14 research outputs found
Role of Iodine Recycling on Sea-Salt Aerosols in the Global Marine Boundary Layer
Heterogeneous uptake of hypoiodous acid (HOI), the dominant inorganic iodine species in the marine boundary layer (MBL), on sea-salt aerosol (SSA) to form iodine monobromide and iodine monochloride has been adopted in models with assumed efficiency. Recently, field measurements have reported a much faster rate of this recycling process than previously assumed in models. Here, we conduct global model simulations to quantify the range of effects of iodine recycling within the MBL, using Conventional, Updated, and Upper-limit coefficients. When considering the Updated coefficient, iodine recycling significantly enhances gaseous inorganic iodine abundance (similar to 40%), increases halogen atom production rates (similar to 40% in I, >100% in Br, and similar to 60% in Cl), and reduces oxidant levels (-7% in O-3, -2% in OH, and -4% in HO2) compared to the simulation without the process. We appeal for further direct measurements of iodine species, laboratory experiments on the controlling factors, and multiscale simulations of iodine heterogeneous recycling.Peer reviewe
Gigahertz-rate-switchable wavefront shaping through integration of metasurfaces with photonic integrated circuit
Achieving spatiotemporal control of light at high-speeds presents immense
possibilities for various applications in communication, computation,
metrology, and sensing. The integration of subwavelength metasurfaces and
optical waveguides offers a promising approach to manipulate light across
multiple degrees of freedom at high-speed in compact photonic integrated
circuit (PICs) devices. Here, we demonstrate a gigahertz-rate-switchable
wavefront shaping by integrating metasurface, lithium niobite on insulator
(LNOI) photonic waveguide and electrodes within a PIC device. As proofs of
concept, we showcase the generation of a focus beam with reconfigurable
arbitrary polarizations, switchable focusing with lateral focal positions and
focal length, orbital angular momentum light beams (OAMs) as well as Bessel
beams. Our measurements indicate modulation speeds of up to gigahertz rate.
This integrated platform offers a versatile and efficient means of controlling
light field at high-speed within a compact system, paving the way for potential
applications in optical communication, computation, sensing, and imaging
Direct field evidence of autocatalytic iodine release from atmospheric aerosol
Reactive iodine plays a key role in determining the oxidation capacity, or cleansing capacity, of the atmosphere in addition to being implicated in the formation of new particles in the marine boundary layer. The postulation that heterogeneous cycling of reactive iodine on aerosols may significantly influence the lifetime of ozone in the troposphere not only remains poorly understood but also heretofore has never been observed or quantified in the field. Here, we report direct ambient observations of hypoiodous acid (HOI) and heterogeneous recycling of interhalogen product species (i.e., iodine monochloride [ICI] and iodine monobromide [IBr]) in a midlatitude coastal environment. Significant levels of ICI and IBr with mean daily maxima of 4.3 and 3.0 parts per trillion by volume (1-min average), respectively, have been observed throughout the campaign. We show that the heterogeneous reaction of HOI on marine aerosol and subsequent production of iodine interhalogens are much faster than previously thought. These results indicate that the fast formation of iodine interhalogens, together with their rapid photolysis, results in more efficient recycling of atomic iodine than currently considered in models. Photolysis of the observed ICI and IBr leads to a 32% increase in the daytime average of atomic iodine production rate, thereby enhancing the average daytime iodine-catalyzed ozone loss rate by 10 to 20%. Our findings provide direct field evidence that the autocatalytic mechanism of iodine release from marine aerosol is important in the atmosphere and can have significant impacts on atmospheric oxidation capacity.Peer reviewe
Graft Diameter Should Reflect the Size of the Native Anterior Cruciate Ligament (ACL) to Improve the Outcome of ACL Reconstruction: A Finite Element Analysis
