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Melt electrospinning is a facile fabrication technique that can be utilized in the creation of microfibers without the use of solvent and with good control over feature placement. The available thermal energy of the melt electrospinning technique is often only utilized in the formation of the polymer melt but can also be used to thermodynamically drive chemical reactions. In this study, hybrid perovskite microcrystallites are synthesized in the polymer melt and electrospun to form composite microfibers. Unique hybrid perovskite microstructures were studied, elucidating mechanisms of formation at work in the polymer melt.
Bacterial cultures exposed to iron-doped apatite nanoparticles (IDANPs) prior to the introduction of antagonistic viruses experience up to 2.3 times the bacterial destruction observed in control cultures. Maximum antibacterial activity of these bacteria-specific viruses, or phage, occurs after bacterial cultures have been exposed to IDANPs for 1 hr prior to phage introduction, demonstrating that IDANP-assisted phage therapy would not be straight forward, but would instead require controlled time release of IDANPs and phage. These findings motivated the design of an electrospun nanofiber mesh treatment delivery system that allows burst release of IDANPs, followed by slow, consistent release of phage for treatment of topical bacterial infections. IDANPs resemble hydroxyapatite, a biocompatible mineral analogous to the inorganic constituent of mammalian bone, which has been approved by the Food and Drug Administration for many biomedical purposes. The composite nanofiber mesh was designed for IDANP-assisted phage therapy treatment of topical wounds and consists of a superficial, rapid release layer of polyethylene oxide (PEO) fibers doped with IDANPs, followed by inner, coaxial polycaprolactone / polyethylene glycol (PCL/PEG) blended polymer fiber layer for slower phage delivery. Our investigations have established that IDANP-doped PEO fibers are effective vehicles for dissemination of IDANPs for bacterial exposure and resultant increased bacterial death by phage. In this work, slower delivery of the phage behind IDANPs was accomplished using coaxial, electrospun fibers composed of PCL/PEG polymer blend.
n-3 PUFA are lipids that play crucial roles in immune-regulation, cardio-protection and neurodevelopment. However, little is known about the role that these essential dietary fats play in modulating caecal microbiota composition and the subsequent production of functional metabolites. To investigate this, female C57BL/6 mice were assigned to one of three diets (control (CON), n-3 supplemented (n3+) or n-3 deficient (n3−)) during gestation, following which their male offspring were continued on the same diets for 12 weeks. Caecal content of mothers and offspring were collected for 16S sequencing and metabolic phenotyping. n3− male offspring displayed significantly less % fat mass than n3+ and CON. n-3 Status also induced a number of changes to gut microbiota composition such that n3− offspring had greater abundance of Tenericutes, Anaeroplasma and Coriobacteriaceae. Metabolomics analysis revealed an increase in caecal metabolites involved in energy metabolism in n3+ including α-ketoglutaric acid, malic acid and fumaric acid. n3− animals displayed significantly reduced acetate, butyrate and total caecal SCFA production. These results demonstrate that dietary n-3 PUFA regulate gut microbiota homoeostasis whereby n-3 deficiency may induce a state of disturbance. Further studies are warranted to examine whether these microbial and metabolic disturbances are causally related to changes in metabolic health outcomes.
Hybrid organic-inorganic perovskites (HOIPs) have been previously compounded with hydrophobic polymers in order to improve the resilience of HOIPs in humid environments. In this study HOIP particles were synthesized and dispersed into a polymer solution. The weight loading of the HOIP phase in the composite was increased until an abrupt change in the electrical conduction was observed indicating a percolation threshold was approached. Additionally, the CH3NH3PbI3/ polystyrene composite media was characterized to assess morphology and the effect it has on the observed electrical properties.
Composite nanostructured foams consisting of a metallic shell deposited on a polymeric core were formed by plating copper via electroless deposition on electrospun polycaprolactone (PCL) fiber mats. The final structure consisted of 1000-nm scale PCL fibers coated with 100s of nm of copper, leading to final core-shell thicknesses on the order of 1000-3000 nm. The resulting open cell, core-shell foams had relative densities between 4 and 15 %. By controlling the composition of the adjuncts in the plating bath, particularly the composition of formaldehyde, the relative thickness of copper coating as the fiber diameter could be controlled. As-spun PCL mats had a nominal compressive modulus on the order of 0.1 MPa; adding a uniform metallic shell increased the modulus up to 2 MPa for sub-10 % relative density foams. A computational materials science analysis using density functional theory was used to explore the effects pre-treatment with Pd may have on the density of nuclei formed during electroless plating.
