Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
ACS Omega ; 7(7): 5774-5781, 2022 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-35224337

RESUMO

Ceramsite concrete is used in lining structures of underground engineering in the geothermal environment. This study, by means of mixing fly ash and silica fume, aims at diminishing the adverse effects on concrete performance caused by elevated temperature in high geothermal underground engineering. Under simulated geothermal conditions (20, 40, and 60 °C, RH ≥ 90%), it was first proposed that 15 and 5 wt % cement replacements by fly ash and silica fume, respectively, were most optimal. Then, the effect of mineral admixtures on ceramsite shotcrete performance was investigated. The results show that the mixing of fly ash and silica fume could improve ceramsite shotcrete adaptability in elevated curing temperature. Particularly for silica fume, at 40 °C curing temperature, the 28-day compressive strength and splitting tensile strength increased by 12.6 and 50.9%, respectively. The improvement effect of silica fume on permeability resistance and resistance to chloride ion permeability was higher than that of fly ash. Nevertheless, the mixing of fly ash was more effective than silica fume for reducing thermal conductivity.

2.
Comput Math Methods Med ; 2021: 1840613, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34858517

RESUMO

Knee osteoarthritis (KOA) is a degenerative joint disease characterized by articular cartilage degeneration, cartilage exfoliation, osteophyte formation, and synovitis. It seriously affects the knee joint function and quality of life of patients. Total knee arthroplasty is now the most frequently used therapy for end-stage knee arthritis because it can successfully modify the line of lower extremities, restore knee joint function, alleviate pain, and enhance patients' quality of life; nevertheless, it may cause significant trauma and bleeding. It can easily lead to infection and anemia. In this study, the control group chose total knee arthroplasty and the observation group chose total knee arthroplasty combined with PRP. The results showed that the knee joint function score, visual analog score, blood transfusion, total blood loss, total postoperative drainage, and complications in the observation group were superior to those in the control group. Total knee arthroplasty takes a long time and needs a lot of soft tissue incision, which leads to a lot of blood loss and can cause a variety of complications. Gel has been shown in studies to successfully decrease blood loss during and after total knee arthroplasty, enhance knee joint function recovery, and improve patient quality of life. In this paper, the complications and causes of knee osteoarthritis after total knee arthroplasty were studied. Combined with comprehensive nursing intervention for postoperative recovery, it helps to improve the formation of thrombin and calcium ion, which can effectively reduce blood loss, relieve pain, and promote the recovery of knee joint function. This study analyzed the application of total knee arthroplasty combined with gel in the treatment of knee osteoarthritis.


Assuntos
Osteoartrite do Joelho/cirurgia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/enfermagem , Idoso , Idoso de 80 Anos ou mais , Artroplastia do Joelho/efeitos adversos , Artroplastia do Joelho/enfermagem , Biologia Computacional , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite do Joelho/complicações , Osteoartrite do Joelho/enfermagem , Plasma Rico em Plaquetas , Cuidados Pós-Operatórios/métodos , Cuidados Pós-Operatórios/enfermagem , Complicações Pós-Operatórias/terapia , Qualidade de Vida , Recuperação de Função Fisiológica , Resultado do Tratamento
3.
Front Psychiatry ; 11: 643, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760297

