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1.
Nucleic Acids Res ; 50(16): 9072-9082, 2022 09 09.
Artículo en Inglés | MEDLINE | ID: mdl-35979954

RESUMEN

The static and dynamic structures of DNA duplexes affected by 5S-Tg (Tg, Thymine glycol) epimers were studied using MD simulations and Markov State Models (MSMs) analysis. The results show that the 5S,6S-Tg base caused little perturbation to the helix, and the base-flipping barrier was determined to be 4.4 kcal mol-1 through the use of enhanced sampling meta-eABF calculations, comparable to 5.4 kcal mol-1 of the corresponding thymine flipping. Two conformations with the different hydrogen bond structures between 5S,6R-Tg and A19 were identified in several independent MD trajectories. The 5S,6R-Tg:O6HO6•••N1:A19 hydrogen bond is present in the high-energy conformation displaying a clear helical distortion, and near barrier-free Tg base flipping. The low-energy conformation always maintains Watson-Crick base pairing between 5S,6R-Tg and A19, and 5S-Tg base flipping is accompanied by a small barrier of ca. 2.0 KBT (T = 298 K). The same conformations are observed in the MSMs analysis. Moreover, the transition path and metastable structures of the damaged base flipping are for the first time verified through MSMs analysis. The data clearly show that the epimers have completely different influence on the stability of the DNA duplex, thus implying different enzymatic mechanisms for DNA repair.


Asunto(s)
Reparación del ADN , ADN , Emparejamiento Base , ADN/química , Daño del ADN , Enlace de Hidrógeno , Conformación de Ácido Nucleico , Termodinámica
2.
Sensors (Basel) ; 23(15)2023 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-37571476

RESUMEN

Finding ways to enable seamless communication between deaf and able-bodied individuals has been a challenging and pressing issue. This paper proposes a solution to this problem by designing a low-cost data glove that utilizes multiple inertial sensors with the purpose of achieving efficient and accurate sign language recognition. In this study, four machine learning models-decision tree (DT), support vector machine (SVM), K-nearest neighbor method (KNN), and random forest (RF)-were employed to recognize 20 different types of dynamic sign language data used by deaf individuals. Additionally, a proposed attention-based mechanism of long and short-term memory neural networks (Attention-BiLSTM) was utilized in the process. Furthermore, this study verifies the impact of the number and position of data glove nodes on the accuracy of recognizing complex dynamic sign language. Finally, the proposed method is compared with existing state-of-the-art algorithms using nine public datasets. The results indicate that both the Attention-BiLSTM and RF algorithms have the highest performance in recognizing the twenty dynamic sign language gestures, with an accuracy of 98.85% and 97.58%, respectively. This provides evidence for the feasibility of our proposed data glove and recognition methods. This study may serve as a valuable reference for the development of wearable sign language recognition devices and promote easier communication between deaf and able-bodied individuals.


Asunto(s)
Lengua de Signos , Dispositivos Electrónicos Vestibles , Humanos , Habla , Algoritmos , Audición
3.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 45(3): 410-415, 2023 Jun.
Artículo en Zh | MEDLINE | ID: mdl-37407527

