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Layered metal–insulator–semiconductor (MIS) materials represent a promising platform for photoelectrocatalytic chemical transformations including solar water splitting. The introduction of insulato...

Protective insulating layers between a semiconductor and an electrocatalyst enable otherwise unstable semiconductors to be used in photocatalytic water splitting. It is generally argued that in these systems the metal electrocatalyst must have work function properties that set a high inherent barrier height between the semiconductor and electrocatalyst and that the insulating layer should be as thin as possible. In this study we show that, for systems which suffer from inherently low barrier heights, the photovoltage can be significantly improved by tuning the thickness of the insulating layer. We demonstrate this in a case study of a system consisting of n-type silicon, a hafnium oxide protective layer (thickness 0–3 nm), and a Ni electrocatalyst. By optimizing the protective layer thickness, we observe increased efficiencies for photocatalytic oxygen evolution with a thick Ni electrocatalyst supported on n-Si. Our findings open avenues for the use of inexpensive electrocatalysts with favorable electroca...

The inclusion of metal nanoparticle electrocatalysts on semiconductor photoelectrodes is often used to increase the efficiency of photocatalytic reactions on semiconductors. It is well established that metal electrocatalysts can limit overpotential losses associated with many important photocatalytic reactions, significantly increasing the efficiency of the conversion of solar into chemical energy. On the other hand, the introduction of metal nanoparticles can also impact the light-absorbing properties of semiconductors. We have studied the impact of the introduction of Pt nanoparticles on the optical and catalytic properties of flat Si photoelectrodes for the photoelectrocatalytic evolution of hydrogen. We demonstrate that the deposition of platinum nanoparticles onto planar Si photocathodes results in improved catalytic rates for the hydrogen evolution reaction, but also a diminished light-limited rate of photon to hydrogen conversion. We also show that by embedding Pt nanoparticles into Si, the light-l...

Military service assimilates individuals into a socially cohesive force to address dangerous and traumatic situations that have no counterpart in civilian life. Upon leaving active duty, many veterans experience a “reverse culture shock” when trying to reintegrate into civilian institutions and cultivate supportive social networks. Poor social reintegration is associated with greater morbidity and premature mortality in part due to adoption of risky health behaviors, social isolation, and inadequate engagement in health care services. Although institutions like the Veterans Health Administration (VA) do much to address the complex psychosocial and health care needs of veterans and their families with evidence-based care, only 61% of Operations Enduring and Iraqi Freedom (OEF/OIF) Veterans are enrolled in VA care and there are numerous perceived barriers to care for enrollees. To address this gap, a community-based nonprofit organization, Team Red, White & Blue (RWB), was created to help veterans establish health-enriching social connections with communities through the consistent provision of inclusive and locally tailored physical, social, and service activities. This article provides an overview of the development and refinement of a theory-based framework for veteran health called the Enrichment Equation, comprised of three core constructs: health, people, and purpose. By operationalizing programming activities and roles, we describe how theoretical components were translated into a social networking implementation package that enabled rapid national spread of Team RWB. We conclude with future opportunities to partner with researchers and other organizations to understand program impact, and to identify effective intervention components that could be adapted for similar vulnerable groups., Team Red, White & Blue is a non-profit that enriches veterans’ lives by connecting them to their communities through activities that build positive social networks.

A major limitation in tissue engineering strategies for congenital birth defects is the inability to provide a significant source of oxygen, nutrient, and waste transport in an avascular scaffold. Successful vascularization requires a reliable method to generate vascular cells and a scaffold capable of supporting vessel formation. The broad potential for differentiation, high proliferation rates, and autologous availability for neonatal surgeries make amniotic fluid-derived stem cells (AFSC) well suited for regenerative medicine strategies. AFSC-derived endothelial cells (AFSC-EC) express key proteins and functional phenotypes associated with endothelial cells. Fibrin-based hydrogels were shown to stimulate AFSC-derived network formation in vitro but were limited by rapid degradation. Incorporation of poly(ethylene glycol) (PEG) provided mechanical stability (65%±9% weight retention vs. 0% for fibrin-only at day 14) while retaining key benefits of fibrin-based scaffolds—quick formation (10±3 s), biocompatibility (88%±5% viability), and vasculogenic stimulation. To determine the feasibility of AFSC-derived microvasculature, we compared AFSC-EC as a vascular cell source and AFSC as a perivascular cell source to established sources of these cell types—human umbilical vein endothelial cells (HUVEC) and mesenchymal stem cells (MSC), respectively. Cocultures were seeded at a 4:1 endothelial-to-perivascular cell ratio, and gels were incubated at 37°C for 2 weeks. Mechanical testing was performed using a stress-controlled rheometer (G′=95±10 Pa), and cell-seeded hydrogels were assessed based on morphology. Network formation was analyzed based on key parameters such as vessel thickness, length, and area, as well as the degree of branching. There was no statistical difference between individual cultures of AFSC-EC and HUVEC in regard to these parameters, suggesting the vasculogenic potential of AFSC-EC; however, the development of robust vessels required the presence of both an endothelial and a perivascular cell source and was seen in AFSC cocultures (70%±20% vessel length, 90%±10% vessel area, and 105%±10% vessel thickness compared to HUVEC/MSC). At a fixed seeding density, the coculture of AFSC with AFSC-EC resulted in a synergistic effect on network parameters similar to MSC (150% vessel length, 147% vessel area, 150% vessel thickness, and 155% branching). These results suggest that AFSC-EC and AFSC have significant vasculogenic and perivasculogenic potential, respectively, and are suited for in vivo evaluation.

