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1.
PLoS Pathog ; 20(9): e1012594, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39348396

RESUMO

Coxsackievirus B (CVB) is the major causative pathogen for severe diseases such as viral myocarditis, meningitis, and pancreatitis. There is no effective antiviral therapy currently available for CVB infection primarily due to that the pathogenesis of CVB has not been completely understood. Viruses are obligate intracellular pathogens which subvert cellular processes to ensure viral replication. Dysregulation of ubiquitination has been implicated in CVB infection. However, how ubiquitination is involved in CVB infection remains unclear. Here we found that the 3D protein of CVB3, the RNA-dependent RNA polymerase, was modified at K220 by K48-linked polyubiquitination which promoted its degradation through proteasome. Proteomic analysis showed that the E3 ligase TRIM56 was upregulated in CVB3-infected cells, while the majority of TRIMs remained unchanged. Pull-down and immunoprecipitation analyses showed that TRIM56 interacted with CVB3 3D. Immunofluorescence observation showed that viral 3D protein was colocalized with TRIM56. TRIM56 overexpression resulted in enhanced ubiquitination of CVB3 3D and decreased virus yield. Moreover, TRIM56 was cleaved by viral 3C protease in CVB3-infected cells. Taken together, this study demonstrated that TRIM56 mediates the ubiquitination and proteasomal degradation of the CVB3 3D protein. These findings demonstrate that TRIM56 is an intrinsic cellular restriction factor against CVB infection, and enhancing viral protein degradation could be a potential strategy to control CVB infection.


Assuntos
Infecções por Coxsackievirus , Enterovirus Humano B , RNA Polimerase Dependente de RNA , Proteínas com Motivo Tripartido , Ubiquitina-Proteína Ligases , Ubiquitinação , Humanos , Enterovirus Humano B/fisiologia , Ubiquitina-Proteína Ligases/metabolismo , Proteínas com Motivo Tripartido/metabolismo , Infecções por Coxsackievirus/metabolismo , Infecções por Coxsackievirus/virologia , RNA Polimerase Dependente de RNA/metabolismo , Replicação Viral/fisiologia , Células HeLa , Proteínas Virais/metabolismo , Proteínas Virais/genética
2.
J Am Chem Soc ; 146(43): 29272-29277, 2024 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-39316512

RESUMO

Sustainable electricity-to-chemical conversion via the utilization of artificial catalysts inspired by redox biological systems holds great significance for catalyzing synthesis. Herein, we develop a biomimetic electrosynthesis strategy mediated by a nicotinamide adenine dinucleotide (NADH) mimic-containing coordination capsule for efficiently producing α-hydroxy/amino esters. The coordination saturated metal centers worked as an electron relay to consecutively accept single electrons while donating two electrons to the NAD+ mimics simultaneously. The protonation of the intermediate generated active NADH mimics for biomimetic hydrogenation of the substrates via the conventional enzymatic manifold with or without the presence of natural enzymes. The pocket of the capsule encapsulated the substrate and enforced the close proximity between the substrate and the NADH mimics, forming a preorganized intermediate to shift the redox potential by 0.4 V anodically. The cobalt capsule gave methyl mandelate over a range of applied potentials, with an improved yield of 92% when operated at -1.2 V compared to that of Hantzsch ester or natural NADH. Kinetic experiments revealed a Michaelis-Menten mechanism with a Km of 7.5 mM and a Kcat of 1.1 × 10-2 s-1. This extended strategy in tandem with an enzyme exhibited a TON of 650 molE-1 with an initial TOF of 185 molE-1·h-1, outperforming relevant Rh-mediated enzymatic electrosynthesis systems and providing an attractive avenue toward advanced artificial electrosynthesis.


