Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 52
Filtrar
1.
Injury ; 55(6): 111549, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38621349

RESUMO

BACKGROUND: Spinal anesthesia is used for femoral trochanteric fracture surgery, but frequently induces hypotension and the causative factors remain unclear. We examined background factors for the use of an intraoperative vasopressor in elderly patients receiving spinal anesthesia for femoral trochanteric fracture surgery. METHODS: We retrospectively analyzed 203 patients >75 years (mean age, 87.9 years) with femoral trochanteric fractures who underwent short nail fixation under orthopedically managed spinal anesthesia at our hospital between April 2020 and July 2023. Patients were divided into two groups: group A (intraoperative vasopressor) and group B (no vasopressor). The following data were compared: age, sex, height, weight, body mass index, antihypertensive medication, years of experience as a primary surgeon, bupivacaine dose, puncture level, anesthesia time, operation time, hemoglobin level and blood urea nitrogen/creatinine ratio on the day of surgery, brain natriuretic peptide level, left ventricular ejection fraction, and percentage of patients operated on the day of transport. RESULTS: There were 65 patients in group A and 138 in group B. The average dose of bupivacaine was 11.7 mg. In a univariate analysis, group A was slightly younger (87.0 vs. 88.3 years), had a higher blood urea nitrogen/creatinine ratio (27.1 vs. 24.5), more frequently received ß-blockers (14.1% vs. 5.8 %) and diuretic medications (21.9% vs. 11.6 %), and had a higher puncture level. A logistic regression analysis identified younger age (p = 0.02) and diuretic medication (p = 0.001) as independent risk factors in group A. Vasopressor use was more frequent at a higher puncture level in group A (57 % for L2/3, 33 % for L3/4, 15 % for L4/5, 0 % for L5/S). CONCLUSIONS: Spinal anesthesia-induced hypotension is attributed to volume deficit or extensive sympathetic blockade and may be prevented by avoiding high puncture levels and increasing preoperative fluid supplementation in patients on diuretics. There is currently no consensus on anesthetic dosages.

2.
Chem Sci ; 15(6): 1953-1965, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38332834

RESUMO

Precise template synthesis will realize three-dimensionally ordered nanoporous graphenes (NPGs) with a spatially controlled seamless graphene structure and fewer edges. These structural features result in superelastic nature, high electrochemical stability, high electrical conductivity, and fast diffusion of gases and ions at the same time. Such innovative 3D graphene materials are conducive to solving energy-related issues for a better future. To further improve the attractive properties of NPGs, we review the template synthesis and its mechanism by chemical vapor deposition of hydrocarbons, analysis of the nanoporous graphene structure, and applications in electrochemical and mechanical devices.

3.
Phys Chem Chem Phys ; 25(48): 32972-32978, 2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38019669

RESUMO

Nanoporous graphene (NPG) materials have the pronounced electrochemical stability of the seamless graphene structures developed over the 3D space. We revisited the Raman spectra of nanoporous carbons (NPCs) synthesized using θ-/γ-Al2O3 templates and NPGs converted from NPCs by annealing at 1800 °C to identify the type and density of defects. We found that both the NPCs and NPGs mostly consist of single-layered graphene with a few single vacancies and Stone-Wales defects. The density of vacancy defect per hexagon in the graphene sheet is estimated to be 10-2 for NPCs, while the annealing reduced the value to 10-3-10-4 for NPGs. This supports the outstanding chemical and electrochemical stability of the novel porous carbon materials.

4.
Int J Surg Case Rep ; 110: 108794, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37689022

RESUMO

INTRODUCTION: Proximal tibial epiphyseal injuries are rare, accounting for 0.5-3 % of all epiphyseal injuries, of which bilateral cases are extremely rare. Only five cases of bilateral proximal tibial epiphyseal injuries have so far been reported in patients with osteogenesis imperfecta. We herein present a case of repeated bilateral proximal tibial epiphyseal injuries with a diagnosis of osteogenesis imperfecta. We also performed a literature review of 46 cases of bilateral proximal tibial epiphyseal injuries reported since 1955, including 5 of osteogenesis imperfecta. PRESENTATION OF CASE: A 10-year-old boy repeatedly sustained bilateral simultaneous proximal tibial epiphyseal injuries due to minor trauma. Blue sclera was noted and, thus, genetic testing was performed and revealed osteogenesis imperfecta. After the fourth injury, we performed internal fixation with cannulated cancellous screw bilaterally. The patient had a short stature and the marked loss of bone density; therefore, the screw was kept in place until epiphyseal closure and bisphosphonate and human growth hormone were administered to prevent re-fracture and increase bone density and the growth rate. DISCUSSION: The literature review revealed that the mean age of injury was 11.2 years for osteogenesis imperfecta cases and 14.9 years for non-osteogenesis imperfecta cases, with the former being injured at a younger age. CONCLUSION: Osteogenesis imperfecta often causes diaphyseal fractures, which may be attributed to the fragility of the epiphyseal line. Therefore, the possibility of osteogenesis imperfecta needs to be considered when treating patients with epiphyseal injuries at rare sites, particularly younger children.

