16 research outputs found
A Chemical, High-Temperature Way to Ag<sub>1.9</sub>Te via Quasi-Topotactic Reaction of Stuetzite-type Ag<sub>1.54</sub>Te: Structural and Thermoelectric Properties
Semiconducting
silver tellurides gained reasonable interest in the past years due
to its thermoelectric, magneto-caloric, and nonlinear optic properties.
Nanostructuring has been frequently used to address quantum-confinement
effects of minerals and synthetic compounds in the AgâTe system.
Here, we report on the structural, thermal, and thermoelectric properties
of stuetzite-like Ag<sub>1.54</sub>Te (or Ag<sub>4.63</sub>Te<sub>3</sub>) and Ag<sub>1.9</sub>Te. By a quasi-topotactic reaction upon
tellurium evaporation Ag<sub>1.54</sub>Te can be transferred to Ag<sub>1.9</sub>Te after heat treatment. Crystal structures, thermal and
thermoelectric properties of stuetzite-like Ag<sub>1.54</sub>Te (or
Ag<sub>4.63</sub>Te<sub>3</sub>) and Ag<sub>1.9</sub>Te were determined
by ex situ and in situ experiments. This method represents an elegant
chemical way to Ag<sub>1.9</sub>Te, which was so far only accessible
electrochemically via electrochemical removal of silver from the mineral
hessite (Ag<sub>2</sub>Te). The mixed conductors show reasonable high
total electric conductivities, very low thermal conductivities, and
large Seebeck coefficients, which result in a significant high thermoelectric
figure of 0.57 at 680 K
Polymorphism in Zintl Phases ACd<sub>4</sub>Pn<sub>3</sub>: Modulated Structures of NaCd<sub>4</sub>Pn<sub>3</sub> with Pn = P, As
NaCd<sub>4</sub>P<sub>3</sub> and
NaCd<sub>4</sub>As<sub>3</sub> were synthesized via short-way transport
using the corresponding elements and CdI<sub>2</sub> as mineralizer.
At room temperature, the two ÎČ-polymorphs adopt the RbCd<sub>4</sub>As<sub>3</sub> structure type which has been recently reported
for alkali metal (A)âd<sup>10</sup> transition metal (T)âpnictides
(Pn). The title compounds crystallize rhombohedrally in space group <i>R</i>3Ì
<i>m</i> at room temperature and show
reversible phase transitions to incommensurately modulated α-polymorphs
at lower temperatures. The low-temperature phases are monoclinic and
can be described in space group <i>Cm</i>(α0γ)<i>s</i> with <i>q</i> vectors of <i>q</i> =
(â0.04,0,0.34) for α-NaCd<sub>4</sub>P<sub>3</sub> and <i>q</i><sub>1</sub> = (â0.02,0,0.34) for α-NaCd<sub>4</sub>As<sub>3</sub>. Thermal properties, Raman spectroscopy, and
electronic structures have been determined. Both compounds are Zintl
phases with band gaps of 1.05 eV for ÎČ-NaCd<sub>4</sub>P<sub>3</sub> and âŒ0.4 eV for ÎČ-NaCd<sub>4</sub>As<sub>3</sub>
Synthesis, Characterization, and Device Application of Antimony-Substituted Violet Phosphorus: A Layered Material
Two-dimensional
(2D) nanoflakes have emerged as a class of materials
that may impact electronic technologies in the near future. A challenging
but rewarding work is to experimentally identify 2D materials and
explore their properties. Here, we report the synthesis of a layered
material, P<sub>20.56(1)</sub>Sb<sub>0.44(1)</sub>, with a systematic
study on characterizations and device applications. This material
demonstrates a direct band gap of around 1.67 eV. Using a laser-cutting
method, the thin flakes of this material can be separated into multiple
segments. We have also fabricated field effect transistors based on
few-layer P<sub>20.56(1)</sub>Sb<sub>0.44(1)</sub> flakes with a thickness
down to a few nanometers. Interestingly, these field effect transistors
show strong photoresponse within the wavelength range of visible light.