RESUMEN

Objective To compare the clinical effects of three treatment methods including systemic thrombolysis(ST),catheter-directed thrombolysis(CDT),and AngioJet percutaneous mechanical thrombectomy(PMT)in acute lower extremity deep venous thrombosis(LEDVT). Methods The data of 82 patients diagnosed with LEDVT in the Department of Vascular and Gland Surgery of the First Affiliated Hospital of Hebei North University from January 2017 to December 2020 were collected.The patients were assigned into a ST group(n=50),a CDT group(n=16),and a PMT group(n=16)according to different treatment methods.The efficacy and safety were compared among the three groups. Results Compared with that before treatment,the circumferential diameter difference of both lower limbs on days 1,2,and 3 of treatment in the ST,CDT,and PMT groups reduced(all P<0.001).The PMT group showed smaller circumferential diameter difference of lower limbs on days 1,2,and 3 of treatment than the ST group(all P<0.001)and smaller circumferential diameter difference of the lower patellar margin on day 1 of treatment than the CDT group(P<0.001).The PMT group showed higher diminution rate for swelling of the affected limb at the upper and lower edges of the patella than the ST group(P<0.001)and higher diminution rate for swelling at the upper edge of the patella than the CDT group(P=0.026).The incidence of complications after treatment showed no significant differences among the three groups(all P>0.05).The median of hospital stay in the PMT group was shorter than that in the ST and CDT groups(P=0.002,P=0.001).The PMT group had higher thrombus clearance rate than the ST group(P=0.002)and no significant difference in the thrombus clearance rate from the CDT group(P=0.361).The vascular recanalization rates in the PMT(all P<0.001)and CDT(P<0.001,P=0.002,P=0.009)groups 3,6,and 12 months after treatment were higher than those in ST group,and there were no significant differences between PMT and CDT groups(P=0.341,P=0.210,P=0.341). Conclusions ST,CDT,and PMT demonstrated significant efficacy in the treatment of LEDVT,and PMT was superior to ST and CDT in terms of circumferential diameter difference of the lower limbs,diminution rate for swelling of the affected limb,thrombus clearance rate,length of hospital stay,and long-term vascular recanalization.There was no obvious difference in safety among the three therapies.


Asunto(s)
Terapia Trombolítica , Trombosis de la Vena , Humanos , Terapia Trombolítica/métodos , Fibrinolíticos/uso terapéutico , Resultado del Tratamiento , Trombectomía/métodos , Trombosis de la Vena/complicaciones , Trombosis de la Vena/tratamiento farmacológico , Extremidad Inferior/irrigación sanguínea , Catéteres , Estudios Retrospectivos
4.
J Chem Inf Model ; 62(2): 386-398, 2022 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-34994562

RESUMEN

Damaged or mismatched DNA bases are normally thought to be able to flip out of the helical stack, providing enzymes with access to the faulty genetic information otherwise hidden inside the helix. Thymine glycol (Tg) is one of the most common products of nucleic acid damage. However, the static and dynamic structures of DNA duplexes affected by 5R-Tg epimers are still not clearly understood, including the ability of these to undergo spontaneous base flipping. Structural effects of the 5R-Tg epimers on the duplex DNA are herein studied using molecular dynamics together with reliable DFT based calculations. In comparison with the corresponding intact DNA, the cis-5R,6S-Tg epimer base causes little perturbation to the duplex DNA, and a barrier of 4.9 kcal mol-1 is obtained by meta-eABF for cis-5R,6S-Tg base flipping out of the duplex DNA, comparable to the 5.4 kcal mol-1 obtained for the corresponding thymine flipping in intact DNA. For the trans-5R,6R-Tg epimer, three stable local structures were identified, of which the most stable disrupts the Watson-Crick hydrogen-bonded G5/C20 base pair, leading to conformational distortion of the duplex. Interestingly, the relative barrier height of the 5R-Tg flipping is only 1.0 kcal mol-1 for one of these trans-5R,6R-Tg epimers. Water bridge interactions were identified to be essential for 5R-Tg flipping. The study clearly demonstrates the occurrence of partial trans-5R,6R-Tg epimer flipping in solution.


Asunto(s)
ADN , Timina , Emparejamiento Base , ADN/química , Daño del ADN , Conformación de Ácido Nucleico , Termodinámica , Timina/análogos & derivados , Timina/química
5.
Nucleic Acids Res ; 48(12): 6471-6480, 2020 07 09.
Artículo en Inglés | MEDLINE | ID: mdl-32442296

RESUMEN

Despite their great success in recognizing small molecules in vitro, nucleic acid aptamers are rarely used in clinical settings. This is partially due to the lack of structure-based mechanistic information. In this work, atomistic molecular dynamics simulations are used to study the static and dynamic supramolecular structures relevant to the process of the wild-type (wt) nucleic acid aptamer recognition and binding of ATP. The effects brought about by mutation of key residues in the recognition site are also explored. The simulations reveal that the aptamer displays a high degree of rigidity and is structurally very little affected by the binding of ATP. Interaction energy decomposition shows that dispersion forces from π-stacking between ATP and the G6 and A23 nucleobases in the aptamer binding site plays a more important role in stabilizing the supramolecular complex, compared to hydrogen-bond interaction between ATP and G22. Moreover, metadynamics simulations show that during the association process, water molecules act as essential bridges connecting ATP with G22, which favors the dynamic stability of the complex. The calculations carried out on three mutated aptamer structures confirm the crucial role of the hydrogen bonds and π-stacking interactions for the binding affinity of the ATP nucleic acid aptamer.


