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"Li, T"
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An Aharonov-Bohm interferometer for determining Bloch band topology
The geometric structure of a single-particle energy band in a solid is fundamental for a wide range of many-body phenomena and is uniquely characterized by the distribution of Berry curvature over the Brillouin zone. We realize an atomic interferometer to measure Berry flux in momentum space, in analogy to an Aharonov-Bohm interferometer that measures magnetic flux in real space. We demonstrate the interferometer for a graphene-type hexagonal optical lattice loaded with bosonic atoms. By detecting the singular π Berry flux localized at each Dirac point, we establish the high momentum resolution of this interferometric technique. Our work forms the basis for a general framework to fully characterize topological band structures.
Journal Article
50 years of ASEAN and Singapore
\"On the 8th of August 2017, ASEAN will celebrate the 50th anniversary of its founding. ASEAN is of great importance to Singapore, the region and the world. In 1967, the Association of Southeast Asian Nations, or ASEAN in short, was founded by five countries in Southeast Asia which had just gained independence from their former colonial masters, united by a determination for the region to live in peace and stability. Singapore was one of the five founding members of ASEAN, together with Indonesia, Malaysia, Philippines and Thailand. The grouping was joined later by Brunei (1984), Vietnam (1995), Laos and Myanmar (1997), and finally, Cambodia (1999). ASEAN is today a very successful inter-governmental organization which promotes peace, stability, economic development and regional integration. This volume brings together 50 essays written by Singaporeans who have played a part in the partnership between ASEAN and Singapore. The reader will be able to glean an insight into the workings of ASEAN and Singapore's contributions to ASEAN through the lens of diplomats, academics, civil society leaders and officials\"--Provided by publisher.
Book
TP53 mutations as potential prognostic markers for specific cancers: analysis of data from The Cancer Genome Atlas and the International Agency for Research on Cancer TP53 Database
PurposeMutations in the tumor suppressor gene TP53 are associated with a variety of cancers. Therefore, it is important to know the occurrence and prognostic effects of TP53 mutations in certain cancers.MethodsOver 29,000 cases from the April 2016 release of the International Agency for Research on Cancer (IARC) TP53 Database were analyzed to determine the distribution of germline and somatic mutations in the TP53 gene. Subsequently, 7,893 cancer cases were compiled in cBioPortal for Cancer Genomics from the 33 most recent The Cancer Genome Atlas (TCGA) studies to determine the prevalence of TP53 mutations in cancers and their effects on survival and disease-free survival times.ResultsThe data were analyzed, and it was found that the majority of TP53 mutations were missense and the major mutational hotspots were located at codons 248, 273, 175, and 245 in exons 4–8 for somatic mutations with the addition of codon 337 and other mutations in exons 9–10 for germline mutations. Out of 33 TGCA studies, the effects of TP53 mutations were statistically significant in nine cancers (lung adenocarcinoma, hepatocellular carcinoma, head and neck squamous cell carcinoma, acute myeloid leukemia, clear cell renal cell carcinoma (RCC), papillary RCC, chromophobe RCC, uterine endometrial carcinoma, and thymoma) for survival time and in five cancers (pancreatic adenocarcinoma, hepatocellular carcinoma, chromophobe RCC, acute myeloid leukemia, and thymoma) for disease-free survival time. It was also found that the most common p53 mutation in hepatocellular carcinomas (R249S) was a much better indicator for poor prognosis than TP53 mutations as a whole. In addition, in cases of ovarian serous cystadenocarcinoma, the co-occurrence of TP53 and BRCA mutations resulted in longer survival and disease-free survival times than the presence of neither TP53 nor BRCA mutations.ConclusionTP53 mutations are potential prognostic markers that can be used to further improve the accuracy of predicting survival and disease-free survival times of cancer patients.
