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1.
Int J Pharm ; 638: 122893, 2023 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-36990167

RESUMO

The dehydration behavior of pharmaceutical hydrates has a great influence on its physiochemical properties such as stability, dissolution rate and bioavailability. However, how the intermolecular interactions vary during dehydration process remains elusive. In this work, we employed terahertz time-domain spectroscopy (THz-TDS) to probe the low-frequency vibrations and the dehydration process of isonicotinamide hydrate I (INA-H I). Theoretical solid-state DFT calculation was conducted to reveal its mechanism. Vibrational modes which are responsible for the THz absorption peaks were decomposed for better understanding the characters of these low-frequency modes. The result suggests translational motion is the dominant component for water molecules in THz region. Evolution of the THz spectrum of INA-H I during dehydration provides direct evidence of the variations of crystal structure. Based on the THz measurements, a two-step kinetics mode including first-rate reaction and three-dimensional nuclei growth is proposed. And we figure that the low-frequency vibrations of water molecules are the origin of dehydration process of hydrate.


Assuntos
Espectroscopia Terahertz , Humanos , Espectroscopia Terahertz/métodos , Teoria da Densidade Funcional , Desidratação , Cinética , Água , Vibração
2.
Nanotechnology ; 33(4)2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-34654004

RESUMO

Due to the high demand for more convenient flexible devices, there are more requirements for higher performance of flexible batteries. The layered lithium-rich manganese-based Li1.2Ni0.13Co0.13Mn0.54O2cathode material has the advantages of higher energy density, higher discharge capacity and environmentally friendly, so it can be used for high-performance flexible electrode cathode material. Its theoretical capacity can reach more than 250 mAh g-1, which is higher than most cathode materials currently used in commercialization. Here we synthesize Li1.2Ni0.13Co0.13Mn0.54O2(LNCM) cathode, and then use a simple method to make a current collect-free LNCM flexible film. This film has excellent flexibility and electrochemical performance. At 25 mA g-1, its initial discharge capacity reaches 314.0 mAh g-1. After 200 cycles of 500 mA g-1, its capacity retention rate is 82.1%, the attenuation is about 0.08% per cycle. Moreover, by bending at any position of the flexible film, it can still remain intact, and the soft-packaged battery made by the flexible film can still be used under the bending condition and keep the brightness of the LED lamp unchanged. This shows that using Li1.2Ni0.13Co0.13Mn0.54O2to make high-performance flexible electrodes is a simple and effective method, which is expected to be practically applied to flexible electronic devices.

3.
Nanotechnology ; 32(15): 155703, 2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33378747

RESUMO

Lithium ion batteries have widely been used for electronic devices and electric vehicles. However, commercial anodes, generally graphite, have not been improved a great deal. Thus, we successfully constructed ReS2/carbon nanotube (CNT) composites by a chemical vapor deposition method, which exhibit excellent electrochemical performances when serving as anode materials for lithium ion batteries (LIBs). We confirmed that ReS2 crystals are grown on the surface of the CNTs by using scanning electron microscopy and transmission electron microscopy. As a result, the LIBs show much better long-cycle and rate performances than bare ReS2 and CNTs. The ReS2/CNTs were assembled in coin cells CR2025, presenting a stability capacity of 488 mAh g-1 at a rate of 5C. The anodes maintain a reversible capacity of 1050 mAh g-1 after nearly 60 cycles at 0.2C, which indicates that it is a promising technique to improve the performance of LIBs.

4.
Oncol Lett ; 3(2): 351-362, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22740911

RESUMO

In this report, we describe a case control study in a Chinese population aimed at identifying possible associations between susceptibility to cervical cancer and single nucleotide polymorphisms in XRCC1 194C>T, XRCC1 280G>A, XRCC1 399G>A, ERCC2 751A>C, ERCC2 156C>A, ERCC1 118C>T, PARP1 762T>C, RAD51 135G>C and HER2 655A>G. The cases comprised 154 patients: 80 cervical squamous cell carcinomas (SCCs), 2 adenocarcinomas and 72 cervical intraepithelial neoplasias (CINs). A total of 177 healthy women were recruited as the controls. A significant association was found between ERCC1 118C>T and SCC in the additive genetic model [odds ratio (OR)=1.711; 95% confidence interval (CI), 1.089-2.880; p=0.021] and the dominant genetic model (OR=1.947; 95% CI, 1.056-3.590; p=0.033). Among women with a smoking family member, ERCC1 118C>T increased SCC risk in the additive model (OR=2.800; 95% CI, 1.314-5.968; p=0.008). For women who had first intercourse before 22 years of age, XRCC1 280G>A was found to act as a protective factor for SCC under the additive model (OR=0.228; 95% CI, 0.058-0.900; p=0.035), while RAD51 135G>C was a risk factor for CIN (OR=4.246; 95% CI, 1.335-13.502; p=0.014). For women who had first intercourse after 22 years of age, the additive genetic model showed RAD51 135G>C (OR=0.359; 95% CI, 0.138-0.934; p=0.036) and HER2 655A>G (OR=0.309; 95% CI, 0.098-0.972; p=0.045) to be protective factors for SCC. XRCC1 399G>A increased CIN risk among women who first gave birth before the age of 22 in the additive genetic model (OR=4.459; 95% CI, 1.139-17.453; p=0.032). For those who first gave birth after age 22, ERCC1 118C>T was found to be a risk factor for SCC in the additive genetic model (OR=1.884; 95% CI, 1.088-3.264; p=0.024). A significant interaction was observed between RAD51 135G>C and age at first intercourse (p(interaction)=0.033 for SCC, p(interaction)=0.021 for CIN), as well with sexual partner number (p(interaction)=0.001 for SCC). The interaction between HER2 655A>G and age at first intercourse, ERCC2 156C>A and family smoking status and XRCC1 280G>A and alcohol consumption were significant, with p(interaction)=0.023 for SCC, p(interaction)=0.021 for CIN and p(interaction)=0.025 for SCC, respectively.

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