Investigation of poly(methyl acrylate) grafted chitosan as a polymeric drug carrier

The graft copolymerization of methyl acrylate (MA) onto chitosan in aqueous medium was investigated using potassium persulfate (KPS) as initiator. The grafting conditions were optimized by studying the effects of the polymerization variables (the initiator concentration, the ratio of monomer to chitosan, and reaction temperature) on the percentage of grafting (PG). PG was found to depend on these variables, and the highest grafting percentage (256 %) could be obtained at chitosan = 1 g, KPS = 4.5 × 10^?3 M, methyl acrylate monomer = 6 g, T = 60 °C and t = 180 min. The graft copolymer was characterized by Fourier transform infrared spectra analysis, thermogravimetry (differential thermogravimetry, differential scanning calorimetric), X-ray powder diffraction as well as CP-MAS ¹³C NMR spectroscopy. These analyses are highly confirmed the formation of poly(methyl acrylate) grafted chitosan (PMAGC). Furthermore, the gelation of the grafted polymers (PG 68, 122, 218 and 256 %) in distilled water has been studied, and the results revealed that the percentage of swelling number increase with increasing PG of the polymers. Controlled release of niacin (vitamin B₃) from the hydrogel of the grafted polymers (PG 68, 122 and 256 %) in aqueous medium has been studied using ultraviolet absorption to follow quantities released at different times (for each experiment: PMAGC 100 mg, niacin 2.46 mg, distilled water 100 ml). The study was repeated again with same conditions except the using of 4.92 mg of niacin instead of 2.46 mg (PG of the grafted polymer is 256 %). The diffusion coefficient (D, cm²/h) of niacin from the hydrogel of the grafted polymer (PG 256 %) was calculated depending on Higuchi model (diffusion coefficient of the first load is 0.00194 cm²/h while 0.00255 cm²/h of the second load).     

Technical note: Developing a heat stress model in dairy cows using an electric heat blanket

Precisely studying the biological consequences of heat stress (HS) in agriculturally relevant animals typically requires expensive climate-controlled facilities, infrastructure inaccessible to most researchers. Thus, study objectives were to explore the efficacy of an electric heat blanket (EHB) as an alternative method for evaluating HS and to determine whether EHB-induced hyperthermia affects production parameters similar to natural HS. Lactating Holstein cows (n = 8; 133 ± 3 d in milk; 709 ± 31 kg; 2.6 ± 0.3 parity) were housed in individual box stalls and allowed to acclimate for 3 d. After acclimation, the trial consisted of 2 experimental periods (P). During P1 (3 d), cows were housed in thermoneutral conditions for collecting baseline data. During P2 (7 d), cows were fitted with an EHB. During the entire experiment cows were fed ad libitum, and dry matter intake (DMI) was recorded daily. Cows were milked twice daily (0600 and 1800 h), and milk samples were collected on d 2 and 3 of P1 and d 3 and 7 of P2. Rectal temperature, respiration rate, heart rate, and skin temperature were obtained twice daily (0600 and 1800 h) during both P1 and P2. Overall, there was an increase in rectal temperature and respiration rate at 0600 h (1.0°C and 25 breaths/min, respectively) and 1800 h (1.2°C and 29 breaths/min, respectively) during P2. The EHB decreased DMI and milk yield (25 and 21%, respectively) by the end of P2. During P2, milk protein tended to decrease (4.4%) compared with P1. In contrast, milk urea nitrogen increased (33%) during P2 relative to P1. No other differences were observed in milk composition. In summary, our results indicate that employing an EHB affects physiological and production parameters similarly to natural HS (i.e., increased rectal temperature and respiration rate, decreased DMI and milk yield); thus, the EHB is an effective and inexpensive research tool for evaluating the biological consequences of HS in lactating dairy cows.     

Effect of chromium on bioenergetics and leukocyte dynamics following immunoactivation in lactating Holstein cows