5.
Clin Case Rep ; 11(1): e6877, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36694645

RESUMO

We report a case of neurogenic pulmonary edema (NPE) caused by middle cerebral artery infarction involving the right insular cortex. Hyperactivity of the insular cortex, which regulates sympathetic function, can cause NPE. The NPE should be considered in the differential diagnosis of dyspneic patients with insular cortex infarction.

6.
Phys Chem Chem Phys ; 24(38): 23357-23366, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36165844

RESUMO

Chemical vapor deposition of methane onto a template of alumina (Al2O3) nanoparticles is a prominent synthetic strategy of graphene meso-sponge, a new class of nano porous carbon materials consisting of single-layer graphene walls. However, the elementary steps controlling the early stages of graphene growth on Al2O3 surfaces are still not well understood. In this study, density functional theory calculations provide insights into the initial stages of graphene growth. We have modelled the mechanism of CH4 dissociation on the (111), (110), (100), and (001) γ-Al2O3 surfaces. Subsequently, we have considered the reaction pathway leading to the formation of a C6 ring. The γ-Al2O3(110) and γ-Al2O3(100) are both active for CH4 dissociation, but the (100) surface has higher catalytic activity towards the carbon growth reaction. The overall mechanism involves the formation of the reactive intermediate CH2* that then can couple to form CnH2n* (n = 2-6) intermediates with unsaturated CH2 ends. The formation of these species, which are not bound to the surface-active sites, promotes the sustained carbon growth in a nearly barrierless process. Also, the short distance between terminal carbon atoms leads to strong interactions, which might lead to the high activity between unsaturated CH2* of the hydrocarbon chain. Analysis of the electron localization and geometries of the carbon chains reveals the formation of C-Al-σ bonds with the chain growing towards the vacuum rather than C-Al-π bonds covering the γ-Al2O3(100) surface. This growth behaviour prevents catalyst poisoning during the initial stage of graphene nucleation.

7.
Chem Sci ; 13(11): 3140-3146, 2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35414888

RESUMO

γ-Al2O3 nanoparticles promote pyrolytic carbon deposition of CH4 at temperatures higher than 800 °C to give single-walled nanoporous graphene (NPG) materials without the need for transition metals as reaction centers. To accelerate the development of efficient reactions for NPG synthesis, we have investigated early-stage CH4 activation for NPG formation on γ-Al2O3 nanoparticles via reaction kinetics and surface analysis. The formation of NPG was promoted at oxygen vacancies on (100) surfaces of γ-Al2O3 nanoparticles following surface activation by CH4. The kinetic analysis was well corroborated by a computational study using density functional theory. Surface defects generated as a result of surface activation by CH4 make it kinetically feasible to obtain single-layered NPG, demonstrating the importance of precise control of oxygen vacancies for carbon growth.