Journal Article
Tales from dayrut
\"This collection of fourteen connected stories and a novella takes us deep into Upper Egypt and the village of Dayrut al-Sharif, in which Mohamed Mustagab was born. To depict a world renowned for its poverty, ignorance, vendettas, and implacable code of honor, Mustagab deploys the black humor and Swiftian sarcasm of the insider who knows his society only too well. When the stillness of a day's end is shattered by a single gunshot, poignant beauty merges seamlessly into horror, and when a police officer seeking to unravel a murder finds himself with more body parts than he knows what to do with, violence tips as easily into farce. In counterpoint, the author's often surrealist imagination explores the mysteries of a landscape where seductive women haunt dusty paths and a man may find himself crushed like a worm beneath another's foot. Elsewhere, the horizons of 'my village' expand to include other countries (the author worked in the Arabian Peninsula for a number of years), where equally disastrous consequences follow on folly and self-delusion. Previously almost unknown in English, Mustagab's voice is both original and disturbing.\"--Back cover.
Book
Glycolysis gatekeeper PDK1 reprograms breast cancer stem cells under hypoxia
Glycolysis is critical for cancer stem cell reprogramming; however, the underlying regulatory mechanisms remain elusive. Here, we show that pyruvate dehydrogenase kinase 1 (PDK1) is enriched in breast cancer stem cells (BCSCs), whereas depletion of PDK1 remarkably diminishes ALDH
+
subpopulations, decreases stemness-related transcriptional factor expression, and inhibits sphere-formation ability and tumor growth. Conversely, high levels of PDK1 enhance BCSC properties and are correlated with poor overall survival. In mouse xenograft tumor, PDK1 is accumulated in hypoxic regions and activates glycolysis to promote stem-like traits. Moreover, through screening hypoxia-related long non-coding RNAs (lncRNAs) in PDK1-positive tissue, we find that lncRNA H19 is responsible for glycolysis and BCSC maintenance. Furthermore,
H19
knockdown decreases PDK1 expression in hypoxia, and ablation of
PDK1
counteracts H19-mediated glycolysis and self-renewal ability
in vitro
and
in vivo
. Accordingly, H19 and PDK1 expression exhibits strong correlations in primary breast carcinomas. H19 acting as a competitive endogenous RNA sequesters miRNA let-7 to release Hypoxia-inducible factor 1α, leading to an increase in PDK1 expression. Lastly, aspirin markedly attenuates glycolysis and cancer stem-like characteristics by suppressing both H19 and PDK1. Thus, these novel findings demonstrate that the glycolysis gatekeeper PDK1 has a critical role in BCSC reprogramming and provides a potential therapeutic strategy for breast malignancy.
Journal Article
COMPREHENSIVE STUDY OF OPTICAL, PHYSICAL, CHEMICAL, AND RADIATIVE PROPERTIES OF TOTAL COLUMNAR ATMOSPHERIC AEROSOLS OVER CHINA
An overview of Sun–Sky Radiometer Observation Network (SONET) measurements in China is presented. Based on observations at 16 distributed SONET sites in China, atmospheric aerosol parameters are acquired via standardization processes of operational measurement, maintenance, calibration, inversion, and quality control implemented since 2010. A climatology study is performed focusing on total columnar atmospheric aerosol characteristics, including optical (aerosol optical depth, ÅngstrÖm exponent, fine-mode fraction, single-scattering albedo), physical (volume particle size distribution), chemical composition (black carbon; brown carbon; fine-mode scattering component, coarse-mode component; and aerosol water), and radiative properties (aerosol radiative forcing and efficiency). Data analyses show that aerosol optical depth is low in the west but high in the east of China. Aerosol composition also shows significant spatial and temporal variations, leading to noticeable diversities in optical and physical property patterns. In west and north China, aerosols are generally affected by dust particles, while monsoon climate and human activities impose remarkable influences on aerosols in east and south China. Aerosols in China exhibit strong light-scattering capability and result in significant radiative cooling effects.
