julilili42/papers huggingface dataset:
Dopamine Regulates Two Classes of Primate Prefrontal Neurons That Represent Sensory Signals
2013-08-21

The lateral prefrontal cortex (PFC), a hub of higher-level cognitive processing, is strongly modulated by midbrain dopamine (DA) neurons. The cellular mechanisms have been comprehensively studied in the context of short-term memory, but little is known about how DA regulates sensory inputs to PFC that precede and give rise to such memory activity. By preparing recipient cortical circuits for incoming signals, DA could be a powerful determinant of downstream cognitive processing. Here, we tested the hypothesis that prefrontal DA regulates the representation of sensory signals that are required for perceptual decisions. In rhesus monkeys trained to report the presence or absence of visual stimuli at varying levels of contrast, we simultaneously recorded extracellular single-unit activity and applied DA to the immediate vicinity of the neurons by micro-iontophoresis. We found that DA modulation of prefrontal neurons is not uniform but tailored to specialized neuronal classes. In one population of neurons, DA suppressed activity with high temporal precision but preserved signal/noise ratio. Neurons in this group had short visual response latencies and comprised all recorded narrow-spiking, putative interneurons. In a distinct population, DA increased excitability and enhanced signal/noise ratio by reducing response variability. These neurons had longer visual response latencies and were composed exclusively of broad-spiking, putative pyramidal neurons. By gating sensory inputs to PFC and subsequently strengthening the representation of sensory signals, DA might play an important role in shaping how the PFC initiates appropriate behavior in response to changes in the sensory environment.
A general unified expression for solute and heat dispersion in homogeneous porous media
2013-08-21

[1] Perturbations of temperature or solute concentration in a porous medium spread out by heat or molecular diffusion, respectively. If the pore-filling medium (e.g., water in soil) flows, this causes additional spreading of the perturbation due to the variation of local flow velocities and the tortuous flow lines through pore space. Together, this is termed dispersion, which plays an important role in geothermal energy production, contaminant transport, and reactor beds. Numerous models have been proposed to describe the dispersion coefficient as a function of flow rates, diffusion rates and other parameters, such as pore geometry. These models are either for heat (thermal) or solute dispersion, and often only valid for a limited range of flow rates, typically expressed in terms of the Péclet number. Here we present a single, universal expression for both the heat and solute dispersion coefficient in homogeneous porous media, valid over a wide range of Péclet numbers. Only three parameters have to be determined, which depend mainly on the pore geometry of the material. The expression facilitates the physical understanding of dispersion and may be helpful for the interpretation of numerical microscopic modeling results. It has the practical advantage that the heat dispersion coefficient can easily be calculated from the solute dispersion coefficient (or vice versa) and that dispersion coefficients over a wide range of Péclet numbers can be estimated from measurements over only a limited range.
Anti-inflammatory depsides from Cetrelia monachorum potently targeting mPGES-1, 5-LO and NF-κB
2013-08-21

Lichens, often underestimated and still underexplored with respect to pharmaceutical lead discovery, provide a vast diversity of small chemical entities with a variety of reported bioactivities. Based on a previously performed pharmacophore-based virtual screening, we identified lichen constituents as potent microsomal prostaglandine E2 synthase 1 (mPGES-1) inhibitors [1]. Here, we focused on further in vitro anti-inflammatory activities of lichen compounds. An in vitro screening of 17 Alpine lichen species for inhibition of 5-LO, mPGES-1 and NF-κB revealed Cetrelia monachorum (Zahlbr.) W.L. Culb. & C.F. Culb. as promising source for novel anti-inflammatory leads. Phytochemical investigation of the ethanolic crude extract resulted in the isolation and identification of 11 constituents, belonging to depsides and derivatives of orsellinic acid, olivetolic acid and olivetol. The two depsides imbricaric acid and perlatolic acid exerted inhibitory activities on mPGES-1 (IC50 1.9 and 0.4μM, resp) and 5-LO as demonstrated in a cell-based assay (IC50 5.3 and 1.8μM, resp) and on the purified enzyme (IC50 3.5 and 0.4μM, resp). Dual inhibition of mPGES-1 and 5-LO provides safer and more effective anti-inflammatory properties [2]. Furthermore, the two main constituents, imbricaric acid and perlatolic acid, quantified in the extract with a content of 15.22% and 9.10%, resp, showed significant inhibition of TNF-α-induced NF-κB activation in luciferase reporter cells with IC50 values of 2.0 and 7.0μM, resp. These findings attest imbricaric acid and perlatolic acid a pronounced threefold anti-inflammatory profile [3], which warrants further investigation on their pharmacokinetics and in vivo efficacy.
Brightly Blue and Green Emitting Cu(I) Dimers for Singlet Harvesting in OLEDs
2013-08-22