Activated immune cells are insulin sensitive and utilize copious amounts of glucose. Because chromium (Cr) increases insulin sensitivity and may be immunomodulatory, our objective was to evaluate the effect of supplemental Cr (KemTrace Cr propionate, 20 g/d; Kemin Industries Inc., Des Moines, IA) on immune system glucose utilization and immune system dynamics following an intravenous endotoxin challenge in lactating Holstein cows. Twenty cows (320 ± 18 d in milk) were randomly assigned to 1 of 4 treatments: (1) pair-fed (PF) control (PF-CON; 5 mL of saline; n = 5), (2) PF and Cr supplemented (PF-Cr; 5 mL of saline; n = 5), (3) lipopolysaccharide (LPS)-euglycemic clamp and control supplemented (LPS-CON; 0.375 µg/kg of body weight LPS; n = 5), and (4) LPS-euglycemic clamp and Cr supplemented (LPS-Cr; 0.375 µg/kg of body weight LPS; n = 5). The experiment was conducted serially in 3 periods (P). During P1 (3 d), cows received their respective dietary treatments and baseline values were obtained. At the initiation of P2 (2 d), either a 12-h LPS-euglycemic clamp was conducted or cows were PF to their respective dietary counterparts. During P3 (3 d), cows consumed feed ad libitum and continued to receive their respective dietary treatment. During P2, LPS administration decreased dry matter intake (DMI; 40%) similarly among diets, and by experimental design the pattern and magnitude of reduced DMI were similar in the PF cohorts. During P3, LPS-Cr cows tended to have decreased DMI (6%) relative to LPS-CON cows. Relative to controls, milk yield from LPS-challenged cows decreased (58%) during P2 and LPS-Cr cows produced less (16%) milk than LPS-CON cows. During P3, milk yield progressively increased similarly in LPS-administered cows, but overall milk yield remained decreased (24%) compared with PF controls. There were no dietary treatment differences in milk yield during P3. Circulating insulin increased 9- and 15-fold in LPS-administered cows at 6 and 12 h postbolus, respectively, compared with PF controls. Compared with LPS-CON cows, circulating insulin in LPS-Cr cows was decreased (48%) at 6 h postbolus. Relative to PF cows, circulating LPS binding protein and serum amyloid A from LPS-administered cows increased 2- and 5-fold, respectively. Compared with PF cows, blood neutrophil counts in LPS-infused cows initially decreased, then gradually increased 163%. Between 18 and 48 h postbolus, the number of neutrophils was increased (12%) in LPS-Cr versus LPS-CON cows. The 12-h total glucose deficit was 220 and 1,777 g for the PF and LPS treatments, respectively, but glucose utilization following immune activation was not influenced by Cr. In summary, supplemental Cr reduced the insulin response and increased circulating neutrophils following an LPS challenge but did not appear to alter the immune system's glucose requirement following acute and intense activation.     

Differences between Human and Mouse IgM Fc Receptor (FcµR)

Both non-immune “natural” and antigen-induced “immune” IgM are important for protection against pathogens and for regulation of immune responses to self-antigens. Since the bona fide IgM Fc receptor (FcµR) was identified in humans by a functional cloning strategy in 2009, the roles of FcµR in these IgM effector functions have begun to be explored. In this short essay, we describe the differences between human and mouse FcµRs in terms of their identification processes, cellular distributions and ligand binding activities with emphasis on our recent findings from the mutational analysis of human FcµR. We have identified at least three sites of human FcµR, i.e., Asn66 in the CDR2, Lys79 to Arg83 in the DE loop and Asn109 in the CDR3, responsible for its constitutive IgM-ligand binding. Results of computational structural modeling analysis are consistent with these mutational data and a model of the ligand binding, Ig-like domain of human FcµR is proposed. Serendipitously, substitution of Glu41 and Met42 in the CDR1 of human FcµR with mouse equivalents Gln and Leu, either single or more prominently in combination, enhances both the receptor expression and IgM binding. These findings would help in the future development of preventive and therapeutic interventions targeting FcµR.     

Multilink Solution for Seamless Transition Between Multicast and Unicast Areas in 5G Core Network

Wireless Personal Communications - The exponential growth in technology observed over the past decade has introduced newer ways to exploit network and cyber-physical system-related vulnerabilities....     

The effects of zinc amino acid complex on biomarkers of gut integrity,inflammation, and metabolism in heat-stressed ruminants

