Electronic structures and magnetic properties of RB4 (R=Yb,Pr,Gd,Tb,Dy)

Most rare-earth tetraborides RB4 have antiferromagnetic ground states except for YbB4 and PrB4. We have investigated the electronic structures and magnetic properties of RB4 (R=Yb, Pr, Gd, Tb, Dy) employing the first-principles total energy band method. It is found that YbB4 has the paramagnetic ground state, while the other tetraborides are in the magnetic ground state, which is in agreement with experiments. We have obtained the spin and orbital magnetic moments and discussed the importance of the spin-orbit interaction and the on-site Coulomb repulsion (U) in these systems. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3058707]ope

TonEBP/NFAT5 stimulates transcription of HSP70 in response to hypertonicity

While hyperosmolality of the kidney medulla is essential for urinary concentration, it imposes a great deal of stress. Cells in the renal medulla adapt to the stress of hypertonicity (hyperosmotic salt) by accumulating organic osmolytes. Tonicity-responsive enhancer (TonE) binding protein (TonEBP) (or NFAT5) stimulates transcription of transporters and a synthetic enzyme for the cellular accumulation of organic osmolytes. We found that dominant-negative TonEBP reduced expression of HSP70 as well as the transporters and enzyme. Near the major histocompatibility complex class III locus, there are three HSP70 genes named HSP70-1, HSP70-2, and HSC70t. While HSP70-1 and HSP70-2 were heat inducible, only HSP70-2 was induced by hypertonicity. In the 5' flanking region of the HSP70-2 gene, there are three sites for TonEBP binding. In cells transfected with a reporter plasmid containing this region, expression of luciferase was markedly stimulated in response to hypertonicity. Coexpression of the dominant-negative TonEBP reduced the luciferase expression. Mutating all three sites in the reporter plasmid led to a complete loss of induction by hypertonicity. Thus, TonEBP rather than heat shock factor stimulates transcription of the HSP70-2 gene in response to hypertonicity. We conclude that TonEBP is a master regulator of the renal medulla for cellular protection against high osmolality via organic osmolytes and molecular chaperones.open12

Negative differential resistance of carbon nanotube electrodes with asymmetric coupling phenomena

An intricate problem in molecular electronics is to control the molecule-electrodes contacts. Asymmetric couplings between both contacts are important in driving novel nonlinear transport characteristics like negative differential resistance (NDR). We find that in the presence of an applied field, metallic carbon nanotubes (CNTs) can form asymmetric couplings even if symmetric structures are employed. This origin is due to the CNT itself, while the NDR phenomenon can be obtained by tuning the threshold voltage for the asymmetric couplings by a proper choice of a molecule.open1162sciescopu

Biodegradable Nitrogen-Doped Carbon Nanodots for Non-Invasive Photoacoustic Imaging and Photothermal Therapy

Multifunctional nanoparticles have been widely investigated for biomedical applications, such as imaging, therapy, and drug delivery. Especially, photoactive nanoparticles have received great attention as theranostic agents because of their heat-generating abilities after exposure to laser irradiation. However, photostability and safety issues have been the technical hurdles for further clinical applications. Here, we designed nitrogen (N)-doped carbon nanodots (N-CNDs) that have strong absorption in the near-infrared region, high photostability, and excellent biodegradability. Optimized N-CNDs can be utilized not only as a new photoacoustic (PA) imaging agent but also as a superior photothermal therapy (PTT) agent in vivo because of their strong optical absorption at a specific wavelength. We used N-CNDs to perform in vivo/ex vivo noninvasive PA imaging of sentinel lymph nodes via local delivery and performed PTT for cancer ablation therapy. Finally, biodegradation and renal clearance were confirmed by performing whole-body PA monitoring and a degradation test

Biodegradable Nitrogen-Doped Carbon Nanodots for Non-Invasive Photoacoustic Imaging and Photothermal Therapy

