Efficient and long-lived quantum memory with cold atoms inside a ring cavity

Quantum memories are regarded as one of the fundamental building blocks of linear-optical quantum computation and long-distance quantum communication. A long standing goal to realize scalable quantum information processing is to build a long-lived and efficient quantum memory. There have been significant efforts distributed towards this goal. However, either efficient but short-lived or long-lived but inefficient quantum memories have been demonstrated so far. Here we report a high-performance quantum memory in which long lifetime and high retrieval efficiency meet for the first time. By placing a ring cavity around an atomic ensemble, employing a pair of clock states, creating a long-wavelength spin wave, and arranging the setup in the gravitational direction, we realize a quantum memory with an intrinsic spin wave to photon conversion efficiency of 73(2)% together with a storage lifetime of 3.2(1) ms. This realization provides an essential tool towards scalable linear-optical quantum information processing.Comment: 6 pages, 4 figure

The mitochondrial genomes of the ciliates Euplotes minuta and Euplotes crassus

Contains fulltext : 75729.pdf (publisher's version ) (Open Access)BACKGROUND: There are thousands of very diverse ciliate species from which only a handful mitochondrial genomes have been studied so far. These genomes are rather similar because the ciliates analysed (Tetrahymena spp. and Paramecium aurelia) are closely related. Here we study the mitochondrial genomes of the hypotrichous ciliates Euplotes minuta and Euplotes crassus. These ciliates are only distantly related to Tetrahymena spp. and Paramecium aurelia, but more closely related to Nyctotherus ovalis, which possesses a hydrogenosomal (mitochondrial) genome. RESULTS: The linear mitochondrial genomes of the hypotrichous ciliates Euplotes minuta and Euplotes crassus were sequenced and compared with the mitochondrial genomes of several Tetrahymena species, Paramecium aurelia and the partially sequenced mitochondrial genome of the anaerobic ciliate Nyctotherus ovalis. This study reports new features such as long 5'gene extensions of several mitochondrial genes, extremely long cox1 and cox2 open reading frames and a large repeat in the middle of the linear mitochondrial genome. The repeat separates the open reading frames into two blocks, each having a single direction of transcription, from the repeat towards the ends of the chromosome. Although the Euplotes mitochondrial gene content is almost identical to that of Paramecium and Tetrahymena, the order of the genes is completely different. In contrast, the 33273 bp (excluding the repeat region) piece of the mitochondrial genome that has been sequenced in both Euplotes species exhibits no difference in gene order. Unexpectedly, many of the mitochondrial genes of E. minuta encoding ribosomal proteins possess N-terminal extensions that are similar to mitochondrial targeting signals. CONCLUSION: The mitochondrial genomes of the hypotrichous ciliates Euplotes minuta and Euplotes crassus are rather different from the previously studied genomes. Many genes are extended in size compared to mitochondrial genes from other sources

Laser Cooling of Optically Trapped Molecules

Calcium monofluoride (CaF) molecules are loaded into an optical dipole trap (ODT) and subsequently laser cooled within the trap. Starting with magneto-optical trapping, we sub-Doppler cool CaF and then load $150(30)$ CaF molecules into an ODT. Enhanced loading by a factor of five is obtained when sub-Doppler cooling light and trapping light are on simultaneously. For trapped molecules, we directly observe efficient sub-Doppler cooling to a temperature of $60(5)$ $\mu\text{K}$. The trapped molecular density of $8(2)\times10^7$ cm$^{-3}$ is an order of magnitude greater than in the initial sub-Doppler cooled sample. The trap lifetime of 750(40) ms is dominated by background gas collisions.Comment: 5 pages, 5 figure

Lipid-soluble smoke particles damage endothelial cells and reduce endothelium-dependent dilatation in rat and man

BACKGROUND: Cigarette smoking is a strong risk factor for vascular disease and known to cause dysfunction of the endothelium. However, the molecular mechanisms involved are still not fully understood. METHODS: In order to reveal the direct effects of lipid-soluble smoke particles on the endothelium, ring segments isolated from rat mesenteric arteries and human middle cerebral arteries (MCA) obtained at autopsy were incubated for 6 to 48 hrs in the presence of dimethylsulphoxide (DMSO)-soluble particles from cigarette smoke (DSP), i.e. lipid-soluble smoke particles. The endothelial microstructure was examined by transmission electron microscopy. The endothelial function was evaluated by acetylcholine (ACh)-induced endothelium-dependent vasodilatation, using a sensitive myograph. RESULTS: After DSP treatment, the arterial endothelium was swollen and loosing its attachment. In functional tests, the total ACh-induced dilatation, the nitric oxide (NO)-mediated and the endothelium-derived hyperpolarization factor (EDHF)-mediated dilatations were significantly decreased by DSP in a time- and concentration-dependent manner (p < 0.05). Nicotine, an important compound in cigarette smoke had, in an equivalent concentration as in DSP, no such effects (p > 0.05). Similar results were obtained in the human MCA. CONCLUSION: Thus, we demonstrate that the lipid-soluble smoke particles, but not nicotine, caused damage to arterial endothelium and reduced the endothelium-dependent dilatation in man and rat

