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1.
J Phys Chem B ; 128(26): 6422-6433, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38906826

RESUMO

The existence of liquid carbon as an intermediate phase preceding the formation of novel carbon materials has been a point of contention for several decades. Experimental observation of such a liquid state requires nonthermal melting of solid carbon materials at various laser fluences and pulse properties. Reflectivity experiments performed in the mid-1980s reached opposing conclusions regarding the metallic or insulating properties of the purported liquid state. Time-resolved X-ray absorption studies showed shortening of C-C bonds and increasing diffraction densities, thought to evidence a liquid or glassy carbon state, respectively. Nevertheless, none of these experiments provided information on the electronic structure of the proposed liquid state. Herein, we report the results of time-resolved resonant inelastic X-ray scattering (RIXS) and time-resolved X-ray emission spectroscopy (XES) studies on amorphous carbon (a-C) and ultrananocrystalline diamond (UNCD) as a function of delay time between the irradiating pulse and X-ray probe. For both a-C and UNCD, we attribute decreases in RIXS or XES signals to transition blocking, relaxation, and finally, ablation. Increased signal at 20 ps following the irradiation of the UNCD is attributed to the probable formation of nanoscale structures in the ablation plume. Differences in the amount of signal observed between a-C and UNCD are explained by the difference in sample thickness and, specifically, incomplete melting of the UNCD film. Comparisons to spectral simulations based on MD trajectories at extreme conditions indicate that the carbon state in our experiments is crystalline. Normal mode analysis confirmed that symmetrical bending or stretching of the C-C bonds in the diamond lattice results in XES spectra with small intensity differences. Overall, we observed no evidence of melting to a liquid state, as determined by the lack of changes in the spectral properties for up to 100 ps delays following the melting pulses.

2.
Inflamm Intest Dis ; 9(1): 103-114, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38681186

RESUMO

Introduction: Currently, no self-care measurement tool specific to inflammatory bowel disease (IBD) exists in Japan. The Instrument for Diabetes Self-care Agency (IDSCA) is a reliable and valid self-care measurement tool for patients with diabetes. Factors affecting self-care ability assessed by IDSCA appear to meet the requirements for patients with IBD. Therefore, we created a self-care ability measurement tool adapted from IDSCA as an original draft for the Instrument for IBD Self-care Agency and extracted factors and items required to measure the self-care ability of patients with IBD. Methods: An anonymous questionnaire survey was distributed among 226 patients. Exploratory factor analysis examined the relationship of factors from multiple perspectives, identified factors based on their content, and confirmed their internal consistency. Statistical analyses were performed using JMP® 14.0.0. Results: Five factors with 23 items were extracted from the IDSCA, including ability to build a human support system, ability to acquire knowledge, ability to maintain self-care, ability to self-manage, and ability to self-assess. Cronbach's alpha was 0.765-0.861 for each factor and 0.904 for the entire scale. Conclusion: We could identify the self-care agencies of patients with IBD, including 5 factors and 23 items. Focusing on these self-care factors may provide critical information to guide nurses' self-care interventions.

3.
J Phys Chem Lett ; 13(39): 8963-8970, 2022 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-36165491

RESUMO

The interaction of intense light with matter gives rise to competing nonlinear responses that can dynamically change material properties. Prominent examples are saturable absorption (SA) and two-photon absorption (TPA), which dynamically increase and decrease the transmission of a sample depending on pulse intensity, respectively. The availability of intense soft X-ray pulses from free-electron lasers (FELs) has led to observations of SA and TPA in separate experiments, leaving open questions about the possible interplay between and relative strength of the two phenomena. Here, we systematically study both phenomena in one experiment by exposing graphite films to soft X-ray FEL pulses of varying intensity. By applying real-time electronic structure calculations, we find that for lower intensities the nonlinear contribution to the absorption is dominated by SA attributed to ground-state depletion; our model suggests that TPA becomes more dominant for larger intensities (>1014 W/cm2). Our results demonstrate an approach of general utility for interpreting FEL spectroscopies.

4.
J Clin Med ; 10(17)2021 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-34501223

RESUMO

OBJECT: Although many Japanese patients infected with coronavirus disease 2019 (COVID-19) only experience mild symptoms, in some cases a patient's condition deteriorates, resulting in a poor outcome. This study examines the behavior of biomarkers in patients with mild to severe COVID-19. METHODS: The disease severity of 152 COVID-19 patients was classified into mild, moderate I, moderate II, and severe, and the behavior of laboratory biomarkers was examined across these four disease stages. RESULTS: The median age and male/female ratio increased with severity. The mortality rate was 12.5% in both moderate II and severe stages. Underlying diseases, which were not observed in 45% of mild stage patients, increased with severity. An ROC analysis showed that C-reactive protein (CRP), ferritin, procalcitonin (PCT), hemoglobin (Hb) A1c, albumin, and lactate dehydrogenase (LDH) levels were significantly useful for the differential diagnosis of mild/moderate I stage and moderate II/severe stage. In the severe stage, Hb levels, coagulation time, total protein, and albumin were significantly different on the day of worsening from those observed on the day of admission. The frequency of hemostatic biomarker abnormalities was high in the severe disease stage. CONCLUSION: The evaluation of severity is valuable, as the mortality rate was high in the moderate II and severe stages. The levels of CRP, ferritin, PCT, albumin, and LDH were useful markers of severity, and hemostatic abnormalities were frequently observed in patients in the severe disease stage.

