Elevated concentrations of crude glycerin in diets for beef cattle: feedlot performance, carcass traits, and ruminal metabolism1

Three experiments were conducted to evaluate the inclusion of crude glycerin (CG) in diets for beef cattle. In Exp. 1, 4 ruminally cannulated steers were fed diets with 0 or 15% CG (DM basis), to evaluate DM disappearance, VFA profiles, and gas production. There was a tendency for an interaction (P = 0.06) between diet fed to donor animals and substrate fed to in vitro system, and digestion was increased when CG was added to cultures with ruminal fluid from CG-fed animals. Total VFA were unaffected by diets or by substrate incubated. The CG increased production of propionate, butyrate, and valerate (P < 0.01) while the gas production was unaffected (P = 0.16). In Exp. 2, 24 crossbred heifers (334.4 ± 0.9 kg BW) were fed the same diets as Exp. 1, for 35 d. Fecal grab samples were collected 3 times daily on day 7, 21, and 35, to evaluate total tract digestibilities of DM, OM, and NDF. The CG improved digestibility of diet OM (P = 0.04), and DM followed a similar trend (P = 0.06), while the NDF digestibility was unaffected (P = 0.29). In Exp. 3, crossbred heifers (n = 374; 375.8 ± 36.1 kg BW) were used to evaluate feedlot performance and carcass traits when fed diets with 0, 7.5, or 15% CG, with or without added 0.3% salt. Heifers were assigned to 25 pens and were harvested on day 125. Removing salt from CG-based diets did not impact performance (P = 0.50). The CG did not influence average daily gain (P = 0.27), but decreased DM intake (P = 0.003), USDA Yield Grade (P = 0.01), and improved feed efficiency (P = 0.03), while tended to decrease USDA prime carcasses (P = 0.10). Carcass weight (P = 0.24), Longissimus muscle area (P = 0.63), and kidney, pelvic, heart fat (P = 0.59) were unaffected by CG. Twelfth-rib fat was less for heifers fed 15% CG without salt compared with the other treatments (P = 0.005), while marbling was less for heifers fed CG diets compared with the control-fed animals (linear, P = 0.004; quadratic, P = 0.02). In conclusion, GC can replace dry-rolled corn in diets for beef heifers when fed at 15% of diet DM, improving OM digestion, increasing ruminal propionate and butyrate without affecting greenhouse gas emissions. Feeding up to 15% CG improves feed efficiency but depresses marbling and tends to decrease Quality Grade. Removing supplemental salt from CG-diets has no impact on performance or carcass traits.

Antifouling Properties of Dendritic Polyglycerols against Marine Macrofouling Organisms

Dendritic polyglycerols (PGs) were synthesized and postmodified by grafting of poly(ethylene glycol) (PEG) and polypropylene glycol (PPG) diglycidyl ether groups, and their antifouling and fouling-release properties were tested. Coating characterization by spectroscopic ellipsometry, contact angle goniometry, attenuated total internal reflection-Fourier transform infrared spectroscopy (ATR-FTIR), and atomic force microscopy showed brushlike morphologies with a high degree of microscale roughness and the ability to absorb large amounts of water within seconds. PGs with three different thicknesses were tested in laboratory assays against settlement of larvae of the barnacle Balanus improvisus and against the settlement and removal of zoospores of the alga Ulva linza. Very low coating thicknesses, e.g., 11 nm, reduced the settlement of barnacles, under static conditions, to 2% compared with 55% for an octadecyltrichlorosilane reference surface. In contrast, zoospores of U. linza settled readily but the vast majority were removed by exposure to a shear force of 52 Pa. Both PEG and PPG modification increased the antifouling properties of the PG films, providing a direct comparison of the ultralow fouling properties of all three polymers. Both, the modified and the nonmodified PGs are promising components for incorporation into amphiphilic fouling-resistant coatings.

Suppression treatment differentially influences the microbial community and the occurrence of broad host range plasmids in the rhizosphere of the model cover crop Avena sativa L