Assuntos
Elétrons , Ésteres , NAD , Ésteres/química , NAD/química , NAD/metabolismo , Materiais Biomiméticos/química , Materiais Biomiméticos/metabolismo , Materiais Biomiméticos/síntese química , Biomimética , Complexos de Coordenação/química , Oxirredução , Técnicas Eletroquímicas , Estrutura Molecular
3.
J Am Chem Soc ; 145(12): 6719-6729, 2023 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-36916689

RESUMO

Semi-artificial approaches to solar-to-chemical conversion can achieve chemical transformations that are beyond the capability of natural enzymes, but face marked challenges to facilitate in vivo cascades, due to their inevitable need for cofactor shuttling and regeneration. Here, we report on an enzyme grafting strategy to build a metal-organic capsule-docking artificial enzyme (metal-organic-enzyme, MOE) that comprised the self-assembly of a cofactor-decorated capsule and the supramolecular enzyme-recognition features between the enzyme scaffold and the capsule to bypass cofactor shuttling and regeneration. The incorporated NADH mimics within the metal-organic capsule interacted with the imine intermediate that formed from the condensation of the amines and the dehydrogenation of alcohol substrates in the microenvironment to form complexes within the capsule and subsequently served as an in situ-generated photoresponsive cofactor. Upon illumination, the photoresponsive cofactor facilitates efficient proton/electron transport between the inner space (supramolecular hydrogenation) and outer space (enzymatic dehydrogenation) of the capsule to dehydrogenize the alcohols and hydrogenize the imine intermediates, respectively, circumventing the conventionally complex multistep cofactor shuttling and regeneration. The semi-artificial enzyme endows the conversion of diverse types of alcohol to amine products in both aqueous/organic solutions and Escherichia coli with high efficiency, offering a wide range of opportunities for sustainable and environmentally friendly biomanufacturing of commodity and fine chemicals.


Assuntos
Álcoois , Metais , Transporte de Elétrons , Escherichia coli , Aminas , Iminas
4.
Opt Express ; 31(14): 22964-22981, 2023 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-37475393

RESUMO

The effective sea-surface skylight reflectance (ρ) is an important parameter for removing the contribution of surface-reflected radiance when measuring water-leaving radiance (Lw) using the above-water approach (AWA). Radiative simulations and field measurements show that ρ varies spectrally. To improve the determination of Lw (and then remote sensing reflectance, Rrs) from the AWA, we further developed a wavelength-dependent model for ρ to remove surface-reflected radiance, which is applied with a spectral optimization approach for the determination of Rrs. Excellent agreement was achieved between the AWA-derived and skylight-blocked approach (SBA)-obtained Rrs (coefficient of determination > 0.92, mean absolute percentage deviation < ∼ 11% for Rrs > 0.0005 sr-1), even during high wave conditions. We found that the optimization approach with the new ρ model worked very well for a wide range of water types and observation geometries. For developing remote sensing algorithms and evaluating satellite products, it would be beneficial to apply this approach to current and historical above-water in situ measurements of Rrs to improve the quality of these data. In addition, this approach could also increase the number of useable spectra where previously rendered unusable when processed with a traditional scheme.

5.
Inorg Chem ; 61(25): 9493-9503, 2022 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-35696346

RESUMO

Metal-organic frameworks (MOFs) have gained attention as multifunctional catalytic platforms, allowing us to gain important insights into synergistically activating both C-H bonds and oxygen for improving oxidation. Herein, by ingenious incorporation of anthraquinone, we report an anthraquinone-based MOF as a bifunctional heterogeneous photocatalytic platform to simultaneously activate inert C(sp3)-H bonds and oxygen for C-H bond oxidation. Making use of the rigid framework with the fixation and isolation effect, both a great chemical stability and bifunctional synergistic photocatalytic effects were obtained through the immobilization of anthraquinone into a MOF. Importantly, while decorating two carboxyl groups on anthraquinone, the carbonyl groups of anthraquinone photosensitizers were not involved in coordinating the self-assembly and orderly arranged on the wall of channels that were constructed through a π-π interaction between the anthraquinone moieties in the adjacent layers, which was beneficial to form and stabilize the excited-state radical intermediates in the molecule-fenced channels, and the close proximity between the catalytic sites and the substrates to abstract a hydrogen atom from the substrate through the hydrogen atom transfer process aimed at activating the inertness of C-H bonds. Moreover, high-density-distributed anthraquinone dyes in the confined channels would activate oxygen to form singlet oxygen (1O2) through an energy transfer pathway, further promoting inert C(sp3)-H bond oxidation efficiency. Under visible light irradiation, this anthraquinone-based MOF was successfully applied to explore activation and oxidation of a series of substrates containing benzylic C(sp3)-H bonds in the presence of air or oxygen to produce the corresponding carbonyl products. This bifunctional photocatalytic platform based on a heterogeneous MOF provides an available catalytic avenue to develop a scalable and sustainable synthetic strategy using green and sustainable oxygen as the potent oxidant.