Changed epitopes drive the antigenic drift for influenza A (H3N2) viruses

<p>Abstract</p> <p>Background</p> <p>In circulating influenza viruses, gradually accumulated mutations on the glycoprotein hemagglutinin (HA), which interacts with infectivity-neutralizing antibodies, lead to the escape of immune system (called antigenic drift). The antibody recognition is highly correlated to the conformation change on the antigenic sites (epitopes), which locate on HA surface. To quantify a changed epitope for escaping from neutralizing antibodies is the basis for the antigenic drift and vaccine development.</p> <p>Results</p> <p>We have developed an epitope-based method to identify the antigenic drift of influenza A utilizing the conformation changes on epitopes. A changed epitope, an antigenic site on HA with an accumulated conformation change to escape from neutralizing antibody, can be considered as a "key feature" for representing the antigenic drift. According to hemagglutination inhibition (HI) assays and HA/antibody complex structures, we statistically measured the conformation change of an epitope by considering the number of critical position mutations with high genetic diversity and antigenic scores. Experimental results show that two critical position mutations can induce the conformation change of an epitope to escape from the antibody recognition. Among five epitopes of HA, epitopes A and B, which are near to the receptor binding site, play a key role for neutralizing antibodies. In addition, two changed epitopes often drive the antigenic drift and can explain the selections of 24 WHO vaccine strains.</p> <p>Conclusions</p> <p>Our method is able to quantify the changed epitopes on HA for predicting the antigenic variants and providing biological insights to the vaccine updates. We believe that our method is robust and useful for studying influenza virus evolution and vaccine development.</p

Grp78 promotes the invasion of hepatocellular carcinoma

<p>Abstract</p> <p>Background</p> <p>Glucose regulated protein 78 (Grp78) is involved in the invasion and metastasis in many human cancers including gastric cancer, breast cancer, prostate cancer. But the role of Grp78 in the invasion of human hepatocellular carcinoma has not been reported. In this article, we examined if Grp78 was associated with the invasion of hepatocellular carcinoma and explored the possible underlying mechanism.</p> <p>Methods</p> <p>The Grp78 and FAK expression levels in 44 patients with hepatocellular carcinoma were examined using immunohistochemistry. Grp78 overexpressing SMMC7721 cells were established by pcDNA3.1 (+)-Grp78 transfection and screened by G418. Grp78 and FAK levels in Grp78 overexpressing cells were down-regulated by siRNA transfection. The invasion status of tumor cells was evaluated by transwell assay in vitro, and chick embryo metastasis model in vivo. Cell spreading was determined by cell spreading assay, and quantitatively measured by Orisis software HUG. Grp78, pY397 FAK, pY576/577 FAK and FAK levels were detected by western blot. RhoA activity was detected by GST pulldown assay. The distribution of actin cytoskeleton was observed by fluorescent staining.</p> <p>Results</p> <p>Grp78 expression levels in 44 patients with hepatocellular carcinoma were negatively correlated with tumor grading, and positively correlated with portal invasion and intra-hepatic invasion. Overexpression of Grp78 in SMMC7721 cells promoted the invasion of cancer cells in vitro and in vivo, and this increase in tumor cell invasion was blocked by Grp78 siRNA knockdown. Our results also revealed that overexpression of Grp78 in SMMC7721 cells accelerated the process of cell spreading and promoted lamellipodia formation. Further analysis showed that overexpression of Grp78 in SMMC7721 cells increased pY397 and pY576/577 levels of FAK. Grp78 siRNA knockdown decreased FAK activation and activity. Our results also revealed that Grp78 overexpression in SMMC7721 cells decreased RhoA-GTP level, and Grp78 siRNA knockdown rescued RhoA-GTP level in Grp78 overexpressing cells, indicating Grp78 inhibited RhoA activity in hepatocellular carcinoma cells. Furthermore, overexpression of Grp78 in SMMC7721 cells increased phospho-p190RhoGAP level. FAK siRNA knockdown in Grp78 overexpressing cells reversed phospho-p190RhoGAP level. These data suggested that Grp78 inhibited RhoA activity by up-regulated phospho-p190RhoGAP level and Grp78 mediated p190RhoGAP phosphorylation is FAK dependent.</p> <p>Conclusion</p> <p>Grp78 promoted the invasion of hepatocellular carcinoma both in vitro and in vivo. Overexpression of Grp78 in hepatocellular carcinoma cells enhanced the activation and activity of FAK which negatively regulated Rock kinase activity by promoting the phosphorylation of p190RhoGAP.</p

ER stress drives Lipocalin 2 upregulation in prostate cancer cells in an NF-κB-dependent manner