Cover crop suppression with glyphosate-based herbicides (GBHs) represents a common agricultural practice. The objective of this study was to compare rhizospheric microbial communities of A. sativa plants treated with a GBH relative to the mechanical suppression (mowing) in order to assess their differences and the potential implications for soil processes. Samples were obtained at 4, 10, 17 and 26 days post-suppression. Soil catabolic profiling and DNA-based methods were applied. At 26 days, higher respiration responses and functional diversity indices (Shannon index and catabolic evenness) were observed under glyphosate suppression and a neat separation of catabolic profiles was detected in multivariate analysis. Sarcosine and Tween 20 showed the highest contribution to this separation. Metabarcoding revealed a non-significant effect of suppression method on either alpha-diversity metrics or beta-diversity. Conversely, differences were detected in the relative abundance of specific bacterial taxa. Mesorhizobium sequences were detected in higher relative abundance in glyphosate-treated plants at the end of the experiment while the opposite trend was observed for Gaiella. Quantitative PCR of amoA gene from ammonia-oxidizing archaea showed a lower abundance under GBH suppression again at 26 days, while ammonia-oxidizing bacteria remained lower at all sampling times. Broad host range plasmids IncP-1β and IncP-1ε were exclusively detected in the rhizosphere of glyphosate-treated plants at 10 days and at 26 days, respectively. Overall, our study demonstrates differential effects of suppression methods on the abundance of specific bacterial taxa, on the physiology and mobile genetic elements of microbial communities while no differences were detected in taxonomic diversity.

Calcium Phosphate-Mediated Transfection of Cells with High-Molecular-Weight Genomic DNA

This protocol describes a calcium phosphate-mediated transfection method for use with high-molecular-weight genomic DNAs.

Antiproliferative Acylated Glycerols from New Zealand Propolis

Previous work has shown that a number of phenolic components of NZ propolis possess antiproliferative activity against certain human gastrointestinal cancer cell lines. Here we report on a series of acylglycerols isolated from the nonpolar fraction of propolis resin, which represent further bioactive constituents unrelated to the more usual phenolic compounds generally found in propolis. NZ propolis is sourced from poplar trees, and the acylglycerols have been shown to be present in the leaves and buds of some common poplars. The compounds are a series of monoglycerides containing 3,8-dihydroxy fatty acids, many of which are further acylated with acetic acid residues. The dihydroxy fatty acids are C₁₈ to C₂₄, with the most abundant being C₂₀ and C₂₂. These acylglycerols were found to have strong antiproliferative activity against three human gastrointestinal cell lines, particularly gastric cancer cell line NCI-N87, where one example shows an IC₅₀ of less than 50 μM.

Semisolid culture medium improves mycelial recovery of Agaricus subrufescens cryopreserved in cereal grains

This study aimed to evaluate the effects of the solid and semisolid culture medium on the mycelial viability of A. subrufescens after 5-year cryopreservation at - 70 °C. Mycelia were grown in three types of whole or ground grains, with or without 5% glycerol addition in the substrate and/or in a cryotube. After 5 years of cryopreservation at - 70 °C, every treatment was thawed and recovered in malt extract culture medium with 15 (solid culture medium) or 5 g L-1 (semisolid culture medium) of agar. The semisolid recovery culture medium increased the mycelial viability recovery capacity of A. subrufescens cryopreserved for 5 years in grains with glycerol only in the cryotube, and specifically with medium-hard wheat grain without glycerol addition at all. Agar-based substrates such as malt extract agar, agar-ground grain, or the one with glycerol addition to the substrate were not effective to keep the mycelial viability, regardless of the recovery culture medium consistency. Hard and medium-hard endosperm wheat grains or hard endosperm rye grains with addition of glycerol as cryoprotectant only to the cryotube were effective to cryopreserve the fungus for 5 years without cryoprotectant addition in the substrate.

Antiadhesion effect of the C17 glycerin ester of isoprenoid-type lipid forming a nonlamellar liquid crystal

Postoperative adhesion is a relevant clinical problem that causes a variety of clinical complications after abdominal surgery. The objective of this study is to develop a liquid-type antiadhesion agent and evaluate its efficacy in preventing tissue adhesion in a rat peritoneal adhesion model. The liquid-type agent was prepared by submicron-sized emulsification of C17 glycerin ester (C17GE), squalene, pluronic F127, ethanol, and water with a high-pressure homogenizer. The primary component was C17GE, which is an amphiphilic lipid of one isoprenoid-type hydrophobic chain and can form two phases of self-assembly nonlamellar liquid crystals. The C17GE agent consisted of nanoparticles with an internal inverted hexagonal phase when evaluated by small-angle X-ray scattering (SAXS) and cryo-transmission electron microscopy (cryo-TEM). Upon contact with the biological tissue, this agent formed a thin membrane with a bioadhesive property. After this agent was applied to a sidewall injury of rats, it showed a percentage average of adhesion significantly less than that obtained with the Seprafilm® antiadhesion membrane in a rat model. Additionally, the retention of the agent prolonged at the applied site in the peritoneal cavity of rats. In conclusion, the C17GE agent is promising as an antiadhesion material. STATEMENT OF SIGNIFICANCE: Postoperative adhesion remains a common adverse effect. Although various materials have been investigated, there are few products commercially available to prevent adhesion. For the sheet-type agent, it is inconvenient to be applied through small laparotomy, especially in laparoscopic surgery. Additionally, the liquid-type agent currently used requires a complicated procedure to spray at the targeted site. Our liquid-type antiadhesion agent can form liquid crystals and act as a thin membrane-like physical barrier between the peritoneum and tissues to prevent adhesion. Indeed, the antiadhesion agent used in our present study significantly prevents adhesion compared with the antiadhesion membrane most used clinically. Moreover, our agent is highly stable by itself and easy to use in laparoscopic surgery, thus leading to a promising new candidate as an antiadhesion material.