Asunto(s)
Adenosina Trifosfato/química , Aptámeros de Nucleótidos/química , Simulación de Dinámica Molecular , Aptámeros de Nucleótidos/genética , Emparejamiento Base , Enlace de Hidrógeno , Mutación
6.
Org Biomol Chem ; 18(18): 3536-3543, 2020 05 13.
Artículo en Inglés | MEDLINE | ID: mdl-32338268

RESUMEN

Selective C-H oxidation is thought to be a highly suitable strategy for building synthetic blocks and generating bioactive compounds. Noncovalent DNA catalysis for C-H bond cleavage is studied for the first time in order to delineate the so-called 'oxidation enhancement effect' on oxidatively generated damage in DNA duplex structures. Herein, DFT methods have been used to gain insight into the reactivity of the 5-hydroxy-6-peroxyl-5,6-dihydrothymine radical using ten single-stranded and duplex DNA models. Reliable M06-2X/6-31+G(d,p) calculations indicate that hydrogen bonding between the complementary base pairs significantly enhances the reactivity of the thymine peroxyl radical in duplex DNA models towards the C1'-H1' bond. An excellent linear relationship of the reaction activation barrier vs. the difference between the bond dissociation free energies (BDFE) of the C-H and O-H bonds is observed. With the noted role of charge transfer from LPO4' on 2-deoxyribose to its adjacent C1'-H1' anti-bonding orbital, a hyperconjugation effect is proposed to explain the reason why the barrier heights are close to each other for the studied duplex DNA models. The difference in the reactivity of the thymine peroxyl radical in the duplex and related single-strand DNA models is rationalized in terms of the preparatory energy and the optimal σC1'-H1' and oxyl-p based π*-orbital interactions.


Asunto(s)
ADN/química , Teoría Funcional de la Densidad , Peróxidos/química , Pirimidinas/química , Estructura Molecular
7.
Sensors (Basel) ; 20(4)2020 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-32098239

RESUMEN

Human gait reflects health condition and is widely adopted as a diagnostic basisin clinical practice. This research adopts compact inertial sensor nodes to monitor the functionof human lower limbs, which implies the most fundamental locomotion ability. The proposedwearable gait analysis system captures limb motion and reconstructs 3D models with high accuracy.It can output the kinematic parameters of joint flexion and extension, as well as the displacementdata of human limbs. The experimental results provide strong support for quick access to accuratehuman gait data. This paper aims to provide a clue for how to learn more about gait postureand how wearable gait analysis can enhance clinical outcomes. With an ever-expanding gait database,it is possible to help physiotherapists to quickly discover the causes of abnormal gaits, sports injuryrisks, and chronic pain, and provides guidance for arranging personalized rehabilitation programsfor patients. The proposed framework may eventually become a useful tool for continually monitoringspatio-temporal gait parameters and decision-making in an ambulatory environment.


Asunto(s)
Marcha/fisiología , Dispositivos Electrónicos Vestibles , Adulto , Algoritmos , Humanos , Masculino , Monitoreo Fisiológico/métodos , Rango del Movimiento Articular/fisiología , Adulto Joven
8.
Int J Cancer ; 145(5): 1423-1431, 2019 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-30664810