6.
BMC Musculoskelet Disord ; 23(1): 1027, 2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36447169

RESUMO

BACKGROUND: Both denosumab and bisphosphonates have been demonstrated effective for glucocorticoid-induced osteoporosis. However, evidence-based medicine is still lacking to prove the clinical results between denosumab and bisphosphonates. This meta-analysis aims to compare the efficacy and safety between denosumab and oral bisphosphonates for the treatment of glucocorticoid-induced osteoporosis through evidence-based medicine. METHODS: MEDLINE, EMBASE, and the Cochrane library databases were searched up to June 2022 for randomized controlled trials that compared denosumab and oral bisphosphonates in the treatment of glucocorticoid-induced osteoporosis. The following outcomes were extracted for comparison: percentage change in bone mineral density from baseline at the lumbar spine, total hip, femoral neck, and ultra-distal radius; percentage change from baseline in serum concentration of bone turnover markers; and incidence of treatment-emergent adverse events. RESULTS: Four randomized controlled trials involving 714 patients were included. The pooled results showed that denosumab was superior to bisphosphonates in improving bone mineral density in lumbar spine (mean difference (MD) 1.70; 95% confidence interval (CI) 1.11-2.30; P < 0.001) and ultra-distal radius (MD 0.87; 95% CI 0.29-1.45; P = 0.003), and in suppressing C-terminal telopeptide of type 1 collagen (MD -34.83; 95% CI -67.37--2.28; P = 0.04) and procollagen type 1 N-terminal propeptide (MD -14.29; 95% CI -23.65- -4.94; P = 0.003) at 12 months. No significant differences were found in percentage change in total hip or femoral neck bone mineral density at 12 months, or in the incidence of treatment-emergent adverse events or osteoporosis-related fracture. CONCLUSIONS: Compared with bisphosphonates, denosumab is superior in improving bone mineral density in lumbar spine and ultra-distal radius for glucocorticoid-induced osteoporosis. Further studies are needed to prove the efficacy of denosumab.


Assuntos
Denosumab , Difosfonatos , Osteoporose , Fraturas por Osteoporose , Humanos , Densidade Óssea , Denosumab/uso terapêutico , Difosfonatos/uso terapêutico , Glucocorticoides/efeitos adversos , Osteoporose/induzido quimicamente , Osteoporose/tratamento farmacológico , Ensaios Clínicos Controlados Aleatórios como Assunto
7.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 47(1): 79-85, 2022 Jan 28.
Artigo em Inglês, Zh | MEDLINE | ID: mdl-35545366