With the chelating aminophosphane ligands Ph2P-(o-C6H4)-N(CH3)2 (PNMe2) and Ph2P-(o-C6H4)-NC4H8 (PNpy), the four halide (Cl, Br, I)-bridged copper coordination compounds [Cu(μ-Cl)(PNMe2)]2 (1), [Cu(μ-Br)(PNMe2)]2 (2), [Cu(μ-I)(PNMe2)]2 (3), and [Cu(μ-I)(PNpy)]2 (4) were synthesized and structurally characterized. Their photophysical properties were studied in detail. The complexes exhibit strong blue (λmax = 464 (3) and 465 nm (4)) and green (λmax = 506 (1) and 490 nm (2)) luminescence as powders with quantum yields of up to 65% at decay times as short as 4.1 μs. An investigation of the emission decay behavior between 1.3 and 300 K gives insight into the nature of the emitting states. At temperatures below T ≈ 60 K, the decay times of the studied compounds are several hundred microseconds long, which indicates that the emission originates from a triplet state (T1 state). DFT calculations show that this state is of (metal+halide)-to-ligand charge transfer (3)(M+X)LCT character. Investigations at 1.3 K allow us to gain insight into the three triplet substates, in particular, to determine the individual substate decay times being as long as a few milliseconds. The zero-field splittings are smaller than 1 or 2 cm(-1). With an analysis of these data, conclusions about the effectiveness of spin-orbit coupling (SOC) can be drawn. Interestingly, the large differences of SOC constants of the halides are not obviously displayed in the triplet state properties. With a temperature increase from T ≈ 60 to 300 K, a significant decrease of the emission decay time by almost 2 orders of magnitude is observed, and at ambient temperature, the decay times amount only to ∼4-7 μs without a significant reduction of the emission quantum yields. This drastic decrease of the (radiative) decay time is a result of the thermal population of a short-lived singlet state (S1 state) that lies energetically only a few hundred wavenumbers (460-630 cm(-1)) higher than the T1 state. Such an emission mechanism corresponds to a thermally activated delayed fluorescence (TADF). At ambient temperature, almost only a delayed fluorescence (∼98%) is observed. Compounds showing this mechanism are highly attractive for applications in OLEDs or LEECs as, in principle, it is possible to harvest all singlet and triplet excitons for the generation of light in the lowest excited singlet state. This effect represents the singlet harvesting mechanism.
Wall teichoic acid structure governs horizontal gene transfer between major bacterial pathogens
2013-08-22

Mobile genetic elements (MGEs) encoding virulence and resistance genes are widespread in bacterial pathogens, but it has remained unclear how they occasionally jump to new host species. Staphylococcus aureus clones exchange MGEs such as S. aureus pathogenicity islands (SaPIs) with high frequency via helper phages. Here we report that the S. aureus ST395 lineage is refractory to horizontal gene transfer (HGT) with typical S. aureus but exchanges SaPIs with other species and genera including Staphylococcus epidermidis and Listeria monocytogenes. ST395 produces an unusual wall teichoic acid (WTA) resembling that of its HGT partner species. Notably, distantly related bacterial species and genera undergo efficient HGT with typical S. aureus upon ectopic expression of S. aureus WTA. Combined with genomic analyses, these results indicate that a 'glycocode' of WTA structures and WTA-binding helper phages permits HGT even across long phylogenetic distances thereby shaping the evolution of Gram-positive pathogens.
Prediction of tamoxifen outcome by genetic variation of CYP2D6 in post‐menopausal women with early breast cancer
2013-08-22