RESUMO

Understanding the brain mechanisms of heroin dependence is invaluable for developing effective treatment. Measurement of regional cerebral blood flow (CBF) provides a method to visualize brain circuits that are functionally impaired by heroin dependence. This study examined regional CBF alterations and their clinical associations in unmedicated heroin-dependent individuals (HDIs) using a relatively large sample. Sixty-eight (42 males, 26 females; age: 40.9 ± 7.3 years) HDIs and forty-seven (34 males, 13 females; age: 39.3 ± 9.2 years) matched healthy controls (HCs) underwent high-resolution T1 and whole-brain arterial spin labeling (ASL) perfusion magnetic resonance imaging (MRI) scans. Additionally, clinical characteristics were collected for neurocognitive assessments. HDIs showed worse neuropsychological performance than HCs and had decreased relative CBF (rCBF) in the bilateral middle frontal gyrus (MFG), inferior temporal gyrus, precuneus, posterior cerebellar lobe, cerebellar vermis, and the midbrain adjacent to the ventral tegmental area; right posterior cingulate gyrus, thalamus, and calcarine. rCBF in the bilateral MFG was negatively correlated with Trail Making Test time in HDIs. HDIs had limbic, frontal, and parietal hypoperfusion areas. Low CBF in the MFG indicated cognitive impairment in HDIs. Together, these findings suggest the MFG as a critical region in HDIs and suggest ASL-derived CBF as a potential marker for use in heroin addiction studies.

4.
Materials (Basel) ; 12(17)2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31480249

RESUMO

Due to the rapid growth of the electric power system, the silicone rubber composite insulator is so widely employed around the world. However, the aging damage and decommission of it inevitably generates plenty of waste silicone rubber. It takes up large amounts of land for non-degradation, which is becoming a serious environmental issue. In this paper, the effort has been made to reuse the silicone rubber of composite insulator by peeling, breaking and adding it into the cement mortar to partly replace river sand by 5%, 10%, 15%, 20% and 30% in volume. Moreover, the surface modification of silicone rubber particles with H2O2 and KOH is explored to improve hydrophilicity. The mechanical strength of silicone rubber mortar and modified silicone rubber mortar are measured in detail, and the effects of particle size, content and modification of silicone rubber on the properties of mortar are investigated. This study shows that at least a 5% addition of silicone rubber can reduce the strengths, while the 15% addition is obviously favorable for increasing the toughness. Furthermore, the mortar strength gets promoted due to the surface modification. Lastly, the superior thermal insulation and noise reduction of the mortar are obtained as the addition of silicone rubber particles, and an equation between dry apparent density and thermal conductivity of mortar has been developed.

5.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 44(5): 491-500, 2019 May 28.
Artigo em Chinês | MEDLINE | ID: mdl-31303611

RESUMO

OBJECTIVE: To explore the mechanism for changes in brain microstructure in long-term abstinent from methamphetamine-dependence by using the diffusion tensor imaging (DTI).
 Methods: A total of 26 patients with long-term abstinent methamphetamine-dependence, whose abstinence time more than 14 months, and 26 normal controls all underwent cognitive executive function tests and DTI scans. We used voxel-based analysis to compare the fractional anisotropy (FA) and mean diffusivity (MD) to obtain the abnormal brain regions of DTI parameters between the two groups. Spearman correlation analysis was used to explore the correlation between FA, MD of the brain regions with abnormal parameters and cognitive executive function tests.
 Results: There were no statistical differences in the cognitive executive function tests between the two groups (P>0.05). Compared with the normal control group, the long-term abstinent from methamphetamine-dependence group showed the decreased FA in the right precuneus, right superior frontal gyrus, right calcarine, left inferior temporal gyrus and the increased MD in the right triangular part of inferior frontal gyrus, right precuneus, right posterior cingulate, right middle temporal gyrus, bilateral middle occipital gyrus, left superior parietal lobule, and lobule VIII of cerebellar hemisphere. The MD values of the right middle temporal gyrus in the long-term abstinent group were negatively correlated with the number of completions within 60 seconds (r=-0.504) and within 120 seconds (r=-0.464) .
 Conclusion: The DTI parameters in multiple brain regions from the methamphetamine-dependence patients are still abnormal after a long-term abstinence. DTI can provide imaging evidence for brain microstructural abnormalities in long-term abstinent from methamphetamine-dependence.