8.
Phys Chem Chem Phys ; 23(2): 834-845, 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33284297

RESUMO

Cinnamate derivatives are very useful as UV protectors in nature and as sunscreen reagents in daily life. They convert harmful UV energy to thermal energy through effective nonradiative decay (NRD) including trans → cis photoisomerization. However, the mechanism is not simple because different photoisomeirzation routes have been observed for different substituted cinnamates. Here, we theoretically examined the substitution effects at the phenyl ring of methylcinnamate (MC), a non-substituted cinnamate, on the electronic structure and the NRD route involving trans → cis isomerization based on time-dependent density functional theory. A systematic reaction pathway search using the single-component artificial force-induced reaction method shows that the very efficient photoisomerization route of MC can be essentially described as "1ππ* (trans) → 1nπ* → T1 (3ππ*) → S0 (trans or cis)". We found that for efficient 1ππ* (trans) → 1nπ* internal conversion (IC), MC should have the substituent at the appropriate position of the phenyl ring to stabilize the highest occupied π orbital. Substitution at the para position of MC slightly lowers the 1ππ* state energy and photoisomerization occurs via a slightly less efficient "1ππ* (trans) → 3nπ* → T1 (3ππ*) → S0 (trans or cis)" pathway. Substitution at the meta or ortho positions of MC significantly lowers the 1ππ* state energy so that the energy barrier of IC (1ππ* → 1nπ*) becomes very high. This substitution leads to a much longer 1ππ* state lifetime than that of MC and para-substituted MC, and a change in the dominant photoisomerization route to "1ππ* (trans) → C[double bond, length as m-dash]C bond twisting on 1ππ* → S0 (trans or cis)". As a whole, the "1ππ* → 1nπ*" IC observed in MC is the most important initial step for the rapid change of UV energy to thermal energy. We also found that the stabilization of the π orbital (i) minimizes the energy gap between 1ππ* and 1nπ* at the 1ππ* minimum and (ii) makes the 0-0 level of 1ππ* higher than 1nπ* as observed in MC. These MC-like relationships between the 1ππ* and 1nπ* energies should be ideal to maximize the "1ππ* → 1nπ*" IC rate constant according to Marcus theory.


Assuntos
Cinamatos/química , Processos Fotoquímicos , Protetores Solares/química , Cinamatos/efeitos da radiação , Teoria da Densidade Funcional , Isomerismo , Modelos Químicos , Protetores Solares/efeitos da radiação , Raios Ultravioleta
9.
Appl Opt ; 59(31): 9850-9854, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-33175824

RESUMO

We present a method for less-invasive imaging through scattering media. We use an image-to-image translation, which is called a cycle generative adversarial network (CycleGAN), based on semi-supervised learning with an unlabeled dataset. Our method was experimentally demonstrated by reconstructing object images displayed on a spatial light modulator between diffusers. In the demonstration, CycleGAN was trained with captured images and object candidate images that were not used for image capturing through the diffusers and were not paired with the captured images.

10.
J Chem Phys ; 151(12): 124305, 2019 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-31575189

RESUMO

We performed reaction dynamics simulations to demonstrate that the vibrational dynamics of C60 induced by infrared (IR) pulses can be traced by triggering Coulomb explosion with intense femtosecond X-ray free electron laser (XFEL) probe pulses. The time series of the angular anisotropy ß(t) of fast C+ and C2+ fragments of C60 60+ produced by such an XFEL pulse reflects the instantaneous structure of C60 vibrationally excited by IR pulses. The phases and amplitudes of excited vibrational modes and the coupling between excited modes can be successfully extracted from the expansion of ß(t) in terms of vibrational modes. This proof-of-principle simulation clearly demonstrates that various information of the structures and reaction dynamics of large clusters or biomolecules can be retrieved by decomposing the experimentally determined ß(t) into vibrational modes.

11.
Phys Chem Chem Phys ; 21(36): 19755-19763, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31259349

RESUMO

The electronic states and photochemistry including nonradiative decay (NRD) and trans(E) → cis(Z) isomerization of methylcinnamate (MC) and its hydrogen-bonded complex with methanol have been investigated under jet-cooled conditions. S1(1nπ*) and S2(1ππ*) are directly observed in MC. This is the first direct observation of S1(1nπ*) in cinnamate derivatives. Surprisingly, the order of the energies between the nπ* and ππ* states is opposite to substituted cinnamates. TD-DFT and SAC-CI calculations support the observed result and show that the substitution to the benzene ring largely lowers the 1ππ* energy while the effect on 1nπ* is rather small. The S2(ππ*) state lifetime of MC is determined to be equal to or shorter than 10 ps, and the production of the transient T1 state is observed. The T1(ππ*) state is calculated to have a structure in which propenyl C[double bond, length as m-dash]C is twisted by 90°, suggesting the trans → cis isomerization proceeds via T1. The production of the cis isomer is confirmed by low-temperature matrix-isolated FTIR spectroscopy. The effect of H-bonding is examined for the MC-methanol complex. The S2 lifetime of MC-methanol is determined to be 180 ps, indicating that the H-bonding to the C[double bond, length as m-dash]O group largely prohibits the 1ππ* → 1nπ* internal conversion. This lifetime elongation in the methanol complex also describes well a higher fluorescence quantum yield of MC in methanol solution than in cyclohexane, while such a solvent dependence is not observed in para-substituted MC. Determination of the photochemical reaction pathways of MC and MC-methanol will help us to design photofunctional cinnamate derivatives.