According to the Centers for Disease Control (CDC) and prevention, at least 2 million people in the United States become infected with antibiotic-resistant bacteria, and at least 23,000 people die each year as a direct result of those infections. One alternative to traditional antibiotics is bacteriophage (phage) therapy. Phage therapy utilizes bacteria-specific viruses to infect and kill bacteria cells. The specificity of these viruses is beneficial in that phage used for therapeutic purposes do not harm the human microbiota, nor do phage infect eukaryotic cells. It has been discovered that iron-doped apatite nanoparticles (IDANPs) significantly enhance phage killing of bacteria cells. The biocompatibility of apatite, coupled with its effectiveness as an adjuvant to enhance an alternative antibiotic therapy, makes it of interest for medical applications. Previously, researchers have encased phage in a microfluidic channel in coaxially electrospun fibers, allowing phage to remain viable after several weeks storage at 4 °C. Here, we have constructed a polymer fiber layer using electrospinning (ES) for delivery of IDANP adjuvants to compliment phage treatment delivery fibers. The IDANP delivery layer constructed is composed of polyethylene oxide (PEO) doped with the nanoparticles. When compared to media-only and IDANP-only controls, results show IDANPs delivered through a PEO fiber mesh remain effective at enhancement of phage infectivity.
A new organometallic halide perovskite (OHP) synthesis method, whereby a polymer melt is used to thermodynamically drive the reaction that forms OHP crystallites, is demonstrated. The synthesis method allows for the facile encapsulation of moisture-sensitive OHP without the loss of simplicity during fabrication, which makes OHP materials so attractive for the photovoltaic industry. Degradation of OHP crystallites embedded in a polystyrene matrix was studied using UV-Vis absorbance over a period of several days. The OHP crystallites degrade as a result of the reversible nature of the reaction that forms the crystallites. After the reversion to precursors (PbI2 and CH3NH3I) the CH3NH3I irreversibly degrades  allowing the degradation to be tracked via optical interrogation. Additionally, surface morphology and elemental analysis of fabricated samples was carried out using SEM/EDS techniques.
In the United States alone, ∼14,000 children are hospitalised annually with acute heart failure. The science and art of caring for these patients continues to evolve. The International Pediatric Heart Failure Summit of Johns Hopkins All Children’s Heart Institute was held on February 4 and 5, 2015. The 2015 International Pediatric Heart Failure Summit of Johns Hopkins All Children’s Heart Institute was funded through the Andrews/Daicoff Cardiovascular Program Endowment, a philanthropic collaboration between All Children’s Hospital and the Morsani College of Medicine at the University of South Florida (USF). Sponsored by All Children’s Hospital Andrews/Daicoff Cardiovascular Program, the International Pediatric Heart Failure Summit assembled leaders in clinical and scientific disciplines related to paediatric heart failure and created a multi-disciplinary “think-tank”. The purpose of this manuscript is to summarise the lessons from the 2015 International Pediatric Heart Failure Summit of Johns Hopkins All Children’s Heart Institute, to describe the “state of the art” of the treatment of paediatric cardiac failure, and to discuss future directions for research in the domain of paediatric cardiac failure.
Little is known about vitamin D status in preterm infants and their response to supplementation. To investigate this, we assessed serum 25-hydroxyvitamin D (25OHD) levels using RIA in a consecutive sample of stable preterm very low birth weight (VLBW) infants (born ≤ 32 weeks gestation or birth weight ≤ 1·5 kg), and we explored associated factors. Serum 25OHD level was first assessed once infants were tolerating feeds (n 274). If this first 25OHD level was below 50 nmol/l (20 ng/ml), which is the level associated with covering requirements in terms of skeletal health in the majority, then we recommended prolonged augmented vitamin D intake ( ≥ 10 μg (400 IU) daily) from a combination of fortified feeds and vitamin supplements and follow-up re-assessment at approximately 6 weeks corrected age (n 148). The first assessment, conducted at a median for chronological age of 18 (interquartile range (IQR) 11–28) d, found that 78 % had serum 25OHD levels below 50 nmol/l. Multivariable analysis demonstrated that the determinants of serum 25OHD levels were duration of vitamin D supplementation and gestational age at birth (r2 0·215; P< 0·001). At follow-up, after a median of 104 (IQR 78–127) d, 87 % achieved levels ≥ 50 nmol/l and 8 % had levels >125 nmol/l, a level associated with potential risk of harm. We conclude that low 25OHD levels are an issue for preterm VLBW infants, warranting early nutritional intervention. In infants with serum 25OHD levels < 50 nmol/l, a vitamin D intake of ≥ 10 μg (400 IU) daily achieves target levels in the majority; however, further work is needed to determine the exact dose to safely meet target levels without overcorrection.
According to the 2007–2008 National Health and Nutrition Examination Survey, the prevalence of obesity in the US population was 33·8 %; 34·3 % and 38·2 %, respectively, in middle-aged men and women. We asked whether available blood donor data could be used for obesity surveillance.
Cross-sectional study of BMI and obesity, defined as BMI ≥ 30·0 kg/m2. Adjusted odds ratios (aOR) were calculated with logistic regression.
