The generation of intense electron beams with low emittance is key to both the production of coherent x rays from free electron lasers, and electron pulses with large transverse coherence length used ...in ultrafast electron diffraction. These beams are generated today by photoemission from disordered polycrystalline surfaces. We show that the use of single crystal surfaces with appropriate electronic structures allows us to effectively utilize the physics of photoemission to generate highly directed electron emission, thus reducing the emittance of the electron beam being generated.
Heme oxygenase-1 (HO-1) is a heme-degrading enzyme anchored in the endoplasmic reticulum by a carboxyl-terminal transmembrane segment (TMS). HO-1 is highly expressed in various cancers and its ...nuclear localization is associated with the progression of some cancers. Nevertheless, the mechanism underlying HO-1 nuclear translocation and its pathological significance remain elusive. Here we show that the signal peptide peptidase (SPP) catalyzes the intramembrane cleavage of HO-1. Coexpression of HO-1 with wild-type SPP, but not a dominant-negative SPP, promoted the nuclear localization of HO-1 in cells. Mass spectrometry analysis of cytosolic HO-1 isolated from HeLa cells overexpressing HO-1 and SPP revealed two adjacent intramembrane cleavage sites located after S275 and F276 within the TMS. Mutations of S275F276 to A275L276 significantly hindered SPP-mediated HO-1 cleavage and nuclear localization. Nuclear HO-1 was detected in A549 and DU145 cancer cell lines expressing high levels of endogenous HO-1 and SPP. SPP knockdown or inhibition significantly reduced nuclear HO-1 localization in A549 and DU145 cells. The positive nuclear HO-1 stain was also evident in lung cancer tissues expressing high levels of HO-1 and SPP. Overexpression of a truncated HO-1 (t-HO-1) lacking the TMS in HeLa and H1299 cells promoted cell proliferation and migration/invasion. The effect of t-HO-1 was not affected by a mutation in the catalytic site. However, blockade of t-HO-1 nuclear localization abolished t-HO-1-mediated effect. The tumorigenic effect of t-HO-1 was also demonstrated in the mouse model. These findings disclose that SPP-mediated intramembrane cleavage of HO-1 promotes HO-1 nuclear localization and cancer progression independent of HO-1 enzymatic activity.
One-third of a monolayer of Bi alloyed into the Ag(111) surface yields a pair of Rashba spin-split free-electron-like surface states. The splitting in momentum space is the largest of all surface ...alloys investigated. Using first-principles calculations, we have determined the spin splitting in this system as a function of atomic corrugation of the top atomic layer and the strengths of the atomic spin-orbit coupling in Bi and Ag. The calculated splitting is proportional to the strengths of the atomic spin-orbit coupling, but it peaks at a certain surface corrugation parameter. These findings indicate that the observed giant spin splitting is caused by a near-optimal surface corrugation and a large atomic spin-orbit coupling in Bi. The results offer a useful guide for searching for two-dimensional systems with large surface spin effects.
We use femtosecond electron diffraction to study ultrafast lattice dynamics in the highly correlated antiferromagnetic (AFM) semiconductor NiO. Using the scattering vector (Q) dependence of Bragg ...diffraction, we introduce Q-resolved effective temperatures describing the transient lattice. We identify a nonthermal lattice state with preferential displacement of O compared to Ni ions, which occurs within ∼0.3 ps and persists for 25 ps. We associate this with transient changes to the AFM exchange striction-induced lattice distortion, supported by the observation of a transient Q asymmetry of Friedel pairs. Our observation highlights the role of spin-lattice coupling in routes towards ultrafast control of spin order.
This study aimed to develop biodegradable calcium alginate microcarriers with uniform particle size and spherical integrity for sustained-release targeting transarterial chemoembolization. To ...determine related parameters including the ratio of cross-linking volume (sodium alginate: CaCl
), concentrations of sodium alginate and CaCl
solutions, collection distance, flow rate, stirring speed, syringe needle diameter and hardening time to fabricate the microcarriers, the Taguchi method was applied. Using different conditions, a total of 18 groups were prepared. The average size of microspheres from different groups was estimated as ~ 2 mm (range 1.1 to 1.6 mm). Signal-to-noise ratio analysis showed the optimal spherical integrity (F1) achieved when the above parameters were designed as 0.1, 2.5 wt%, 6 wt%, 8 cm, 30 mL/h, 150 rpm, 0.25 mm and 2 h, respectively. The best (F1), middle (F2) and worst (F3) groups were used for further experiments. Fourier-transform infrared spectroscopy spectrum showed that F1, F2 and F3 conformations were distinct from original sodium alginate. Drug-loaded calcium alginate microcarriers demonstrated rougher surfaces compared to microspheres without drug under transmission electron microscopy. Compared to pH 7.4, swelling rates in PBS were decreased at pH 6.5. Encapsulation and loaded efficiencies of the Dox-loaded microcarriers were estimated as ~ 40.617% and ~ 3.517%. In vitro experiments indicated that the F1 Dox-loaded microcarriers provide a well sustained-release efficacy for about two weeks at 37 °C in PBS. Treatments of calcium alginate microcarriers without the Dox in two distinct hepatocellular carcinoma-derived cell lines, Huh-7 and Hep-3B, indicated that these microcarriers were non-toxic. The Dox-loaded microcarriers displayed sustained-release capacity and reduced cell viabilities to ~ 30% in both cell lines on Day 12.
