Owing to the diversity of composition and excellent transport properties, the ternary I–III–VI2 type diamond-like chalcopyrite compounds are attractive functional semiconductors, including as ...thermoelectric materials. In this family, CuInTe2 and CuGaTe2 are well investigated and achieve maximum ZT values of ∼1.4 at 950 K and an average ZT of 0.43. However, both compounds have poor electrical conductivity at low temperature, resulting in low ZT below 450 K. In this work, we have greatly improved the thermoelectric performance in the quinary diamondoid compound (Cu0.8Ag0.2)(In0.2Ga0.8)Te2 by understanding and controlling the effects of different constituent elements on the thermoelectric transport properties. Our combined theoretical and experimental effort indicates that Ga in the In site of the lattice decreases the carrier effective mass and improves the electrical conductivity and power factor of Cu0.8Ag0.2In1–x Ga x Te2. Furthermore, Ag in the Cu site strongly suppresses the heat transport via the enhanced acoustic phonon–optical phonon coupling effects, leading to the ultralow thermal conductivity of ∼0.49 W m–1 K–1 at 850 K in Cu0.8Ag0.2In0.2Ga0.8Te2. Defect formation energy calculations suggest intrinsic Cu vacancies introduce defect levels that are important to the temperature-dependent hole density and electrical conductivity. Therefore, we introduced extra Cu vacancies to optimize the hole carrier density and improve the power factor of Cu0.8Ag0.2In0.2Ga0.8Te2. As a result, a maximum ZT of ∼1.5 at 850 K and an average ZT of 0.78 in the temperature range of 400–850 K are obtained, which is among the highest in the diamond-like compound family.
Converting waste heat into useful electricity using solid-state thermoelectrics has a potential for enormous global energy savings. Lead chalcogenides are among the most prominent thermoelectric ...materials, whose performance decreases with an increase in chalcogen amounts (e.g., PbTe > PbSe > PbS). Herein, we demonstrate the simultaneous optimization of the electrical and thermal transport properties of PbS-based compounds by alloying with GeS. The addition of GeS triggers a complex cascade of beneficial events as follows: Ge2+ substitution in Pb2+ and discordant off-center behavior; formation of Pb5Ge5S12 as stable second-phase inclusions through valence disproportionation of Ge2+ to Ge0 and Ge4+. PbS and Pb5Ge5S12 exhibit good conduction band energy alignment that preserves the high electron mobility; the formation of Pb5Ge5S12 increases the electron carrier concentration by introducing S vacancies. Sb doping as the electron donor produces a large power factor and low lattice thermal conductivity (κlat) of ∼0.61 W m–1 K–1. The highest performance was obtained for the 14% GeS-alloyed samples, which exhibited an increased room-temperature electron mobility of ∼121 cm2 V–1 s–1 for 3 × 1019 cm–3 carrier density and a ZT of 1.32 at 923 K. This is ∼55% greater than the corresponding Sb-doped PbS sample and is one of the highest reported for the n-type PbS system. Moreover, the average ZT (ZTavg) of ∼0.76 from 400 to 923 K is the highest for PbS-based systems.
Considering the high energy consumption during processing, and the low compliance and adhesion of ceramic electrolytes, the integration of polymer into ceramic electrolytes provides a way to mitigate ...the interfacial issues. However, the severe ion concentration gradient, low ionic conductivity, and instability toward Li metal and high-voltage cathodes become the major concerns in applying hybrid electrolytes. In this work, we report a single-ion-conducting hybrid electrolyte (SIE-LLZO) with 64 wt % Li7La3Zr2O12(LLZO) particles embedded in a fluoroboron-centered Li-conductive polymer framework (LiBFSIE). The SIE-LLZO electrolyte exhibited a high Li transference number of 0.94 and electrochemical stability up to 5.6 V vs Li/Li+. Promising averaged Coulombic efficiencies of 99.97% and 99.91% were achieved in cells with LiNi0.8Co0.15Al0.05O2 and LiNi0.6Mn0.2Co0.2O2 cathodes for 400 and 200 cycles, respectively. The Li-conducting pathway in the hybrid electrolyte was further investigated by a 6Li-to-7Li isotope replacement method, indicating that Li transport mainly relies on the LLZO and interface between LiBFSIE and LLZO.
