PrBi, a sister member of the rare-earth monopnictide family, is an excellent candidate for studying extreme magnetoresistance and nontrivial topological electronic states. In this study, we perform ...angular magnetoresistance measurements as well as bulk and surface band structure calculations on this compound. PrBi's magnetoresistance is revealed to be significantly angle-dependent and shows a fourfold symmetry as always observed in the nonmagnetic isostructural counterparts, including LaSb, LaBi, and LuBi. Its angular magnetoresistance can be reproduced well using the semiclassical two-band model. The deduced parameters suggest that PrBi hosts an elongated electron pocket with a mobility anisotropy of 3.13 and is slightly uncompensated in its carrier concentration. Our bulk and surface band structure calculations confirm the anisotropic electronic features. Moreover, we reveal that a nodal-line-shaped surface state appears at the
X&cmb.macr;
point, and is associated with the quadratic dispersion along the
&z.Ggrm;
X&cmb.macr;
direction, and the linear type-I Dirac dispersion along the
X&cmb.macr;
M&cmb.macr;
direction. Owing to the type-I Dirac dispersion feature, PrBi could serve as a promising material platform for studying many unexpected physical properties, such as the highly anisotropic transport and valley polarization of electrons.
PrBi shows extreme and anisotropic magnetoresistance as well as nontrivial electronic band structures with a nodal-line-shaped surface state at the
X&cmb.macr;
point.
Essentials
Perioperative blood loss and inflammatory response can significantly affect recovery after surgery.
We studied the effects of multiple‐dose oral tranexamic acid on blood loss and ...inflammatory response.
A postoperative four‐dose regimen brought about maximum reduction in postoperative blood loss.
A postoperative four‐dose regimen reduced inflammatory response and promoted early rehabilitation.
Summary
Background
Tranexamic acid (TXA) can reduce blood loss and the inflammatory response at multiple doses in total knee arthroplasty patients. However, the optimal regimen has not been determined.
Objectives
To identify the most effective regimen for achieving maximum reductions in blood loss and the inflammatory response.
Patients/Methods
Two hundred and seventy‐five patients were randomized to receive a placebo (group A), a single 2‐g oral dose of TXA 2 h preoperatively followed by 1 g of oral TXA 3 h postoperatively (group B), a single dose followed by 1 g of oral TXA 3 h and 7 h postoperatively (group C), a single dose followed by 1 g of oral TXA 3 h, 7 h and 11 h postoperatively (group D), or a single dose followed by 1 g of oral TXA 3 h, 7 h, 11 h and 15 h postoperatively (group E). The primary outcome was total blood loss on postoperative day (POD) 3. Secondary outcomes included a decrease in the hemoglobin level, coagulation parameters, inflammatory marker levels, and thromboembolic complications.
Results
Groups D and E had significantly lower blood loss and smaller decreases in hemoglobin level than groups A, B, and C, with no significant difference on POD 3 between groups D and E. Significantly enhanced coagulation was identified for the four multiple‐dose regimens; however, all thromboelastographic parameters remained within normal ranges. Group E had the lowest inflammatory marker levels and pain, and the greatest range of motion. No thromboembolic complications were identified.
Conclusion
The four‐dose regimen yielded the maximum reductions in blood loss and inflammatory response, improved analgesia, and promoted early rehabilitation. Further studies are required to ensure that these findings are reproducible.
We report the observation of Kirkendall voids at the epitaxial titanium nitride (TiN)/magnesium oxide(MgO)(001) interface. While epitaxial growth of TiN on MgO has been known for years, many reports ...show a perfectly sharp epitaxial interface. Because TiN is a prototypical diffusion barrier material, observing the consequence of rapid diffusion at a TiN interface is interesting. Structural characterization of the interface using X-ray diffraction and electron microscopy confirms the diffuse nature of the interface. Rectangular voids that form at the TiN/MgO(001) interface and extend into both TiN and MgO result from a large chemical potential gradient at the interface, which contributes a strong chemical driving force for diffusion. The spatial localization of the observed voids is limited to within ∼10 nm from the interface, consistent with a chemical potential gradient driving force. A composition gradient on the nanometer scale is also observed. Observation of Kirkendall voids at this nitride/oxide interface suggests possibilities for engineering oxygen and nitrogen vacancies at thin film interfaces.
We report the observation of Kirkendall voids at the epitaxial titanium nitride (TiN)/magnesium oxide(MgO)(001) interface.
Despite the considerable potential and significant promise of aluminum scandium nitride (AlScN) ferroelectric materials for neuromorphic computing applications, challenges related to device ...engineering, along with the considerable structural disorder in thin films grown on various substrates using different vapor synthesis methods, make it difficult to systematically study the structure-property relationship. In this work, we approach such issues from the crystal growth side by successfully growing high-quality single crystal AlScN nanowires through ultra-high vacuum reactive sputtering under high substrate bias and low atomic flux conditions, which leads to simultaneous growth and etching. Characterization of nanowire arrays using X-ray diffraction and transmission electron microscopy shows that the wires are epitaxial single crystals with significantly reduced mosaic spread and predominantly single ferroelectric domains. Moreover, ferroelectric and piezoelectric properties were evaluated using Piezoresponse Force Microscopy. The single crystal AlScN nanowires show an out-of-plane piezoelectric constant
d
33
that is greater than 20 pm V
−1
, which is higher than that of pure AlN by a factor of ∼4.
Single crystal ferroelectric AlScN nanowires.