We investigate holographic optical trapping combined with step-and-repeat maskless projection stereolithography for fine control of 3D position of living cells within a 3D microstructured hydrogel. C2C12 myoblast cells were chosen as a demonstration platform since their development into multinucleated myotubes requires linear arrangements of myoblasts. C2C12 cells are positioned in the monomer solution with multiple optical traps at 1064 nm and then encapsulated by photopolymerization of monomer via projection of a 512x512 spatial light modulator illuminated at 405 nm. High 405 nm sensitivity and complete insensitivity to 1064 nm was enabled by a lithium acylphosphinate (LAP) salt photoinitiator. These wavelengths, in addition to brightfield imaging with a white light LED, could be simultaneously focused by a single oil immersion objective. Large lateral dimensions of the patterned gel/cell structure are achieved by x and y step-and-repeat process. Large thickness is achieved through multi-layer stereolithography, allowing fabrication of precisely-arranged 3D live cell scaffolds with micron-scale structure and millimeter dimensions. Cells are shown to retain viability after the trapping and encapsulation procedure.

SUMMARYBetween 1961 and 1974, 11934 samples of serum were tested by the Sabin- Feldman Dye test for the presence of antibodies to Toxoplasma gondii.Analysis of high-titred sera suggested that a 6-year cycle of high disease prevalence occurred across Canada. In addition, a decline in the percentage of positive reactions occurred each year in the Fall. The suggestion that this decline was due to dry conditions during the summer months was supported by the observation that differences in the prevalence of toxoplasma infection in ten Canadian cities were related to their average summer rainfall. The significance of these observations in relation to the epidemiology of toxoplasmosis in this country is discussed. The influence of patient age on the prevalence of infection was also investigated; the results obtained suggested that at least 75% of infants with high antibody titres against T. gondii had obtained these antibodies by placental transfer from their mothers.

CONSIDERABLE interest has been manifested in recent years in crossbred progeny for meat and egg production. Although their use for egg production has been questioned, it is generally conceded that crossbreds are superior for broiler production. Several reviews of existing scientific literature on the subject have been published. Particular attention is called to those of Phillips (1913, 1915 and 1921), Knox and Olsen (1938), and Knox (1939). Because of the interest in crossbreeding and the diversity of results thus far obtained, controlled experiments were undertaken and repeated for several years at the Beltsville Research Center with Rhode Island Reds, White Wyandottes, and Light Sussex. Two- and three-way crosses were made among these breeds and data obtained on production and growth characteristics of the progeny from the standardbreds and their crosses. Records obtained on mass-mated stock were used as a basis of comparison between the standardbreds and crossbreds. This had the . . .

IN A PREVIOUS paper (Byerly and Quinn, 1936) it was shown that 47.5 percent of 1,102 Rhode Island Red chicks hatched at the National Agricultural Research Center, Beltsville, Maryland, carried black spotting on the head or black striping on either head or body, also that 42.1 percent of 663 chicks from an excellent standard bred flock carried spotting or striping, indicating that these characteristics may be rather widely distributed among Rhode Island Red flocks. It was further shown that 84.9 percent of the striped or spotted Beltsville chicks were females, whereas 77.8 percent of the non-spotted, non-striped chicks were males. Several breeders and hatcherymen have questioned the extent of the distribution of the characteristics mentioned above. They have also pointed out that little melanic pigment (black spotting and striping) appears in the Rhode Island Red Chicks shown in commercial and standard bred exhibition classes. It was the opinion of the . . .

IT HAS been shown previously (Byerly and Quinn, 1936, and Quinn and Byerly, 1937) that sexual dimorphism existed in the down color of Rhode Island Red chicks observed at Beltsville and elsewhere, most of the non-spotted, non-striped chicks being males and most of the black spotted and striped chicks being females. In the down color of the Red-Splashed White variety, a mutation from the Rhode Island Red (Quinn, 1934, 1935), no striping is evident but some of the chicks carry red, or red and black, head spotting, the others being pure white. Preliminary observations indicated that most of the chicks with black head spots were females. Observations were then made on the down color and sexes of a larger number of Red-Splashed White chicks to determine whether or not a dimorphism similar to that found in Rhode Island Reds could be noted. These observations of Red-Splashed White chicks were made . . .