Flatfoot is a condition commonly seen in children; however, there is general disagreement over its incidence, characterization and correction. Painful flatfoot accompanied with musculoskeletal and ...soft tissue problems requires surgery to avoid arthritis in adulthood, the most common surgical approach being two osteotomies to the calcaneus and medial cuneiform bones of the foot.
This study focuses on the parametrization of these two bones to understand their bone morphology differences in a population sample among 23 normal subjects. Population differences could help in understanding whether bone shape may be an important factor in aiding surgical planning and outcomes.
A total of 45 sets of CT scans of these subjects were used to generate surface meshes of the two bones and converted to be iso-topological meshes, simplifying the application of Generalized Procrustes Analysis and Principal Component Analysis, allowing the main sources of variation between the subjects to be quantified.
For the calcaneus, 16 Principal Components (PCs) and, for the medial cuneiform, 12 PCs were sufficient to describe 90% of the dataset variability. The quantitative and qualitative analyses confirm that for the calcaneus PC1 describes the Achilles attachment location and PC2 largely describes the anterior part of the bone. For the medial cuneiform, PC1 describes the medial part of the bone, while PC2 mainly describes the superior part.
Most importantly, the PCs did not seem to describe the osteotomy sites for both bones, suggesting low population variability at the bone cutting points. Further studies are needed to evaluate how shape variability impacts surgical outcomes. Future implications could include better surgical planning and may pave the way for complex robotic surgeries to become a reality.
We present an effective approach to favorably modify the electronic structure of PbSe using Ag doping coupled with SrSe or BaSe alloying. The Ag 4d states make a contribution to in the top of the ...heavy hole valence band and raise its energy. The Sr and Ba atoms diminish the contribution of Pb 6s2 states and decrease the energy of the light hole valence band. This electronic structure modification increases the density‐of‐states effective mass, and strongly enhances the thermoelectric performance. Moreover, the Ag‐rich nanoscale precipitates, discordant Ag atoms, and Pb/Sr, Pb/Ba point defects in the PbSe matrix work together to reduce the lattice thermal conductivity, resulting a record high average ZTavg of around 0.86 over 400–923 K.
We find a new mechanism of strong band convergence with low onset temperature for p‐type PbSe. The discordant Ag doping raises the heavy hole band and Sr/BaSe alloying lowers the light hole band, leading to the fast and strong band convergence and significantly enhanced Seebeck coefficient.
The phase of inorganic lead halide perovskite film can be controlled in the chemical vapor deposition process.
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Inorganic lead halide perovskites are attractive optoelectronic ...materials owing to their relative stability compared to organic cation alternatives. The chemical vapor deposition (CVD) method offers potential for high quality perovskite film growth. The deposition temperature is a critical parameter determining the film quality owing to the melting difference between the precursors. Here, perovskite films were deposited by the CVD method at various temperatures between 500−800 °C. The perovskite phase converts from CsPb2Br5 to CsPbBr3 gradually as the deposition temperature is increased. The grain size of the perovskite films also increases with temperature. The phase transition mechanism was clarified. The photoexcited state dynamics were investigated by spatially and temporally resolved fluorescence measurements. The perovskite film deposited under 750 °C condition is of the CsPbBr3 phase, showing low trap-state density and large crystalline grain size. A photodetector based on perovskite films shows high photocurrent and an on/off ratio of ∼2.5 × 104.