The adherens junction (AJ) is an element of the cell-cell junction in which cadherin receptors bridge the neighboring plasma membranes via their homophilic interactions. Cadherins associate with ...cytoplasmic proteins, called catenins, which in turn bind to cytoskeletal components, such as actin filaments and microtubules. These molecular complexes further interact with other proteins, including signaling molecules, rendering the AJs into highly dynamic and regulatable structures. The AJs of such nature contribute to the physical linking of cells, as well as to the regulation of cell-cell contacts, which is essential for morphogenesis and remodeling of tissues and organs. Thus, elucidating the molecular architecture of the AJs and their regulatory mechanisms are crucial for understanding how the multicellular system is organized.
Crystallization has been applied to a broad range of industries such as bulk and fine chemicals and the pharmaceutical and food industries. It is important to strategically control the in situ ...purification process during crystallization to meet the regulatory and functional specifications of the crystals. While the control of the crystallization–purification process has been widely discussed for batch crystallizers, there has been little focus with the literature on controlling purification for continuous crystallizers. Continuous crystallization is a more intensified approach to crystallization, with lower capital footprint and potentially offering more consistent quality control. This review paper provides an in-depth discussion of the strategies and scientific understanding in controlling the crystallization–purification process in continuous crystallization. In particular, it describes how scientific understanding in the purification process, generated so far for batch crystallization, can be translated to continuous crystallization.
Seven-year measurements of precipitation, lightning flashes, and visibility from 2000 to 2006 have been analyzed in the Pearl River Delta (PRD) region, China, with a focus on the Guangzhou megacity ...area. Statistical analysis shows that the occurrence of heavy rainfall (>25 mm per day) and frequency of lightning strikes are reversely correlated to visibility during this period. To elucidate the effects of aerosols on cloud processes, precipitation, and lightning activity, a cloud resolving - Weather Research and Forecasting (CR-WRF) model with a two-moment bulk microphysical scheme is employed to simulate a mesoscale convective system occurring on 28 Match 2009 in the Guangzhou megacity area. The model predicted evolutions of composite radar reflectivity and accumulated precipitation are in agreement with measurements from S-band weather radars and automatic gauge stations. The calculated lightning potential index (LPI) exhibits temporal and spatial consistence with lightning flashes recorded by a local lightning detection network. Sensitivity experiments have been performed to reflect aerosol conditions representative of polluted and clean cases. The simulations suggest that precipitation and LPI are enhanced by about 16% and 50%, respectively, under the polluted aerosol condition. Our results suggest that elevated aerosol loading suppresses light and moderate precipitation (less than 25 mm per day), but enhances heavy precipitation. The responses of hydrometeors and latent heat release to different aerosol loadings reveal the physical mechanism for the precipitation and lightning enhancement in the Guangzhou megacity area, showing more efficient mixed phase processes and intensified convection under the polluted aerosol condition.
Experiments are performed on micron-scale single-crystal prototypical structural elements experiencing combined torsion and bending to gather data on their load-carrying capacity in the range of size ...and strain relevant to micron-scale structures for which little data are available. The observed strengthening dependence on size for the structural elements is in general accord with trends inferred from prior tests such as indentation and pure torsion. In addition, the experiments systematically reveal the strengthening size-dependence of structural elements whose surface has been passivated by a very thin Cr coating, an effect shown to have substantial strengthening potential. A state-of-the-art strain gradient plasticity theory is used to analyze the structural elements over the entire range of size and loading. While the computed trends replicate the experimental trends with reasonable fidelity, the predictive exercise, which is representative of those that will be required in micron-scale structural analysis, brings to light constitutive and computational issues which will have to be addressed before micron-scale plasticity theory can serve as effectively at the micron scale as conventional plasticity does at larger scales.
Many tissues rely on resident stem cell population to maintain homeostasis. The balance between cell proliferation and differentiation is critical to permit tissue regeneration and prevent dysplasia, ...particularly following tissue damage. Thus, understanding the cellular processes and genetic programs that coordinate these processes is essential. Here, we report that the conserved transcription factor zfh2 is specifically expressed in Drosophila adult intestinal stem cell and progenitors and is a critical regulator of cell differentiation in this lineage. We show that zfh2 expression is required and sufficient to drive the activation of enteroblasts, the non-proliferative progenitors of absorptive cells. This transition is characterized by the transient formation of thin membrane protrusions, morphological changes characteristic of migratory cells and compensatory stem cell proliferation. We found that zfh2 acts in parallel to insulin signaling and upstream of the TOR growth-promoting pathway during early differentiation. Finally, maintaining zfh2 expression in late enteroblasts blocks terminal differentiation and leads to the formation of highly dysplastic lesions, defining a new late cell differentiation transition. Together, our study greatly improves our understanding of the cascade of cellular changes and regulatory steps that control differentiation in the adult fly midgut and identifies zfh2 as a major player in these processes.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Adult organs and their resident stem cells are constantly facing the challenge of adapting cell proliferation to tissue demand, particularly in response to environmental stresses. Whereas most ...stress-signaling pathways are conserved between progenitors and differentiated cells, stem cells have the specific ability to respond by increasing their proliferative rate, using largely unknown mechanisms. Here, we show that a member of the Sox family of transcription factors in Drosophila, Sox21a, is expressed in intestinal stem cells (ISCs) in the adult gut. Sox21a is essential for the proliferation of these cells during both normal epithelium turnover and repair. Its expression is induced in response to tissue damage, downstream of the Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) pathways, to promote ISC proliferation. Although short-lived, Sox21a mutant flies show no developmental defects, supporting the notion that this factor is a specific regulator of adult stem cell proliferation.
Display omitted
•Sox21a is specifically required for adult intestinal stem cell proliferation•Sox21a expression is induced in response to tissue damage•Sox21a is controlled by the JNK- and ERK-signaling pathways
Meng and Biteau show that a Drosophila Sox2 homolog is expressed in adult intestinal stem cells and is essential for proliferation under normal conditions and after tissue damage. They find that this factor is induced by the JNK and ERK pathways to promote epithelial repair.
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