The recessive Red-Splashed White mutant from the Rhode Island Red is a gold. It is differentiated from the Rhode Island Red by thepp genes and from the other two recessive whites byGG andOO. The expression of black and red pigment in day-old chicks is affected similarly by thepp genes, the chicks being white. In many instances the white chicks having black or red pigment appeared with a black or red head spot respectively. The adult plumage of the Red-Splashed White chicks did not show any distinctive red head spot, although in most instances they developed some red and red-splashed feathers throughout their plumage. The adult plumage of the chicks with the black head spot was in conformity with the down colour of the chick, there being no black or black-splashed feathers. All the other white and coloured breeds used in the crosses with the Red-Splashed Whites carriedPP.

DOUBLING of structure is seldom observed in fowls beyond the embryonic stages. In the female embryo, the right ovary and oviduct begin to develop but they usually degenerate as development proceeds, so that at hatching time only rudiments remain. Nevertheless, several cases have been reported in which both a right and left ovary have been found in adult fowls. Brandt (1889) described a hen with a rudimentary right ovary. Gadow (1891) found a persistent right ovary in several orders of birds. Chappellier (1914) made similar observations, including a duck with both right and left ovaries and oviducts, which is said to have laid two eggs on the same day. Kirkpatrick and Card (1916) reported a White Wyandotte with two functional oviducts and ovaries. Kaupp (1922) photographed the gonads of a hen showing two functional ovaries and oviducts. Atwood and Snyder (1923) found a hen which laid eggs of two distinct . . .

INVESTIGATIONS at the National Agricultural Research Center, Beltsville, Maryland, have shown that considerable diversity in genotypes exists among white varieties of fowls, probably due to intercrossing of white phenotypes. The results obtained in a study of five white varieties (Quinn, 1936) indicated that the history of the development of some of these varieties may not prove a reliable criterion for the heredity of any particular strain or family, and that only by experimental testing can the genetic constitution be definitely determined. Among the white varieties studied were the White Silkie and White Rose Comb Bantam, concerning the origin of which little is known. However, Bateson and Punnett (1908) found strains of White Silkies and White Rose Comb Bantams which were recessive whites and lacked one of the complementary color-producing genes, AAbb, as proposed by Punnett (1923). They were later designated CCoo, crosses of these two white breeds with ccOO white . . .

INTRODUCTION FIVE investigations reporting losses in egg quality due to Newcastle disease (ND) have been published: Lorenz and Newlon (1944); Berg, Bearse and Hamilton (1947); Parnell (1950); Dearstyne, Lucas, Glazener and Blow (1950); and Pomeroy and Brandly (1953). A preliminary report on the effect of ND on egg quality was made by Quinn (1950). The purpose of this paper is to report observations on egg quality, egg production and mortality from October 1, 1948 to October 18, 1949, in a flock of White Leghorn pullets selected and bred for eggs having superior albumen quality. MATERIALS AND METHODS A naturally occurring outbreak of ND was observed at Beltsville in April, 1949, in a flock of early hatched White Leghorn pullets used in egg quality investigations, and kept in a conventional laying house. At 600 to 700 yards from the laying house were several colony houses which contained later hatched White Leghorn …

INTRODUCTION EGG weight loss results mainly from moisture loss, which begins to manifest itself soon after laying. As egg weight is lost, in stored or incubated eggs, there is a concomitant increase in the size of of the air cell. Size or depth of air cell is an important quality factor, used as a specification 1 in the standardization and grading of market eggs. In order to minimize loss in egg weight and size of air cell, the processing of eggs and various methods of management have been employed. Much less attention has been paid to inherent differences in eggs which might affect egg weight loss and size of air cell. Several investigators, however, have studied egg shell and membrane characters affecting egg weight loss, and concluded that some of them were inherited. Almquist and Holst (1931) reported that egg shell porosity appeared to be nearly uniform for the eggs of . . .

INTRODUCTION WHOLESALE handlers of eggs have been reporting that the quality of market eggs has deteriorated steadily in recent years, according to Brant and Shrader (1951). Several reasons for this deterioration have been given. Increased egg production, the medication of flocks, and faulty nutrition have been cited as factors which might be responsible for lowered egg quality and for the failure of high grade market eggs to retain good quality for reasonable periods of time. Serious damage to egg quality may result from outbreaks of respiratory diseases. Infectious bronchitis may adversely affect shell quality and interior quality. Lorenz and Newlon (1944), Berg et al. (1947), Parnell (1950) and Quinn (1950) have pointed out that Newcastle disease affects shell quality and interior quality and that the total damage is of sufficient magnitude to be of commercial importance. Moreover, Quinn (1950) has demonstrated that the weight and keeping quality of eggs of . . .