RESUMO

OBJECTIVES: To summarize our experience with the sural neurofasciocutaneous flap for reconstructing the soft tissue defects over the forefoot distal to the connecting line of midpoints in the metatarsal bones, and to compare the outcomes between the flap for resurfacing the defects distal and proximal to the connecting line. METHODS: The clinical data of 425 sural neurofasciocutaneous flaps for repairing the soft tissue defects in the middle and lower leg, ankle, and foot between Apr. 2002 and Apr. 2020 were reviewed. Based on the connecting line of midpoints of the metatarsals, the sural neurofasciocutaneous flaps were divided into a forefoot group (flaps with furthest edges distal to the connecting line) and a peri-ankle group (flaps with the furthest edges proximal to the connecting line). RESULTS: The partial necrosis rate in the forefoot group (14.5%, 10/69) was significantly higher than that in the peri-ankle group (7.0%, 25/356), with significant difference (P<0.05). Using the flap alone or in combination with a simple salvage treatment, the ratio of successful coverages of the defects was 98.6% (68/69) in the forefoot group, and 97.8% (348/356) in the peri-ankle group, respectively, with no statistical difference (P>0.05). CONCLUSIONS: The sural neurofasciocutaneous flap is a better choice for covering the soft tissue defects over the forefoot distal to the connecting line of midpoints of the metatarsal bones. The survival reliability of the sural neurofasciocutaneous flap reconstructing the soft tissue defect proximal to the connecting line is superior to that of the flap reconstructing the defect distal to the connecting line.


Assuntos
Procedimentos de Cirurgia Plástica , Lesões dos Tecidos Moles , Tornozelo/cirurgia , Humanos , Reprodutibilidade dos Testes , Lesões dos Tecidos Moles/cirurgia , Retalhos Cirúrgicos
8.
Angew Chem Int Ed Engl ; 61(2): e202114490, 2022 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-34747102

RESUMO

The activation and oxidization of inert C(sp3 )-H bonds into value-added chemicals affords attractively economic and ecological benefits as well as central challenge in modern chemistry. Inspired by the natural enzymatic transformation, herein, we report a new multiphoton excitation approach to activate the inert C(sp3 )-H bonds and oxygen by integrating the photoinduced electron transfer (PET), ligand-to-metal charge transfer (LMCT) and hydrogen atom transfer (HAT) events together into one metal-organic framework. The well-modified nicotinamide adenine dinucleotide (NAD+ ) mimics oxidized CeIII -OEt moieties to generate CeIV -OEt chromophore and its reduced state mimics NAD. via PET. The in situ formed CeIV -OEt moiety triggers a LMCT excitation to form the alkoxy radical EtO. , abstracts a hydrogen atom from the C(sp3 )-H bond, accompanying the recovery of CeIII -OEt and the formation of alkyl radicals. The formed NAD. activates oxygen to regenerate the NAD+ for next recycle, wherein, the activated oxygen species interacts with the intermediates for the oxidization functionalization, paving a catalytic avenue for developing scalable and sustainable synthetic strategy.

9.
Zhongguo Dang Dai Er Ke Za Zhi ; 24(5): 514-520, 2022 May 15.
Artigo em Zh | MEDLINE | ID: mdl-35644191

RESUMO

OBJECTIVES: To study the effect of sex on the clinical outcome of extremely preterm infants (EPIs)/extremely low birth weight infants (ELBWIs) by propensity score matching. METHODS: A retrospective analysis was performed for the medical data of 731 EPIs or ELBWIs who were admitted from January 1, 2011 to December 31, 2020. These infants were divided into two groups: male and female. A propensity score matching analysis was performed at a ratio of 1:1. The matching variables included gestational age, birth weight, percentage of withdrawal from active treatment, percentage of small-for-gestational-age infant, percentage of use of pulmonary surfactant, percentage of 1-minute Apgar score ≤3, percentage of mechanical ventilation, duration of mechanical ventilation, percentage of antenatal use of inadequate glucocorticoids, and percentage of hypertensive disorders in pregnancy. The two groups were compared in the incidence rate of main complications during hospitalization and the rate of survival at discharge. RESULTS: Before matching, compared with the female group, the male group had significantly higher incidence rates of neonatal respiratory distress syndrome, bronchopulmonary dysplasia (BPD), severe intraventricular hemorrhage, periventricular leukomalacia, necrotizing enterocolitis, and patent ductus arteriosus (P<0.05), while after matching, the male group only had a significantly higher incidence rate of BPD than the female group (P<0.05). There was no significant difference in the rate of survival at discharge between the two groups before and after matching (P>0.05). CONCLUSIONS: Male EPIs/ELBWIs have a higher risk of BPD than female EPIs/ELBWIs, but male and female EPIs/ELBWIs tend to have similar outcomes.


