Gray-matter volume, midbrain dopamine D2/D3 receptors and drug craving in methamphetamine users.

Dysfunction of the mesocorticolimbic system has a critical role in clinical features of addiction. Despite evidence suggesting that midbrain dopamine receptors influence amphetamine-induced dopamine release and that dopamine is involved in methamphetamine-induced neurotoxicity, associations between dopamine receptors and gray-matter volume have been unexplored in methamphetamine users. Here we used magnetic resonance imaging and [(18)F]fallypride positron emission tomography, respectively, to measure gray-matter volume (in 58 methamphetamine users) and dopamine D2/D3 receptor availability (binding potential relative to nondisplaceable uptake of the radiotracer, BPnd) (in 31 methamphetamine users and 37 control participants). Relationships between these measures and self-reported drug craving were examined. Although no difference in midbrain D2/D3 BPnd was detected between methamphetamine and control groups, midbrain D2/D3 BPnd was positively correlated with gray-matter volume in the striatum, prefrontal cortex, insula, hippocampus and temporal cortex in methamphetamine users, but not in control participants (group-by-midbrain D2/D3 BPnd interaction, P<0.05 corrected for multiple comparisons). Craving for methamphetamine was negatively associated with gray-matter volume in the insula, prefrontal cortex, amygdala, temporal cortex, occipital cortex, cerebellum and thalamus (P<0.05 corrected for multiple comparisons). A relationship between midbrain D2/D3 BPnd and methamphetamine craving was not detected. Lower midbrain D2/D3 BPnd may increase vulnerability to deficits in gray-matter volume in mesocorticolimbic circuitry in methamphetamine users, possibly reflecting greater dopamine-induced toxicity. Identifying factors that influence prefrontal and limbic volume, such as midbrain BPnd, may be important for understanding the basis of drug craving, a key factor in the maintenance of substance-use disorders

Striatal dopamine D1-type receptor availability: no difference from control but association with cortical thickness in methamphetamine users.

Chronic methamphetamine use poses potentially devastating consequences for directly affected individuals and for society. Lower dopamine D2-type receptor availability has been observed in striata of methamphetamine users as compared with controls, but an analogous comparison of D1-type receptors has been conducted only on post-mortem material, with no differences in methamphetamine users from controls in the caudate nucleus and putamen and higher D1-receptor density in the nucleus accumbens. Released from neurons when methamphetamine is self-administered, dopamine binds to both D1- and D2-type receptors in the striatum, with downstream effects on cortical activity. Thus, both receptor subtypes may contribute to methamphetamine-induced alterations in cortical morphology and behavior. In this study, 21 methamphetamine-dependent subjects and 23 healthy controls participated in positron emission tomography and structural magnetic resonance imaging for assessment of striatal D1- and D2-type receptor availability and cortical gray-matter thickness, respectively. Although D2-type receptor availability (BPnd) was lower in the methamphetamine group, as shown previously, the groups did not differ in D1-type BPnd. In the methamphetamine group, mean cortical gray-matter thickness was negatively associated with cumulative methamphetamine use and craving for the drug. Striatal D1-type but not D2-type BPnd was negatively associated with global mean cortical gray-matter thickness in the methamphetamine group, but no association was found between gray-matter thickness and BPnd for either dopamine receptor subtype in the control group. These results suggest a role of striatal D1-type receptors in cortical adaptation to chronic methamphetamine use

An electrostatic interaction between TEA and an introduced pore aromatic drives spring-in-the-door inactivation in Shaker potassium channels