RESUMEN

Lung cancer is one of the greatest threats to human health, and is initially detected and attacked by the immune system through tumor-reactive T cells. The aim of this study was to determine the basic characteristics and clinical significance of the peripheral blood T-cell receptor (TCR) repertoire in patients with advanced lung cancer. To comprehensively profile the TCR repertoire, high-throughput sequencing was used to identify hypervariable rearrangements of complementarity determining region 3 (CDR3) of the TCR ß chain in peripheral blood samples from 64 advanced lung cancer patients and 31 healthy controls. We found that the TCR repertoire differed substantially between lung cancer patients and healthy controls in terms of CDR3 clonotype, diversity, V/J segment usage, and sequence. Specifically, baseline diversity correlated with several clinical characteristics, and high diversity reflected a better immune status. Dynamic detection of the TCR repertoire during anticancer treatment was useful for prognosis. Both increased diversity and high overlap rate between the pre- and post-treatment TCR repertoires indicated clinical benefit. Combination of the diversity and overlap rate was used to categorize patients into immune improved or immune worsened groups and demonstrated enhanced prognostic significance. In conclusion, TCR repertoire analysis served as a useful indicator of disease development and prognosis in advanced lung cancer and may be utilized to direct future immunotherapy.


Asunto(s)
Neoplasias Pulmonares/sangre , Receptores de Antígenos de Linfocitos T/sangre , Linfocitos T/inmunología , Estudios de Casos y Controles , Femenino , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Neoplasias Pulmonares/inmunología , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Pronóstico , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/inmunología , Receptores de Antígenos de Linfocitos T alfa-beta/sangre , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Linfocitos T/patología
9.
Phys Chem Chem Phys ; 21(24): 13186-13193, 2019 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-31172997

RESUMEN

Fluorinated carbonates have attracted increasing attention in high-voltage lithium ion battery applications. Under free and electric fields, their structure-related solvent dynamic properties such as charge and discharge rate, however, are rarely reported. Herein, solutions including linear fluorinated carbonates have been simulated using joint MD/DFT calculations. For the first time, the dielectric constants of the four pure fluorinated carbonates have been predicted to be ca. 5.4 (4: ethyl-2,2,2-trifluoroethyl carbonate)-12.1 (7: di-1,1,2,2,2-pentafluoroethyl carbonate), which are dependent on the number of fluorine atoms. Minor difference in the solvation free energies and few contact ion associations were observed in the ETFEC and DTFEC solvents. Their comparable viscosity values were found through calculations of ion diffusivity and conductivity. In the electric fields, the Li+ mobilities in the two solutions have similar values, showing that the dynamic properties of the electrolytic solutions are almost independent of the number of fluorine atoms on these carbonates. There emerges an oriented and ordered arrangement of the solvent molecules and thus the largely decreased dielectric constants under the electric fields, even though the field strength is very low. These interesting phenomena should be relevant in the formation of contact and aggregate ion pairs, leading to unexpected reduction of the charge-discharge rate-related ion mobility in mixed solvents.

10.
J Phys Chem A ; 122(1): 431-438, 2018 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-29206039

RESUMEN

Oxidative damage to RNA has been linked to change or loss of RNA function and development of many human age-related diseases. However, knowledge on the nature of RNA oxidative damage is relatively limited. In this study, oxidative damage to RNA is investigated under anaerobic and aerobic conditions by exploring the properties and reactions of 5-hydroxyl-2'-uridin-6-yl and its peroxyl diastereoisomers in the RNA strand, respectively. Selective addition of OH to the nucleic base from the 5'-end is studied at the molecular level for the first time, explaining the large number of the 5S-isomer available for further reactions. Our results provide clear evidence that the efficiency of C2'-H2' bond activation in the peroxyl isomers is lower than in the carbon radical species. An exception is observed for the isomer cis-(5S,6R)-A1, whose internucleotidyl H2'-abstraction barrier is far smaller than that in the corresponding C6-yl radical. However, analysis of the equilibrium species distribution reveals that the amount of cis-(5S,6R)-A1 is very small among the peroxyl diastereoisomers, and hence the resulting products from direct strand scission should be a less important component in RNA oxidative damage. The species with maximum distribution is the cis-(5S,6R)-B1 isomer, which is derived from cis-(5S,6R)-A1 and has a moderate intranucleotidyl H2'-abstraction barrier. More importantly, the reaction is mildly exothermic. These results show that the main fraction of the intranucleotidyl H2'-abstraction intermediates can be formed from the cis-(5S,6R)-B1 isomer. The absolute reduction potentials, the hydrogen atom binding energies, and the key structural parameters of the C6-peroxyl species are used to understand the diverse reactivity of the cis-(5S,6R) diastereoisomers toward the C2'-H2' bonds activation. The present study shows that in addition to the selectivity of the OH radical addition, there is a strong correlation between the conformation of the modified uracil base and its reactivity in RNA oxidative damage.