13.
Nat Commun ; 10(1): 2186, 2019 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-31097703

RESUMO

The increasing availability of X-ray free-electron lasers (XFELs) has catalyzed the development of single-object structural determination and of structural dynamics tracking in real-time. Disentangling the molecular-level reactions triggered by the interaction with an XFEL pulse is a fundamental step towards developing such applications. Here we report real-time observations of XFEL-induced electronic decay via short-lived transient electronic states in the diiodomethane molecule, using a femtosecond near-infrared probe laser. We determine the lifetimes of the transient states populated during the XFEL-induced Auger cascades and find that multiply charged iodine ions are issued from short-lived (∼20 fs) transient states, whereas the singly charged ones originate from significantly longer-lived states (∼100 fs). We identify the mechanisms behind these different time scales: contrary to the short-lived transient states which relax by molecular Auger decay, the long-lived ones decay by an interatomic Coulombic decay between two iodine atoms, during the molecular fragmentation.

14.
Mov Disord Clin Pract ; 6(3): 213-221, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30949552

RESUMO

BACKGROUND: Postural abnormalities in Parkinson's disease (PD) patients and unimpaired elderly are not well differentiated. Factors related to postural abnormality associated with PD are controversial. OBJECTIVE: We assessed differences in postural change between PD patients and unimpaired elderly and elucidated factors related to abnormal posture in PD patients. METHODS: We measured the dropped head angle (DHA), anterior flexion angle (AFA), and lateral flexion angle (LFA) of the thoracolumbar spine of an unprecedented 1,117 PD patients and 2,732 general population participants (GPPs) using digital photographs. Two statistical analyses were used for elucidating factors related to these angles. RESULTS: In GPPs, age was correlated with DHA, AFA, and LFA. DHAs, AFAs, and LFAs of PD patients and age-matched GPPs were 21.70° ± 14.40° and 13.13° ± 10.79°, 5.98° ± 12.67,°and - 3.82° ± 4.04°, and 0.86° ± 4.25° and 1.33° ± 2.16°, respectively. In PD patients, factors related to DHA were age, male sex, and H & Y stage during ON time. Factors related to AFA were age, duration of disease, H & Y stage during ON and OFF times, pain, vertebral disease, and bending to the right. A factor related to LFA was AFA. CONCLUSIONS: DHA and AFA of GGPs correlated with age and were larger in PD patients than those with in GPPs. Some PD patients showed angles far beyond the normal distribution. Thus, factors associated with disease aggravation affected postural abnormality in PD patients.

15.
Phys Rev Lett ; 122(5): 053002, 2019 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-30822022

RESUMO

Theoretical studies indicated that C_{60} exposed to linearly polarized intense infrared pulses undergoes periodic cage structural distortions with typical periods around 100 fs (1 fs=10^{-15} s). Here, we use the laser-driven self-imaging electron diffraction technique, previously developed for atoms and small molecules, to measure laser-induced deformation of C_{60} in an intense 3.6 µm laser field. A prolate molecular elongation along the laser polarization axis is determined to be (6.1±1.4)% via both angular- and energy-resolved measurements of electrons that are released, driven back, and diffracted from the molecule within the same laser field. The observed deformation is confirmed by density functional theory simulations of nuclear dynamics on time-dependent adiabatic states and indicates a nonadiabatic excitation of the h_{g}(1) prolate-oblate mode. The results demonstrate the applicability of laser-driven electron diffraction methods for studying macromolecular structural dynamics in four dimensions with atomic time and spatial resolutions.

16.
J Phys Chem Lett ; 9(24): 6927-6933, 2018 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-30444124

RESUMO

Ultrafast XUV chemistry is offering new opportunities to decipher the complex dynamics taking place in highly excited molecular states and thus better understand fundamental natural phenomena as molecule formation in interstellar media. We used ultrashort XUV light pulses to perform XUV pump-IR probe experiments in caffeine as a model of prebiotic molecule. We observed a 40 fs decay of excited cationic states. Guided by quantum calculations, this time scale is interpreted in terms of a nonadiabatic cascade through a large number of highly correlated states. This shows that the correlation driven nonadiabatic relaxation seems to be a general process for highly excited states, which might impact our understanding of molecular processing in interstellar media.

