Ultra-low-loss nanofiber Fabry-Perot cavities optimized for cavity quantum electrodynamics.

We demonstrate the fabrication of ultra-low-loss, all-fiber Fabry-Perot cavities that contain a nanofiber section, optimized for cavity quantum electrodynamics. By continuously monitoring the finesse and fiber radius during the fabrication of a nanofiber between two fiber Bragg gratings, we were able to precisely evaluate taper transmission as a function of radius. The resulting cavities have an internal round-trip loss of only 0.31% at a nanofiber waist radius of 207 nm, with a total finesse of 1380, and a maximum expected internal cooperativity of ∼1050 for a cesium atom on the nanofiber surface. Our ability to fabricate such high-finesse nanofiber cavities may open the door for the realization of high-fidelity scalable quantum networks.

Measurement of microresonator frequency comb coherence by spectral interferometry.

We experimentally investigate the spectral coherence of microresonator optical frequency combs. Specifically, we use a spectral interference method, typically used in the context of supercontinuum generation, to explore the variation of the magnitude of the complex degree of first-order coherence across the full comb bandwidth. We measure the coherence of two different frequency combs and observe wholly different coherence characteristics. In particular, we find that the observed dynamical regimes are similar to the stable and unstable modulation instability regimes reported in previous theoretical studies. Results from numerical simulations are found to be in good agreement with experimental observations. In addition to demonstrating a new technique to assess comb stability, our results provide strong experimental support for previous theoretical analyses.

Efficiency of dispersive wave generation from a dual-frequency beat signal.

The emission of dispersive waves (DWs) by temporal solitons can be described as a cascaded four-wave mixing process triggered by a pair of monochromatic continuous waves (CWs). We report experimental and numerical results demonstrating that the efficiency of this process is strongly and nontrivially affected by the frequency detuning of the CW pump lasers. We explain our results by showing that individual cycles of the input dual-frequency beat signal can evolve as higher-order solitons whose temporal compression and soliton fission govern the DW efficiency. Analytical predictions based on the detuning dependence of the soliton order are shown to be in excellent agreement with experimental and numerical observations.

Generalized dispersive wave emission in nonlinear fiber optics.

We show that the emission of dispersive waves in nonlinear fiber optics is not limited to soliton-like pulses propagating in the anomalous dispersion regime. We demonstrate, both numerically and experimentally, that pulses propagating in the normal dispersion regime can excite resonant dispersive radiation across the zero-dispersion wavelength into the anomalous regime.

Dietary protein composition influences abundance of peptide and amino acid transporter messenger ribonucleic acid in the small intestine of 2 lines of broiler chicks.

This study evaluated the effect of dietary protein composition on mRNA abundance of a peptide transporter (peptide transporter 1, PepT1), amino acid (AA) transporters [Na(+)-independent cationic and zwitterionic AA transporter (b(o,+)AT), excitatory AA transporter 3 (EAAT3), Na(+)-independent cationic and Na(+)-dependent neutral AA transporter 2 (y(+)LAT2), L-type AA transporter 1 (LAT1), and cationic AA transporter 1 (CAT1)], and a digestive enzyme (aminopeptidase N) in 2 lines (A and B) of broilers that differentially express PepT1 mRNA (line B > line A). From d 8 to 15 posthatch, birds were fed 1 of 3 diets. Protein sources included whey protein concentrate, a whey partial hydrolysate (WPH), or a mixture of free AA (AA) identical to the composition of whey. Quantities of mRNA were assayed by real-time PCR in the small intestine of males at d 8, 9, 11, 13, and 15. For all genes except LAT1, abundance of mRNA was greatest in line B birds that consumed the WPH diet (P < 0.006). When mRNA abundance was normalized to beta-actin quantities, this effect disappeared, demonstrating a generalized effect on gene expression in line B birds that consumed the hydrolysate. There was a greater villus height:crypt depth ratio (P < 0.05) in line B birds fed the WPH diet as compared with line A. In conclusion, line B birds, which express greater PepT1, displayed enhanced intestinal mucosal absorptive surface area and differential regulation of PepT1, AA transporters, and aminopeptidase N in response to dietary protein composition.

Expression profiling of the solute carrier gene family in chicken intestine from the late embryonic to early post-hatch stages.

Intestinal development during late embryogenesis and early post-hatch has a long-term influence on digestive and absorptive capacity in chickens. The objective of this research was to obtain a global view of intestinal solute carrier (SLC) gene family member expression from late embryogenesis until 2 weeks post-hatch with a focus on SLC genes involved in uptake of sugars and amino acids. Small intestine samples from male chicks were collected on embryonic days 18 (E18) and 20 (E20), day of hatch and days 1, 3, 7 and 14 post-hatch. The expression profiles of 162 SLC genes belonging to 41 SLC families were determined using Affymetrix chicken genome microarrays. The majority of SLC genes showed little or no difference in level of expression during E18-D14. A number of well-known intestinal transporters were upregulated between E18 and D14 including the amino acid transporters rBAT, y(+)LAT-2 and EAAT3, the peptide transporter PepT1 and the sugar transporters SGLT1, GLUT2 and GLUT5. The amino acid transporters CAT-1 and CAT-2 were downregulated. In addition, several glucose and amino acid transporters that are novel to our understanding of nutrient absorption in the chicken intestine were discovered through the arrays (SGLT6, SNAT1, SNAT2 and AST). These results represent a comprehensive characterization of the expression profiles of the SLC family of genes at different stages of development in the chicken intestine and lay the ground work for future nutritional studies.