The question of whether genetic polymorphisms of CYP2D6 can affect treatment outcome in patients with early post‐menopausal oestrogen receptor ( ER )‐positive breast cancer has been a matter of debate over the past few years. In this article we revisit the hypothesis of CYP2D6 being a potential tamoxifen outcome predictor and provide detailed insight into the ongoing controversy that prevented the CYP2D6 marker from being accepted by the scientific and clinical community. We summarize the available pharmacokinetic, pharmacodynamic and pharmacogenetic evidence and resolve the controversy based on the recognized methodological and statistical issues. The cumulative evidence suggests that genotyping for CYP2D6 is clinically relevant in post‐menopausal women. This is important, because the clarification of this issue has the potential to resolve a clinical management question that is relevant to hundreds of thousands of women diagnosed with ER ‐positive breast cancer each year, who should not be denied effective endocrine therapy.
Two fast temperature sensors for probing of the atmospheric boundary layer using small remotely piloted aircraft (RPA)
2013-08-22

Abstract. Two types of temperature sensors are designed and tested: a thermocouple and a fine wire resistance thermometer. The intention of this study is to figure out which kind of measurement principle is in general more suited for atmospheric boundary layer meteorology with small remotely piloted aircraft (RPA). The sensors are calibrated in a NIST traceable climate chamber and validated in flight against tower measurements, radiosondes and remote sensing. The sensors have a measurement range of at least −10–50 °C, an absolute RMS error of less than ±0.2 K which is stable over the lifetime of the sensors, and a resolution of about 0.01 K. Both devices are tested for typical errors like radiation error and adiabatic heating, as well as for their dynamic response. Spectral resolutions of up to approximately 10 Hz can be obtained with both sensors, which makes them suitable for turbulence measurement. Their low cost of less than 100 EUR in pure hardware is a major advantage for research with small RPA.
Effects of cerebellar lesions on working memory interacting with motor tasks of different complexities
2013-08-22

We examined the influence of focal cerebellar lesions on working memory ( n-back task), gait, and the interaction between working memory and different gait tasks in a dual-task paradigm. The analysis included 17 young patients with chronic focal lesions after cerebellar tumor resection and 17 age-matched controls. Patients have shown mild to moderate ataxia. Lesion sites were examined on the basis of structural magnetic resonance imaging. N-back tasks were executed with different levels of difficulty ( n = 1–4) during sitting (baseline), treadmill walking, and treadmill tandem walking (dual-task conditions). Patients exhibited decreased n-back performance particularly at difficult n-back levels and in dual-task conditions. Voxel-based lesion-symptom mapping revealed that decreased baseline n-back performance was associated with lesions of the posterolateral cerebellar hemisphere and the dentate nucleus. By contrast, decreased n-back performance in dual-task conditions was more associated with motor-related areas including dorsal portions of the dentate and the interposed nucleus, suggesting a prioritization of the motor task. During baseline walking, increased gait variability was associated with lesions in medial and intermediate regions, whereas for baseline tandem gait, lesions in the posterolateral hemispheres and the dentate nucleus became important. Posterolateral regions overlapped with regions related to baseline n-back performance. Consistently, we observed increased tandem gait variability with growing n-back difficulty in the dual-task condition. These findings suggest that dual-task effects in cerebellar patients are at least partially caused by a common involvement of posterolateral cerebellar regions in working memory and complex motor tasks.
U–Pb zircon ages and (isotope) geochemical signatures of the Kamanjab Inlier (NW Namibia): constraints on Palaeoproterozoic crustal evolution along the southern Congo craton
2013-08-22

