Social reward is critical for social relationships, and yet we know little about the characteristics of social interactions that are rewarding or the neural mechanisms underlying that reward. Here, ...we investigate the sex-dependent role of oxytocin receptors within the ventral tegmental area (VTA) in mediating the magnitude and valence of social reward. Operant and classical conditioning tests were used to measure social reward associated with same-sex social interactions. The effects of oxytocin, selective oxytocin receptor agonists, antagonists, and vehicle injected into the VTA on social reward was determined in male and female Syrian hamsters. The colocalization of FOS and oxytocin in sites that project to the VTA following social interaction was also determined. Females find same-sex social interactions more rewarding than males and activation of oxytocin receptors in the VTA is critical for social reward in females, as well as males. These studies provide support for the hypothesis that there is an inverted U relationship between the duration of social interaction and social reward, mediated by oxytocin; and that in females the dose-response relationship is initiated at lower doses compared with males. Same-sex social interaction is more rewarding in females than in males, and an inverted U relationship mediated by oxytocin may have a critical role in assigning positive and negative valence to social stimuli. Understanding these sex differences in social reward processing may be essential for understanding the sex differences in the prevalence of many psychiatric disorders and the development of gender-specific treatments of neuropsychiatric disorders.
Hydrophobic selection: Reversible polymerization and folding of amphiphilic dialdehyde and dihydrazide monomers yields nanostructured rods. The resulting dynamers are stable enough to resist the ...incorporation of excess dihydrazide. In water, a more hydrophobic dihydrazide component (see picture, green) is favored over a less hydrophobic one (purple). This selectivity is lost when MeCN is added, implicating that hydrophobicity drives selectivity.
A nanostructured poly(acylhydrazone), which is reversibly formed in acidic aqueous solution from di(aldehyde) and di(acylhydrazine) monomers with appended hexaglyme groups, was found to display lower ...critical solution (LCS) behavior. Remarkably, under acidic conditions in which polymerization is reversible, large and reversible molecular weight (M w) increases were observed in response to elevated temperatures, both below and above the LCS temperature. No variation in M w was evident under neutral and alkaline conditions, in which the acylhydrazone condensation is essentially irreversible. Results of turbidometry studies, size-exclusion chromatography–multiangle laser light scattering (SEC–MALLS), and transmission electron microscopy (TEM) suggest that heating the polymer below the LCS temperature leads to polymer growth with preservation of the characteristic nanostructured morphology, whereas the onset of the microphase separated state causes a fundamental change in morphology, in which the polymer chains aggregate into larger bundles and fibers. van’t Hoff analysis of a small molecule model system indicates that the acylhydrazone condensation is enthalpy driven (ΔH eq = −8.2 ± 0.2 kcal·mol–1 and ΔS eq = −11.1 ± 0.4 = cal·mol–1·K–1), which suggests that the observed polymer growth with temperature is not a consequence of the intrinsic thermodynamics of the intermonomer linkage but is likely the result of the thermoresponsive characteristics conferred by the multiple hexaglyme groups. The system described displays double control of the dynamer state by two orthogonal agents, heat and protons (pH). It also represents a prototype for dynamic materials displaying multiple control adaptive behavior.
Muscle wasting accompanies aging and pathological conditions ranging from cancer, cachexia, and diabetes to denervation and immobilization. We show that activation of NF-κB, through muscle-specific ...transgenic expression of activated IκB kinase β (MIKK), causes profound muscle wasting that resembles clinical cachexia. In contrast, no overt phenotype was seen upon muscle-specific inhibition of NF-κB through expression of IκBα superrepressor (MISR). Muscle loss was due to accelerated protein breakdown through ubiquitin-dependent proteolysis. Expression of the E3 ligase MuRF1, a mediator of muscle atrophy, was increased in MIKK mice. Pharmacological or genetic inhibition of the IKKβ/NF-κB/MuRF1 pathway reversed muscle atrophy. Denervation- and tumor-induced muscle loss were substantially reduced and survival rates improved by NF-κB inhibition in MISR mice, consistent with a critical role for NF-κB in the pathology of muscle wasting and establishing it as an important clinical target for the treatment of muscle atrophy.
Working effectively with other disciplines has become an important competency as a graduate attribute in higher education institutions. Educational experiences should begin to foster the prerequisite ...competencies needed to collaborate successfully with other healthcare professionals. The purpose of this study was to determine how ready first year students are for interprofessional learning, and whether this readiness improves along the continuum of learning into their final year of undergraduate studies. First year undergraduate students from ten disciplines completed the Readiness for Interprofessional Learning Scale prior to participating in a compulsory interprofessional module, and the results were compared with that of senior students who completed the same questionnaire. Results for the study show that there were significant differences between first and senior–year level students on the subscales of negative professional identity (0.02 < 0.05); positive professional identity (0.00 < 0.05); and teamwork and collaboration (0.00 < 0.05). There was no significant difference found on the subscale roles and responsibilities (0.54 > 0.05). The results clearly show that senior students are more ready for learning interprofessionally compared to first year students. It is recommended that a scaffolded approach to learning be adopted, to ensure that students attain competence in all Interprofessional Education (IPE) core competencies when reaching their final year of study. This type of curriculum, with its specific activities and assessment methods, should be packaged in the form of an IPE model to create a clear understanding of the type of health profession graduate that will be produced.