Assuntos
Displasia Broncopulmonar , Recém-Nascido de Peso Extremamente Baixo ao Nascer , Displasia Broncopulmonar/epidemiologia , Displasia Broncopulmonar/etiologia , Feminino , Humanos , Lactente , Lactente Extremamente Prematuro , Recém-Nascido , Masculino , Gravidez , Pontuação de Propensão , Estudos Retrospectivos , Caracteres Sexuais
10.
Opt Express ; 29(2): 2780-2797, 2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-33726468

RESUMO

The on-water radiometric approach employs a unique provision to obtain water-leaving radiance from nadir (Lw(λ)) which can be used for the calibration of ocean color satellites. In this effort, we address the measurement precision associated with Lw(λ) from a single on-water instrument, which is an important aspect of measurement uncertainty. First, we estimated the precision as the ratio of the standard deviation of the means of repeated measurements to the mean of these measurements. We show that the measurement precision for Lw(λ) is within 2.7-3.7% over 360-700 nm. The corresponding remote sensing reflectance spectra (Rrs(λ)) from the same instrument also exhibit a high precision of 1.9-2.8% in the same spectral domain. These measured precisions of radiance and reflectance over the 360-700 nm range are independent of the optical water type. Second, we quantified the consistency of on-water Lw(λ) and Rrs(λ) from two collocated systems for further insight into their measurement repeatability. The comparison reveals that Lw(λ) measurements in the 360-700 nm agree with each other with an absolute percentage difference of less than 3.5%. The corresponding Rrs(λ) data pairs are subjected to increased differences of up to 8.5%, partly due to variable irradiance measurements (Es(λ)). The evaluation of measurement precision corroborates the reliability of the on-water acquisition of radiometric data for supporting satellite calibration and validation.

11.
Opt Express ; 29(12): 19218-19221, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34154163

RESUMO

Reliable in situ water-leaving radiance (Lw) measurements are critical for calibrating and validating the ocean color products from remote platforms (e.g., satellite). In an experimental effort, Wei et al. [Opt. Express29, 2780 (2021)10.1364/OE.413784] reported that the on-water radiometry allows for high-precision radiance determination. Zibordi [Opt. Express29, 19214 (2021)10.1364/OE.421786] questioned the use of the "1% radiometry" term in the former and commented on the data collection with the sensor's optical window submerged in water. This reply responds to the comments and discusses the on-water data processing protocol, which shows the obtained Lw is not affected by the questions raised therein.

12.
BMC Surg ; 21(1): 167, 2021 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-33775250

RESUMO

BACKGROUND: Reconstructions the soft-tissue defects of the distal lower extremities in the elderly patients (≥ 60 years old) are full of challenges because of many comorbidities. The purpose of this study was to report the clinical application of the distally based sural flap in the elderly patients, and to verify the reliability of this flap in the elderly patients. METHODS: Between March of 2005 and December of 2019, 53 patients aged over 60-year-old and 55 patients aged 18 to 30-year-old who underwent the procedure have been included in this study. The reconstruction outcomes, medical-related complications, flap viability-related complications and potential risk factors are compared between the group A (≥ 60 years old) and group B (ranging from 18 to 30 years old). RESULTS: The partial necrosis rate in group A (9.43%) is higher than group B (9.09%), but the difference is not significant (P > 0.05). The constitute ratio of the defects that were successfully covered using the sural flap alone or combining with simple salvage method (i.e., skin grafting) is 96.22% and 98.18% in group A and B, respectively (P > 0.05). The differences of the risk flaps factors that affected the survival of distally based sural flap were not significant between group A and B (P > 0.05). CONCLUSIONS: The distally based sural flap can be effectively used to repair the soft-tissue defect of the lower extremity in the elderly patients. It is safe and reliable to harvest and transfer the flap in one stage, and the delay surgery is not necessary.