FOR many years farmers and commercial poultrymen have sorted the birds in their flocks in July, August, and later, into two groups. One group they considered keeping for another year and the other group they sent to market. These hens were sorted on characteristics that are supposed to indicate production qualities. In selecting his birds, the poultryman must interpret the value of certain biological characters, which are visible externally, in estimating egg production. The interpretative and biological nature of the selection practiced have made it extremely difficult to evaluate many of the characteristics used in such selection. It has been equally difficult to determine the relative importance of any single character to serve as a criterion for estimating egg production. Arbitrary standards often based upon personal bias instead of proved facts have frequently served as a basis for estimating egg production. It was thought that possibly some of the characters . . .

QUINN and Burrows (1936) reported that they obtained 97 percent fertility of eggs from hens which were inseminated five days a week with 0.2 c.c. of undiluted semen. This treatment was admittedly more than adequate to produce good results, both as to dosage and frequency of insemination. The investigations herein reported were carried out at the National Agricultural Research Center, Beltsville, Maryland, for the purpose of determining satisfactory dosages of semen and frequencies of insemination for use in practical artificial breeding of chickens. Three distinct objectives were kept in view during the investigations: (1) a practical means of obtaining the largest number of fertile eggs from any given hen, (2) of obtaining the largest number of fertile eggs from the services of any given male, and (3) of obtaining the largest number of fertile eggs from a flock of females with the least amount of labor and expense. EXPERIMENTAL PROCEDURE

THE phenotypic method of selecting layers and breeders based on the visible characters they possess constitutes the fundamental basis of judging fowls, whether in the showroom or in production classes. So long as the selection of breeding stock is based upon such an empirical method of procedure just so long will progress be retarded in the development of strains of fowls excelling in any particular. It is probably safe to say that there have been very few poultrymen anywhere in the world who have ever produced from year to year any more than a small percentage of their flock possessing reasonably good standard quality. The reason for such mediocre results in poultry breeding work is that the phenotypic instead of the genotypic method of selecting the breeders has been practised. If poultrymen breeding exhibition poultry had practised the progeny test, basing the selection of their breeding stock on the quality . . .

POULTRYMEN have been interested in segregating male and female chicks at hatching time for practical reasons. This has been accomplished by making sex linked crosses involving color of plumage, by mating rapid-feathering males to slow-feathering females, and by observing the copulatory organ, a method of sex prediction known as the Japanese method. Bureau of Animal Industry investigators at the National Agricultural Research Center have been interested for some time in the possibilities of distinguishing the sex of baby chicks, of standard breeds and varieties, by the observation of such external characteristics as down color, down striping, beak color, or shank color. It has been shown previously (Byerly and Quinn, 1936) that spotting and striping may be used to determine sex in Rhode Island Red baby chicks, 84.9 percent of the striped and spotted chicks being females, and 77.8 percent of the non-spotted, non-striped chicks being males. It was also demonstrated . . .

IT HAS been previously shown by Quinn and Knox (1939) that it was possible to distinguish the sexes in standardbred Barred Plymouth Rock chicks with an accuracy of 91.8 percent, using down and shank color characteristics to separate the sexes. As the cross of Barred Plymouth Rock male x Rhode Island Red female is a popular one among broiler raisers, it seemed desirable to test the feasibility of segregating the sexes in the hybrid baby chicks. The method of sexing was identical with that used by Quinn and Knox (1939) in sexing standardbred Barred Plymouth Rock chicks. Down and shank color descriptions were followed by a prediction of sex. The chicks were then dissected and notations made as to the agreement between the prediction and the actual sex. Eleven hundred and five chicks were used in this investigation. These chicks were sired by an exhibition Barred Plymouth Rock cock mated . . .

An experiment was initiated in the fall of 1953 to combine high egg production and desirable egg quality traits. The source population was the White Leghorn stock maintained at the Agricultural Research Center, Beltsville, Maryland, and designated as the “heat resistant thick-white egg line.” This line had been selected for desirable albumen quality traits but not for high egg production. Data obtained from this five year study were study were utilized to estimate some of the genetic parameters involved. Six single-male breeding pens of ten females each were used the first year, while six single-male matings of 6 to 10 females each were used in the four subsequent years. All pullets hatched, approximately 200–250, were trapnested each year from 1954 to 1958. Weekly egg weights were recorded throughout a 12 month laying period. For the first three years, egg quality data were recorded in July and during the last…