Journal Article
Modeling study of PM2.5 pollutant transport across cities in China's Jing-Jin-Ji region during a severe haze episode in December 2013
To study the influence of particulate matter (PM) transported from surrounding regions on the high PM2.5 pollution levels in Beijing, the GRAPES-CUACE model was used to simulate a serious haze episode that occurred on 6-7~December 2013. The results demonstrate the model's suitability for describing haze episodes throughout China, especially in the Beijing-Tianjin-Hebei (Jing-Jin-Ji) region. A very close positive correlation was found between the southerly wind speed over the plain to the south of Beijing and changes in PM2.5 in Beijing, both reaching maximum values at about 900 hPa, suggesting that the lower atmosphere was the principal layer for pollutant PM transport from its southern neighbouring region to Beijing. During haze episodes, and dependent upon the period, Beijing was either a pollution source or sink for its surrounding area. PM input from Beijing's environs was much higher than the output from the city, resulting in the most serious pollution episode, with the highest PM2.5 values occurring from 00:00 to 10:00 UTC (08:00 to 18:00 LT), 7 December 2013. PM pollutants from the environs of the city accounted for over 50 % of the maximum PM2.5 values reached in Beijing. At other times, the Beijing area was a net contributor to pollution in its environs.
Journal Article
Common variants on 2p16.1, 6p22.1 and 10q24.32 are associated with schizophrenia in Han Chinese population
Many schizophrenia susceptibility loci have been identified through genome-wide association studies (GWASs) in European populations. However, until recently, schizophrenia GWASs in non-European populations were limited to small sample sizes and have yielded few loci associated with schizophrenia. To identify genetic risk variations for schizophrenia in the Han Chinese population, we performed a two-stage GWAS of schizophrenia comprising 4384 cases and 5770 controls, followed by independent replications of 13 single-nucleotide polymorphisms in an additional 4339 schizophrenia cases and 7043 controls of Han Chinese ancestry. Furthermore, we conducted additional analyses based on the results in the discovery stage. The combined analysis confirmed evidence of genome-wide significant associations in the Han Chinese population for three loci, at 2p16.1 (rs1051061, in an exon of
VRK2
,
P
=1.14 × 10
−12
, odds ratio (OR)=1.17), 6p22.1 (rs115070292 in an intron of
GABBR1
,
P
=4.96 × 10
−10
, OR=0.77) and 10q24.32 (rs10883795 in an intron of
AS3MT
,
P
=7.94 × 10
−10
, OR=0.87; rs10883765 at an intron of
ARL3
,
P
=3.06 × 10
−9
, OR=0.87). The polygenic risk score based on Psychiatric Genomics Consortium schizophrenia GWAS data modestly predicted case–control status in the Chinese population (Nagelkerke
R
2
: 1.7% ~5.7%). Our pathway analysis suggested that neurological biological pathways such as GABAergic signaling, dopaminergic signaling, cell adhesion molecules and myelination pathways are involved in schizophrenia. These findings provide new insights into the pathogenesis of schizophrenia in the Han Chinese population. Further studies are needed to establish the biological context and potential clinical utility of these findings.
Journal Article
Detecting deformed commutators with exceptional points in optomechanical sensors
Models of quantum gravity imply a modification of the canonical position-momentum commutation relations. In this paper, working with a binary mechanical system, we examine the effect of quantum gravity on the exceptional points of the system. On the one side, we find that the exceedingly weak effect of quantum gravity can be sensed via pushing the system towards a second-order exceptional point, where the spectra of the non-Hermitian system exhibits non-analytic and even discontinuous behavior. On the other side, the gravity perturbation will affect the sensitivity of the system to deposition mass. In order to further enhance the sensitivity of the system to quantum gravity, we extend the system to the other one which has a third-order exceptional point. Our work provides a feasible way to use exceptional points as a new tool to explore the effect of quantum gravity.
Journal Article