Asunto(s)
ARN/química , Aerobiosis , Oxidación-Reducción , Teoría Cuántica
11.
J Stroke Cerebrovasc Dis ; 27(10): 2877-2886, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30077603

RESUMEN

BACKGROUND: Acute ischemic stroke (AIS) has a higher morbidity and mortality rate. Many prediction tools have been developed to predict the risk of poor outcomes in patients after AIS, such as the THRIVE score, the iScore score, and the ASTRAL score. However, the predictive value of above 3 prediction tools in Chinese patients with AIS need to be further verified. So, this study aimed to determine the ability of the THRIVE score, the iScore score, and the ASTRAL score in predicting clinical poor outcomes in Chinese patients with AIS at 1 year. METHODS: A total of 772 patients with AIS were included in this study. The baseline data of all patients were collected. The THRIVE score, the iScore score, and the ASTRAL score were calculated. All patients were followed up at 1 year. The poor outcome was defined as death, moderate/severe disabilities (modified Rankin scale, mRS > 2), most severe disability (mRS ≥ 5). Model discrimination was quantified by calculating the area under the receiver operating characteristic curve (AUC). The calibration was assessed using Hosmer-Lemeshow goodness-of-fit test and Pearson correlation coefficient. RESULTS: We identified 576 (74.6%) patients with good prognosis and 196 (25.4%) patients with poor prognosis. AUC values of THRIVE score in predicting 1-year poor prognosis was lower than the iScore score and the ASTRAL scores (P < .05). The chi-square values of Hosmer-Lemeshow for the 3 prediction tools were 2.114, 4.877, 5.838 (all P < .05), respectively. There was a high correlation between the observed and the expected poor prognosis (Pearson correlation coefficient, .985, .693, and .620; all P < .05). AUC values of THRIVE score in predicting 1-year mortality and severe disability were lower than the iScore scores (all P < .05). CONCLUSIONS: The iScore score and the ASTRAL score reliably predict 1-year poor outcomes in Chinese patients with AIS, and the iScore score can accurately predict 1-year mortality and severe disability in Chinese AIS patients.


Asunto(s)
Isquemia Encefálica/diagnóstico , Técnicas de Apoyo para la Decisión , Accidente Cerebrovascular/diagnóstico , Anciano , Anciano de 80 o más Años , Área Bajo la Curva , Pueblo Asiatico , Isquemia Encefálica/etnología , Isquemia Encefálica/mortalidad , Isquemia Encefálica/terapia , Distribución de Chi-Cuadrado , China/epidemiología , Evaluación de la Discapacidad , Femenino , Estado de Salud , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Pronóstico , Curva ROC , Reproducibilidad de los Resultados , Medición de Riesgo , Factores de Riesgo , Índice de Severidad de la Enfermedad , Accidente Cerebrovascular/etnología , Accidente Cerebrovascular/mortalidad , Accidente Cerebrovascular/terapia , Factores de Tiempo
12.
Cell Physiol Biochem ; 41(4): 1393-1402, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28494456

RESUMEN

OBJECTIVE: To study the metabolic changes of cerebellum by proton magnetic resonance Spectroscopy (1H-MRS) and discuss the relationships between the cerebellar changes and depression severity in patients with post-stroke depression. METHODS AND RESULTS: Data of demographic characteristics, individual history and life style of all subjects were collected. 40 patients with stroke and 20 controls were enrolled. All groups received T1WI, T2WI, DWI and 1H-MRS examination. The cerebral infarction volume and the distribution and severity of leukoaraiosis were evaluated. The ratios of NAA/Cr, Cho/Cr and Cho/NAA in the cerebellum were calculated. There were no statistical significant difference in the NAA/Cr, Cho/Cr and Cho/NAA ratios in bilateral cerebellum between CONT group and NORM group. The Cho/Cr and Cho/NAA ratios in the cerebellum contralateral to the stroke region were higher in PSD group than those in NORM and CONT groups, and the Cho/Cr and Cho/NAA ratios in the cerebellum ipsilateral to the stroke region were similar with those in NORM and CONT groups. However, there were no statistical significant difference in the NAA/Cr ratios in bilateral cerebellum among three groups. CONCLUSION: The result shows preliminarily that the cerebellum involves in the development of post-stroke depression.