Assuntos
Extremidade Inferior , Procedimentos de Cirurgia Plástica , Nervo Sural , Retalhos Cirúrgicos , Adolescente , Adulto , Idoso , Humanos , Extremidade Inferior/lesões , Extremidade Inferior/cirurgia , Pessoa de Meia-Idade , Procedimentos de Cirurgia Plástica/métodos , Reprodutibilidade dos Testes , Lesões dos Tecidos Moles/cirurgia , Adulto Jovem
13.
J Reconstr Microsurg ; 37(7): 580-588, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33592636

RESUMO

BACKGROUND: This study is to describe the distribution of natural true anastomoses associated with the distally based perforator-plus sural neurocutaneous flap (sural flap), summarize our experience in the flap with high pivot point, and compare the outcomes between the flaps with high and low pivot points. METHODS: Five amputated lower limbs were perfused, and the integuments were radiographed. We retrospectively analyzed 378 flaps, which were divided into two groups: pivot points located ≤8.0 cm (low pivot point group) and >8.0 cm (high pivot point group) proximal to the tip of the lateral malleolus. Partial necrosis rates were compared between two groups. RESULTS: The arterial chain surrounding the sural nerve was linked by true anastomoses from the intermalleolar line to popliteal crease. True anastomoses existed among peroneal perforators and between these perforators and the arterial chain. There were 93 flaps with high pivot point and 285 flaps with low pivot point. Partial necrosis rates were 16 and 9.1% in the high and low pivot point group (p = 0.059), respectively. CONCLUSION: True anastomosis connections among peroneal perforators and the whole arterial chain around sural nerve enable the sural flap to survive with a greater length. The sural flap with high pivot point is a good option for reconstructing soft-tissue defects in the middle and distal leg, ankle, and foot, particularly when the lowest peroneal perforator presents damage, greater distance to the defects, discontinuity with the donor site, or anatomical variation.


Assuntos
Retalho Perfurante , Procedimentos de Cirurgia Plástica , Lesões dos Tecidos Moles , Tornozelo , , Humanos , Estudos Retrospectivos , Lesões dos Tecidos Moles/cirurgia , Nervo Sural
14.
Angew Chem Int Ed Engl ; 60(44): 23569-23573, 2021 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-34347334

RESUMO

Organic self-assembled co-crystals have garnered considerable attention due to their facile synthesis and intriguing properties, but supramolecular interactions restrict their stability in aqueous solution, which is especially important for biological applications. Herein, we report on the first biological application of aqueous dispersible self-assembled organic co-crystals via the construction of metal-organic framework (MOF) -stabilized co-crystals. In particular, we built an electron-deficient MOF with naphthalene diimide (NDI) as the ligand and biocompatible Ca2+ as the metal nodes. An electron donor molecule, pyrene, was encapsulated to form the host-guest MOF self-assembled co-crystal. We observed that such MOF structure leads to uniquely high-density ordered arrangement and the close intermolecular distance (3.47 Å) of the charge transfer pairs. Hence, the concomitant superior charge transfer interaction between pyrene/NDI can be attained and the resultant photothermal conversion efficiency of Py@Ca-NDI in aqueous solution can thus reach up to 41.8 %, which, to the best of our knowledge, is the highest value among the reported organic co-crystal materials; it is also much higher than that of the FDA approved photothermal agent ICG as well as most of the reported MOFs. Based on this realization, as a proof of concept, we demonstrated that such a self-assembled organic co-crystal platform can be used in biological applications that are exemplified via highly effective long wavelength light photothermal therapy.


