacterial biomass in most seawater samples, ranging from 32.29 to 359.51% that of bacterioplankton. The abundance of thraustochytrids appeared to be largely related to that of bacterioplankton and to chemical oxygen demand in water columns. High-throughput sequencing analyses revealed a total of 105 OTUs (97% similarity), which were members of genera Thraustochytrium, Aplanochytrium, Oblongichytrium, Ulkenia, Labyrinthula and undescribed novel phylotypes. Results of this study indicated unprecedented high diversity of labyrinthulomycetes as well as the presence of novel labyrinthulomycete and thraustochytrid lineages, and also provided new information on the significant role of thraustochytrids in microbial food webs in a coastal marine ecosystem.

[Mutational analysis of RNA splicing machinery genes SF3B1, U2AF1 and SRSF2 in 118 patients with myelodysplastic syndromes and related diseases]

目的

探讨RNA剪接体复合物编码基因SF3B1、U2AF1和SRSF2突变在MDS及相关疾病中的突变率、突变特点及临床意义。

方法

以118例MDS及相关疾病患者为研究对象，采用PCR扩增产物直接测序法分别检测SF3B1（K700E）、U2AF1（S34、Q157P）和SRSF2（P95）突变情况。

结果

118例MDS患者中，男76例，女42例，中位年龄53.5（13~84）岁。对全部患者均进行SF3B1（K700E）基因突变分析，SF3B1（K700E）的突变率为19.49%（118例中23例）。在突变的22例MDS患者中，14例环形铁粒幼红细胞（RS）比例≥15%，其中难治性贫血伴环状铁粒幼红细胞（RARS）7例、难治性血细胞减少伴有多系发育异常（RCMD）6例、难治性贫血（RA）1例。与未突变组相比，突变组患者的年龄偏大[58（32~78）岁对51（13~84）岁，z=−1.981，P=0.048]、PLT偏高[121（22~888）×10⁹/L对59（6~1 561）× 10⁹/L，z=−3.305，P=0.001]、骨髓原始细胞比例偏低[0.007（0~0.122）对0.017（0~0.268），z=−2.885，P=0.004]、RS比例偏高[0（0~64%）对0（0~58%），z=−4.664，P<0.001]，HGB偏低[63（40~95）g/L对77（34~144）g/L，z=−3.192，P=0.001]。对105例患者进行U2AF1（S34、Q157P）基因突变分析，突变率为21.90%（105例中23例）。突变组患者各临床特征与未突变组相比差异均无统计学意义。107例患者有SRSF2（P95）突变结果，8例突变，突变率为7.48%，突变组患者初诊时年龄偏高，中位年龄63（50~84）岁，其中难治性贫血伴有原始细胞增多-1（RAEB-1）4例，突变率为14.29%（28例中4例）；MDS转化的急性髓系白血病3例。1例患者同时出现SF3B1（K700E）和SRSF2（P95H）突变，2例患者同时出现SF3B1（K700E）和U2AF1（S34Y）突变。

结论

SF3B1、U2AF1和SRSF2剪接体复合物蛋白编码基因中，仅SF3B1基因突变与环状铁粒幼红细胞增多性贫血密切相关，是该亚型的主要致病基因。

Symmetrical acral keratoderma revisited: proposal for a new term, 'pigmented carpotarsal hyperkeratosis'

First reported from Taiwan mistakenly as acral acanthosis nigricans in 1991, pigmented carpotarsal hyperkeratosis or hyperkeratosis nigricans carpi et tarsi displays a peculiar distribution of velvety brown-grey hyperpigmented plaques symmetrically on the flexural side of the wrists and ankles and on the dorsal sides of the hands and feet. A marked epidermal hyperkeratosis with typically mild acanthosis and papillomatosis is observed in histology. Whitish maceration upon perspiration or water exposure, with exacerbation in summer but remission in winter, is common. The association with obesity, endocrine disorders, atopic dermatitis, ichthyosis or malignancy is unknown. Familial occurrence and hereditary patterns are ill-defined. There is preliminary evidence indicating a pathogenic role of missense mutation in the transcription factor 4 gene. Treatment is empirical, with good outcome with topical retinoids and keratolytic agents. Recurrence is common, and long-term prognosis is unclear. To be distinguished are acral acanthosis nigricans, palmoplantar keratoderma of the Nagashima type, palmoplantar keratoderma of the Bothnian type and aquagenic palmoplantar keratoderma. Most reported cases are from Southern China and are predominantly observed in men between the ages of 20 and 40 years. The currently used term 'symmetrical acral keratoderma' is non-specific and misleading and may lead to global unawareness, underreporting or misdiagnosis of this phenomenon. Further genetic and molecular studies are required to clarify its pathogenesis and relation to palmoplantar keratoderma.