Assuntos
Transtornos Relacionados ao Uso de Anfetaminas , Encéfalo , Anisotropia , Imagem de Tensor de Difusão , Humanos , Metanfetamina
6.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 43(1): 41-48, 2018 Jan 28.
Artigo em Chinês | MEDLINE | ID: mdl-30154290

RESUMO

OBJECTIVE: To explore the characteristics of brain structure in patients with long-term withdrawal of methamphetamine-dependence.
 Methods: A total of 44 patients with withdrawal of methamphetamine-dependent for more than 14 months were recruited, who met the diagnostic criteria for substance dependence in the fifth edition of the American Mental Disorders Diagnostic and Statistical Manual (DSM-V), and 40 healthy subjects were used as the control. In addition to the general scale of drug-relevant survey, the subjects received the 3.0T magnetic resonance high-resolution scan. The voxel-based morphometric measurements for the subject's brain gray volume were conducted.
 Results: There was no significant difference in age, education, smoking and alcohol consumption between the methamphetamine-dependent withdrawal group and the control group (P>0.05). The volumes for the bilateral cerebellum, the left side of temporal gyrus and the right side of the lingual gyrus in the methamphetamine-dependent withdrawal group were increased than those in the control group. The volumes for the bilateral lingual gyrus and bilateral cuneus in the methamphetamine-dependent withdrawal group were decreased than those in the control group. The volumes of left of cuneus and cerebellum were positively correlated with the duration of abstinence.
 Conclusion: After long-term abstinence, although the patients still show abnormal brain structure, their behavior and cognitive function is improved. The cerebral nerve structural is recovered from long-term abstinence.


Assuntos
Transtornos Relacionados ao Uso de Anfetaminas/patologia , Encéfalo/patologia , Temperança , Fatores Etários , Transtornos Relacionados ao Uso de Anfetaminas/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Estudos de Casos e Controles , Estimulantes do Sistema Nervoso Central , Cerebelo/diagnóstico por imagem , Cerebelo/patologia , Escolaridade , Humanos , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Metanfetamina , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/patologia , Fatores de Tempo
7.
Front Psychiatry ; 9: 145, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29725310

RESUMO

Studies utilizing functional magnetic resonance imaging (fMRI) cue-reactivity paradigms have demonstrated that short-term abstinent or current methamphetamine (MA) users have increased brain activity in the ventral striatum, caudate nucleus and medial frontal cortex, when exposed to MA-related visual cues. However, patterns of brain activity following cue-reactivity in subjects with long-term MA abstinence, especially long-term compulsory drug rehabilitation, have not been well studied. To enrich knowledge in this field, functional brain imaging was conducted during a cue-reactivity paradigm task in 28 individuals with MA use disorder following long-term compulsory drug rehabilitation, and 27 healthy control subjects. The results showed that, when compared with controls, individuals with MA use disorder displayed elevated activity in the bilateral medial prefrontal cortex (mPFC) and right lateral posterior cingulate cortex in response to MA-related images. Additionally, the anterior cingulate region of mPFC activation during the MA-related cue-reactivity paradigm was positively correlated with craving alterations and previous frequency of drug use. No significant differences in brain activity in response to pornographic images were found between the two groups. Compared to MA cues, individuals with MA use disorder had increased activation in the occipital lobe when exposed to pornographic cues. In conclusion, the present study indicates that, even after long-term drug rehabilitation, individuals with MA use disorder have unique brain activity when exposed to MA-related cues. Additionally, our results illustrate that the libido brain response might be restored, and that sexual demand might be more robust than drug demand, in individuals with MA use disorder following long-term drug rehabilitation.

