342 research outputs found
GaN directional couplers for integrated quantum photonics
Large cross-section GaN waveguides are proposed as a suitable architecture to
achieve integrated quantum photonic circuits. Directional couplers with this
geometry have been designed with aid of the beam propagation method and
fabricated using inductively coupled plasma etching. Scanning electron
microscopy inspection shows high quality facets for end coupling and a well
defined gap between rib pairs in the coupling region. Optical characterization
at 800 nm shows single-mode operation and coupling-length-dependent splitting
ratios. Two photon interference of degenerate photon pairs has been observed in
the directional coupler by measurement of the Hong-Ou-Mandel dip with 96%
visibility.Comment: 4 pages, 5 figure
Escape from an optoelectronic tweezer trap: experimental results and simulations
Optoelectronic tweezers (OET) are a microsystem actuation technology capable of moving microparticles at mm s−1 velocities with nN forces. In this work, we analyze the behavior of particles manipulated by negative dielectrophoresis (DEP) forces in an OET trap. A user-friendly computer interface was developed to generate a circular rotating light pattern to control the movement of the particles, allowing their force profiles to be conveniently measured. Three-dimensional simulations were carried out to clarify the experimental results, and the DEP forces acting on the particles were simulated by integrating the Maxwell stress tensor. The simulations matched the experimental results and enabled the determination of a new “hopping” mechanism for particle-escape from the trap. As indicated by the simulations, there exists a vertical DEP force at the edge of the light pattern that pushes up particles to a region with a smaller horizontal DEP force. We propose that this phenomenon will be important to consider for the design of OET micromanipulation experiments for a wide range of applications
Optimal Pavement Design and Rehabilitation Planning Using a Mechanistic-Empirical Approach
This paper presents the development of a pavement design and rehabilitation optimization decision-making framework based on Mechanistic-Empirical (ME) roughness transfer models. The AASHTOWare Pavement ME Design (the software of Pavement ME Design) is used to estimate pavement deterioration based on the combined effects of permanent deformation, fatigue, and thermal cracking. The optimization problem is first formulated into a mixed-integer nonlinear programming model to address the predominant trade-off between agency and user costs. To deal with the complexity associated with the pavement roughness transfer functions in the software and to use the roughness values as input to the optimization framework, a dynamic programming subroutine is developed for determining the optimal rehabilitation timing and asphalt concrete design thickness. An application of the proposed model is demonstrated in a case study. Managerial insights from a series of sensitivity analyses on different unit user cost values and model comparisons are presented
Effect of Central Antileptin Antibody on the Onset of Female Rat Puberty
The effect of intracerebroventricular (ICV) antileptin antibody on the onset of puberty in
the female rat and the relationship between serum leptin, luteinizing hormone (LH), and body
weight were investigated. Antileptin antibody (group A) was infused ICV from days 23–36
in prepubertal female rats whereas the control (group B) received ICV goat immunoglobulin
G (IgG).
In the antileptin group, mean day of vaginal opening (VO) was postponed (day 34 versus day 30,
P < .01
). Body weight trended higher after 30 days in the antileptin group but not significantly. However, there was no difference in serum leptin and LH between the two
groups on the day of VO. Serum leptin was relatively constant from day 23 through day 31
and did not correlate with LH (r = 0.14, P = .10).
These studies demonstrate that central leptin promotes the onset of female rat puberty as
evidenced by VO. Finally, central leptin impacts female rat pubertal onset in distinction from
serum leptin and body weight
Synergistic effects of ginsenoside Rg3 and cyclophosphamine on tumor growth and angiogenesis in lung cancer
To evaluate the effectiveness of ginsenoside Rg3 alone or in combination with cyclophosphamide (CPA) on tumor growth and angiogenesis in human lung cancer, 54 female athymic mice were transplanted with lung cancer cells (A549) which then were randomly divided into 4 groups: Ginsenoside Rg3 group, CPA group, ginsenoside Rg3 plus CPA group and control group. Ginsenoside Rg3 of 3.0 mg/kg (once/day for 10 days) and CPA of 20.0 mg/kg (once/day for 10 days) were intraperitoneally given to mice for consecutive 10 days. Seven mice selected from each group were sacrificed 18 days later. The survival time of the remaining 7 mice in each group was recorded. The life elongation rate, proliferating cell nuclear antigen labeling index (PCNALI), expression of vascular endothelial cell growth factor (VEGF) and microvessel density (MVD) in the tumor tissues were evaluated. The quality of life of mice with administration of ginsenoside Rg3 alone or ginsenoside Rg3 plus CPA were better with longer survival time, when compared with other groups. The PCNALI, MVD and VEGF expression in mice of the treated groups were significantly lowered when compared with that of the control group. Additionally, the MVD of mice in groups with treatment of ginsenoside Rg3 alone or ginsenoside Rg3 plus CPA were lower than that in the CPA group. Tumor growth and angiogenesis in lung cancer were profoundly inhibited by ginsenoside Rg3 alone or in combination with CPA. The synergistic anticancer effects of ginsenoside Rg3 and CPA improved the survival time in lung cancer.Key words: Ginseng, cyclophosphamide, angiogenesis, lung cancer
Do we all perceive food-related wellbeing in the same way? : results from a cross-cultural
Interest in measuring consumers' perceived wellbeing in a food-related context has been
growing. Understanding how foods influence consumers' perceived wellbeing can contribute to
better understand eating patterns. Culture is expected to largely influence how consumers
perceive food-related wellbeing. People in different cultures have different values and are
exposed to different socio-economic contexts, which make them likely to consider different
criteria when evaluating food-related wellbeing. In this context, the present work aimed at
investigating cross-cultural differences in perceived wellbeing of food products using a new
scale.