Natural history of serum HBV-RNA in chronic HBV infection

Virus-like particles encapsulating HBV-RNA represent a serum biomarker for assessing viral replication activity in clinical practice. However, baseline levels of serum HBV-RNA and their associations with viral replicative intermediates and liver disease in phases of chronic hepatitis B remain unknown. In this cross-sectional study, 102 patients were categorized into immune-tolerant (IT), HBeAg-positive immune active (HBeAg+IA), inactive carrier (IC) and HBeAg-negative immune active (HBeAg-IA) phases. HBV-RNA in serum samples and in 66 paired liver biopsies were quantified and correlated with serum ALT levels, histopathological scores and the levels of other viral replicative intermediates. Mean levels of serum HBV-RNA differed among phases, with the highest levels among IT (6.78 ± 0.83 log₁₀ copies mL^-1 ) patients, followed by HBeAg+IA (5.73 ± 1.16 log₁₀ copies mL^-1 ), HBeAg-IA (4.52 ± 1.25 log₁₀ copies mL^-1 ) and IC (2.96 ± 0.40 log₁₀ copies mL^-1 ) patients. Serum HBV-RNA levels correlated with HBV DNA in all phases, although correlations with other viral replicative intermediates weakened or disappeared when cases were stratified into phases. Distinct compositions of viral products were found among phases: the ratio of HBsAg to serum HBV-RNA was highest in IC patients, while the ratio of serum HBV-RNA to intrahepatic HBV-RNA and the ratio of intrahepatic HBV-DNA to intrahepatic HBV-RNA were significantly higher in IT patients. In conclusion, baseline levels of HBV-RNA and the composition of viral replicative intermediates differ significantly across the natural course of chronic HBV infection. These findings shed light on the nature of viral replication and pathogenesis of disease among different phases of chronic HBV infection.

High phylogenetic diversity and abundance pattern of Labyrinthulomycete protists in the coastal waters of the Bohai Sea

The unicellular Labyrinthulomycete protists have long been considered to play a significant role in ocean carbon cycling. However, their distribution and biogeochemical function remain poorly understood. We present a large-scale study of their spatiotemporal abundance and diversity in the coastal waters of Bohai Sea using flow cytometry and high-throughput sequencing. These protists display niche preferences and episodic higher biomass than that of bacterioplankton with much phylogenetic diversity (> 4000 OTUs) ever reported. They were ubiquitous with a typical abundance range of 100-1000 cells ml^-1 and biomass range of 0.06-574.59 μg C L^-1 . The observed spatiotemporal abundance variations support the current 'left-over scavengers' nutritional model and highlight these protists as a significant component of the marine microbial loop. The higher average abundance and phylogenetic diversity in the nearshore compared with those in the offshore reveal their predominant role in the terrigenous matter decomposition. Furthermore, the differential relationship of the protist genera to environmental conditions together with their co-occurrence network suggests their unique substrate preferences and niche partitioning. With few subnetworks and possible keystone species, their network topology indicates community resilience and high connectance level of few operational taxonomic units (OTUs). We demonstrate the significant contribution of these protists to the secondary production and nutrient cycling in the coastal waters. As secondary producers, their role will become more important with increasingly coastal eutrophication.

Incident Direction Independent Wave Propagation and Unidirectional Lasing

We propose an incident direction independent wave propagation generated by properly assembling different unidirectional destructive interferences (UDIs), which is a consequence of the appropriate match between synthetic magnetic fluxes and the incident wave vector. Single-direction lasing at spectral singularity is feasible without introducing nonlinearity. UDI allows unidirectional lasing and unidirectional perfect absorption; when they are combined in a parity-time-symmetric manner, the spectral singularities vanish with bounded reflections and transmissions. Furthermore, the simultaneous unidirectional lasing and perfect absorption for incidences from opposite directions is created. Our findings provide insights into light control and may shed light on the explorations of desirable functionality in fundamental research and practical applications.

Maximal distant entanglement in Kitaev tube

We study the Kitaev model on a finite-size square lattice with periodic boundary conditions in one direction and open boundary conditions in the other. Based on the fact that the Majorana representation of Kitaev model is equivalent to a brick wall model under the condition t = Δ = μ, this system is shown to support perfect Majorana bound states which is in strong localization limit. By introducing edge-mode fermionic operator and pseudo-spin representation, we find that such edge modes are always associated with maximal entanglement between two edges of the tube, which is independent of the size of the system.

