Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
1.
Anal Chem ; 94(4): 2348-2355, 2022 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-35041394

RESUMEN

A supramolecular complex may be formed by two solutes via a weak intermolecular interaction in a solution. The spectrum of the complex is often inundated by the spectra of the solutes that are not involved in the intermolecular interaction. Herein, a novel spectral analysis approach is proposed to retrieve the spectrum of the supramolecular complex. First, a two-dimensional (2D) asynchronous spectrum is constructed. Then, a genetic algorithm is used to obtain a heuristic spectrum of the supramolecular complex. The heuristic spectrum is a linear combination of the spectrum of the complex and the spectrum of a solute. The coefficients of the linear combination are then obtained, according to which the equilibrium constants are invariant among the sample solutions used to construct the 2D asynchronous spectrum. We have applied the approach to a supramolecular system formed by benzene and I2. In the analysis, several binding models are evaluated, and a benzene molecule interacting with two iodine molecules via halogen bonding turns out to be the only possible model. Hence, the characteristic band of the benzene/I2 supramolecular complex around 1819 cm-1 in the Fourier transform infrared (FTIR) spectrum and the corresponding equilibrium constant are obtained. The above results indicate that the novel approach provides a chance to get new insight into various intermolecular interactions studied by spectroscopy.


Asunto(s)
Algoritmos , Proyectos de Investigación , Estructura Secundaria de Proteína , Soluciones , Espectroscopía Infrarroja por Transformada de Fourier/métodos
2.
Scand J Gastroenterol ; 57(8): 942-952, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35275769

RESUMEN

BACKGROUND: Pouchitis is the common postoperative complication of ulcerative colitis (UC) and is also considered as inflammatory bowel disease. The aim was to investigate the microbiological and transcriptional differences between the two illnesses. METHODS: Eighty-five participants were enrolled (37 UC, 15 healthy UC pouches, 15 pouchitis and 18 healthy volunteers) and stool samples were collected. Microbial populations were analyzed by pyrosequencing of 16S ribosomal DNA. Furthermore, transcriptome data of 119 UC and 28 pouch patients were obtained from two data sets for bioinformatics analysis. RESULTS: The results of gut microbiota community analysis showed that with aggravation of UC, intestinal microorganisms were characterized by a gradual decreased in diversity and numbers of butyrate-producing bacteria and Bacteroides. Besides, in addition to the decrease of probiotics, the proliferation of Escherichia-Shigella and Ruminococcus gnavus was observed in pouchitis which is related to multiple infection pathways. The function enrichment of differential expression genes and hub genes, as well as the immunological condition was shown to be distinct using transcriptome bioinformatics analysis between UC and pouchitis. A stronger immune response occurs in UC and may be associated with high expression of tumor necrosis factor and interleukin, while multiple hub genes such as CDK1 in pouchitis are associated with cell cycle regulation. CONCLUSIONS: The characteristics of gut microbiota disturbance and transcriptome alteration in UC and pouchitis are different. Our findings suggested that pouchitis may have a unique pathogenesis which was separated from UC.


Asunto(s)
Colitis Ulcerosa , Microbioma Gastrointestinal , Reservoritis , Probióticos , Colitis Ulcerosa/genética , Colitis Ulcerosa/microbiología , Colitis Ulcerosa/cirugía , Microbioma Gastrointestinal/genética , Humanos , Reservoritis/genética , Reservoritis/microbiología , Transcriptoma
3.
Med Sci Monit ; 27: e930329, 2021 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-34099612

RESUMEN

BACKGROUND Colorectal cancer (CRC) is one of the most common malignant tumors. Surgery is the primary treatment for CRC. Recent studies have shown that visceral-to-subcutaneous fat ratio (VSR) may be a potential indicator of risk. The aim of the present study was to determine whether VSR is a suitable predictor of the impact of postoperative complications in CRC. MATERIAL AND METHODS Clinical data from 129 patients were analyzed retrospectively. All patients underwent laparoscopic surgery for CRC. Preoperative imaging was used to quantify VSR. The primary outcome was 30-day postoperative complications. Multivariate logistic regression was used to determine the association between obesity indexes and postoperative complications. RESULTS There were 129 patients who underwent primary resections of colorectal cancer. At 30 days after surgery, postoperative complications had occurred in 33 (25.6%) patients. VSR was significantly associated with postoperative complications in multivariate analysis (P=0.032, OR 6.103, 95% CI 1.173-31.748). In ROC analysis, VSR was a potential predictor of complications (AUC 0.650). A cutoff value of VSR ≥0.707 was associated with 60% sensitivity and 29% specificity for postoperative complications. Patients with VSR ≥0.707 had 41.7% risk of morbidity, whereas those with <0.707 had 16.0% risk (P=0.001). CONCLUSIONS Our study shows that VSR is superior to VFA for prediction of the risk of complications following CRC laparoscopic surgery. We have also identified the optimal cutoff values for the use of VSR for this purpose. Measurement of VSR and identifying patients with increased risk of postoperative complications facilitate making perioperative decisions.