At room temperature, we have achieved good mobility values (up to
58.96 cm<sup>2</sup>/V·s), a reasonably high on/off current ratio
(âŒ10<sup>3</sup>), and intrinsic responsivity up to 10 ÎŒA/W.
Our results demonstrate the potential of P<sub>20.56(1)</sub>Sb<sub>0.44(1)</sub> thin flakes as a two-dimensional material for applications
in visible light detectors
Efficacy and safety of crisaborole ointment, a novel, nonsteroidal phosphodiesterase 4 (PDE4) inhibitor for the topical treatment of atopic dermatitis (AD) in children and adults
BACKGROUND: Additional topical treatments for atopic dermatitis (AD) are needed that provide relief while minimizing risks.
OBJECTIVE: We sought to assess the efficacy and safety of crisaborole ointment, a phosphodiesterase 4 inhibitor, in two phase III AD studies (AD-301: NCT02118766; AD-302: NCT02118792).
METHODS: Two identically designed, vehicle-controlled, double-blind studies enrolled and randomly assigned (2:1, crisaborole:vehicle) patients aged 2 years or older with an Investigator\u27s Static Global Assessment (ISGA) score of mild or moderate for twice-daily application for 28 days. The primary end point was ISGA score at day 29 of clear (0)/almost clear (1) with 2-grade or greater improvement from baseline. Additional analyses included time to success in ISGA score, percentage of patients achieving clear/almost clear, reduction in severity of AD signs, and time to improvement in pruritus.
RESULTS: More crisaborole- than vehicle-treated patients achieved ISGA score success (clear/almost clear with â„2-grade improvement; AD-301: 32.8% vs 25.4%, P = .038; AD-302: 31.4% vs 18.0%, P \u3c .001), with a greater percentage with clear/almost clear (51.7% vs 40.6%, P = .005; 48.5% vs 29.7%, P \u3c .001). Crisaborole-treated patients achieved success in ISGA score and improvement in pruritus earlier than those treated with vehicle (both P †.001). Treatment-related adverse events were infrequent and mild to moderate in severity.
LIMITATIONS: Short study duration was a limitation.
CONCLUSIONS: Crisaborole demonstrated a favorable safety profile and improvement in all measures of efficacy, including overall disease severity, pruritus, and other signs of AD
INTEGRATING RACE, PLACE AND MOTIVE IN SOCIAL DISORGANIZATION THEORY: LESSONS FROM A COMPARISON OF BLACK AND LATINO HOMICIDE TYPES IN TWO IMMIGRANT DESTINATION CITIES*
In this paper, we examine and compare the impact of social disorganization, including recent immigration, and other predictors on community counts of black and Latino motiveâspecific homicides in Miami and San Diego. Homicides for 1985 to 1995 are disaggregated into escalation, intimate, robbery and drugârelated motives. Negative binomial regression models with corrections for spatial autocorrelation demonstrate that there are similarities and differences in effects of social disorganization and other predictors by motiveâspecific outcomes, as well as for outcomes across ethnic groups within cities and within ethnic groups across cities. Recent immigration is negatively or not associated with most outcomes. Overall, the study shows the importance of disaggregating homicide data by race/ethnicity and motive and demonstrates that predictions based on existing theories are qualified on local conditions
Sujetos de la masa. Visiones del nacionalismo después de la Primera Guerra Mundial
One of the most popular or widespread theories of nationalism postulates the existence of dark, atavistic forces, the outbreak of irrational compulsions and the regression to barbarism, in a collective process that would in any case pass through the control and unconscious manipulation of the masses. What is the origin of such an interpretation? In this article we explore the influence of biology and turn-of-the-century psychiatry in the academic representation of nationalism at the end of the Great War. As we shall see, the representation of nationalism after the war would incorporate the concepts and terms atavism, degenerationism and mass psychology, thus initiating an epistemological turn that would not be complete until mid-century, with the popularization of psychoanalysis and denunciation of the Holocaust