Multifunctional nanoparticles have been widely investigated for biomedical applications, such as imaging, therapy, and drug delivery. Especially, photoactive nanoparticles have received great attention as theranostic agents because of their heat-generating abilities after exposure to laser irradiation. However, photostability and safety issues have been the technical hurdles for further clinical applications. Here, we designed nitrogen (N)-doped carbon nanodots (N-CNDs) that have strong absorption in the near-infrared region, high photostability, and excellent biodegradability. Optimized N-CNDs can be utilized not only as a new photoacoustic (PA) imaging agent but also as a superior photothermal therapy (PTT) agent in vivo because of their strong optical absorption at a specific wavelength. We used N-CNDs to perform in vivo/ex vivo noninvasive PA imaging of sentinel lymph nodes via local delivery and performed PTT for cancer ablation therapy. Finally, biodegradation and renal clearance were confirmed by performing whole-body PA monitoring and a degradation test.11269Ysciescopu

Dopamine Regulation of Amygdala Inhibitory Circuits for Expression of Learned Fear.

GABAergic signaling in the amygdala controls learned fear, and its dysfunction potentially contributes to posttraumatic stress disorder (PTSD). We find that sub-threshold fear conditioning leads to dopamine receptor D4-dependent long-term depression (LTD) of glutamatergic excitatory synapses by increasing inhibitory inputs onto neurons of the dorsal intercalated cell mass (ITC) in the amygdala. Pharmacological, genetic, and optogenetic manipulations of the amygdala regions centered on the dorsal ITC reveal that this LTD limits less salient experiences from forming persistent memories. In further support of the idea that LTD has preventive and discriminative roles, we find that LTD at the dorsal ITC is impaired in mice exhibiting PTSD-like behaviors. These findings reveal a novel role of inhibitory circuits in the amygdala, which serves to dampen and restrict the level of fear expression. This mechanism is interfered with by stimuli that give rise to PTSD and may also be recruited for fear-related psychiatric diseases.1110Ysciescopu

Three-dimensionally Ordered Macroporous Structure Enabled Nanothermite Membrane of Mn2O3/Al

Mn2O3 has been selected to realize nanothermite membrane for the first time in the literature. Mn2O3/Al nanothermite has been synthesized by magnetron sputtering a layer of Al film onto three-dimensionally ordered macroporous (3DOM) Mn2O3 skeleton. The energy release is significantly enhanced owing to the unusual 3DOM structure, which ensures Al and Mn2O3 to integrate compactly in nanoscale and greatly increase effective contact area. The morphology and DSC curve of the nanothermite membrane have been investigated at various aluminizing times. At the optimized aluminizing time of 30 min, energy release reaches a maximum of 2.09 kJ∙g−1, where the Al layer thickness plays a decisive role in the total energy release. This method possesses advantages of high compatibility with MEMS and can be applied to other nanothermite systems easily, which will make great contribution to little-known nanothermite research

Clothing insulation and temperature, layer and mass of clothing under comfortable environmental conditions

This study was designed to investigate the relationship between the microclimate temperature and clothing insulation (Icl) under comfortable environmental conditions. In total, 20 subjects (13 women, 7 men) took part in this study. Four environmental temperatures were chosen: 14??C (to represent March/April), 25??C (May/June), 29??C (July/August), and 23??C (September/October). Wind speed (0.14ms-1) and humidity (45%) were held constant. Clothing microclimate temperatures were measured at the chest (Tchest) and on the interscapular region (Tscapular). Clothing temperature of the innermost layer (Tinnermost) was measured on this layer 30 mm above the centre of the left breast. Subjects were free to choose the clothing that offered them thermal comfort under each environmental condition. We found the following results. 1) All clothing factors except the number of lower clothing layers (Llower), showed differences between the different environmental conditions (P<0.05). The ranges of Tchest were 31.6 to 33.5??C and 32.2 to 33.4??C in Tscapular. The range of Tinnermost was 28.6 to 32.0??C. The range of the upper clothing layers (Lupper) and total clothing mass (Mtotal) was 1.1 to 3.2 layers and 473 to 1659 g respectively. The range of Icl was 0.78 to 2.10 clo. 2) Post hoc analyses showed that analysis of Tinnermost produced the same results as for that of Icl. Likewise, the analysis of Lupper produced the same result as the analysis of the number of total layers (Ltotal) within an outfit. 3) Air temperature (ta) had positive relationships with Tchest and Tscapular and with Tinnermost but had inverse correlations with Icl, Mtotal, Lupper and Ltotal. Tchest, Tscapular, and Tinnermost increased as ta rose. 4) Icl had inverse relationships with Tchest and Tinnermost, but positive relationships with Mtotal, Lupper and Ltotal. Icl could be estimated by Mtotal, Lupper, and Tscapular using a multivariate linear regression model. 5) Lupper had positive relationships with Icl and Mtotal, but Llower did not. Subjects hardly changed Llower under environmental comfort conditions between March and October. This indicates that each of the Tchest, Mtotal, and Lupper was a factor in predicting Icl. Tinnermost might also be a more influential factor than the clothing microclimate temperature.open1