5.
ACS Cent Sci ; 7(6): 910-916, 2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34235249

RESUMO

Historically, efforts to improve academic climate have been siloed-many efforts involve the collection of data to understand issues affecting diversity at an institutional level, while others prioritize recruitment and retention of historically marginalized groups. Few initiatives, however, effectively combine the two in order to create concrete action plans to eliminate structural barriers that hinder the retention of minorities in STEM. In this Editorial, we present the history and details of a collaborative effort to improve the academic climate of the Department of Chemistry at University of California, Berkeley. This initiative began in 2016 as a graduate student-led, grassroots movement to develop a method to assess the department's academic climate. Over the past several years-and with support from stakeholders at all levels-it has grown into a department-wide effort to systematically collect data, exchange ideas, and implement goal-oriented interventions to make our academic community more inclusive. With the recent development of a five-year strategic plan and funding increase to provide financial support for student-led programs, we have institutionalized a method to maintain the initiative's momentum. Here, we share our approaches, insights, and perspectives from community members who have shaped this movement. We also provide advice to help other academic communities determine a practical path toward affecting positive cultural change.

6.
ACS Omega ; 6(22): 14410-14419, 2021 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-34124463

RESUMO

Ongoing efforts to improve diversity in science, technology, engineering, and mathematics (STEM) primarily manifest as attempts to recruit more women and individuals from historically marginalized groups. Yet, these efforts fail to repair the specific, systemic issues within academic communities that hinder diverse individuals from persisting and thriving in STEM. Here, we present the results of a quantitative, multiyear effort to make the academic climate of an R1 STEM department more inclusive. We use a student-led, department-specific, faculty-supported initiative to assess and improve the climate of the Department of Chemistry at the University of California, Berkeley, as a case study. Our results provide quantitative evidence that community discussions grounded in our own data, alongside cooperative community efforts to address the issues present in those data, are effective methods for driving positive change. Longitudinal assessment of our academic climate from 2018 to 2020 via annual department-wide surveys indicates that these interventions have succeeded in shifting the perception of our academic climate. This study confirms the positive outcomes of having a practical, sustainable, and data-driven framework for affecting change within a graduate community.

7.
J Phys Chem Lett ; 12(12): 3026-3030, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33734703

RESUMO

"On-water" catalysis, the unusual activity of water molecules at the organic solvent-water interface, has been demonstrated in many organic reactions. However, the catalytic mechanism has remained unclear, largely because of the irreproducibility of the organic-water interface under the common stirring condition. Here, the interfacial area was controlled by employing adsorbed water on mesoporous silica nanoparticles as the catalyst. Reliable kinetics of the cycloaddition reaction of quadricyclane and diethyl azodicarboxylate (DEAD) at the toluene-water interface within the nanoparticle pores were measured. Data reveal an Eley-Rideal mechanism, wherein DEAD adsorbs at the toluene-water interface via hydrogen bonds formed with interfacial water, which lower the activation energy of the cycloaddition reaction. The mechanistic insights gained and preparation of surface water in silica pores described herein may facilitate the future design of improved "on-water" catalysts.

8.
Appl Microbiol Biotechnol ; 105(1): 367-377, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33242127

RESUMO

Although temperature is a crucial factor affecting enzymatic activity on biochemical and biofuel production, the reaction temperature for the generation of these products is usually set at the optimal growth temperature of the host strain, even under non-proliferative conditions. Given that the production of fermentation products only requires a fraction of the cell's metabolic pathways, the optimal temperatures for microbial growth and the fermentative production of a target compound may be different. Here, we investigated the effect of temperature on lactic and succinic acids production, and related enzymatic activities, in wild-type and succinic acid-overproducing strains of Corynebacterium glutamicum. Interestingly, fermentative production of lactic acid increased with the temperature in wild-type: production was 69% higher at 42.5 °C, a temperature that exceeded the upper limit for growth, than that at the optimal growth temperature (30 °C). Conversely, succinic acid production was decreased by 13% under the same conditions in wild-type. The specific activity of phosphoenolpyruvate carboxylase decreased with the increase in temperature. In contrast, the other glycolytic and reductive TCA cycle enzymes demonstrated increased or constant activity as the temperature was increased. When using a succinic acid over-producing strain, succinic acid production was increased by 34% at 42.5 °C. Our findings demonstrate that the profile of fermentation products is dependent upon temperature, which could be caused by the modulation of enzymatic activities. Moreover, we report that elevated temperatures, exceeding the upper limit for cell growth, can be used to increase the production of target compounds in C. glutamicum. KEY POINTS: • Lactate productivity was increased by temperature elevation. • Succinate productivity was increased by temperature elevation when lactate pathway was deleted. • Specific activity of phosphoenolpyruvate carboxylase was decreased by temperature elevation.