Toxicity tests of cryoprotecting agents for Mytilus galloprovincialis (Lamark, 1819) early developmental stages

Global aquaculture production of blue mussel has increased over last years. This work reaffirms the great potential of cryopreservation technique on mussel industry and overcome economic barriers a cause of a traditional and rudimentary management and continue growing. The aim of this work is to set some preliminary basis attending to toxicity of cryoprotecting agents (CPAs) on different development stages of Mytilus galloprovincialis as a start point to develop a stable cryopreservation protocol. Toxicity tests were carried out by using common CPAs (dimethyl-sulfoxide (Me₂SO), glycerol, (GLY), propylene glycol (PG) and ethylene glycol (EG)) in a range from 0.5 to 3 M on fertilized egg, trochophore larva, and D-larva of Mytilus galloprovincialis. Results evidenced more resistance of older development stages to toxicity. Of all CPAs tested, toxicity testing highlights PG or EG as suitable CPAs for cryopreservation of early development stages; whereas D-larva was unaffected by any of the CPAs tested. Preliminary cryopreservation trials were developed to obtain information into cell cryoprotection. Further research should be focused on membrane permeability and other parameters, such as the balance between toxicity and cryoprotective effect of CPAs.

The proof is in the bulb: glycerol influences key stages of lily development

A bulb is a whole plant condensed into an underground organ. A geophyte's bulb comprises both food reserves and important developmental history that may affect its whole growth. In Easter lily (Lilium longiflorum), bulb size is associated with the plant's flowering pathway - vernalization or photoperiod - and also affects sprouting, flower quality and abortion rate. The aim of this study was to investigate the reasons for the major physiological differences between large and small bulbs. Lily bulbs start their development from secondary meristems along the stem, with large bulbs being heavier and bear more scales than small ones. Peeling the outer scales of a large bulb converts its physiological responses into those of a small bulb, implying that the physiological discrepancies in plants developing from large or small bulbs are mediated by factors inherent to the bulb. We therefore performed broad analyses of the metabolite composition in the scales of bulbs subjected to temperature regimes affecting further plant development. We found a striking association between the level of glycerol, a primary metabolite mostly synthesized in the outer scales, and a delay in sprouting and flowering time, and reduction in abortion rate. Exogenous glycerol application to the bulbs before planting corroborated these results. Moreover, transcriptome analyses showed that flowering-promoting gene expression was downregulated in the bulb after glycerol treatment, while potential flowering inhibitor as well as a dormancy-related gene expressions were upregulated. Based on these studies, we postulate that glycerol is a major factor influencing both vegetative and reproductive development in lily.

Cryopreservation of Orchids - A Review

BACKGROUND

The orchids are one of the beautiful creations of nature which stand apart from any other assemblage of flowering plants. They are highly evolutionary and ecologically significant group of plants that have effectively occupied almost every habitat on the earth. Indiscriminate collections and extermination of their natural habitats have threatened many species of orchids with extinction, resulting in a severe reduction of their genetic resources in nature according to recent patents. It is necessary to adopt sound scientific protocols for the preservation of orchid species.

METHOD

This cost-effective technique provides large storage time for the conservation of germplasm. Presently, efforts have been made to explore various cryopreservation techniques utilized so far and factors affecting the longevity of the propagules (in vivo and in vitro) while cryopreserving them. The sample to be cryopreserved is freeze-preserved in two ways, a) stepwise at two different subzero temperatures and b) in the rapid method, the samples are placed directly in the liquid nitrogen.

RESULTS

The orchid seeds and pollen are the most suitable propagules for cryopreservation of orchids due to their minute size and less space requirement.

CONCLUSION

Among the tissues (such as seeds, pollen, protocorms etc.) seeds are the most reliable. The present article reviews the cryopreservation techniques and factors effecting the cryopreservation, for in vitro conservation of orchid gene pool.