Asunto(s)
Cerebelo , Depresión , Espectroscopía de Protones por Resonancia Magnética , Accidente Cerebrovascular , Anciano , Cerebelo/diagnóstico por imagen , Cerebelo/metabolismo , Depresión/diagnóstico por imagen , Depresión/etiología , Depresión/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/metabolismo
13.
Cell Physiol Biochem ; 41(4): 1403-1412, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28315868

RESUMEN

OBJECTIVE: To identify the molecular mechanism of post-stroke depression (PSD), and observe the therapeutic effects of cerebellar fastigial nucleus electrical stimulation (FNS) on the behaviors and regional cerebral blood flow (rCBF) in a PSD rat model. METHODS: Healthy SD rats were randomly divided into four groups (sham, stroke, post-stroke depress and FNS group). Sham group (n = 6) underwent sham operation. The other three groups (n = 6*3) underwent MCAO. Rats were examined twice a week in open filed test. Moreover, neuroprotective effect on cerebellar Purkinje cells and expression of cytokines in hippocampal tissue were examined. RESULTS: The PSD group showed a significant weight loss, decreased consumption of sucrose water, reduced rearing and locomotor activities. The FNS significantly alleviates the body weight loss and sucrose preference, locomotor and rearing activities. The bilateral rCBF was also restored after FNS treatment. Moreover, FNS improved the neuroprotection via suppressing apoptosis of cerebellar Purkinje cells. And the inflammatory cytokines mRNA level in hippocampus was significantly decreased. CONCLUSION: FNS treatment alleviates depressive-like behaviors and rCBF in PSD rats model, which could be attributed to its ability to protect cerebellar Purkinje cells and decrease the mRNA level of inflammatory cytokines.


Asunto(s)
Conducta Animal , Núcleos Cerebelosos , Modelos Animales de Enfermedad , Terapia por Estimulación Eléctrica , Accidente Cerebrovascular , Animales , Núcleos Cerebelosos/metabolismo , Núcleos Cerebelosos/fisiopatología , Citocinas/metabolismo , Depresión/etiología , Depresión/metabolismo , Depresión/fisiopatología , Depresión/terapia , Humanos , Células de Purkinje/metabolismo , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/metabolismo , Accidente Cerebrovascular/fisiopatología , Accidente Cerebrovascular/terapia
14.
Phys Chem Chem Phys ; 19(46): 31236-31244, 2017 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-29143041

RESUMEN

Herein, binding of the ß-cyclodextrin (ß-CD) host to the unstable aryl pentazole guest has been confirmed experimentally and theoretically. After the confinement of aryl pentazole, electron density reorganization was studied by M06-2X dispersion-corrected DFT and further reflected in the characteristic shift in the NMR spectra. Among the host-guest complexes, the inclusion complex is favored with the phenyl ring expectedly encapsulated within the cavity through noncovalent interactions such as hydrogen bonding, C-Hπ, and the special Csp2-HH-Csp3 bonding discovered by the NBO, QTAIM, and NCI-RDG theories. The host-guest binding renders the enhancement of the nitrogen-ring aromatic character; this has been analyzed by employing nucleus-independent chemical shift (NICS)-based profiles. The non-covalent interaction largely enhances the thermal stability of the guest through a change of the decomposition reaction path whether the guest is encapsulated or not by the host. By comparison of the structures of B1-B4, the enhancement could be assigned to the ion-type transition structure stabilized by the C-H bonds of the host.