Assuntos
Materiais Biocompatíveis/química , Cálcio/química , Imidas/química , Estruturas Metalorgânicas/síntese química , Naftalenos/química , Fototerapia , Pirenos/química , Catálise , Estruturas Metalorgânicas/química
15.
Opt Express ; 28(18): 26953-26976, 2020 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-32906959

RESUMO

In this paper, with a revised POLYMER (POLYnomial based approach applied to MERIS data) atmospheric correction model, we present a novel scheme (two-angle atmospheric correction algorithm, termed as TAACA) to remove atmospheric contributions in satellite ocean color measurements for coastal environments, especially when there are absorbing aerosols. TAACA essentially uses the same water properties as a constraint to determine oceanic and atmospheric properties simultaneously using two same-day consecutive satellite images having different sun-sensor geometries. The performance of TAACA is first evaluated with a synthetic dataset, where the retrieved remote-sensing reflectance (Rrs) by TAACA matches very well (the coefficient of determination (R2) ≥ 0.98) with the simulated Rrs for each wavelength, and the unbiased root mean square error (uRMSE) is ∼12.2% for cases of both non-absorbing and strongly absorbing aerosols. When this dataset is handled by POLYMER, for non-absorbing aerosol cases, the R2 and uRMSE values are ∼0.99 and ∼7.5%, respectively, but they are ∼0.92 and ∼39.5% for strongly absorbing aerosols. TAACA is further assessed using co-located VIIRS measurements for waters in Boston Harbor and Massachusetts Bay, and the retrieved Rrs from VIIRS agrees with in situ measurements within ∼27.3% at the visible wavelengths. By contrast, a traditional algorithm resulted in uRMSE as 3890.4% and 58.9% at 410 and 443 nm, respectively, for these measurements. The Rrs products derived from POLYMER also show large deviations from in situ measurements. It is envisioned that more reliable Rrs products in coastal waters could be obtained from satellite ocean color measurements with a scheme like TAACA, especially when there are strongly absorbing aerosols.

16.
Opt Express ; 28(2): 1439-1455, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-32121855

RESUMO

The presence of a ship in water disturbs the ambient light field and propagates errors to radiometric measurements. This study investigated the ship perturbation via Monte Carlo simulations with a reflective 3D ship. It is found that the height of ship could cause significant perturbation. However, these perturbations could be compensated by the reflection of the ship's hull, where such compensations vary from sun angle to hull's reflectance. Further, as a rule of thumb, to keep the perturbation on water-leaving radiance under ∼3% from an operating ship, a look-up table is generated with the requirements of viewing angle for the radiometers operated at the deck and for the deployment distance of floating and profiling instruments.

17.
J Am Chem Soc ; 141(32): 12707-12716, 2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31319035

RESUMO

Switchable selective hydrogenation among the groups in multifunctional compounds is challenging because selective hydrogenation is of great interest in the synthesis of fine chemicals and pharmaceuticals as a result of the importance of key intermediates. Herein, we report a new approach to highly selectively (>99%) reducing C═X (X = O, N) over the thermodynamically more favorable nitro groups locating the substrate in a metal-organic capsule containing NADH active sites. Within the capsule, the NADH active sites reduce the double bonds via a typical 2e- hydride transfer hydrogenation, and the formed excited-state NAD+ mimics oxidize the reductant via two consecutive 1e- processes to regenerate the NADH active sites under illumination. Outside the capsule, nitro groups are highly selectively reduced through a typical 1e- hydrogenation. By combining photoinduced 1e- transfer regeneration outside the cage, both 1e- and 2e- hydrogenation can be switched controllably by varying the concentrations of the substrates and the redox potential of electron donors. This promising alternative approach, which could proceed under mild reaction conditions and use easy-to-handle hydrogen donors with enhanced high selectivity toward different groups, is based on the localization and differentiation of the 2e- and 1e- hydrogenation pathways inside and outside the capsules, provides a deep comprehension of photocatalytic microscopic reaction processes, and will allow the design and optimization of catalysts. We demonstrate the advantage of this method over typical hydrogenation that involves specific activation via well-modified catalytic sites and present results on the high, well-controlled, and switchable selectivity for the hydrogenation of a variety of substituted and bifunctional aldehydes, ketones, and imines.