A web-based study was carried with 1332 participants in seven countries: Brazil, China,
France, Portugal, Spain, Uruguay and USA. A new scale to measure wellbeing in a food-related
context was constructed considering results from previous studies and other wellbeing scales.
The scale contained 31 statements related to six main dimensions (general, emotional,
intellectual, physical, social and spiritual). Six out of nine food concepts (apple, beef, beer,
broccoli, chocolate cake, coffee, fish, French fries and milk) were presented to participants
following an incomplete balanced design. For each of the concepts participants rated their
degree of agreement with the 31 statements using a 7-point scale.
The scores of the 31 items of the scale were significantly affected by country and food concept,
as well as their interaction. Using factor analysis, the items were grouped into four main factors
related to physical, intellectual and emotional aspects of food consumption. The items related to
physical aspects showed the greatest differences among products, followed by those related to
the intellectual aspects. Average scores of the food concepts in the four factors differed among
countries. The largest differences were found for the two emotional related factors. These
results provide insight on how consumers perceive different dimensions of wellbeing and stress
the influence of cultural differences on the conceptualization of this construct
Use of Transcriptional Profiling and Assessment of Blood Parameters to Understand Biological Mechanisms Controlling Feed Intake and Efficiency in Pigs
In this study, using transcriptional profiling of key tissues, we aimed to identify genetic mechanisms differing between control pigs and pigs that have been under selection for low residual feed intake (RFI) for three generations. A further aim was to determine the pathways responding to feed restriction within these lines and any line x treatment interactions resulting in gene expression differences. Preliminary results indicate that 2,809 genes in fat (p\u3c0.04, q\u3c0.2) and 61 genes in liver (p\u3c0.001, q\u3c0.2) showed differential expression in response to feed restriction. Also, 1,247 genes (p\u3c0.02, q\u3c0.2) showed differential expression between low RFI and control pigs and 38 genes (p\u3c0.001, q\u3c0.2) showed a line x feed interaction in liver. In addition, we measured the concentration of some of the important feed intake regulators in the blood such as leptin, triglyceride, and glucose. We found that the average blood leptin level to be significantly higher in the control ad libitum (CA) pigs than the control restricted (CR) group. Interestingly, the selected line of pigs on both restricted (SR) and ad libitum (SA) feed had similar blood leptin levels as found in the CR group pigs. Serum glucose levels were higher in CR than CA, however, we observed an opposite trend in the selected group. Combined with the transcriptional profiling results, blood hormone parameters may help us understand potential pathways that control FI and FE in pigs
Resolution of hepatic fibrosis after ZFN-mediated gene editing in the PiZ mouse model of human α1-antitrypsin deficiency
BACKGROUND: α1-antitrypsin deficiency is most commonly caused by a mutation in exon-7 of SERPINA1 (SA1-ATZ), resulting in hepatocellular accumulation of a misfolded variant (ATZ). Human SA1-ATZ-transgenic (PiZ) mice exhibit hepatocellular ATZ accumulation and liver fibrosis. We hypothesized that disrupting the SA1-ATZ transgene in PiZ mice by in vivo genome editing would confer a proliferative advantage to the genome-edited hepatocytes, enabling them to repopulate the liver.
