Unexpected Dirac-Node Arc in the Topological Line-Node Semimetal HfSiS

We have performed angle-resolved photoemission spectroscopy on HfSiS, which has been predicted to be a topological line-node semimetal with square Si lattice. We found a quasi-two-dimensional Fermi surface hosting bulk nodal lines, alongside the surface states at the Brillouin-zone corner exhibiting a sizable Rashba splitting and band-mass renormalization due to many-body interactions. Most notably, we discovered an unexpected Dirac-like dispersion extending one-dimensionally in k space - the Dirac-node arc - near the bulk node at the zone diagonal. These novel Dirac states reside on the surface and could be related to hybridizations of bulk states, but currently we have no explanation for its origin. This discovery poses an intriguing challenge to the theoretical understanding of topological line-node semimetals.Comment: 5 pages, 4 figures (paper proper) + 2 pages, figures (supplemental material

Regression of murine lung tumors by the let-7 microRNA.

MicroRNAs (miRNAs) have recently emerged as an important new class of cellular regulators that control various cellular processes and are implicated in human diseases, including cancer. Here, we show that loss of let-7 function enhances lung tumor formation in vivo, strongly supporting the hypothesis that let-7 is a tumor suppressor. Moreover, we report that exogenous delivery of let-7 to established tumors in mouse models of non-small-cell lung cancer (NSCLC) significantly reduces the tumor burden. These results demonstrate the therapeutic potential of let-7 in NSCLC and point to miRNA replacement therapy as a promising approach in cancer treatment

Membrane receptors of mouse leukocytes. II. Sequential expression of membrane receptors and phagocytic capacity during leukocyte differentiation

Analysis of four mature cell markers on mouse bone marrow leukocytes grown in vitro, demonstrated a distinct sequence of marker appearance during the terminal phases of granulocytic cell differentiation. A similar pattern of marker expression was also suggested by analysis of mature neutrophils and macrophages isolated from normal tissues. Among cultured neutrophils, receptors for the Fc portion of IgG (FcR) were first expressed on myelocytes and metamyelocytes, and then subsequently on more mature cells. Morphologically mature colony neutrophils (polymorphs) from agar cultures contained only FcR and complement receptor type two (CR(2)) (C3d receptor), and lacked both complement receptor type one (CR(1)) (C3b receptor) and the capacity to ingest latex, bacteria, or iron particles. Neutrophils from 2 and 3 wk liquid media cultures of marrow cells differed from agar grown neutrophils in that they had phagocytic capacity (particle ingestion) [Pi] in addition to FcR and CR(2). Furthermore, in the 4th and 5th wk of these continuous liquid cultures, CR(1) was also expressed, completing the surface marker profile of normal blood neutrophils. Based on these studies, the following order of appearance of these four markers on cells from the myelocytic series was proposed: FcR {arrow} FcR CR(2) {arrow} FcR CR(2) Pi {arrow} FcR CR(2) Pi CR(1). Differential studies of tissue leukocytes containing these same markers revealed that a heterogeneity existed among morphologically mature neutrophils. Even though 95 percent of blood polymorphs contained all four markers, the same was true of only half of spleen polymorphs and only 20 percent of bone marrow polymorphs. Cells of the monocyte-macrophage series were studies in parallel with neutrophils. Cultured marrow monocytes acquired the four mature cell markers so rapidly that the order of receptor appearance could not be determined. However, it was found that CR2 was lost during the terminal phase of monocyte maturation into activated macrophages

Lessons from market-based approaches to improved hygiene for the rural poor in developing countries

The countries that adopted the Millennium Development Goals (MDGs) have pledged to halve the proportion of the people without access to water supply and sanitation by the year 2015. Existing strategies have been slowed in closing the gap. Few countries have long-term, financially viable programs and many programs deliver a standard heavily subsidized model, which does not reach many of the poor in the short-term. This paper discusses alternative strategies that focus on effective, low-cost water treatment and sanitation technologies that aim to reach more people for far less cost than conventional approaches. This approach is particularly relevant to the vulnerable groups of the population and poor regions of developing countries. Experience and illustrations come from Cambodia and Vietnam where nearly 80% of the poor live in rural areas and the market for small-scale water supply and sanitation is relatively underdeveloped