Gene expression of nutrient transporters in the small intestine of chickens from lines divergently selected for high or low juvenile body weight.

Nutrient transporters in the small intestine are responsible for dietary nutrient assimilation; therefore, the expression of these transporters can influence overall nutrient status as well as the growth and development of the animal. This study examined correlated responses to selection in the developmental gene expression of PepT1, EAAT3, SGLT1, and GLUT5 in the small intestine of chickens from lines divergently selected for 48 generations for high (HH) or low (LL) 56-d BW and their reciprocal crosses (HL and LH). Duodenum, jejunum, and ileum were collected from male and female chicks on embryonic d 20, day of hatch with no access to feed, and d 3, 7, and 14 posthatch. Total RNA was extracted, and nutrient transporter expression was assayed by real-time PCR using the relative quantification method. In comparing male and female HH and LL chicks, there was a mating combination x age x sex interaction for PepT1 expression (P < 0.001), a main effect of sex for EAAT3 (P < 0.05) and SGLT1 (P < 0.001) expression, and an age x sex interaction for SGLT1 expression (P < 0.001). These results demonstrate a sexual dimorphism in the capacity to absorb nutrients from the intestine, which has implications for the poultry industry with regard to diet formulations for straight-run and sex-separate grow-out operations. Results from comparing male LL, LH, HL, and HH chicks indicate that selection for high or low juvenile BW may have influenced the gene expression profiles of these nutrient transporters in the small intestine, which may contribute to the overall differences in the growth and development of these lines of chickens.

Developmental regulation of nutrient transporter and enzyme mRNA abundance in the small intestine of broilers.

The objective of this study was to investigate intestinal nutrient transporter and enzyme mRNA in broilers selected on corn- and soybean-based (line A) or wheat-based (line B) diets. We investigated the peptide transporter PepT1, 10 amino acid transporters (rBAT, b(o,+)AT, ATB(o,+), CAT1, CAT2, LAT1, y(+)LAT1, y(+)LAT2, B(o)AT, and EAAT3), 4 sugar transporters (SGLT1, SGLT5, GLUT5, and GLUT2), and a digestive enzyme (aminopeptidase N). Intestine was collected at embryo d 18 and 20, day of hatch, and d 1, 3, 7, and 14 posthatch. The mRNA abundance of each gene was assayed using real-time PCR and the absolute quantification method. For PepT1, line B had greater quantities of mRNA compared with line A (P = 0.001), suggesting a greater capacity for absorption of amino acids as peptides. Levels of PepT1 mRNA were greatest in the duodenum (P < 0.05), whereas the abundances of SGLT1, GLUT5, and GLUT2 mRNA were greatest in the jejunum (P < 0.05). Abundances of EAAT3, b(o,+)AT, rBAT, B(o)AT, LAT1, CAT2, SGLT5, and aminopeptidase N mRNA were greatest in the ileum (P < 0.05). Quantities of PepT1, EAAT3, B(o)AT, SGLT1, GLUT5, and GLUT2 mRNA increased linearly (P < 0.01), whereas CAT1, CAT2, y(+)LAT1, and LAT1 mRNA decreased linearly (P < 0.05) with age. Abundance of y(+)LAT2 mRNA changed cubically (P = 0.002) with peaks of expression at day of hatch and d 7, and aminopeptidase N and SGLT5 mRNA changed quadratically (P = 0.005) with age. These results provide a comprehensive profile of the temporal and spatial expression of nutrient transporter mRNA in the small intestine of chicks.

Effects of body weight and nutrition on mammary protein expression profiles in Holstein heifers.

A proteomics approach was used to characterize biochemical and cellular mechanisms governing effects of peripubertal feeding on heifer mammary development. Mammary parenchymal tissue from 24 Holstein heifers randomly assigned to treatments arranged in a 2 x 2 factorial design was used to generate 2-dimensional protein maps of mammary tissue extracts. Heifers were reared on 1 of 2 dietary treatments, restricted (650 g/ d of daily gain) or elevated (950 g/d of daily gain) and killed at 1 of 2 body weights (BW, 200 or 350 kg). Cytosolic mammary gland extracts were prepared from frozen mammary parenchyma. Proteome maps of extracts were constructed using PDQuest software. Densities of 820 protein spots were analyzed using the MIXED procedure of SAS. Protein spots were characterized by changes in profiles of expression in response to increased BW, dietary treatment, or both. Dietary treatment influenced the expression of 131 protein spots, whereas heifer BW influenced the expression of 108 spots. The 22 most highly influenced (statistically) spots were excised and submitted for mass spectrometric analyses. Returned protein names and accession numbers were used in National Center for Biotechnology Information database searches to obtain information on the identified proteins. For example, one of the proteins that differed by dietary treatment, transferrin, a binding protein of insulin-like growth factor binding protein-3, was identified via these methods. Possible roles of this and other proteins in mammary development are described. We concluded that a proteomic approach is an effective tool for identifying the proteins involved in bovine mammary development.

Parental IQ and cognitive development of malnourished Indonesian children.

A cross-sectional study of children in West Kalimantan, Indonesia, was conducted to examine the relationship between malnutrition history, child IQ, school attendance, socioeconomic status, parental education and parental IQ. In unadjusted analyses, severely stunted children had significantly lower IQ scores than mild-moderately stunted children. This effect was significant when stunting, school attendance and parental education were included in multivariable models but was attenuated when parental IQ was included. Our research underscores the importance of accounting for parental IQ as a critical covariate when modeling the association between childhood stunting and IQ.