Stimulus effects of propylene glycol and vegetable glycerin in electronic cigarette liquids

BACKGROUND

Little is known about the behavioral effects of non-nicotine ingredients in electronic cigarette liquids. Propylene glycol (PG) and vegetable glycerin (VG) are the most common humectants used in electronic cigarette liquids. These ingredients may influence stimulus effects (e.g., visibility of exhalant, taste, or smell), which have played a role in the abuse liability of conventional cigarettes. In the current study, the stimulus effects of aerosol from liquids varying only in PG and VG content were assessed.

METHODS

Sixteen electronic cigarette users completed five sessions (one practice and four testing sessions). Following one hour of nicotine deprivation, two sampling puffs from liquid formulations containing 100/0, 75/25, 50/50, 25/75, and 0/100% PG/VG concentrations were administered in random order during five assessments, each separated by 20 min. Measures included self-reported stimulus effects and breakpoint on a multiple-choice procedure with options consisting of sampled puffs or varying amounts of money.

RESULTS

VG content was associated with greater reports of visibility of the exhalant (i.e., "cloud"). Liquids with only PG or VG engendered lower reports of inhalation sensations (e.g., throat hit) and greater reductions of systolic blood pressure compared to mixtures of PG and VG. There was no effect of liquid formulation on the multiple-choice procedure, but puffs were rarely chosen over even the smallest monetary option ($0.05), suggesting minimal reinforcing efficacy.

CONCLUSIONS

Liquids containing greater concentrations of VG are more capable of producing visible exhalant and mixtures of PG and VG engender greater airway sensory effects than either ingredient alone.

Does Adding Various Accelerators to Mineral Trioxide Aggregate Have a Negatively Effect on Push-Out Bond Strength?

OBJECTIVE

This study compares the effect of the white mineral trioxide aggregate (WMTA) accelerators, including disodium hydrogen orthophosphate (Na2HPO4; 2.5 wt%), calcium chloride (CaCl2; 5 and 10 wt%), and KY jelly, on the push-out bond strength of WMTA. The null hypothesis was that the WMTA accelerators would not affect the push-out bond strength of WMTA.

MATERIALS AND METHODS

Slices (2-mm-thick) were obtained from 75 human mandibular molar distal roots. The slices were enlarged up to size 6 Gates-Glidden burs to obtain a 1.5-mm canal diameter. The slices were randomly divided into 4 experimental groups and a control group (n = 15 in each group). Freshly prepared WMTA mixture was placed into the root slices and stored at 37°C in a 100% humidified atmosphere for 60 days. The force required to dislodge the WMTA cement from the root slice was determined using a universal testing machine. The push-out bond strength was calculated.

RESULTS

Push- out bond strength of 5- and 10-wt% CaCl2, and 2.5-wt% Na2HPO4 WMTA groups was significantly lower than in the KY-jelly and control groups (p < 0.05). The mean push-out bond strength of KY jelly was lower than in the control group but not statistically significant.

CONCLUSION

The addition of KY jelly to WMTA did not have an adverse effect on the push-out bond strength of WMTA, in contrast to the other accelerators, including Na2HPO4 and CaCl2, which reduced the push-out bond strength.

Cryopreservation of Red Blood Cells

Glycerol and trehalose are widely used protective agents in the cryopreservation of red blood cells (RBCs). This chapter presents a protocol for use of these agents as cryoprotectants of RBCs, with post-thaw assessment of cell survival and cellular oxidative-reductive status. The main aim is to provide a framework for further studies aimed at improving RBC survival and function and to supply improved biomaterials for studies on RBC biochemistry, major operations, as well as those for urgent use in emergency room situations.

Fouling-Release Properties of Dendritic Polyglycerols against Marine Diatoms

Dendritic polyglycerols (PGs) were grafted onto surfaces using a ring-opening polymerization reaction, and the fouling-release properties against marine organisms were determined. The coatings were characterized by spectroscopic ellipsometry, contact angle goniometry, ATR-FTIR, and stability tests in different aqueous media. A high resistance toward the attachment of different proteins was found. The PG coatings with three different thicknesses were tested in a laboratory assay against the diatom Navicula incerta and in a field assay using a rotating disk. Under static conditions, the PG coatings did not inhibit the initial attachment of diatoms, but up to 94% of attached diatoms could be removed from the coatings after exposure to a shear stress of 19 Pa. Fouling release was found to be enhanced if the coatings were sufficiently thick. The excellent fouling-release properties were supported in dynamic field-immersion experiments in which the samples were continually exposed to a shear stress of 0.18 Pa.