18.
Opt Express ; 27(24): 34974-34984, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31878675

RESUMO

The spectral absorption coefficient of pure seawater (aw(λ)) in published studies differ significantly in the blue domain, yet the impacts of such discrepancies on the inherent optical properties (IOPs) derived from ocean color have been scarcely documented. In this study, we confirm that changes in aw(λ) may have significant impacts on retrieved IOPs in oligotrophic waters, especially for the phytoplankton absorption coefficient (aph(λ)). Two sets of aw(λ) data, aw_PF97 (Appl. Opt. 36, 8710, 1997) and aw_Lee15 (Appl. Opt. 54, 546, 2015), were selected for optical inversion analysis. It is found that aph(λ) retrieved with aw_Lee15 agree better with the in-situ measurements in oligotrophic waters. Further applications to satellite images show that the derived aph(λ) using aw_Lee15 can be up to 238% higher than the retrievals using aw_PF97 in the core zone of the subtropical ocean gyres. Given that aw_PF97 is commonly accepted as the "standard" aw(λ) by the ocean color community in the past decades, this study highlights the need and importance to update aw(λ) with aw_Lee15 for IOPs retrievals in oligotrophic waters.

19.
Appl Opt ; 57(13): 3463-3473, 2018 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29726515

RESUMO

Inversion of the total absorption (a) and backscattering coefficients of bulk water through a fusion of remote sensing reflectance (Rrs) and Secchi disk depth (ZSD) is developed. An application of such a system to a synthesized wide-range dataset shows a reduction of ∼3 folds in the uncertainties of inverted a(λ) (in a range of ∼0.01-6.8 m-1) from Rrs(λ) for the 350-560 nm range. Such a fusion is further proposed to process concurrent active (ocean LiDAR) and passive (ocean-color) measurements, which can lead to nearly "exact" analytical inversion of an Rrs spectrum. With such a fusion, it is found that the uncertainty in the inverted total a in the 350-560 nm range could be reduced to ∼2% for the synthesized data, which can thus significantly improve the derivation of a coefficients of other varying components. Although the inclusion of ZSD places an extra constraint in the inversion of Rrs, no apparent improvement over the quasi-analytical algorithm (QAA) was found when the fusion of ZSD and Rrs was applied to a field dataset, which calls for more accurate determination of the absorption coefficients from water samples.

20.
Eur Spine J ; 27(10): 2609-2620, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30008063

RESUMO

PURPOSE: This study aimed to investigate the potential mechanism and value of lupeol in inhibiting high-glucose-induced apoptosis in rabbit nucleus pulposus cells (NPCs). METHODS: NPCs were divided into four groups: control (CON), high glucose (HG), LUP, and HG + LUP. Viability, reactive oxygen species (ROS) levels, and apoptosis were examined in NPCs. The protein expression levels of Bax, Bcl-2, cytochrome C, and caspase 9/3 were measured using reverse transcription-polymerase chain reaction and Western blot assay. RESULTS: The apoptotic rate and total ROS level of the HG group significantly increased compared with the CON group (P < 0.01). The total ROS level in the HG + LUP group significantly decreased compared with the HG group(P < 0.05). The mRNA expression of Bcl-2 was significantly upregulated, whereas the expression of Bax, cytochrome C, and caspase 9/3 was downregulated in the HG + LUP group compared with those in the HG group(P < 0.05).The Western blot assay showed that the expression of Bcl-2 was upregulated, but the expression of Bax, cytochrome C, and caspase 9/3 was significantly downregulated in the HG + LUP group compared with the HG group (P < 0.05). CONCLUSIONS: Lupeol inhibited high-glucose-induced apoptosis in NPCs by enhancing the anti-oxidative stress in the mitochondria. This study suggested lupeol as a potential therapeutic drug for treating intervertebral disc degeneration under hyperglycaemic conditions. These slides can be retrieved under Electronic Supplementary Material.


Assuntos
Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Glucose/farmacologia , Núcleo Pulposo/citologia , Triterpenos Pentacíclicos/farmacologia , Animais , Células Cultivadas , Estresse Oxidativo/efeitos dos fármacos , Coelhos
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