Abstract The formation of the Kamanjab Inlier (KI) in NW Namibia is poorly known and constrained to Palaeoproterozoic times. With the Epupa complex (EC) and Grootfontein Inlier (GI), the KI marks the southwestern Congo craton margin. Our new geochemical data for granitoids and orthogneisses indicate formation along an active continental margin. Single zircon ages frame granitoid emplacement to 1.86–1.83 Ga, roughly 75 myr older than ages from the northern EC and approximately 100 myr younger than from the GI. The southern EC is the only known Archaean Namibian basement with εNd 1.85 Ga of −10.2 to −6.3, in contrast to northern EC (−1.8 to 4.4) and KI (−6.2 to 2.6). Thus, earlier speculation that the southern EC is an exotic terrane, among the Namibian basement complexes, is supported by our data. In contrast, the KI is geochemically comparable to the northern EC and GI. The c. 2.0 Ga Lufubu metamorphic complex roughly 1000 km further east shows similar geochemistry, and a common evolution in the Kamanjab–Bangeweulu magmatic arc has already been proposed. Therefore, our new data point to a major Palaeoproterozoic crustal growth event at the southwestern margin of the Congo Craton starting in the present east and gradually moving towards the present NW.
Late Pliocene–Quaternary evolution of redox conditions in the western Qaidam paleolake (NE Tibetan Plateau) deduced from Mn geochemistry in the drilling core SG-1
2013-08-22

Manganese (Mn) in lake sediments reacts strongly to changes of redox conditions. This study analyzed Mn concentrations in oxides, carbonates, and bulk phases of the calcareous lacustrine sediments of a 938.5-m-long core (SG-1) taken from the western Qaidam Basin, well dated from 2.77 Ma to 0.1 Ma. Comparisons of extractions from diluted hydrochloric acid, acetic acid and citrate"bicarbonate"dithionite demonstrate that variations of Mn concentrations from acetic acid leaching (Mn HOAc ) are mostly responsible for Mn (II) fluctuations in the carbonate phase. Taking into account the relevant processes during weathering, transportation, deposition and post-deposition of Mn-bearing rocks, we conclude that Mn input from catchment weathering and paleolake redox condition provide the primary controls on variations in the Mn records of carbonate and oxide phases. We propose Mn HOAc as a new sensitive indicator of paleolake redox evolution and catchment-scale climate change. The Mn HOAc variations show a long-term upward decreasing trend, indicating a long-term decrease of Mn input from catchment weathering associated with increasing oxygen content in the paleolake bottom water. The great similarities of the Mn HOAc record with other regional and global records suggest that paleolake redox changes and climatic drying in the Qaidam Basin may be largely related to global cooling.
What Do I Want and When Do I Want It: Brain Correlates of Decisions Made for Self and Other
2013-08-22

A number of recent functional Magnetic Resonance Imaging (fMRI) studies on intertemporal choice behavior have demonstrated that so-called emotion- and reward-related brain areas are preferentially activated by decisions involving immediately available (but smaller) rewards as compared to (larger) delayed rewards. This pattern of activation was not seen, however, when intertemporal choices were made for another (unknown) individual, which speaks to that activation having been triggered by self-relatedness. In the present fMRI study, we investigated the brain correlates of individuals who passively observed intertemporal choices being made either for themselves or for an unknown person. We found higher activation within the ventral striatum, medial prefrontal and orbitofrontal cortex, pregenual anterior cingulate cortex, and posterior cingulate cortex when an immediate reward was possible for the observer herself, which is in line with findings from studies in which individuals actively chose immediately available rewards. Additionally, activation in the dorsal anterior cingulate cortex, posterior cingulate cortex, and precuneus was higher for choices that included immediate options than for choices that offered only delayed options, irrespective of who was to be the beneficiary. These results indicate that (1) the activations found in active intertemporal decision making are also present when the same decisions are merely observed, thus supporting the assumption that a robust brain network is engaged in immediate gratification; and (2) with immediate rewards, certain brain areas are activated irrespective of whether the observer or another person is the beneficiary of a decision, suggesting that immediacy plays a more general role for neural activation. An explorative analysis of participants' brain activation corresponding to chosen rewards, further indicates that activation in the aforementioned brain areas depends on the mere presence, availability, or actual reception of immediate rewards.
A virtual reality setup for controllable, stylized real-time interactions between humans and avatars with sparse Gaussian process dynamical models
2013-08-22