Additive manufactured biodegradable poly(glycerol sebacate methacrylate) nerve guidance conduits

Entubulating devices to repair peripheral nerve injuries are limited in their effectiveness particularly for critical gap injuries. Current clinically used nerve guidance conduits are often simple tubes, far stiffer than that of the native tissue. This study assesses the use of poly(glycerol sebacate methacrylate) (PGSm), a photocurable formulation of the soft biodegradable material, PGS, for peripheral nerve repair. The material was synthesized, the degradation rate and mechanical properties of material were assessed and nerve guidance conduits were structured via stereolithography. In vitro cell studies confirmed PGSm as a supporting substrate for both neuronal and glial cell growth. Ex vivo studies highlight the ability of the cells from a dissociated dorsal root ganglion to grow out and align along the internal topographical grooves of printed nerve guide conduits. In vivo results in a mouse common fibular nerve injury model show regeneration of axons through the PGSm conduit into the distal stump after 21 days. After conduit repair levels of spinal cord glial activation (an indicator for neuropathic pain development) were equivalent to those seen following graft repair. In conclusion, results indicate that PGSm can be structured via additive manufacturing into functional NGCs. This study opens the route of personalized conduit manufacture for nerve injury repair.

STATEMENT OF SIGNIFICANCE

This study describes the use of photocurable of Poly(Glycerol Sebacate) (PGS) for light-based additive manufacturing of Nerve Guidance Conduits (NGCs). PGS is a promising flexible biomaterial for soft tissue engineering, and in particular for nerve repair. Its mechanical properties and degradation rate are within the desirable range for use in neuronal applications. The nerve regeneration supported by the PGS NGCs is similar to an autologous nerve transplant, the current gold standard. A second assessment of regeneration is the activation of glial cells within the spinal cord of the tested animals which reveals no significant increase in neuropathic pain by using the NGCs. This study highlights the successful use of a biodegradable additive manufactured NGC for peripheral nerve repair.

The growth of Pichia pastoris Mut+ on methanol-glycerol mixtures fits to interactive dual-limited kinetics: model development and application to optimised fed-batch operation for heterologous protein production

The methanol-glycerol co-feeding during the induction stage for heterologous protein production in Pichia pastoris has shown significant productive applications. Available model analysis applied to this dual-limited condition is scarce and normally does not consider the interaction effects between the substrates. In this work, a dual-limited growth model of P. pastoris considering an interactive kinetic effect was applied to an optimised fed-batch process production of heterologous Rhizopus oryzae lipase (ROL). In the proposed model, the growth kinetics on glycerol is fully expressed, whereas methanol kinetics is modulated by the co-metabolisation of glycerol, resulting in an enhancing effect of glycerol-specific growth rate. The modelling approach of fed-batch cultures also included the methanol volatilisation caused by the aeration that was found to be a not-negligible phenomenon. The model predicts the ability of P. pastoris to keep control of the methanol concentration in the broth during ROL-optimised production process in fed batch and fits satisfactorily the specific cell growth rate and ROL production. Implications of interaction effect are discussed applying the general procedure of modelling approach.

Multivalent Flexible Nanogels Exhibit Broad-Spectrum Antiviral Activity by Blocking Virus Entry

The entry process of viruses into host cells is complex and involves stable but transient multivalent interactions with different cell surface receptors. The initial contact of several viruses begins with attachment to heparan sulfate (HS) proteoglycans on the cell surface, which results in a cascade of events that end up with virus entry. The development of antiviral agents based on multivalent interactions to shield virus particles and block initial interactions with cellular receptors has attracted attention in antiviral research. Here, we designed nanogels with different degrees of flexibility based on dendritic polyglycerol sulfate to mimic cellular HS. The designed nanogels are nontoxic and broad-spectrum, can multivalently interact with viral glycoproteins, shield virus surfaces, and efficiently block infection. We also visualized virus-nanogel interactions as well as the uptake of nanogels by the cells through clathrin-mediated endocytosis using confocal microscopy. As many human viruses attach to the cells through HS moieties, we introduce our flexible nanogels as robust inhibitors for these viruses.

