We propose a plausible microscopic mechanism for charge transfer during rebounding collisions between ice crystals and graupel within thunderstorms. The key concept is that charge is transferred through the diffusional transport of H+ ions across the ice-ice contact junction during collisions. The transferred charges are stabilized by the trapping of H+ ions at L-orientational defects in ice particles. The distinct formation pathways of ice crystals and graupel within a cloud lead to asymmetries in their respective H+ ion and L-defect concentrations. Graupel, formed by the accretion of supercooled droplets containing dissolved atmospheric CO2, has a higher H+ concentration than ice crystals, which grow exclusively from vapor. Additionally, warming of graupel due to riming increases its L-defect concentration relative to that of crystals, according to microscopic analyses of ice growth processes. These differences in H+ and L-defect concentrations between ice crystals and graupel drive charges in opposite directions, with the net charge transfer determined by the interplay of these two factors. A theoretical model based on this mechanism predicts that positive charge on graupel increases with rising liquid water content (LWC), while negative charge becomes stronger in low LWC regions at colder temperatures. These trends align with common features observed in most laboratory studies and with the formation of two polarities of storm dipoles under different LWC regimes. We show that the magnitude of charge separation during crystal-graupel collisions, calculated based on this model, broadly agrees with the values found in laboratory studies.

The spin structure functions of the proton and the deuteron were measured during the EG4 experiment at Jefferson Lab in 2006. Data were collected for longitudinally polarized electron scattering off longitudinally polarized NH_3 and ND_3 targets, for Q^2 values as small as 0.012 and 0.02 GeV^2, respectively, using the CEBAF Large Acceptance Spectrometer (CLAS). This is the archival paper of the EG4 experiment that summaries the previously reported results of the polarized structure functions g_1, A_1F_1, and their moments Γ_1, γ_0, and I_TT, for both the proton and the deuteron. In addition, we report on new results on the neutron g_1 extracted by combining proton and deuteron data and correcting for Fermi smearing, and on the neutron moments Γ_1, γ_0, and I_TT formed directly from those of the proton and the deuteron. Our data are in good agreement with the Gerasimov-Drell-Hearn sum rule for the proton, deuteron, and neutron. Furthermore, the isovector combination was formed for g_1 and the Bjorken integral Γ_1^p-n, and compared to available theoretical predictions. All of our results provide for the first time extensive tests of spin observable predictions from chiral effective field theory (χEFT) in a Q^2 range commensurate with the pion mass. They motivate further improvement in χEFT calculations from other approaches such as the lattice gauge method.

Tissues on a chip are sophisticated three-dimensional (3D) in vitro microphysiological systems designed to replicate human tissue conditions within dynamic physicochemical environments. However, the current fabrication methods for tissue spheroids on a chip require multiple parts and manual processing steps, including the deposition of spheroids onto prefabricated "chips." These challenges also lead to limitations regarding scalability and reproducibility. To overcome these challenges, we employed 3D printing techniques to automate the fabrication process of tissue spheroids on a chip. This allowed the simultaneous high-throughput printing of human liver spheroids and their surrounding polymeric flow chamber "chips" containing inner channels in a single step. The fabricated liver tissue spheroids on a liver-on-a-chip (LOC) were subsequently subjected to dynamic culturing by a peristaltic pump, enabling assessment of cell viability and metabolic activities. The 3D printed liver spheroids within the printed chips demonstrated high cell viability (>80%), increased spheroid size, and consistent adenosine triphosphate (ATP) activity and albumin production for up to 14 days. Furthermore, we conducted a study on the effects of acetaminophen (APAP), a nonsteroidal anti-inflammatory drug, on the LOC. Comparative analysis revealed a substantial decline in cell viability (<40%), diminished ATP activity, and reduced spheroid size after 7 days of culture within the APAP-treated LOC group, compared to the nontreated groups. These results underscore the potential of 3D bioprinted tissue chips as an advanced in vitro model that holds promise for accurately studying in vivo biological processes, including the assessment of tissue response to administered drugs, in a high-throughput manner.