A network of six US blood centres.
Existing data on self-reported height and weight from blood donors, excluding persons deferred for very low body weight.
Among 1 042 817 donors between January 2007 and December 2008, the prevalence of obesity was 25·1 %; 25·7 % in men and 24·4 % in women. Obesity was associated with middle age (age 50–59 years v. <20 years: aOR = 1·92 for men and 1·81 for women), black (aOR = 1·57 for men and 2·35 for women) and Hispanic (aOR = 1·47 for men and 1·49 for women) race/ethnicity compared with white race/ethnicity, and inversely associated with higher educational attainment (college degree v. high school or lower: aOR = 0·56 for men and 0·48 for women) and double red cell donation and platelet donation.
Obesity is common among US blood donors, although of modestly lower prevalence than in the general population, and is associated with recognized demographic factors. Blood donors with higher BMI are specifically recruited for certain blood collection procedures. Blood centres can play a public health role in obesity surveillance and interventions.
Pulsed laser deposition of Yba2Cu3O7-δ?(YBCO) coated conductors was studied for the range of P(O2) from 120 mTorr to 1200 mTorr, higher than typically used oxygen partial pressures during deposition. The purpose of the investigation was to determine the sensitivity of YBCO film quality to varying P(O2) for scaled-up fabrication of long-length coated conductors. Deposition at high P(O2) (≥?400 mTorr) gave very high and more consistent critical temperatures (Tc ≈?92 ±?0.4 °K) than results obtained at lower oxygen partial pressures (≤?200 mTorr) as determined by magnetic susceptibility measurements. Typically, the lower partial pressures are used although the laser fluence used in this research (3.2 J/cm2) is higher than typical. Transport Jc's were consistantly high for a wide range of oxygen pressures, 5–8 ×?106 A/cm2 at 77 K, self-field for P(O2) = 200–1200 mTorr. These results indicate that pulsed laser deposition of YBCO is relatively insensitive to P(O2) at the higher pressures of oxygen considered.
The effects on milk composition and processing characteristics of varying
grass supply by changing stocking density and of offering a concentrate supplement
were investigated. The experiment was conducted over 28 weeks of the lactation
(April–October) using 48 spring-calved Friesian–Holstein cows. Three herds each of
16 cows were offered a restricted grass supply, a standard grass supply and a
standard grass supply with a supplement of 3 kg concentrate/d. Treatment groups
were grazed separately with a residence time of 3 d/paddock. Milk production,
composition and processing characteristics such as renneting properties, ethanol
stability and plasmin activity were measured weekly. Increasing stocking density
above the standard system resulted in significant reductions in milk fat and protein
yields, the concentrations of total protein, casein and whey proteins, and a
deterioration in most processing characteristics. Imposing concentrate supplementation
on the standard system increased total protein, casein and whey protein
concentrations but generally did not improve processing characteristics except for
ethanol stability. These results suggest that the standard grass supply in a rotational
grazing paddock system can support efficient production of quality milk, and
concentrate supplementation will not improve processing characteristics when an
adequate supply of good quality herbage is available.
Low-moisture part-skim Mozzarella cheeses were made, at pilot scale
(450 kg), on five occasions at weekly intervals from milks containing κ-casein
or BB genetic variants. Compared with κ-casein A variant milks, the
variant milks were associated with higher concentrations of casein
(P<0·001), whey protein (P<0·02)
total protein (P<0·001), superior curd-forming properties
(P<0·05) and increased cheese yields (P<0·05).
The moisture-adjusted (to 465 g/kg) cheese yields for the
κ-casein AA, AB and BB cheeses were 91·5, 100·6, and
102·5 kg/1000 kg milk respectively. κ-Casein variant
had no significant effect on the
proteolysis and ripening of uncooked cheese or on the functionality (melt
flowability and stretchability) of the cooked cheese during the course
of a 90 d
Milk was collected from three spring-calving herds,
on different daily
herbage allowances (DHA) of perennial rye-grass (16, 20 or
24 kg dry matter (DM)/cow for a 17 week period. On
five occasions, at weekly intervals in the middle
of the period, the three different milks were converted
into low-moisture part-skim
Mozzarella cheese. Increasing the DHA resulted in significant
increases in the concentrations of protein in the cheesemilk
(P<0·05) and cheese whey
(P<0·02). The moisture-adjusted cheese
yield increased significantly (P<0·01) on
raising the DHA from 16 to 24 kg grass DM/cow. DHA had no
significant effects on any of the
gross compositional values of the cheese (although moisture
and fat-in-DM levels
tended to decrease and increase respectively with increasing
DHA). The hardness of
the uncooked cheese and functionality of cooked cheese
(i.e. melt time, flowability,
stretch and viscosity) were not significantly influenced by
DHA over the 115 d ripening period at 4°C.