Assuntos
Corynebacterium glutamicum , Fermentação , Ácido Láctico , Ácido Succínico , Temperatura
9.
Appl Microbiol Biotechnol ; 104(15): 6719-6729, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32556410

RESUMO

Cell proliferation is achieved through numerous enzyme reactions. Temperature governs the activity of each enzyme, ultimately determining the optimal growth temperature. The synthesis of useful chemicals and fuels utilizes a fraction of available metabolic pathways, primarily central metabolic pathways including glycolysis and the tricarboxylic acid cycle. However, it remains unclear whether the optimal temperature for these pathways is correlated with that for cell proliferation. Here, we found that wild-type Corynebacterium glutamicum displayed increased glycolytic activity under non-growing anaerobic conditions at 42.5 °C, at which cells do not proliferate under aerobic conditions. At this temperature, glucose consumption was not inhibited and increased by 28% compared with that at the optimal growth temperature of 30 °C. Transcriptional analysis revealed that a gene encoding glucose transporter (iolT2) was upregulated by 12.3-fold compared with that at 30 °C, with concomitant upregulation of NCgl2954 encoding the iolT2-regulating transcription factor. Deletion of iolT2 decreased glucose consumption rate at 42.5 °C by 28%. Complementation of iolT2 restored glucose consumption rate, highlighting the involvement of iolT2 in the accelerating glucose consumption at an elevated temperature. This study shows that the optimal temperature for glucose metabolism in C. glutamicum under anaerobic conditions differs greatly from that for cell growth under aerobic conditions, being beyond the upper limit of the growth temperature. This is beneficial for fuel and chemical production not only in terms of increasing productivity but also for saving cooling costs. KEY POINTS: • C. glutamicum accelerated anaerobic glucose consumption at elevated temperature. • The optimal temperature for glucose consumption was above the upper limit for growth. • Gene expression involved in glucose transport was upregulated at elevated temperature. Graphical abstract.


Assuntos
Corynebacterium glutamicum/genética , Proteínas Facilitadoras de Transporte de Glucose/genética , Glucose/metabolismo , Temperatura Alta , Redes e Vias Metabólicas , Anaerobiose , Transporte Biológico , Corynebacterium glutamicum/metabolismo , Expressão Gênica , Perfilação da Expressão Gênica , Proteínas Facilitadoras de Transporte de Glucose/metabolismo , Regulação para Cima
10.
J Phys Chem Lett ; 11(5): 1656-1661, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-32040333

RESUMO

Liquid phase charge-transfer-to-solvent (CTTS) transitions are important, as they serve as photochemical routes to solvated electrons. In this work, broadband deep-ultraviolet electronic sum frequency generation (DUV-ESFG) and two-photon absorption (2PA) spectroscopic techniques were used to assign and compare the nature of the aqueous iodide CTTS excitations at the air/water interface and in bulk solution. In the one-photon absorption (1PA) spectrum, excitation to the 6s Rydberg-like orbital (5p → 6s) gives rise to a pair of spin-orbit split iodine states, 2P3/2 and 2P1/2. In the 2PA spectra, the lower-energy 2P3/2 peak is absent and the observed 2PA peak, which is ∼0.14 eV blue-shifted relative to the upper 2P1/2 CTTS peak seen in 1PA, arises from 5p → 6p electronic promotion. The band observed in the ESFG spectrum is attributed to mixing of excited states involving 5p → 6p and 5p → 6s promotions caused by both vibronic coupling and the external electric field generated by asymmetric interfacial solvation.

11.
J Phys Chem Lett ; 9(16): 4753-4757, 2018 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-30074801

RESUMO

Measurement of interfacial electronic spectra is a powerful tool for characterizing the properties of ions in physical, biological, environmental, and industrial systems. Here, we describe measurement of the complete charge-transfer-to-solvent (CTTS) spectrum of thiocyanate at the air/water interface using our recently developed femtosecond broadband deep ultraviolet electronic sum frequency generation technique. We find that the lower energy CTTS band characterized in bulk thiocyanate spectra is not observed in the | χ(2)|2-power spectrum of the air/water interface, likely reflecting the different solvation environments, altering of the charge distribution of the ion, and possible ion-ion effects, and that sodium and potassium salts yield identical spectra. Additional experiments and comparison with theoretical calculations are necessary to extract the interesting chemical details responsible for these salient spectral differences.

12.
Opt Lett ; 39(24): 6942-5, 2014 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-25503036

RESUMO

We present a simple method for continuous snapshot multispectral imaging or multispectral videography that achieves high-speed spectral video recording without the need for mechanical scanning and much computation for datacube construction. The enabling component of this method is an array of periscopes placed in a prism-based spectral shaper that spectrally separates the image without image deformation. As a proof-of-principle demonstration, we show five-color multispectral video recording in the visible range (200×200 pixels per spectral image frame) at a record high frame rate of at least 2800 frames per second. Our experimental results indicate that this method holds promise for various industrial and biomedical applications such as remote sensing, food inspection, and endoscopy.


Assuntos
Gravação em Vídeo/métodos , Imagem Óptica , Análise Espectral , Gravação em Vídeo/instrumentação
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