Rare red‐fluorescent fluorene derivatives have been designed and synthesized. The long‐wavelength red fluorescence is achieved by incorporating a di(4‐tolyl)amino or diphenylamino electron donor and ...a dicyanovinyl electron acceptor. The single‐crystal X‐ray structures of the di(4‐tolyl)amino (pTSPDCV) and diphenylamino (PhSPDCV) compounds indicate only weak non‐π van der Waals contacts in addition to long‐distance dipole–dipole interactions of the red‐emitting fluorene molecules in the solid state. The aggregation of the dipolar fluorene is largely suppressed by introducing bulky 9,9‐substituents (spiro‐fused bifluorene) as well as a non‐planar di(4‐tolyl)amino or diphenylamino group. In the solid state, these fluorene derivatives all show red fluorescence that is much brighter than with the red dopants Nile Red and DCM (4‐(dicyanomethylene)‐2‐methyl‐6‐4‐(dimethylaminostyryl)‐4H‐pyran). The unique photophysical properties of red‐emitting fluorene derivatives differ from other known red dopants and facilitate the fabrication of non‐doped red organic light‐emitting diodes (OLEDs). Authentic red (CIE, x = 0.65, y = 0.35) electroluminescence with a brightness of more than 12 000 cd m–2 (greater than 600 cd m–2 at 20 mA cm–2) and a remarkable external quantum efficiency as high as 3.6 % have been observed for the red‐emitting OLEDs with pTSPDCV or PhSPDCV as the sole emitting host.
Brilliant red‐light‐emitting fluorenes, diphenylamino‐ and dicyanovinyl‐ substituted spirobifluorenes are reported. These compounds perform far better than Nile Red and DCM in the solid state (see Figure); non‐doped light‐emitting diodes with a red‐emitting fluorene as host‐emitter show external quantum efficiencies as high as 3.6 % and electroluminescence of over 12 000 cd m–2.
Time-restricted eating (TRE) has gained popularity in recent years as a weight loss option. Although many studies have explored the effectiveness of fasting, few have investigated the successful ...implementation of this method. Therefore, the purpose of this study is to examine the successful and failed experiences of overweight adults who have implemented TRE for weight loss, in order to identify strategies for maintaining a favorable weight over time. The study utilized semi-structured interviews and followed Constructivist Grounded Theory to collect and analyze data. Data saturation was achieved through purposive and theoretical sampling of 30 overweight adults. The research confirms four stages in the process of weight loss using a TRE strategy, namely, preparation, adaptation, challenge, and maintenance. The findings revealed that the successful implementation of TRE and its maintenance over time require viewing TRE as a lifestyle rather than a tool for short-term weight loss, the development of specific action plans to overcome obstacles, and a positive attitude and self-belief as important sources of support. Based on the study's results, a guide has been provided for those who wish to use TRE as a dietary control method.
•BB = behavioral beliefs; CB = control beliefs; NB = normative beliefs•The BB→VI (behavioral/visit intention) impact is completely mediated by attitude.•The NB→VI impact is not mediated subjective ...norm.•The CB→VI impact is partially mediated by perceived behavioral control.•TPB model with mediators can better predict the green hotel consumption intention.
The main aim of this paper was to understand a guest’s decision to stay at a green hotel by using the theory of planned behavior (TPB) developed by Ajzen (1991). The population for this study was green hotel customers in Taiwan. A total of 425 usable responses were received from the willing participants around the parking area of green hotels. This study performed a PLS-SEM to examine the proposed model. The results of this study showed that social pressure has very little direct impact on behavioral intention to stay at a green hotel. The results of the estimated standardized regression coefficients and t-values indicated that perceived behavioral control has a slightly higher impact on behavioral intention than attitude. This study also verified the proposed mediating relationships between the first-order and second-order antecedents. This study provided theoretical and managerial implications for understanding respondents’ decision to stay at a green hotel.
Superconductivity in so-called unconventional superconductors is nearly always found in the vicinity of another ordered state, such as antiferromagnetism, charge density wave (CDW), or stripe order. ...This suggests a fundamental connection between superconductivity and fluctuations in some other order parameter. To better understand this connection, we used high-pressure X-ray scattering to directly study the CDW order in the layered dichalcogenide TiSe2, which was previously shown to exhibit superconductivity when the CDW is suppressed by pressure1 or intercalation of Cu atoms2. We succeeded in suppressing the CDW fully to zero temperature, establishing for the first time the existence of a quantum critical point (QCP) at Pc = 5.1 ± 0.2 GPa, which is more than 1 GPa beyond the end of the superconducting region. Unexpectedly, at P = 3 GPa we observed a reentrant, weakly first order, incommensurate phase, indicating the presence of a Lifshitz tricritical point somewhere above the superconducting dome. Our study suggests that superconductivity in TiSe2 may not be connected to the QCP itself, but to the formation of CDW domain walls.
PDF