Cryopreservation in rhinoceros-Setting a new benchmark for sperm cryosurvival

At times when rhinoceros are fiercely poached, when some rhinoceros species are closer than ever to extinction, and when the scientific community is in debate over the use of advanced cell technologies as a remaining resort it is time to simplify and improve existing assisted reproduction techniques to enhance breeding and genetic diversity in the living populations under our care. Semen cryopreservation has been performed in all captive rhinoceros species with limited degree of success. Here we tested three freezing extenders, containing different cryoprotectants and various freezing rates for the cryopreservation of rhinoceros sperm from 14 bulls. In experiment I, semen from 9 bulls was used to determine the most suitable diluent, cryoprotectant and freezing rate for the successful cryopreservation of rhinoceros sperm. In experiment II, semen from 5 bulls was used to assess whether the removal of seminal plasma could further improve post thaw sperm quality following cryopreservation with conditions identified in Experiment I. Semen was diluted with Berliner Cryomedia, ButoCrio® or INRA Freeze®, packaged in 0.5 mL straws and frozen 3, 4, and 5 cm over liquid nitrogen (LN) vapour or directly in a dryshipper. It was found that semen extended with ButoCrio® (containing glycerol and methylformamide) and frozen 3cm over LN vapour provided the best protection to rhinoceros spermatozoa during cryopreservation. When pooled over treatments, total and progressive post thaw motility was 75.3 ± 4.2% and 68.5 ± 5.7%, respectively marking a new benchmark for the cryopreservation of rhinoceros sperm. Post thaw total and progressive motility, viability and acrosome integrity of semen diluted in ButoCrio® was significantly higher than semen extended in Berliner Cryomedia or INRA Freeze®. The removal of seminal plasma did not improve post thaw sperm survival (p > 0.05). In conclusion, the cryosurvival of rhinoceros spermatozoa was significantly improved when using a mixture of glycerol and methylformamide in combination with a fast freezing rate at 3 cm. These results describe a new protocol for the improved cryosurvival of rhinoceros spermatozoa and will enable a more successful preservation of genetic diversity between males, especially in donors whose spermatozoa may already be compromised prior to or during collection. The successful reduction of glycerol concentration in favour of methylformamide as a cryoprotectant could be a novel suggestion for the improvement of cryopreservation techniques in other wildlife species.

Effects of electronic cigarette liquid solvents propylene glycol and vegetable glycerin on user nicotine delivery, heart rate, subjective effects, and puff topography

BACKGROUND

Electronic cigarettes (ECIGs) are a class of tobacco products that produce different effects (e.g., nicotine delivery), depending on the device, liquid, and behavioral factors. However, the influence of the two primary ECIG liquid solvents, propylene glycol (PG) and vegetable glycerin (VG), on ECIG acute effects is unknown.

METHODS

Thirty ECIG-experienced, ≥12-h nicotine- abstinent participants completed four conditions consisting of two ECIG-use bouts (10 puffs, 30 s interpuff-interval) differing only by liquid PG:VG ratio (2PG:98VG, 20PG:80VG, 55PG:45VG, 100PG). Device power (7.3 W) and liquid nicotine concentration (18 mg/ml) remained constant. Nicotine delivery, subjective effects, heart rate (HR), and puff topography were assessed.

RESULTS

In the 100PG condition, participants took shorter and smaller puffs but obtained significantly more nicotine relative to the two VG-based conditions. Total nicotine exposure (i.e., area under the curve) was also significantly higher during use of the two PG-based liquids. However, participants reported that the 100 PG liquid was significantly less "pleasant" and "satisfying" relative to the other liquids (all ps < .05). Increases in HR and decreases in abstinence symptoms (e.g., "craving") did not differ across conditions.

CONCLUSIONS

PG:VG ratio influenced nicotine delivery, some subjective effects, and puff topography. Lower overall product satisfaction associated with the 100PG liquid suggests factors other than nicotine delivery (e.g., aerosol visibility) may play a role in maintaining ECIG use. Regulating ECIG acute effects such as nicotine delivery and subjective effects may require simultaneous attention to liquid PG:VG ratio as well as device, liquid, and behavioral factors known to influence these outcomes.

Glycerol Solvates DPPC Headgroups and Localizes in the Interfacial Regions of Model Pulmonary Interfaces Altering Bilayer Structure