Collagen type I, commonly derived from xenogenic sources, is extensively used as a biomaterial for tissue engineering applications. However, the use of xenogenic collagen is typically associated with ...species specific variation in mechanical, structural, and biological properties that are known to influence cellular response and remodeling. In addition, immunological complications and risks of disease transmission are also major concerns. The goal of this study is to characterize a new xeno-free human skin-derived collagen and assess its applicability as a bioink for cell-laden 3 D bioprinting. Four different concentrations of human collagen (i.e., 0.5 mg/mL, 1 mg/mL, 3 mg/mL and 6 mg/mL) were employed for the synthesis of collagen hydrogels. In addition, bovine collagen was used as a xenogenic control. Results from SDS-PAGE analysis showed the presence of α1, α2, and β chains, confirming that the integrity of type I human collagen is maintained post isolation. Polymerization rate and compressive modulus increased significantly with increase in the concentration of human collagen. When comparing two different sources of collagen, the polymerization rate of xenogenic collagen was significantly faster (p < 0.05) than human collagen while the compressive modulus was comparable. Raman spectroscopy showed a large peak in the Amide I band around 1600 cm−1, indicating a dense and supraorganized fibrillar structure in human collagen hydrogels. Conversely, Amide I band intensity for xenogenic collagen was comparable to that of Amide II and Amide III bands. Further, the use of 6 mg/mL human collagen as a bioink yielded 3 D printed constructs with high shape fidelity and cell viability. On the other hand, xenogenic collagen failed to yield stable 3 D printed constructs. Together, the results from this study provides an impetus for using human-derived collagen as a viable alternative to xenogenic sources for 3 D bioprinting of clinically relevant scaffolds for tissue engineering applications.
Natural cotton was dissolved in a room-temperature ionic liquid 1-ethyl-3-methyl acetate and wet-jet electrospun to obtain nanoscale cotton fibers with a substantially reduced diameter-and therefore ...an increased surface area-relative to natural cotton fibers. The resulting nano-cotton fibers were esterified with trityl-3-mercaptopropionic acid, which after selective de-tritylation afforded nano-cotton fibers containing reactive thiol functionality. Silver nanoparticles that were covalently attached to these sulfhydryl groups were assembled next. The microstructure of the resulting nanocomposite was characterized, and the antibacterial activity of the resulting nano-cotton Ag-nanoparticle composite was also studied. This nanocomposite showed significant activity against both Gram-negative and Gram-positive bacteria.
SARS-CoV-2-neutralizing antibodies (NAbs) protect against COVID-19. A concern regarding SARS-CoV-2 antibodies is whether they mediate disease enhancement. Here, we isolated NAbs against the ...receptor-binding domain (RBD) or the N-terminal domain (NTD) of SARS-CoV-2 spike from individuals with acute or convalescent SARS-CoV-2 or a history of SARS-CoV infection. Cryo-electron microscopy of RBD and NTD antibodies demonstrated function-specific modes of binding. Select RBD NAbs also demonstrated Fc receptor-γ (FcγR)-mediated enhancement of virus infection in vitro, while five non-neutralizing NTD antibodies mediated FcγR-independent in vitro infection enhancement. However, both types of infection-enhancing antibodies protected from SARS-CoV-2 replication in monkeys and mice. Three of 46 monkeys infused with enhancing antibodies had higher lung inflammation scores compared to controls. One monkey had alveolar edema and elevated bronchoalveolar lavage inflammatory cytokines. Thus, while in vitro antibody-enhanced infection does not necessarily herald enhanced infection in vivo, increased lung inflammation can rarely occur in SARS-CoV-2 antibody-infused macaques.
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•RBD or NTD antibodies exhibited infection enhancement in vitro but not in vivo•Neutralizing or infection-enhancing NTD antibodies bound distinct epitopes•In vitro infection-enhancing antibodies protected from SARS-CoV-2 in vivo•Cross-reactive RBD-neutralizing antibodies were protective—most potent DH1047
Convalescent human-derived SARS-CoV-2 RBD and NTD antibodies mediated neutralization as well as infection enhancement in vitro, yet infusion of these antibodies in mice or cynomolgus macaques resulted in suppression of virus replication.
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