INTRODUCTION:Repetitive transcranial magnetic stimulation (rTMS) has been used as a potential treatment for tinnitus; however, its effectiveness is variable and unpredictable. We hypothesized that resting-state functional connectivity before rTMS may be correlated with rTMS treatment effectiveness.METHODS:We applied 1-Hz rTMS to the left primary auditory (A1) and dorsolateral prefrontal cortices (DLPFC) of 10 individuals with tinnitus and 10 age-matched controls. Resting-state functional magnetic resonance imaging (fMRI) studies were performed approximately one week before rTMS. Seed-based connectivity analyses were conducted for each individual, with seed regions as rTMS target areas.RESULTS:Compared to controls, the left superior temporal areas showed significantly increased positive connectivity with the left A1 and negative connectivity with the left DLPFC in the tinnitus group. The left frontoparietal and right cerebellar areas showed significantly increased negative connectivity with the left A1 and positive connectivity with the left DLPFC. Seed-based hyperconnectivity was correlated with tinnitus improvement (pre-rTMS vs. 2-week post-rTMS Tinnitus Handicap Inventory scores). Tinnitus improvement was significantly correlated with left A1 hyperconnectivity; however, no correlation was observed with left DLPFC connectivity. Positive rTMS outcomes were associated with significantly increased positive connectivity in bilateral superior temporal areas and significantly increased negative connectivity in bilateral frontal areas.CONCLUSIONS:Our results suggest that oversynchronisation of left A1 connectivity before rTMS of the left A1 and DLPFC is associated with treatment effectiveness.

The direct observation of the structure of micrometer-sized vapor-deposited ice is performed at Pohang Accelerator Laboratory x-ray free electron laser (PAL-XFEL). The formation of micrometer-sized ice crystals and their structure is important in various fields, including atmospheric science, cryobiology, and astrophysics, but understanding the structure of micrometer-sized ice crystals remains challenging due to the lack of direct observation. Using intense x-ray diffraction from PAL-XFEL, we could observe the structure of micrometer-sized vapor-deposited ice below 150 K with a thickness of 2–50 μm grown in an ultrahigh vacuum chamber. The structure of the ice grown comprises cubic and hexagonal sequences that are randomly arranged to produce a stacking-disordered ice. We observed that ice with a high cubicity of more than 80% was transformed to partially oriented hexagonal ice when the thickness of the ice deposition grew beyond 5 μm. This suggests that precise temperature control and clean deposition conditions allow μm-thick ice films with high cubicity to be grown on hydrophilic Si3N4 membranes. The low influence of impurities could enable in situ diffraction experiments of ice nucleation and growth from interfacial layers to bulk ice.

Field and laboratory observations strongly support the view that the development of electric fields in thunderstorms is caused by charge separation during rebounding collisions between ice crystals and graupels, followed by their gravitational separation. Although several plausible microphysical mechanisms have been proposed to explain the physics of charge separation, none have been found to be fully consistent with the experimental evidence, and a fresh approach is necessary. We propose a new mechanism for charge separation in ice‐ice collisions based on the fundamental molecular mechanism of charge transport in ice, involving the diffusion of H + ions (excess protons or positive ionic defects) via a proton hopping relay along the hydrogen‐bond network of ice and the trapping and release of H + ions from L ‐orientational defects. The collision of two ice particles leads to the formation of a transient crystalline ice bridge at the contact point, which is spontaneously driven by the tendency for ice sintering, permitting rapid H + diffusion between the two particles. Charge separation is achieved by the asymmetry in the concentrations of H + ions or L ‐orientational defects between the two ice surfaces. The proposed H + transport mechanism successfully explains the direction and magnitude of charge transfer as well as its dependence on the relative growth rates of the two ice surfaces observed in laboratory studies. In addition, it offers a molecular‐level interpretation of the empirical rule that, during a collision, the faster‐growing ice surface is positively charged at the expense of negative charging of the slower‐growing or sublimating ice surface.

The structural heterogeneity of an ice surface at the atomic level is an important characteristic that influences the interactions between adsorbate molecules and the ice surface. In this study, we investigated the adsorption of ammonia on the basal (0001) surface of crystalline ice (CI) films to examine the adsorption selectivity of ammonia molecules on atomistically different sites of the ice surface. The adsorption structure and site-selectivity of ammonia adsorption on ice surfaces were examined by conducting temperature-programmed desorption, low energy sputtering, reactive ion scattering, reflection- absorption infrared spectroscopy, and surface voltage measurements. Ammonia adsorbs on ice surfaces without undergoing protonation, dissociation, or penetration into the bulk ice. At low coverages, adsorption occurs exclusively at the dangling H atom sites of the surface via N center dot center dot center dot H-O bond formation. The average orientation of the adsorbed molecular dipoles leans substantially toward the surface. After saturation of the dangling H sites, further adsorption of ammonia leads to the formation of a multilayer with isotropic molecular orientation. Titration experiment for the surface population of dangling H sites with ammonia reveals that the surface density of free O-H groups is 0.29 +/- 0.04 monolayers for the CI films prepared by water vapor deposition at 140 K and postannealing at 160 K, indicating that the basal ice surface is not significantly reconstructed under vacuum conditions.

Hypofractionated RT demonstrated promising local PVTT control with acceptable toxicity. These data suggest that 10-fraction image-guided hypofractionated RT (BED10 = 56-75 Gy10) is a feasible treatment option for PVTT in HCC patients.