The inclusion of glycerol in formulations for pulmonary drug delivery may affect the bioavailability of inhaled steroids by retarding their transport across the lung epithelium. The aim of this study was to evaluate whether the molecular interactions of glycerol with model pulmonary interfaces provide a biophysical basis for glycerol modifying inhaled drug transport. Dipalmitoylphosphatidylcholine (DPPC) monolayers and liposomes were used as model pulmonary interfaces, in order to examine the effects of bulk glycerol (0-30% w/w) on their structures and dynamics using complementary biophysical measurements and molecular dynamics (MD) simulations. Glycerol was found to preferentially interact with the carbonyl groups in the interfacial region of DPPC and with phosphate and choline in the headgroup, thus causing an increase in the size of the headgroup solvation shell, as evidenced by an expansion of DPPC monolayers (molecular area increased from 52 to 68 Ų) and bilayers seen in both Langmuir isotherms and MD simulations. Both small angle neutron scattering and MD simulations indicated a reduction in gel phase DPPC bilayer thickness by ∼3 Å in 30% w/w glycerol, a phenomenon consistent with the observation from FTIR data, that glycerol caused the lipid headgroup to remain oriented parallel to the membrane plane in contrast to its more perpendicular conformation adopted in pure water. Furthermore, FTIR measurements suggested that the terminal methyl groups of the DPPC acyl chains were constrained in the presence of glycerol. This observation is supported by MD simulations, which predict bridging between adjacent DPPC headgroups by glycerol as a possible source of its putative membrane stiffening effect. Collectively, these data indicate that glycerol preferentially solvates DPPC headgroups and localizes in specific areas of the interfacial region, resulting in structural changes to DPPC bilayers which may influence cell permeability to drugs.

Microwave-assisted facile fabrication of porous poly (glycerol sebacate) scaffolds

The biodegradable elastomeric polyester poly(glycerol sebacate) (PGS) was developed for soft-tissue engineering. It has been used in various research applications such as wound healing, cartilage tissue engineering, and vascular grafting due to its biocompatibility and elastomeric properties. However conventional PGS manufacture is generally limited by the laborious reaction conditions needed for curing which requires elevated reaction temperatures, high vacuum and multi-day reaction times. In this study, we developed a microwave irradiation methodology to fabricate PGS scaffolds under milder conditions with curing times that are 8 times faster than conventional methods. In particular, we determined microwave reaction temperatures and times for maximum crosslinking of PGS elastomers, demonstrating that PGS is fully crosslinked using gradual heating up to 160 °C for 3 h. Porosity and mechanical properties of these microwave-cured PGS elastomers were shown to be similar to PGS elastomers fabricated by the conventional polycondensation method (150 °C under 30 Torr for 24 h). To move one step closer to clinical application, we also examined the biocompatibility of microwave-cured PGS using in vitro cell viability assays with primary baboon arterial smooth muscle cells (SMCs). These combined results show microwave curing of PGS is a viable alternative to conventional curing.

Urethane-based low-temperature curing, highly-customized and multifunctional poly(glycerol sebacate)-co-poly(ethylene glycol) copolymers

Poly (glycerol sebacate) (PGS), a tough elastomer, has been widely explored in tissue engineering due to the desirable mechanical properties and biocompatibility. However, the complex curing procedure (high temperature and vacuum) and limited hydrophilicity (∼90° of wetting angle) greatly impede its functionalities. To address these challenges, a urethane-based low-temperature setting, PEGylated PGS bioelastomer was developed with and without solvent. By simultaneously tailoring PEG and hexamethylene diisocyanate (HDI) contents, the elastomers X-P-mUs (X referred to the PEG content and m referred to HDI content) with a broad ranging mechanical properties and customized hydrophilicity were constructed. The X-P-mUs synthesized exhibited adjustable tensile Young's modulus, ultimate tensile strength and elongation at break in the range of 1.0 MPa-14.2 MPa, 0.3 MPa-7.6 MPa and 53.6%-272.8%, with the water contact angle varying from 28.6° to 71.5°, respectively. Accordingly, these elastomers showed favorable biocompatibility in vitro and mild host response in vivo. Furthermore, the potential applications of X-P-mU elastomers prepared with solvent-base and solvent-free techniques in biomedical fields were investigated. The results showed that these X-P-mU elastomers with high molding capacity at mild temperature could be easily fabricated into various shapes, used as reinforcement for fragile materials, and controllable delivery of drugs and proteins with excellent bioactivity, demonstrating that the X-P-mU elastomers could be tailored as potential building blocks for diverse applications in biomedical research.

STATEMENT OF SIGNIFICANCE

Poly(glycerol sebacate) (PGS), a tough biodegradable elastomer, has received great attentions in biomedical field. But the complex curing procedure and limited hydrophilicity greatly hamper its functionality. Herein, a urethane-based low-temperature setting, PEGylated PGS (PEGS-U) bioelastomer with highly-customized mechanical properties, hydrophilicity and biodegradability was first explored. The synthesized PEGS-U showed favorable biocompatibility both in vitro and in vivo. Furthermore, the PEGS-U elastomer could be easily fabricated into various shapes, used as reinforcement for fragile materials, and controllable delivery of drugs and proteins with excellent bioactivity. This versatile, user-tunable bioelastomers should be a promising biomaterials for biomedical applications.