17.
Phys Chem Chem Phys ; 20(26): 17583-17598, 2018 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-29693100

RESUMO

An experimental and theoretical study has been carried out to elucidate the nonradiative decay (NRD) and trans(E) → cis(Z) isomerization from the S1 (1ππ*) state of structural isomers of hydroxy methylcinnamate (HMC); ortho-, meta- and para-HMC (o-, m- and p-HMC). A low temperature matrix-isolation Fourier Transform Infrared (FTIR) spectroscopic study revealed that all the HMCs are cis-isomerized upon UV irradiation. A variety of laser spectroscopic methods have been utilized for jet-cooled gas phase molecules to investigate the vibronic structure and lifetimes of the S1 state, and to detect the transient state appearing in the NRD process. In p-HMC, the zero-point level of the S1 state decays as quickly as 9 ps. A transient electronic state reported by Tan et al. (Faraday Discuss. 2013, 163, 321-340) was reinvestigated by nanosecond UV-tunable deep UV pump-probe spectroscopy and was assigned to the T1 state. For m- and o-HMC, the lifetime at the zero-point energy level of S1 is 10 ns and 6 ns, respectively, but it becomes substantially shorter at an excess energy higher than 1000 cm-1 and 600 cm-1, respectively, indicating the onset of NRD. Different from p-HMC, no transient state (T1) was observed in m- nor o-HMC. These experimental results are interpreted with the aid of TDDFT calculations by considering the excited-state reaction pathways and the radiative/nonradiative rate constants. It is concluded that in p-HMC, the trans → cis isomerization proceeds via a [trans-S1 → 1nπ* → T1 → cis-S0] scheme. On the other hand, in o- and m-HMC, the isomerization proceeds via a [trans-S1 → twisting along the C[double bond, length as m-dash]C double bond by 90° on S1 → cis-S0] scheme. The calculated barrier height along the twisting coordinate agrees well with the observed onset of the NRD channel for both o- and m-HMC.

18.
J Med Ultrason (2001) ; 45(1): 3-13, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28884290

RESUMO

Dual X-ray absorptiometry (DXA) is used to diagnose osteoporosis. On the other hand, quantitative ultrasound (QUS) is widely used to assess bone density as part of medical screening as it is relatively inexpensive and easy to perform. Current QUS devices do not share precise ultrasound-related parameters, such as frequency, waveform, beam pattern, transient response, definition of propagation time, definition of degree of attenuation, and precise measurement site, resulting in different measurements across models. The Japan Osteoporosis Society established a QUS Standardization Committee in 2007 to investigate standardization of speed of sound (SOS) and broadband ultrasonic attenuation (BUA) measurements to resolve this issue. The committee came up with a formula to convert SOS and BUA values yielded by each model available in Japan. This has made it possible to convert QUS measurements from different models into standardized values, greatly improving the effectiveness of QUS measurements.


Assuntos
Densidade Óssea , Osso e Ossos/diagnóstico por imagem , Osteoporose/diagnóstico por imagem , Ultrassonografia/normas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Padrões de Referência , Valores de Referência , Ondas Ultrassônicas , Ultrassonografia/instrumentação , Ultrassonografia/métodos , Adulto Jovem
19.
J Med Ultrason (2001) ; 45(1): 15, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28933006

RESUMO

In the original version of the article, the third author name was incorrectly published. The correct name is Kosei Yoh.

20.
Breed Sci ; 67(3): 320-326, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28744186

RESUMO

'Nagasaki Kogane' is a new potato variety bred from a cross between 'Saikai 35' as a female parent and 'Saikai 33' as a male. 'Saikai 35' is resistant to bacterial wilt, contains the H1 and Rychc genes for resistance to the potato cyst nematode (PCN) and potato virus Y (PVY), respectively, and has high carotenoid content, while 'Saikai 33' has large and high-yielding tubers and is resistant to both bacterial wilt and PCN. The carotenoid content of 'Nagasaki Kogane' is higher than that of 'Dejima', a common double cropping variety. The taste quality of steamed 'Nagasaki Kogane' is comparable to that of 'Inca-no-mezame' tubers, which has high levels of carotenoid, and superior to 'Nishiyutaka', another popular double cropping variety. 'Nagasaki Kogane' is suitable for French fries, because its tuber has high starch content. The marketable yield of 'Nagasaki Kogane' was higher than that of 'Inca-no-mezame' in spring cropping, although it was lower than that of 'Nishiyutaka' in double cropping regions. 'Nagasaki Kogane' tubers are larger on average than 'Inca-no-mezame' tubers in spring cropping. Moreover, the 'Nagasaki Kogane' variety is resistant to PCN and PVY, and exhibits a high level of resistance to bacterial wilt.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...