This study aims to investigate the characteristics of Cherenkov radiation with respect to wavelength and refractive index. Refractive index is a function of wavelength, and when it changes, not only does the gain of Cherenkov radiation increase, but also the photon loss in the medium increases. Therefore, we examine how photons of different wavelengths behave under changing refractive index conditions. We adjust the refractive index to maintain a constant emission angle of Cherenkov radiation based on the deceleration rate of electrons moving in the medium. When electrons generating Cherenkov radiation move a total of 200 μm, both long-wavelength and short-wavelength photons are emitted at the initial stage; however, only short-wavelength photons are emitted at the late stage. Although the shorter-wavelength photons arrive first among the photons that reach the detector, the longer-wavelength photons are detected more, forming a significant peak, which is due to the fact that the former experience more absorption-based photon loss in the medium than the latter.

Under atmospheric conditions, NO2 is in equilibrium with its dimers, N2O4, which can exist in the form of constitutional isomers and stereoisomers whose relative stabilities and reactivities are still being debated. Experimental limitations facing the spectroscopic characterization of the isomers of N2O4 prevent us from determining their relative contributions to reaction mechanisms possibly causing discrepancies in the reported reaction orders and rates. Using reflection-absorption infrared spectroscopy, molecular beam deposition, and matrix isolation techniques, it is shown that the relative abundances of NO2 and its dimers can be controlled by heating or cooling the deposited gas. The comparison of spectra acquired from samples prepared using molecular beam deposition with those obtained using tube dosing deposition demonstrates how the N2O4 isomer distributions are sensitive to details of the experimental conditions and sample preparation protocols. These observations not only provide a better understanding of a possible source for the disagreements found in the literature, but also a methodology to control and quantify the chemical speciation in NO2 vapors in terms of the relative abundances of NO2 and of the various isomers of N2O4.

Background: With the number of solid organ transplantations (SOT) in Korea increasing, interest in long-term complications in solid organ transplant recipients (SOTRs) is also increasing.Malignancy is one of the leading causes of death in recipients and the use of immunosuppressants or cancer-causing virus infection is considered as risk factors.Also, it is known that the distribution and risk factors of cancers are different from those of the general population.So here we reported prevalence and risk factors of cancers in Korean SOTRs.Methods: Using data from Korean National Health Insurance Service, we compared incidence of malignancies after SOT to general population by standardized incidence ratios (SIR) and hazard ratio (HR).Results: Total 25,330 (male:female, 15157:10173; median age, 48) patients were transplanted from 2003 to 2019, of which 1,392 (5.5%) developed cancers.SOTRs had 2-fold higher risk (SIR, 2.31; 95% confidence intervals [CI], 2.19-2.44).The highest risk cancer is Kaposi sarcoma (SIR, 159.14; 95% CI, 90.96-258.43)followed by non-hodgkin lymphoma (SIR, 11.21; 95% CI, 9.39-13.29),and non-melanoma skin cancer (SIR, 9.94; 95% CI,.Of 1,304 patients, under 19 years old, 49 (3.8%;SIR, 36.31;95% CI,) developed cancer, of which 35 were non-hodgkin lymphoma (SIR, 212.14; 95% CI, 147.76-295.03).Cancer incidence was the highest after 1-3 years of transplantation (315 of 1151; SIR, 1.84; 95% CI, 1.65-2.06).Cancer incidence was not significantly different regardless of induction agent use.SOTRs using tacrolimus or mycofenolate mofetil had less cancer than those who did not use ([HR, 0.79; P<0.05] and [HR, 0.71; P<0.05], respectively).Conclusions: Cancer risk after SOT is higher than general population especially under 19 years old.As types of cancer are different from general population, close monitoring and screening is necessary in SOTRs.Also, other risk factors unanalyzed such as EBV infection should be considered.

Excess protons play a key role in the chemical reactions of ice because of their exceptional mobility, even when the diffusion of atoms and molecules is suppressed in ice at low temperatures. This article reviews the current state of knowledge on the properties of excess protons in ice, with a focus on the involvement of protons in chemical reactions. The mechanism of efficient proton transport in ice, which involves a proton-hopping relay along the hydrogen-bond ice network and the reorientation of water, is discussed and compared with the inefficient transport of hydroxide in ice. Distinctly different properties of protons residing in the ice interior and on the ice surface are emphasized. Recent observations of the spontaneous occurrence of reactions in ice at low temperatures, which include the dissociation of protic acids and the hydrolysis of acidic oxides, are discussed with regard to the kinetic and thermodynamic effects of mobile protons on the promotion of unique chemical processes of ice.