8.
Materials (Basel) ; 11(5)2018 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-29701694

RESUMO

Natural bamboo charcoal (BC) powder has been developed as a novel filler in order to further improve performances of the polyvinyl alcohol (PVA)-based alkaline solid polymer electrolyte (ASPE) by solution casting method. X-ray diffraction patterns of composite polymer electrolyte with BC revealed the decrease in the degree of crystallinity with increasing content of BC. Scanning electron microscopy images showed pores on a micrometer scale (average diameter about 2 μm) distributed inside and on the surface of the membranes, indicating a three-dimension network formed in the polymer framework. The ionic conductivity was measured by the alternating-current (AC) impedance method, and the highest conductivity value of 6.63 × 10−2 S·cm−1 was obtained with 16 wt % of BC content and mKOH:mPVA = 2:1.5 at 30 °C. The contents of BC and KOH could significantly influence the conductivity. The temperature dependence of the bulk electrical conductivity displayed a combination of Arrhenius nature, and the activation energy for the ion in polymer electrolyte has been calculated. The electrochemical stability window of the electrolyte membrane was over 1.6 V. The thermogravimetric analysis curves showed that the degradation temperatures of PVA-BC-KOH ASPE membranes shifted toward higher with adding BC. A simple nickel-hydrogen battery containing PVA-BC-KOH electrolyte membrane was assembled with a maximum discharge capacity of 193 mAh·g−1.

9.
Front Psychiatry ; 9: 722, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30618890

RESUMO

Background: A large portion of previous studies that have demonstrated brain gray matter reduction in individuals who use methamphetamine (MA) have focused on short-term abstinence, but few studies have focused on the effects of long-term abstinence of methamphetamine on brain structures. Materials and Methods: Our study includes 40 healthy controls and 44 abstinent methamphetamine-dependent (AMD) subjects who have abstained for at least 14 months. For every AMD subject, the age when they first used MA, the total time of MA use, the frequency of MA use in the last month before abstinence, the duration of abstinence and the craving score were recorded. Here we used magnetic resonance imaging (MRI) to measure the gray matter volume (GMV) of each subject with voxel-based morphometry method. Two-sample t-test (AlphaSim corrected) was performed to obtain brain regions with different gray matter volume (GMV) between groups. In addition, partial correlation coefficients adjusted for age, years of education, smoking, and drinking were calculated in the AMD group to assess associations between the mean GMV values in significant clusters and variables of MA use and abstinence. Results: Compared with the healthy control group, AMD group showed increased gray matter volumes in the bilateral cerebellum and decreased volumes in the right calcarine and right cuneus. Moreover, GMV of left cerebellum are positively correlated with the duration of abstinence in the AMD group (p = 0.040, r = 0.626). Conclusions: The present study showed that the gray matter volume in some brain regions is abnormal in the AMD subjects with long-term abstinence. Changes in gray matter volume of visual and cognitive function regions suggested that these areas play important roles in the progress of MA addiction and abstinence. In addition, positive correlation between GMV of the left cerebellum crus and duration of abstinence suggested that prolonged abstinence is beneficial to cognitive function recovery.

10.
J Neurol Sci ; 359(1-2): 367-72, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26671144

RESUMO

PURPOSE: To investigate the gray matter (GM) atrophy in Progressive supranuclear palsy (PSP) using T1-weighted Fluid-Attenuated Inversion Recovery (FLAIR) images based on voxel based morphometry (VBM) method. MATERIALS AND METHODS: In this study, we firstly modified the conventional VBM method to make it can process the T1-weighted FLAIR brain images. Then, we used this method on the 24 PSP patients and 23 healthy age- and sex-matched control subjects to find the local gray matter density changes of PSP patients. RESULTS: Compared with healthy controls, GM reductions of PSP patients mainly located in the thalamus, basal ganglia, pons, midbrain, insular cortex, frontal cortex, temporal lobe, cerebellum, cingulate cortex and hippocampus. CONCLUSION: We used the modified VBM technique into T1 FLAIR data to study the brain gray matter atrophy in PSP, and found some new atrophy areas, including pallidum, middle and posterior cingulum, lingual, fusiform gyrus and the post part of inferior temporal gyrus. These areas have not been described in the former VBM studies, but they revealed abnormity in the pathologic and other studies on PSP. Our results might be expected to provide significant underlining neurology information and diagnostic value for PSP.


Assuntos
Córtex Cerebral/patologia , Substância Cinzenta/patologia , Paralisia Supranuclear Progressiva/patologia , Idoso , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...