Abstract
We show that an appropriately designed chalcogenide metasurface allows the enhancement of harmonic generation in the UV range, a regime that conventional wisdom deems inaccessible because of ...absorption. Here we exploit a combination of the photonic band structure that forms when stacking As
2
S
3
metasurfaces, phase-locking, nonlinear dispersion, and improved field localization to enhance third harmonic conversion efficiency. We demonstrate an improvement of two orders of magnitude with respect to the single layer counterpart notwithstanding the fact that the harmonic signal is tuned deep in the absorption range at 285 nm.
The fate of pesticide droplets on leaves is significantly influenced by the fine structures found on leaf surfaces. Evaporation times and the maximum coverage areas of single droplets (246, 343, 575, ...762, and 886 μm) on hairy and waxy geranium leaf surfaces were determined under controlled conditions. Stereoscopic sequential images of the droplet evaporation processes were taken for five droplet sizes, three relative humidity (RH) conditions and 13 different sprays. The sprays were combinations of water, a non-ionic colloidal polymer drift retardant, an alkyl polyoxyethylene surfactant, a fungicide and three insecticides. The evaporation time and maximum coverage area of droplets were significantly changed by adding the surfactant or drift retardant to the sprays, but not by adding fungicide or insecticide. Droplet evaporation times on waxy leaves were longer than those on hairy leaves. Evaporation times increased exponentially as droplet diameter and RH increased with limited variability of regression coefficients independent of spray type and leaf surface. The maximum coverage area of droplets also increased exponentially as droplet diameter increased but it was not significantly affected by RH. On the waxy geranium leaf surfaces, the coverage area of pesticide droplets decreased throughout the evaporating process and at all RH conditions, while, on hairy leaf surfaces for the same size droplets, and at the same RH conditions, the coverage area continued to spread until evaporation was nearly completed. Given that the duration of evaporation time and the extent of the coverage area affect pesticide distribution on waxy or hairy leaves, recommendations for pesticide dosage and spray methods should be taken into account for different leaf surfaces to obtain the optimum biological effect and reduced pesticide use.
This manuscript describes an optical enantioselective pattern-based sensing array. A differential array of enantioselective indicator displacement assays was constructed and used to demonstrate ...simultaneous discrimination of enantiomeric and structurally similar α-amino acids. Interpretation of the output patterns by principle component analysis leads to the separation of enantio- and chemoselective information along orthogonal variance axes when chiral receptors of opposite enantiomeric preference are included. A general principle is delineated that correlates array design with the achievement of enantiomeric discrimination analogous to the mammalian gustation response to the amino acids.
•An inverse relationship exists between the duration of social reward and the frequency of seeking it.•Increasing the effort to obtain social reward decreases the frequency of seeking it especially ...when reward value is low.•Activation of oxytocin receptors in the ventral tegmental area modulates the reinforcing properties of social interactions.
The rewarding properties of social interactions play a critical role in the development and maintenance of social relationships, and deficits in social reward are associated with various psychiatric disorders. In the present study, we used a novel Operant Social Preference (OSP) task to investigate the reinforcing properties of social interactions under conditions of high or low reward value, and high or low behavioral effort in male Syrian hamsters. Further, we investigated the role of oxytocin (OT) in a key structure of the mesolimbic reward system, the ventral tegmental area (VTA), in mediating the reinforcing properties of social interaction. Adult male hamsters were placed in a three-chambered apparatus, and allowed access to either a social chamber containing an unrestrained conspecific or a non-social chamber, by pushing through a one-way entry, vertical-swing door. Increasing the duration of social interaction (reward value) decreased the frequency of entering the social interaction chambers, whereas decreasing the duration of social interaction conversely increased the frequency of entries. Moreover, increasing behavioral effort required to access social interaction decreased the frequency of entries, especially under conditions when the duration of social interaction was only 5 s. OT injected into the VTA decreased the frequency of entering social interaction chambers in a manner similar to that observed when duration was increased, whereas injection of an OT receptor antagonist in the VTA increased the frequency of seeking social interaction. Taken together, these data support the hypothesis that activation of OT receptors in the VTA are critical for the reinforcing properties of social interactions. Furthermore, social interactions may exhibit duration and cost dependent reinforcing effects on behavior similar to those observed with food and drugs of abuse.
A series of new chiral macrocycles containing the trans-1,2-diaminocyclohexane (DACH) subunit and arene- and oligoethylene glycol-derived spacers has been prepared in enantiomerically pure form. Four ...of the macrocycles have been characterized by X-ray crystallography, which reveals a consistent mode of intramolecular N–H···N hydrogen bonding and conformational variations about the N-benzylic bonds. Most of the macrocycles were found to differentiate the enantiomers of mandelic acid (MA) by 1H NMR spectroscopy in CDCl3; within the series of macrocycles tested, enantiodiscrimination was promoted by (i) a meta-linkage geometry about the arene spacer, (ii) the presence of naphthalene- rather than phenylene-derived arene spacers, and (iii) increasing length of the oligoethylene glycol bridge. 1H NMR titrations were performed with optically pure MA samples, and the data were fitted to a simultaneous 1:1 and 2:1 binding model, yielding estimates of 2:1 binding constants between some of the macrocycles and MA enantiomers. In several cases, NOESY spectra of the MA:macrocycle complexes show differential intramolecular correlations between protons adjacent to the amine and carboxylic acid groups of the macrocycles and MA enantiomers, respectively, thus demonstrating geometric differences between the diastereomeric intermolecular complexes. The three most effective macrocycles were employed as chiral solvating agents (CSAs) to determine the enantiomeric excess (ee) of 18 MA samples over a wide ee range and with very high accuracy (1% absolute error).
PDF