The size of the anterior cruciate ligament (ACL) often varies between individuals, but such variation is not typically considered during ACL reconstruction (ACLR). This study aimed to explore how the size of the ACL affects the selection of a suitable graft diameter. A finite element model of a human knee was implanted with intact ACLs of different dimensions (0.95, 1 and 1.05 times the size of the original ACL) and with grafts of different diameters, to simulate ACLR (diameter 7.5–12 mm in 0.5 mm increments). The knee models were flexed to 30° and loaded with an anterior tibial load of 103 N, internal tibial moment of 7.5 Nm, and valgus tibial moment of 6.9 Nm. Knee kinematics (anterior tibial translation (ATT), internal tibial rotation (ITR) and valgus tibial rotation (VTR)) and ligament forces were recorded and compared among the different groups. The results showed that, compared with the intact knee, a graft diameter of 7.5 mm was found to increase the ATT and VTR, but reduce the graft force. Increasing the graft diameter reduced knee laxity and increased the graft force. A 10% increase in the size of the ACL corresponded to a 3 mm larger graft diameter required to restore knee stability and graft force after ACLR. It was concluded that the graft diameter should be selected according to the dimensions of the native ACL, for better restoration of knee functionality. This study may help to improve the clinical treatment of ACL ruptures
Influence of point mutations on the flexibility of cytochrome b \u3csub\u3e5\u3c/sub\u3e: Molecular dynamics simulations of holoproteins
Two membrane-bound isoforms of cytochrome b5 have been identified in mammals, one associated with the outer mitochondrial membrane (OM b5) and the other with the endoplasmic reticulum (microsomal, or Mc b5). The soluble heme binding domains of OM and Mc b5 have highly similar three-dimensional structures but differ significantly in physical properties, with OM b5 exhibiting higher stability due to stronger heme association. In this study, we present results of 8.5-ns length molecular dynamics simulations for rat Mc b5, bovine Mc b 5, and rat OM b5, as well as for two rat OM b5 mutants that were anticipated to exhibit properties intermediate between those of rat OM b5 and the two Mc proteins: the A18S/I32L/L47R triple mutant (OM3M) and the A18S/I25L/I32L/L47R/L71S quintuple mutant (OM5M). Analysis of the structure, fluctuations, and interactions showed that the five b5 variants used in this study differed in organization of their molecular surfaces and heme binding cores in a way that could be used to explain certain experimentally observed physical differences. Overall, our simulations provided qualitative microscopic explanations of many of the differences in physical properties between OM and Mc b5 and two mutants in terms of localized changes in structure and flexibility. They also reveal that opening of a surface cleft between hydrophobic cores 1 and 2 in bovine Mc b5, observed in two previously reported simulations (E. M. Storch and V. Daggett, Biochemistry, 1995, Vol. 34, pp. 9682-9693; A. Altuve, Biochemistry, 2001, Vol. 40, pp. 9469-9483), probably resulted from removal of crystal contacts and likely does not occur on the nanosecond time scale. Finally, the MD simulations of OM5M b5 verify that stability and dynamic properties of cytochrome b5 are remarkably resistant to mutations that dramatically alter the stability and structure of the apoprotein. © 2006 Wiley Periodicals, Inc
S1937 Post 9/11 GERD-Like Symptoms: Endoscopic and Pathologic Evaluation of a New Entity
Sorafenib Inhibits Renal Fibrosis Induced by Unilateral Ureteral Obstruction via Inhibition of Macrophage Infiltration
Aims: Sorafenib, which has been used extensively for the treatment of renal cell cancer and advanced hepatocellular carcinoma (HCC), has also been shown to have antifibrotic effects in liver fibrosis. However, the effects of sorafenib on renal fibrosis are unknown. Therefore, we investigated whether sorafenib inhibited renal fibrosis in a mouse model of unilateral ureteral obstruction (UUO) and further explored the potential mechanism. Methods: Mice underwent UUO followed by vehicle or sorafenib treatment. The expression of CD68, a macrophage marker, and the pro-inflammatory cytokines, MCP1 and CXCR3, were immunohistochemically analyzed. The involvement of macrophages in the formation of renal fibrosis was studied using confocal microscopy. Results: Renal histopathology improved in the UUO-sorafenib mice. Sorafenib notably suppressed TGF-β1-mediated renal fibrogenic effects. The mRNA and protein expressions of CD68, MCP1, and CXCR3 in the obstructed kidney were