Study objectives were to evaluate the effects of replacing 40 mg/kg of dietary Zn from Zn sulfate (ZS) with Zn amino acid complex (ZA; Zinpro Corporation, Eden Prairie, MN) on inflammation and intestinal integrity in heat-stressed and pair-fed (PF) ruminants. Forty Holstein steers (173.6 ± 4.9 kg) were randomly assigned to 1 of 5 dietary-environmental treatments: (1) thermoneutral (TN) ad libitum with 75 mg/kg of dry matter (DM) ZS (ZSCON); (2) TN pair-fed with 75 mg/kg DM ZS (ZSPF); (3) TN pair-fed with 40 mg/kg DM ZA and 35 mg/kg DM ZS (ZAPF); (4) heat stress (HS) ad libitum with 75 mg/kg DM ZS (ZSHS); and (5) HS ad libitum 40 mg/kg DM ZA and 35 mg/kg DM ZS (ZAHS). Before study initiation, calves were fed their respective diets for 21 d. Following the pre-feeding phase, steers were transferred into environmental chambers and were subjected to 2 successive experimental periods. During period 1 (5 d), all steers were fed their respective diets ad libitum and housed in TN conditions (20.2 ± 1.4°C, 30.4 ± 4.3% relative humidity). During period 2 (6 d), ZSHS and ZAHS steers were exposed to cyclical HS conditions (27.1 ± 1.5°C to 35.0 ± 2.9°C, 19.3 ± 3.5% relative humidity), whereas the ZSCON, ZSPF, and ZAPF steers remained in TN conditions and were fed ad libitum or pair-fed relative to their ZSHS and ZAHS counterparts. Overall, steers exposed to HS had markedly increased rectal temperature (0.83°C), respiration rate (26 breaths per min), and skin temperature (8.00°C) relative to TN treatments. Rectal temperature from ZAHS steers was decreased (0.24°C) on d 4 to 6 of HS relative to ZSHS steers. Regardless of diet, HS decreased DMI (18%) relative to ZSCON steers. Circulating glucose from HS and PF steers decreased (16%) relative to ZSCON steers. Heat stress and nutrient restriction increased circulating nonesterified fatty acids 2- and 3-fold, respectively, compared with ZSCON steers. Serum amyloid A increased ~2-fold in PF relative to ZSCON and HS steers. We detected no treatment effect on blood pH; however, ZAHS steers had increased HCO₃ relative to ZSHS. Relative to ZSHS, ZAHS steers had increased jejunum villi height (25%), a tendency for increased ileum villi height (9%), and decreased duodenal villi width (16%). In summary, ZA supplementation has some beneficial effects on thermal indices, intestinal architecture characteristics, and biomarkers of leaky gut in heat-stressed steers, indicative of an ameliorated heat load, and thus may be a nutritional strategy to minimize negative consequences of HS.     

Short communication: Ketosis,feed restriction,and an endotoxin challenge do not affect circulating serotonin in lactating dairy cows

Circulating serotonin (5-hydroxytryptamine; 5-HT) appears to be associated with various energetic disorders and hypocalcemia during the transition period. The objective of this study was to evaluate the effects of ketosis, feed restriction (FR), and endotoxin challenge (models in which energetic and calcium metabolism are markedly altered) on circulating 5-HT in lactating Holstein cows. Blood samples were obtained from 3 separate experiments; circulating β-hydroxybutyrate (BHB), nonesterified fatty acids (NEFA), and glucose were measured in all 3 experiments, whereas ionized calcium (iCa²⁺) was measured only in the endotoxin challenge. In the ketosis study, blood samples from cows clinically diagnosed with ketosis (n = 9) or classified as healthy (n = 9) were obtained from a commercial dairy farm at d ?7, 3, and 7 relative to calving. Ketosis was diagnosed using a urine-based test starting at 5 d in milk. There was no effect of health status on circulating 5-HT and no association between 5-HT and BHB, NEFA, or glucose; however, 5-HT concentrations progressively decreased following calving. In the FR experiment, mid-lactation cows were either fed ad libitum (n = 3) or restricted to 20% of their ad libitum intake (n = 5) for 5 d. There were no FR effects on circulating 5-HT, nor was FR correlated with energetic metabolites. In the immune activation model, mid-lactation cows were intravenously challenged with either lipopolysaccharide (LPS; 1.5 µg/kg of BW; n = 6) or sterile saline (control; n = 6). Administering LPS decreased (56%) blood iCa²⁺ but had no effect on circulating 5-HT, nor was there a correlation between circulating 5-HT and NEFA, BHB, or iCa²⁺. Circulating 5-HT tended to be positively correlated (r = 0.54) with glucose in Holstein cows administered LPS. In summary, in contrast to expectations, circulating 5-HT was unaffected in models of severely disturbed energetic and Ca²⁺ homeostasis.     

Ab initio Insight of the Electronic,Structural, Mechanical and Optical Properties of X $$_3$$ 3 P $$_2$$ 2 (X= Mg,Ca) from GGA and Hybrid Functional (HSE06)

Journal of Superconductivity and Novel Magnetism - In this paper, the structural, mechanical and optoelectronic properties of X $$_3$$ P $$_2$$ (X= Mg, Ca) have been investigated by using the...