Comparative analysis reveals unexpected genome features of newly isolated Thraustochytrids strains: on ecological function and PUFAs biosynthesis

BACKGROUND

Thraustochytrids are unicellular fungal-like marine protists with ubiquitous existence in marine environments. They are well-known for their ability to produce high-valued omega-3 polyunsaturated fatty acids (ω-3-PUFAs) (e.g., docosahexaenoic acid (DHA)) and hydrolytic enzymes. Thraustochytrid biomass has been estimated to surpass that of bacterioplankton in both coastal and oceanic waters indicating they have an important role in microbial food-web. Nevertheless, the molecular pathway and regulatory network for PUFAs production and the molecular mechanisms underlying ecological functions of thraustochytrids remain largely unknown.

RESULTS

The genomes of two thraustochytrids strains (Mn4 and SW8) with ability to produce DHA were sequenced and assembled with a hybrid sequencing approach utilizing Illumina short paired-end reads and Pacific Biosciences long reads to generate a highly accurate genome assembly. Phylogenomic and comparative genomic analyses found that DHA-producing thraustochytrid strains were highly similar and possessed similar gene content. Analysis of the conventional fatty acid synthesis (FAS) and the polyketide synthase (PKS) systems for PUFAs production only detected incomplete and fragmentary pathways in the genome of these two strains. Surprisingly, secreted carbohydrate active enzymes (CAZymes) were found to be significantly depleted in the genomes of these 2 strains as compared to other sequenced relatives. Furthermore, these two strains possess an expanded gene repertoire for signal transduction and self-propelled movement, which could be important for their adaptations to dynamic marine environments.

CONCLUSIONS

Our results demonstrate the possibility of a third PUFAs synthesis pathway besides previously described FAS and PKS pathways encoded in the genome of these two thraustochytrid strains. Moreover, lack of a complete set of hydrolytic enzymatic machinery for degrading plant-derived organic materials suggests that these two DHA-producing strains play an important role as a nutritional source rather than a nutrient-producer in marine microbial-food web. Results of this study suggest the existence of two types of saprobic thraustochytrids in the world's ocean. The first group, which does not produce cellulosic enzymes and live as 'left-over' scavenger of bacterioplankton, serves as a dietary source for the plankton of higher trophic levels and the other possesses capacity to live on detrital organic matters in the marine ecosystems.

Clinical efficacy of sequential therapy with voriconazole on COPD patients in acute phase with pulmonary aspergillosis and effects on cytokines and pulmonary functions

OBJECTIVE

To explore the clinical efficacy of sequential therapy with voriconazole on chronic obstructive pulmonary disease (COPD) patients in acute phase with pulmonary aspergillosis and its effects on cytokines and pulmonary functions.

PATIENTS AND METHODS

A total of 110 COPD patients in acute phase with pulmonary aspergillosis who were admitted to the hospital between February 2015 and November 2016 were enrolled. We divided them randomly into two groups, i.e., the control group (n = 55) and the treatment group (n = 55). Patients in the control group took itraconazole capsules orally (200 mg/time, twice per day for three days followed by once per day). Patients in treatment group underwent sequential treatment with voriconazole through intravenous infusion at a dose of 5 mg/kg/time twice a day for 3 days followed by a dose of 4 mg/kg/time, twice a day for 8 days. Then, patients took voriconazole orally at a dose of 150 mL/time, twice a day for 6 days. Patients in two groups received the treatment for a total of 14 days. After treatment, we evaluated the levels of tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and IL-8. The total lung capacity (TLC), diffusing capacity of the lung for carbon monoxide (DLco), and arterial oxygen saturation (SaO2), were measured as well.

RESULTS

The total effectiveness rates of the treatment group and the control group were 83.63% and 61.82%. The differences had statistical significance (p < 0.01). After treatment, the incidence of chest pain, cough, sputum-coughing, hemoptysis, cyanosis, and dyspnea in the treatment group was significantly fewer than that in the control group (p < 0.05). TCL, DLco, and SaO2 in the two groups were significantly ameliorated by treatment (p < 0.05). The amelioration in the treatment group was more prominent than that in the control group (p < 0.05). The levels of TNF-α, IL-8, and IL-6 in the two groups were decreased dramatically by the treatments. The decrease in the treatment group was significantly lower than those in the control group (p < 0.05). Occurrence of adverse reactions in treatment group and control group were 8.33% and 6.25%, respectively; (p > 0.05).

CONCLUSIONS

Sequential therapy with voriconazole exhibits promising clinical efficacy in COPD patients in acute phase with pulmonary aspergillosis. The treatment ameliorated the clinical symptoms and vital signs of patients significantly. It also improved the pulmonary functions and inhibited the inflammatory responses of patients with evident clinical efficacy.