significantly decreased by sorafenib. Immunohistochemistry showed that CD68 and CXCR3 had a similar distribution, whereas MCP1 was observed predominantly in the tubular epithelial cells. Double immunofluorescence demonstrated that CD68-positive macrophages could co-localize with CXCR3. It also revealed that CXCR3 interacted with CXCL11 in the UUO mouse kidneys. Widespread adhesion of macrophages to myofibroblasts was markedly inhibited in UUO-sorafenib mouse kidneys. Conclusions: Taken together, the results indicated that sorafenib had protective effects against renal fibrosis; its mechanism of action was associated with inhibition of macrophage infiltration via the CXCR3/CXCL11 pathway. These data suggest the clinical potential of sorafenib for treatment of renal fibrosis and illustrate the immunological mechanisms underlying the protective effects of sorafenib
Regorafenib-Attenuated, Bleomycin-Induced Pulmonary Fibrosis by Inhibiting the TGF-β1 Signaling Pathway
Idiopathic pulmonary fibrosis (IPF) is a fatal and age-related pulmonary disease. Nintedanib is a receptor tyrosine kinase inhibitor, and one of the only two listed drugs against IPF. Regorafenib is a novel, orally active, multi-kinase inhibitor that has similar targets to nintedanib and is applied to treat colorectal cancer and gastrointestinal stromal tumors in patients. In this study, we first identified that regorafenib could alleviate bleomycin-induced pulmonary fibrosis in mice. The in vivo experiments indicated that regorafenib suppresses collagen accumulation and myofibroblast activation. Further in vitro mechanism studies showed that regorafenib inhibits the activation and migration of myofibroblasts and extracellular matrix production, mainly through suppressing the transforming growth factor (TGF)-β1/Smad and non-Smad signaling pathways. In vitro studies have also indicated that regorafenib could augment autophagy in myofibroblasts by suppressing TGF-β1/mTOR (mechanistic target of rapamycin) signaling, and could promote apoptosis in myofibroblasts. In conclusion, regorafenib attenuates bleomycin-induced pulmonary fibrosis by suppressing the TGF-β1 signaling pathway
A novel telehealth tool using a snack activity to identify autism spectrum disorder
Abstract Background The COVID-19 pandemic has caused an unprecedented need for accessible health care services and significantly accelerated the development processes of telehealth tools for autism spectrum disorder (ASD) early screening and diagnosis. This study aimed to examine the feasibility and utility of a time-efficient telehealth tool combining a structured snack time assessment activity and a novel behaviour coding scheme for identifying ASD. Methods A total of 134 1–6-year-old individuals with ASD (age in months: mean = 51.3, SD = 13.1) and 134 age- and sex-matched typically developing individuals (TD) (age in months: mean = 54, SD = 9.44) completed a 1-min snack time interaction assessment with examiners. The recorded videos were then coded by trained coders for 17 ASD-related behaviours; the beginning and end points and the form and function of each behaviour were recorded, which took 10–15 min. Coded details were transformed into 62 indicators representing the count, duration, rate, and proportion of those behaviours. Results Twenty indicators with good reliability were selected for group difference, univariate and multivariate analyses. Fifteen behaviour indicators differed significantly between the ASD and TD groups and remained significant after Bonferroni correction, including the children’s response to the examiner’s initiation, eye gaze, pointing, facial expressions, vocalization and verbalization, and giving behaviours. Five indicators were included in the final prediction model: total counts of eye gaze, counts of standard pointing divided by the total counts of pointing, counts of appropriate facial expressions, counts of socially oriented vocalizations and verbalizations divided by the total counts of vocalizations and verbalizations, and counts of children using giving behaviours to respond to the examiner's initiations divided by the total counts of the examiner's initiation of snack requisitions. The ROC curve revealed a good prediction performance with an area under the curve (AUC) of 0.955, a sensitivity of 92.5% and a specificity of 84.3%. Conclusion Our results suggest that the snack activity-based ASD telehealth approach shows promise in primary health care settings for early ASD screening