Cryopreservation of sperm bundles (spermatozeugmata) from endangered livebearing goodeids

More than half of fishes in the family Goodeidae are considered to be endangered, threatened, or vulnerable. Sperm cryopreservation is an effective tool for conserving genetic resources of imperiled populations, but development of protocols with livebearing fishes faces numerous challenges including the natural packaging of sperm into bundles. In this study the cryopreservation of sperm bundles (spermatozeugmata) of three goodeids species was evaluated. Sperm quality was evaluated by activation with NaCl-NaOH solution (at 300 mOsmol/kg and pH 11.8), and analysis of dissociable bundles and dissociation duration. Using Redtail Splitfin (Xenotoca eiseni) as a model, the effects of cryoprotectants (dimethyl sulfoxide, methanol, and glycerol) with different concentrations (5-15% v/v %), equilibration exposure times (1-60 min), cooling rates (5-40 °C/min), concentrations (4 × 10⁴-4 × 10⁶ bundles/ml), buffers (HBSS, PBS and NaCl), and buffer osmolalities (200-400 mOsmol/kg) were investigated. After cooling and thawing, sperm bundles maintained their packed form. A specific protocol was developed (10% dimethyl sulfoxide, 20-min equilibration, 10 °C/min cooling rate, 4 × 10⁶ bundles/ml, and 300 mOsmol/kg HBSS). This protocol yielded 89 ± 5% of post-thaw dissociable bundles with 209 ± 10 s of dissociation duration for X. eiseni, 96 ± 9% with 814 ± 14 s for Blackfin Goodea (Goodea atripinni), and 66 ± 2% with 726 ± 25 s for Striped Goodeid (Ataeniobius toweri). This is the first study of cryopreservation of sperm within bundles for livebearing fishes and provides a basis for establishment of germplasm repositories for goodeids and other livebearers.

Performance of individually measured vs population-based C-peptide kinetics to assess β-cell function in the presence and absence of acute insulin resistance

AIMS

To compare the performance of population-based kinetics with that of directly measured C-peptide kinetics when used to calculate β-cell responsivity indices, and to study people with and without acute insulin resistance to ensure that population-based kinetics apply to all conditions where β-cell function is measured.

METHODS

Somatostatin was used to inhibit endogenous insulin secretion in 56 people without diabetes. Subsequently, a C-peptide bolus was administered and the changing concentrations were used to calculate individual kinetic measures of C-peptide clearance. In addition, the participants were studied on 2 occasions in random order using an oral glucose tolerance test (OGTT). On one occasion, free fatty acid elevation, to cause insulin resistance, was achieved by infusion of Intralipid + heparin. The Disposition Index (DI) was then estimated by the oral minimal model using either population-based or individual C-peptide kinetics.

RESULTS

There were marked differences in the exchange variables (k ₁₂ and k ₂₁ ) of the model describing C-peptide kinetics, but smaller differences in the fractional clearance; that is, the irreversible loss from the accessible compartment (k ₀₁ ), obtained from population-based estimates compared with experimental measurement. Because it is predominantly influenced by k ₀₁ , DI estimated using individual kinetics correlated well with DI estimated using population-based kinetics.

CONCLUSIONS

These data support the use of population-based measures of C-peptide kinetics to estimate β-cell function during an OGTT.

Blocking or enhancing effects of some basic emollients in UVA penetration

BACKGROUND

Topical agents used in combination with phototherapy or photochemotherapy may have both blocking or enhancing effects in ultraviolet rays.

OBJECTIVE

In this in vivo study, the effects of topical petrolatum, basis cream, glycerine, and olive oil on the transmission of ultraviolet A radiation were investigated.

METHODS

A test was performed to determine the minimal phototoxic dose on 29 volunteers with only psoralen plus ultraviolet A (PUVA) and then the same test was repeated with white petrolatum, basis cream, glycerine, olive oil, and sunscreen (0.3cc/25cm2). The effects of each agent on the minimal phototoxic dose were determined after 72 h.

RESULTS

When compared to pure PUVA, there was a statistically significant increase in the mean minimal phototoxic dose values by the application of white petrolatum (P = 0.011), but there was no significant increase or decrease in the mean minimal phototoxic dose values after the application of basis cream (P = 0.326), glycerine (P = 0.611) or olive oil (P = 0.799).

STUDY LIMITATIONS

Low number of patients Conclusion: The application of white petrolatum, which has a blocking effect, and also of basis cream immediately before PUVA therapy should not be recommended. Although we specify that glycerine and maybe olive oil can be used before photochemotherapy, there is a need for further research in larger series.