15.
Phys Chem Chem Phys ; 18(34): 23763-8, 2016 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-27523025

RESUMEN

The reactivity of thymine peroxy radicals in DNA and their fate are studied using the reliable DFT methods. The most accessible H1' abstraction by the C6-peroxyl once reported experimentally is effectively competitive to the crosslinking reaction between the C6-peroxyl and the C5 or C6 on the 5'-adjacent thymine base. The rare transfer of the ObH1' group to the C1' radical from the formed hydroperoxide happens with a very strong heat release. Afterwards, the parallel reactions including the H1' and H2' abstractions by the C6-alkoxyl in an inter-nucleotidyl manner lead to direct formation of thymine glycol. After the H1' abstraction by the C6-alkoxyl, the apyrimidinic site can be formed on C1' through effective N1-glycosidic bond rupture. The geometric rearrangements and the orbital interaction between the H donor and the σ-type H acceptor are used to explain the difference of the H2' abstraction barriers by C6-alkoxyl. Hence, new radical reaction paths for the formation of DNA oxidation products are suggested, which are strongly different from the previously suggested paths with the tetraoxide intermediate.


Asunto(s)
ADN/química , Radicales Libres/química , Gases/química , Oxidación-Reducción , Termodinámica , Timina/análogos & derivados , Timina/química , Agua/química
16.
Fa Yi Xue Za Zhi ; 32(1): 54-7, 2016 Feb.
Artículo en Zh | MEDLINE | ID: mdl-27295859

RESUMEN

Hypoxic-ischemic brain damage (HIBD) is referred to a common type of cerebral damage, which is caused by injury, leading to shallow bleeding in the cortex with intact cerebral pia mater. In recent years, studies show that a various kinds of immune cells and immune cellular factors are involved in the occurrence of HIBD. CC chemokine receptor 2 (CCR2) is a representative of CC chemokine receptor, and is widely distributed in cerebral neuron, astrocyte, and microglial cells, and is the main chemo-tactic factor receptor in brain tissue. CC chemokine ligand 2 (CCL2) is a kind of basophilic protein and the ligand of CCR2, and plays an important role in inflammation. In order to provide evidence for correlational studies in HIBD, this review will introduce the biological characteristics of CCR2 and CCL2, and illustrate the relationship between the immunoreactivity and HIBD.


Asunto(s)
Lesiones Encefálicas/metabolismo , Quimiocina CCL2/metabolismo , Hipoxia-Isquemia Encefálica/metabolismo , Animales , Lesiones Encefálicas/tratamiento farmacológico , Lesiones Encefálicas/patología , Corteza Cerebral/metabolismo , Corteza Cerebral/patología , Corteza Cerebral/fisiopatología , Quimiocina CCL2/genética , Quimiocinas CC/metabolismo , Proteínas Inflamatorias de Macrófagos/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores CCR2/antagonistas & inhibidores , Receptores CCR2/genética , Receptores CCR2/metabolismo
17.
Fa Yi Xue Za Zhi ; 32(1): 58-60, 2016 Feb.
Artículo en Zh | MEDLINE | ID: mdl-27295860

RESUMEN

Cyclin-dependent kinase 5 (CDK5) is a member of cyclin-dependent kinase family, which does not directly regulate cell cycle. Through phosphorylation of target protein, CDK5 plays an irreplaceable role in the development, reparation and degeneration of neurons. Brain injury refers to the organic injury of brain tissue caused by external force hit on the head. Owing to the stress and repair system activated by our body itself after injury, various proteins and enzymes of the brain tissues are changed quantitatively, which can be used as indicators for estimating the time of injury. This review summarizes the progress on the distribution, the activity mechanism and the physiological effects of CDK5 after brain injury and its corresponding potential served as a marker for brain injury determination.


Asunto(s)
Lesiones Encefálicas/tratamiento farmacológico , Encéfalo/efectos de los fármacos , Quinasa 5 Dependiente de la Ciclina/antagonistas & inhibidores , Fármacos Neuroprotectores/farmacología , Encéfalo/patología , Encéfalo/fisiopatología , Lesiones Encefálicas/patología , Lesiones Encefálicas/fisiopatología , Quinasa 5 Dependiente de la Ciclina/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Neuronas , Fosforilación/efectos de los fármacos , Factores de Tiempo
18.
Angew Chem Int Ed Engl ; 55(6): 2073-7, 2016 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-26709609

RESUMEN

A crystalline coordination polymer (CP) photocatalyst (Cu-RSH) which combines redox-active copper centers with photoactive rhodamine-derived ligands remains stable in acid and basic solutions from pH 2 to 14, and efficiently catalyzes dihydrogen evolution at a maximum rate of 7.88 mmol g(-1) h(-1) in the absence of a mediator and a co-catalyst. Cyclic voltammetry, control experiments, and DFT calculations established that copper nodes with open coordination sites and favorable redox potentials, aided by spatially ordered stacking of rhodamine-based linkers, account for the high catalytic performance of Cu-RSH. Emission quenching, time-resolved fluorescence decay, and transient photocurrent experiments disclosed the charge separation and transfer process in the catalytic system. The present study demonstrates the potential of crystalline copper CPs for the practical utilization of light.