Slow inactivation of Kv1 channels involves conformational changes near the selectivity filter. We examine such changes in Shaker channels lacking fast inactivation by considering the consequences of mutating two residues, T449 just external to the selectivity filter and V438 in the pore helix near the bottom of the selectivity filter. Single mutant T449F channels with the native V438 inactivate very slowly, and the canonical foot-in-the-door effect of extracellular tetraethylammonium (TEA) is not only absent, but the time course of slow inactivation is accelerated by TEA. The V438A mutation dramatically speeds inactivation in T449F channels, and TEA slows inactivation exactly as predicted by the foot-in-the-door model. We propose that TEA has this effect on V438A/T449F channels because the V438A mutation produces allosteric consequences within the selectivity filter and may reorient the aromatic ring at position 449. We investigated the possibility that the blocker promotes the collapse of the outer vestibule (spring-in-the-door) in single mutant T449F channels by an electrostatic attraction between a cationic TEA and the quadrupole moments of the four aromatic rings. To test this idea, we used in vivo nonsense suppression to serially fluorinate the introduced aromatic ring at the 449 position, a manipulation that withdraws electrons from the aromatic face with little effect on the shape, net charge, or hydrophobicity of the aromatic ring. Progressive fluorination causes monotonically enhanced rates of inactivation. In further agreement with our working hypothesis, increasing fluorination of the aromatic gradually transforms the TEA effect from spring-in-the-door to foot-in-the-door. We further substantiate our electrostatic hypothesis by quantum mechanical calculations

Aproximació a l'entonació del català de València en el marc del projecte AMPER

Aquest treball, seguint les directrius del subgrup AMPERCAT del projecte AMPER, presenta els resultats de l'anàlisi dels paràmetres prosòdics (entonació, durada i intensitat) d'un corpus d'oracions declaratives i interrogatives absolutes de tipus neutre del català de la ciutat de València amb l'objectiu d'identificar els trets prosòdics que el caracteritzen. Les dades obtingudes s'han comparat amb les d'altres varietats i s'ha observat que sobre tot hi difereixen en les interrogatives absolutes

Shifting mediates gendered racial microaggressions and perceived racism among Asian American women

Introduction: Microaggressive attacks on Asian American women increased during the COVID-19 pandemic. The present study tested whether Asian American women\u27s shifting, a coping strategy employed by some women of color to alter their self-presentation in response to perceived racism, mediated the association between gendered racial microaggressions and self-perceived subtle and blatant racism. Methods: A convenience sample of 253 Asian American adult women completed the gendered racial microaggressions scale for Asian American women (GRMSAAW), the Asian American women\u27s shifting scale (AsAWSS), and the subtle and blatant racism scale for Asian American college students (SABR-A2). Results: Results from a structural equation model indicated a partial mediation effect; experiences with increased gendered racial microaggressions were associated with greater levels of shifting, which in turn, were associated with greater perceived subtle and blatant racism. Discussion: These data extend our understanding of the shifting coping mechanism used by some Asian American women. Implications for clinical practice and future research are also discussed

The dissipative effect of thermal radiation loss in high-temperature dense plasmas

A dynamical model based on the two-fluid dynamical equations with energy generation and loss is obtained and used to investigate the self-generated magnetic fields in high-temperature dense plasmas such as the solar core. The self-generation of magnetic fields might be looked at as a self-organization-type behavior of stochastic thermal radiation fields, as expected for an open dissipative system according to Prigogine's theory of dissipative structures.Comment: 4 pages, 1 postscript figure included; RevTeX3.0, epsf.tex neede

Antioksidativna aktivnost ferementiranih i nefermentiranih esktrakata iz otpada nastalog pri proizvodnji kave