METHODS: To create a targeted DNA break in exon-7 of the SA1-ATZ transgene, we generated 2 recombinant adeno-associated viruses (rAAV) expressing a zinc-finger nuclease pair (rAAV-ZFN), and another rAAV for gene correction by targeted insertion (rAAV-TI). PiZ mice were injected i.v. with rAAV-TI alone or the rAAV-ZFNs at a low (7.5×1010vg/mouse, LD) or a high dose (1.5×1011vg/mouse, HD), with or without rAAV-TI. Two weeks and 6 months after treatment, livers were harvested for molecular, histological, and biochemical analyses.
RESULTS: Two weeks after treatment, deep sequencing of the hepatic SA1-ATZ transgene pool showed 6%±3% or 15%±4% nonhomologous end joining in mice receiving LD or HD rAAV-ZFN, respectively, which increased to 36%±12% and 36%±12%, respectively, 6 months after treatment. Two weeks postinjection of rAAV-TI with LD or HD of rAAV-ZFN, repair by targeted insertion occurred in 0.10%±0.09% and 0.25%±0.14% of SA1-ATZ transgenes, respectively, which increased to 5.2%±5.0% and 33%±13%, respectively, 6 months after treatment. Six months after rAAV-ZFN administration, there was a marked clearance of ATZ globules from hepatocytes, and resolution of liver fibrosis, along with reduction of hepatic TAZ/WWTR1, hedgehog ligands, Gli2, a TIMP, and collagen content.
CONCLUSIONS: ZFN-mediated SA1-ATZ transgene disruption provides a proliferative advantage to ATZ-depleted hepatocytes, enabling them to repopulate the liver and reverse hepatic fibrosis
Magnetically induced metal-insulator transition in Pb2CaOsO6
We report on the structural, magnetic, and electronic properties of two new
double-perovskites synthesized under high pressure; Pb2CaOsO6 and Pb2ZnOsO6.
Upon cooling below 80 K, Pb2CaOsO6 simultaneously undergoes a metal--insulator
transition and develops antiferromagnetic order. Pb2ZnOsO6, on the other hand,
remains a paramagnetic metal down to 2 K. The key difference between the two
compounds lies in their crystal structure. The Os atoms in Pb2ZnOsO6 are
arranged on an approximately face-centred cubic lattice with strong
antiferromagnetic nearest-neighbor exchange couplings. The geometrical
frustration inherent to this lattice prevents magnetic order from forming down
to the lowest temperatures. In contrast, the unit cell of Pb2CaOsO6 is heavily
distorted up to at least 500 K, including antiferroelectric-like displacements
of the Pb and O atoms despite metallic conductivity above 80 K. This distortion
relieves the magnetic frustration, facilitating magnetic order which in turn
drives the metal--insulator transition. Our results suggest that the phase
transition in Pb2CaOsO6 is spin-driven, and could be a rare example of a Slater
transition.Comment: 14 pages, 9 figures. Accepted as a regular article in Phys. Rev.
Overexpression of Sterol Carrier Protein 2 in Patients with Hereditary Cholesterol Gallstones
<p>Abstract</p> <p>Background</p> <p>Lithogenic bile is the major cause of cholesterol gallstone, but its pathogenesis is not well understood. The hypersecretion of biliary cholesterol is believed to be an important cause of lithogenic bile. Sterol Carrier Protein 2 (SCP2) participates in cholesterol trafficking and lipid metabolism in hepatocytes and may play a key role in cholesterol gallstone formation.</p> <p>Methods</p> <p>21 cholesterol gallstone genealogies were studied to investigate the expression of SCP2 gene in liver tissue of hereditary and non-hereditary cholesterol gallstone patients as well as non-gallstone patients. The mRNA expression of liver SCP2 in 28 hereditary patients, 30 non-hereditary cholesterol gallstone patients and 32 non-gallstone patients was measured by Reverse Transcription Polymerase Chain Reaction (RT-PCR). The protein expression of liver SCP2 was also detected in all the patients by Western blotting. At the same time, the bile was also analyzed with biochemical techniques and the Cholesterol Saturation Index (CSI) was calculated.</p> <p>Results</p> <p>The mRNA and protein expression of SCP2 was significantly increased in cholesterol gallstone patients compared to those of non-gallstone patients. Moreover, SCP2 was expressed at higher levels in hereditary cholesterol gallstone patients than that of non-hereditary cholesterol gallstone patients. There was significant difference observed in CSI between cholesterol gallstone patients and non-gallstone patients, but not in CSI between hereditary and non-hereditary cholesterol gallstone patients.</p> <p>Conclusions</p> <p>SCP2 was overexpressed in hereditary cholesterol gallstone patients compared to non-hereditary cholesterol gallstone patients. This finding indicated that SCP2 might be one of the genetic factors contributing to cholesterol gallstone formation, which was always accompanied by the increase of bile lithogenicity.</p
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