19.
Fa Yi Xue Za Zhi ; 31(2): 93-6, 2015 Apr.
Artículo en Zh | MEDLINE | ID: mdl-26245083

RESUMEN

OBJECTIVE: To study the expression of p35 and p25 in rat after focal cerebral contusion and to provide experimental data for estimating brain injury time. METHODS: Fifty adult male SD rats were randomly divided into 0 h, 6 h, 12 h, 24 h, 3 d, 5 d, 7 d, 10 d after focal cerebral contusion, control and sham-operated groups (5 rats each group). The focal cerebral contusion rat model was established. The expression of p35 and p25 protein of the damage peripheral zone in brain were detected by HE staining, immunohistochemistry and Western blotting at different injury time. RESULTS: A large number of p35 protein and a small amount of p25 protein were expressed in control group and sham-operated group. After focal cerebral contusion, p35 presented unimodal change with time and p25 presented bimodal changes with time. CONCLUSION: Expression of p35 and p25 showed different regularity with good time correlation, which could help to estimate the brain injury time.


Asunto(s)
Lesiones Encefálicas/metabolismo , Contusiones/metabolismo , Fosfotransferasas/metabolismo , Animales , Western Blotting , Encéfalo , Isquemia Encefálica , Inmunohistoquímica , Masculino , Ratas , Ratas Sprague-Dawley , Coloración y Etiquetado
20.
Malar J ; 13: 302, 2014 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-25098412

RESUMEN

BACKGROUND: Epidemiological data in the border area of the northern Myanmar near China are either of little accuracy or sparse of information, due to the poor public health system in these areas, and malaria cases may be severely underestimated. This study aimed to investigate malaria prevalence and health facilities for malaria services, and to provide the baseline information for malaria control in these areas. METHODS: A cluster, randomized, cross-sectional survey was conducted in four special regions of northern Myanmar, near China: 5,585 people were selected for a malaria prevalence survey and 1,618 households were selected for a mosquito net-owning survey. Meanwhile, a total of 97 health facilities were surveyed on their malaria services. The data were analysed and descriptive statistics were used. RESULTS: A total of 761 people were found positive through microscopy test, including 290 people for Plasmodium falciparum, 460 for Plasmodium vivax, two for Plasmodium malariae, and nine for mixed infection. The average prevalence of malaria infection was 13.6% (95% CI: 12.7-14.6%). There were significant differences of prevalence of malaria infection among the different regions (P < 0.01); 38.1% (95% CI: 28.3-48.0%) of health facilities had malaria microscope examination service, and 35.1% (95% CI: 25.4-44.7%) of these had malaria treatment services, 23.7% (95% CI: 15.1-32.3%) had malaria outreach services. 28.3% (95% CI: 26.1-30.6%) of households owned one or more long-lasting insecticidal bed nets (LLINs). CONCLUSION: The prevalence of malaria infection was high in the four special regions of northern Myanmar, near China. Malaria services in health facilities in these areas were weak. ITNs/LLINs owning rate was also low. The cross-border cooperation mechanism should be further strengthened to share the epidemical data about malaria, support technical assistance, and conduct joint malaria control or elimination activities.


Asunto(s)
Malaria/epidemiología , Adolescente , Adulto , Niño , Preescolar , Servicios de Salud Comunitaria , Estudios Transversales , Femenino , Humanos , Lactante , Recién Nacido , Mosquiteros Tratados con Insecticida , Malaria/diagnóstico , Malaria/parasitología , Malaria/prevención & control , Masculino , Persona de Mediana Edad , Mianmar/epidemiología , Prevalencia , Adulto Joven
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