Gaya Kepemimpinan dan Budaya Organisasi Pengaruhnya terhadap Kinerja Karyawan

Tujuan utama pembangunan Negara Indonesia di bidang sumber daya manusia dewasa ini adalah menciptakan sumber daya manusia yang berkualitas dan masyarakat Indonesia yang sejahtera. Hal ini dilakukan mengingat pentingnya peningkatan kualitas sumberdaya manusia yang terus mengalami Perubahan dengan menuntut setiap individu maupun kelompok harus mampu meningkatkan kinerjanya. Tujuan penelitian ini adalah untuk melihat pengaruh Gaya Kepemimpinan dan Budaya Organisasi terhadap Kinerja Karyawan pada Perwakilan BPKP Provinsi Sulawesi Utara. Populasi terdiri dari 92 orang dengan menggunakan sampel jenuh. Hasil penelitian menunjukkan gaya kepemimpinan memiliki tingkat signifikansi sebesar 0,447 yang artinya gaya kepemimpinan berpengaruh terhadap kinerja karyawan namun tidak signifikan. Budaya organisasi signifikan artinya budaya organisasi memiliki pengaruh positif dan signifikan terhadap kinerja karyawan. Secara simultan gaya kepemimpinan dan budaya organisasi berpengaruh positif dan signifikan terhadap kinerja karyawan. Dengan adanya temuan dalam penelitian ini, sebaiknya gaya kepemimpinan yang ada di Perwakilan BPKP Provinsi Sulawesi Utara disesuaikan dengan situasi dan kondisi yang ada pada saat ini. Kata kunci: gaya kepemimpinan, budaya organisasi, kinerja karyawan

The Effects of Host and Pathogen Variation on Infection Dynamics in the Amphibian-Chytrid System

This dissertation uses manipulative experiments to explore amphibian-Bd infection dynamics. Although there has been almost two decades research since the discovery of Bd, many questions still remain regarding what conditions mediate chytridiomycosis virulence. My research shows how certain host and pathogen factors can influence disease virulence. Identifying how host and pathogen factors mediate disease virulence is important in order to understand, predict, and mitigate this infectious amphibian disease. Worldwide biodiversity loss is occurring at unprecedented rates. Numerous factors are contributing to this loss, including infectious disease. Among vertebrate groups, amphibians are experiencing the highest rate of population declines and extinctions and are vulnerable to numerous infectious pathogens that appear to be contributing to amphibian biodiversity loss. A widespread infectious chytrid fungus, Batrachochytrium dendrobatidis (Bd), causing the disease, chytridiomycosis, is implicated in numerous amphibian population declines and extinctions and can induce sublethal effects within individuals. My dissertation research examines host-pathogen factors that mediate infection outcomes in the amphibian-Bd system. The severity of an infectious disease is the result of specific host-pathogen interactions. Thus, there may be large variation in disease outcome depending on host and pathogen related factors. In Chapter 2, I conducted a comparative experimental study in larval amphibians using multiple host species and Bd strains. I showed that host species varied in Bd susceptibility but that susceptibility was also contingent on Bd strain type. Thus, I showed chytridiomycosis virulence depended upon host and pathogen traits and that a sensitive host species could be robust to certain pathogen strains. In Chapter 3, I experimentally investigated multiple pathogen interactions with amphibian three amphibian host species to examine how Bd infection dynamics might change under simultaneous coinfection with a common water mold, Saprolegnia ferax (Sf). Coinfecting pathogens might interact within a host in a synergistic and antagonistic manner. In two host species, Bd infection intensity was slightly higher in hosts that were exposed to both Bd and Sf compared to just Bd alone indicating a small synergistic interaction with Sf. However, the differences were not significant in either host species. Survival differences were only detected in one host species; hosts exposed to Bd only experienced lower survival than those in the coinfected group. Additionally, I found host weight and days survived were predictive of Bd infection level for some hosts species showing species variation in infection response. Lastly, in Chapter 4, I experimentally examined age-dependent differences in Bd infection heterogeneity in two host species. I followed this with another experiment to test whether age-dependent differences in infection intensity of these hosts (‘donors’) influenced subsequent Bd transmission to a naïve conspecific host (‘recipients’). I found Bd infection intensity differences among juvenile and adult donors of both species. However, trend directions were not consistent; in one host species, adults had significantly higher infection levels than juveniles while the opposite was true in the second host species. Regardless of donor infection intensity, recipients had comparable infection levels within each host species. Survival also differed among host species and age groups suggesting Bd susceptibility may change with age and is species specific.Keywords: chytridiomycosis, amphibian population decline, Batrachochytrium dendrobatidis, infectious diseas