<p>Abstract</p> <p>Background</p> <p>Tumor cells adapt to endoplasmic reticulum (ER) stress through a set of conserved intracellular pathways, as part of a process termed the unfolded protein response (UPR). The expression of UPR genes/proteins correlates with increasing progression and poor clinical outcome of several tumor types, including prostate cancer. UPR signaling can activate NF-κB, a master regulator of transcription of pro-inflammatory, tumorigenic cytokines. Previous studies have shown that Lipocalin 2 (Lcn2) is upregulated in several epithelial cancers, including prostate cancer, and recently Lcn2 was implicated as a key mediator of breast cancer progression. Here, we hypothesize that the tumor cell UPR regulates Lcn2 production.</p> <p>Methods</p> <p>We interrogated Lcn2 regulation in murine and human prostate cancer cells undergoing pharmacological and physiological ER stress, and tested UPR and NF-κB dependence by using pharmacological inhibitors of these signaling pathways.</p> <p>Results</p> <p>Induction of ER stress using thapsigargin (Tg), a canonical pharmacologic ER stress inducer, or via glucose deprivation, a physiologic ER stressor present in the tumor microenvironment, upregulates LCN2 production in murine and human prostate cancer cells. Inhibition of the UPR using 4-phenylbutyric acid (PBA) dramatically decreases Lcn2 transcription and translation. Inhibition of NF-κB in prostate cancer cells undergoing Tg-mediated ER stress by BAY 11-7082 abrogates Lcn2 upregulation.</p> <p>Conclusions</p> <p>We conclude that the UPR activates Lcn2 production in prostate cancer cells in an NF-κB-dependent manner. Our results imply that the observed upregulation of Lipocalin 2 in various types of cancer cells may be the direct consequence of concomitant UPR activation, and that the ER stress/Lipocalin 2 axis is a potential new target for intervention in cancer progression.</p

The GTPase Activating Rap/RanGAP Domain-Like 1 Gene Is Associated with Chicken Reproductive Traits

BACKGROUND: Abundant evidence indicates that chicken reproduction is strictly regulated by the hypothalamic-pituitary-gonad (HPG) axis, and the genes included in the HPG axis have been studied extensively. However, the question remains as to whether any other genes outside of the HPG system are involved in regulating chicken reproduction. The present study was aimed to identify, on a genome-wide level, novel genes associated with chicken reproductive traits. METHODOLOGY/PRINCIPAL FINDING: Suppressive subtractive hybridization (SSH), genome-wide association study (GWAS), and gene-centric GWAS were used to identify novel genes underlying chicken reproduction. Single marker-trait association analysis with a large population and allelic frequency spectrum analysis were used to confirm the effects of candidate genes. Using two full-sib Ningdu Sanhuang (NDH) chickens, GARNL1 was identified as a candidate gene involved in chicken broodiness by SSH analysis. Its expression levels in the hypothalamus and pituitary were significantly higher in brooding chickens than in non-brooding chickens. GWAS analysis with a NDH two tail sample showed that 2802 SNPs were significantly associated with egg number at 300 d of age (EN300). Among the 2802 SNPs, 2 SNPs composed a block overlapping the GARNL1 gene. The gene-centric GWAS analysis with another two tail sample of NDH showed that GARNL1 was strongly associated with EN300 and age at first egg (AFE). Single marker-trait association analysis in 1301 female NDH chickens confirmed that variation in this gene was related to EN300 and AFE. The allelic frequency spectrum of the SNP rs15700989 among 5 different populations supported the above associations. Western blotting, RT-PCR, and qPCR were used to analyze alternative splicing of the GARNL1 gene. RT-PCR detected 5 transcripts and revealed that the transcript, which has a 141 bp insertion, was expressed in a tissue-specific manner. CONCLUSIONS/SIGNIFICANCE: Our findings demonstrate that the GARNL1 gene contributes to chicken reproductive traits

The use of 3D surface scanning for the measurement and assessment of the human foot

<p>Abstract</p> <p>Background</p> <p>A number of surface scanning systems with the ability to quickly and easily obtain 3D digital representations of the foot are now commercially available. This review aims to present a summary of the reported use of these technologies in footwear development, the design of customised orthotics, and investigations for other ergonomic purposes related to the foot.</p> <p>Methods</p> <p>The PubMed and ScienceDirect databases were searched. Reference lists and experts in the field were also consulted to identify additional articles. Studies in English which had 3D surface scanning of the foot as an integral element of their protocol were included in the review.</p> <p>Results</p> <p>Thirty-eight articles meeting the search criteria were included. Advantages and disadvantages of using 3D surface scanning systems are highlighted. A meta-analysis of studies using scanners to investigate the changes in foot dimensions during varying levels of weight bearing was carried out.</p> <p>Conclusions</p> <p>Modern 3D surface scanning systems can obtain accurate and repeatable digital representations of the foot shape and have been successfully used in medical, ergonomic and footwear development applications. The increasing affordability of these systems presents opportunities for researchers investigating the foot and for manufacturers of foot related apparel and devices, particularly those interested in producing items that are customised to the individual. Suggestions are made for future areas of research and for the standardization of the protocols used to produce foot scans.</p