Coffee pulp contains natural antioxidants like hydroxycinnamic acids, most of which are covalently linked to the cell wall. These compounds can be released by fermentation or enzymatic processes. In this study, the antioxidant properties of fermented and nonfermented coffee pulp have been evaluated. Coffee pulp was fermented by solid-state fermentation using the fungus Aspergillus tamarii. Fermented and nonfermented samples of coffee pulp were extracted with aqueous methanol followed by alkaline hydrolysis. In both cases, the total polyphenol concentration was quantified by Folin-Ciocalteu method, then hydroxycinnamic acids were concentrated using ethyl acetate and quantified by HPLC. The antioxidant properties of samples were determined by radical monocation of 2,2’-azinobis-( 3-ethylbenzothiazoline-6-sulphonic acid) [ABTS]·+: the antioxidant activity was determined by kinetic parameters known as ED50, tED50 and antiradical efficiency (AE). Fermented extracts containing free hydroxycinnamic acids showed better antiradical activity against [ABTS]·+ than the other nonfermented ones. There were no significant differences in the total content of polyphenols in fermented and nonfermented coffee pulp, but the content of total hydroxycinnamic acids was higher in the nonfermented coffee pulp extracts (47.1 g/kg) than in the fermented coffee pulp (30.9 g/kg). Nevertheless, the fermentation process increased the fraction of free hydroxycinnamic acids (47 %) and consequently decreased those covalently linked to the cell wall. The results of the antioxidant activity assays could be explained by the presence of free hydroxycinnamic acids. Fermented coffee pulp assays showed that free hydroxycinnamic acids were metabolised by A. tamarii. This study shows the potential of using coffee pulp as a natural source of antioxidants.Otpad nastao pri proizvodnji kave sadržava prirodne antioksidanse, kao što su hidroksicinamične kiseline, od kojih je većina kovalentno vezana za staničnu stijenku. Takvi se spojevi mogu osloboditi fermentacijom ili pomoću enzima. U ovom su radu istražena antioksidativna svojstva fermentiranih i nefermentiranih esktrakata, pri čemu je fermentacija provedena s pomoću plijesni Aspergillus tamarii na čvrstoj podlozi od otpada nastalog pri proizvodnji kave. Fermentirani i nefermentirani spojevi esktrahirani su vodenom otopinom metanola, nakon čega je provedena njihova alkalna hidroliza. U oba je slučaja koncentracija ukupnih polifenola određena Folin-Ciocalteu metodom, a zatim su hidroksicinamične kiseline koncentrirane pomoću etil acetata i analizirane HPLC-om. Antioksidativna su svojstva uzoraka, tj. vrijednosti ED50 i tED50 te antiradikalni učinak, određena pomoću radikala 2,2\u27-azinobis(3-etilbenzotiazolin-6-sulfonske kiseline) [ABTS].+. Fermentirani su ekstrakti sadržavali slobodne hidroksicinamične kiseline i imali su bolju antioksidativnu aktivnost s obzirom na [ABTS].+ od nefermentiranih ekstrakata. Nije bilo bitne razlike u koncentracijama ukupnih polifenola u fermentiranim i nefermentiranim ekstraktima, ali je udio hidroksicinamičnih kiselina bio veći u nefermentiranim (47,1 g/kg) nego u fermentiranim ekstraktima (30,9 g/kg). Fermentacija je povećala udjel slobodnih (na 47 %), a smanjila udjel vezanih hidroksicinamičnih kiselina. Zaključeno je da je antioksidativna aktivnost ekstrakata ovisila o udjelu slobodnih hidroksicinamičnih kiselina, koji se povećao nakon fermentacije otpada nastalog pri proizvodnji kave s pomoću A. tamarii. Time je potvrđeno da se postupak može primijeniti za ekstrakciju prirodnih antioksidanasa

Materials selection for superheater tubes in municipal solid waste incineration plants

Corrosion reduces the lifetime of municipal solid waste incineration (MSWI) superheater tubes more than any other cause. It can be minimized by the careful selection of those materials that are most resistant to corrosion under operating conditions. Since thousands of different materials are already known and many more are developed every year, here the selection methodology developed by Prof. Ashby of the University of Cambridge was used to evaluate the performance of different materials to be used as MSWI superheater tubes. The proposed materials can operate at steam pressures and temperatures over 40 bars and 400ºC, respectively. Two case studies are presented: one makes a balanced selection between mechanical properties and cost per thermal unit; and the other focuses on increasing tube lifetime. The balanced selection showed that AISI 410 martensitic stainless steel (wrought, hard tempered) is the best candidate with a good combination of corrosion resistance, a relatively low price (0.83-0.92 e/kg) and a good thermal conductivity (23-27 W/m K). Meanwhile, Nitronic 50/XM-19 stainless steel is the most promising candidate for longterm selection, as it presents high corrosion resistance with a relatively low price (4.86-5.14 e/kg) compared to Ni-alloys