Building on our previous work [Taubert et al. 2012], we present an approach for real-time interaction between a real human and an avatar. We generate reactive motions by a dynamical extension of a hierarchical Gaussian process latent variable model, including latent dimensions for emotional style variation and target positions. This allows the avatar to produce accurate reactive motions to the human. To validate our approach, we developed a real-time application where an avatar and a human actor engage in emotional 'high fives'. Furthermore, we show preliminary results indicating that humans do perceive emotions more accurately when engaging in interaction as opposed to passive observation.
Archaeobotanical Archiving—Response
2013-08-22

We share Golzari's concern for the conservation of Iran's cultural heritage. Two of us (M.Z. and N.J.C.) are the Iranian and German directors of the Chogha Golan excavations. Furthermore M.Z. is a graduate of Tehran University who has spent most of his professional career employed by the Iranian Department of Antiquities. The project served as an important training excavation for numerous Iranian students, who learned how to use state-of-the-art methods to carefully excavate this pre-ceramic tell. Our team has a formal partnership with the Iranian Department of Antiquities to conduct archaeobotanical research. We were granted a permit to export the botanical materials from Chogha Golan. Given that there is no established facility for conducting archaeobotanical research, nor a facility for long-term storage of archaeobotanical materials in Iran, the University of Tubingen, with its excellent infrastructure and long record of research in the fields of botany and archaeobotany, is an appropriate place to study the botanical remains from Chogha Golan. Our team, which is composed of Iranian and other international scholars, works closely with the Department of Antiquities in Iran, with whom we have a long relationship based on shared scientific goals, trust, and mutual respect. When our research has been completed, we will work closely with our colleagues at the Department of Antiquities to decide where and how to best archive the botanical material from Chogha Golan.
A ntimicrobial peptides and gut microbiota in homeostasis and pathology
2013-08-23

We survive because we adapted to a world of microorganisms. All our epithelial surfaces participate in keeping up an effective barrier against microbes while not initiating ongoing inflammatory processes and risking collateral damage to the host. Major players in this scenario are antimicrobial peptides (AMPs). Such broad-spectrum innate antibiotics are in part produced by specialized cells but also widely sourced from all epithelia as well as circulating inflammatory cells. AMPs belong to an ancient defense system found in all organisms and participated in a preservative co-evolution with a complex microbiome. Particularly interesting interactions between host barrier and microbiota can be found in the gut. The intestinal cell lining not only has to maintain a tightly regulated homeostasis during its high-throughput regeneration, but also a balanced relationship towards an extreme number of mutualistic or commensal inhabitants. Recent research suggests that advancing our understanding of the circumstances of such balanced and sometimes imbalanced interactions between gut microbiota and host AMPs should have therapeutic implications for different intestinal disorders.
Elucidating the evolutionary conserved DNA-binding specificities of WRKY transcription factors by molecular dynamics and in vitro binding assays
2013-08-23

WRKY transcription factors constitute a large protein family in plants that is involved in the regulation of developmental processes and responses to biotic or abiotic stimuli. The question arises how stimulus-specific responses are mediated given that the highly conserved WRKY DNA-binding domain (DBD) exclusively recognizes the 'TTGACY' W-box consensus. We speculated that the W-box consensus might be more degenerate and yet undetected differences in the W-box consensus of WRKYs of different evolutionary descent exist. The phylogenetic analysis of WRKY DBDs suggests that they evolved from an ancestral group IIc-like WRKY early in the eukaryote lineage. A direct descent of group IIc WRKYs supports a monophyletic origin of all other group II and III WRKYs from group I by loss of an N-terminal DBD. Group I WRKYs are of paraphyletic descent and evolved multiple times independently. By homology modeling, molecular dynamics simulations and in vitro DNA-protein interaction-enzyme-linked immunosorbent assay with AtWRKY50 (IIc), AtWRKY33 (I) and AtWRKY11 (IId) DBDs, we revealed differences in DNA-binding specificities. Our data imply that other components are essentially required besides the W-box-specific binding to DNA to facilitate a stimulus-specific WRKY function.
Stannylene-Based Lewis Pairs
2013-08-23

Intramolecular stannylene-based Lewis pairs with phosphine Lewis bases were synthesized at the ortho position in benzene or the peri position in acenaphthene. The spectroscopic data of the Lewis pairs are discussed, and the reactivity toward unsaturated hydrocarbons and organic azides is presented.