Translation initiation mediated by RNA looping

Eukaryotic translation initiation commences at the initiation codon near the 5' end of mRNA by a 40S ribosomal subunit, and the recruitment of a 40S ribosome to an mRNA is facilitated by translation initiation factors interacting with the m7G cap and/or poly (A) tail. The 40S ribosome recruited to an mRNA is then transferred to the AUG initiation codon with the help of translation initiation factors. To understand the mechanism by which the ribosome finds an initiation codon, we investigated the role of eIF4G in finding the translational initiation codon. An artificial polypeptide eIF4G fused with MS2 was localized downstream of the reporter gene through MS2-binding sites inserted in the 3' UTR of the mRNA. Translation of the reporter was greatly enhanced by the eIF4G-MS2 fusion protein regardless of the presence of a cap structure. Moreover, eIF4G-MS2 tethered at the 3' UTR enhanced translation of the second cistron of a dicistronic mRNA. The encephalomyocarditis virus internal ribosome entry site, a natural translational-enhancing element facilitating translation through an interaction with eIF4G, positioned downstream of a reporter gene, also enhanced translation of the upstream gene in a cap-independent manner. Finally, we mathematically modeled the effect of distance between the cap structure and initiation codon on the translation efficiency of mRNAs. The most plausible explanation for translational enhancement by the translational-enhancing sites is recognition of the initiation codon by the ribosome bound to the ribosome-recruiting sites through "RNA looping." The RNA looping hypothesis provides a logical explanation for augmentation of translation by enhancing elements located upstream and/or downstream of a protein-coding region.open112122sciescopu

Health promoting potential of herbal teas and tinctures from Artemisia campestris subsp maritima: from traditional remedies to prospective products

This work explored the biotechnological potential of the medicinal halophyte Artemisia campestris subsp. maritima (dune wormwood) as a source of health promoting commodities. For that purpose, infusions, decoctions and tinctures were prepared from roots and aerial-organs and evaluated for in vitro antioxidant, anti-diabetic and tyrosinase-inhibitory potential, and also for polyphenolic and mineral contents and toxicity. The dune wormwood extracts had high polyphenolic content and several phenolics were identified by ultra-high performance liquid chromatography-photodiode array-mass-spectrometry (UHPLC-PDA-MS). The main compounds were quinic, chlorogenic and caffeic acids, coumarin sulfates and dicaffeoylquinic acids; several of the identified phytoconstituents are here firstly reported in this A. campestris subspecies. Results obtained with this plant's extracts point to nutritional applications as mineral supplementary source, safe for human consumption, as suggested by the moderate to low toxicity of the extracts towards mammalian cell lines. The dune wormwood extracts had in general high antioxidant activity and also the capacity to inhibit a-glucosidase and tyrosinase. In summary, dune wormwood extracts are a significant source of polyphenolic and mineral constituents, antioxidants and a-glucosidase and tyrosinase inhibitors, and thus, relevant for different commercial segments like the pharmaceutical, cosmetic and/or food industries.FCT - Foundation for Science and Technology [CCMAR/Multi/04326/2013]; Portuguese National Budget; FCT [IF/00049/2012, SFRH/BD/94407/2013]; Research Foundation - Flanders (FWO) [12M8315N]info:eu-repo/semantics/publishedVersio