Asunto(s)
Grasa Intraabdominal/fisiología , Complicaciones Posoperatorias/prevención & control , Grasa Subcutánea/fisiología , Anciano , Índice de Masa Corporal , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/cirugía , Femenino , Humanos , Grasa Intraabdominal/metabolismo , Laparoscopía/efectos adversos , Masculino , Persona de Mediana Edad , Obesidad/complicaciones , Pronóstico , Estudios Retrospectivos , Factores de Riesgo , Sensibilidad y Especificidad
4.
Anal Chem ; 92(1): 1477-1484, 2020 01 07.
Artículo en Inglés | MEDLINE | ID: mdl-31808687

RESUMEN

An approach to construct a secondary asynchronous spectrum via sample-sample correlation (SASS) is proposed to analyze bilinear data from hyphenated spectroscopic experiments. In SASS, bilinear data is used to construct a series of two-dimensional (2D) sample-sample correlation spectra. Then a vertical slice is extracted from each 2D sample-sample correlation spectrum so that a secondary 2D asynchronous spectrum is constructed via these slices. The advantage of SASS is demonstrated by a model system with the following challenging situations: (1) Temporal profiles of different components severely overlap, making spectra of pure components difficult to directly obtain from either original bilinear data or multivariate curve resolution-alternating least squares (MCR-ALS) with non-negativity and unimodality constraints. (2) Every peak in the spectra of the eluted samples contains contributions from at least two components. Hence, two-dimensional correlation spectroscopy (2D-COS) and n-dimensional (nD) asynchronous spectroscopic method developed in our previous work, which previously worked so well, are now invalid. SASS managed to reveal different groups of systematic absences of cross peaks (SACPs) that reflect the lack of spectral contributions of different components at different regions in the second asynchronous spectrum. Spectra of different components can still be faithfully retrieved via MCR-ALS calculation using constraints revealed by different groups of SACPs. The results demonstrate that implicit but intrinsic information revealed by SASS is indispensable in solving challenging bilinear data as the model system. We applied SASS on two real-world examples from thermogravimetry-Fourier transform infrared spectroscopy (TG-FT-IR) experiments of mixtures (H2O/HOD/D2O and H2O/isopropanol/pyridine). FT-IR spectra of different components were successfully recovered. Moreover, FT-IR spectrum of HOD, which is difficult to obtain, was successfully extracted. SASS can be applied in the analysis of gaseous mixtures from TG-FT-IR experiment and a combination of quantum cascade lasers with substrate-integrated hollow waveguides in environmental monitoring and biomedical diagnosis. Furthermore, SASS is also useful in various advanced hyphenated spectroscopic experiments.

5.
BMC Neurol ; 17(1): 98, 2017 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-28521736

RESUMEN

BACKGROUND: Impulse control and related disorders (ICRDs) are clinically complications in Parkinson's disease (PD). However, the clinical characteristics of ICRDs in Chinese PD patients were rarely reported. We aimed to explore the prevalence and the clinical profile of ICRDs in Chinese patients with PD. METHODS: 142 Chinese PD patients were consecutively enrolled. The symptoms of ICRDs were assessed with the Questionnaire for Impulsive-Compulsive Disorders. The clinical characteristics of patients with ICRDs and without ICRDs were compared. RESULTS: ICRDs were present in 31% of our patients. The most common ICRDs were compulsive medication use (11.3%) and punding (9.2%); the least frequent were walkabout (1.4%). Variables independently associated with ICRDs were earlier onset of the disease (≤55 years), severe cognitive impairment (MMSE 10-20), the dose of dopamine agonist (>1 mg/d) and dyskinesia. CONCLUSIONS: ICRDs was commonly found in Chinese PD patients. Earlier onset of the disease, the dose of dopamine agonist, severe cognitive impairment and dyskinesia are independent factors associated with ICRDs. Our results will be benefit for clinicians to assess the risk of developing ICRDs before delivering dopaminergic medication.


Asunto(s)
Trastornos Disruptivos, del Control de Impulso y de la Conducta/etiología , Conducta Impulsiva , Enfermedad de Parkinson/complicaciones , Anciano , Pueblo Asiatico , China/epidemiología , Trastornos Disruptivos, del Control de Impulso y de la Conducta/epidemiología , Agonistas de Dopamina/uso terapéutico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/psicología , Prevalencia , Encuestas y Cuestionarios
6.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(5): 1193-8, 2015 May.
Artículo en Zh | MEDLINE | ID: mdl-26415426

RESUMEN

In the present work, computer simulation was performed on a model chemical system where two solutes (denoted as P and Q, respectively) are dissolved in the same solution. Under intermolecular interaction between P and Q, part of P undergoes subtle structural variation and converts into U while part of Q converts into V. The strength of intermolecular interaction can be characterized by the corresponding equilibrium constant K. Our preliminary studies indicate that the S/N ratio of cross peak increases considerably as n increases. Moreover, the S/N ratio of the cross peak from the asynchronous spectra can be improved significantly when the suitable concentrations of P and Q are adopted. This work is helpful for a selection of suitable concentration sequence to maximize S/N ratio of cross peaks in the 2D asynchronous spectra generated by using the DAOSD approach proposed in our previous study so that weak intermolecular interaction can be probed.

7.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(8): 2241-5, 2015 Aug.
Artículo en Zh | MEDLINE | ID: mdl-26672302

RESUMEN

We reported a new super-concentrated hydrochloric acid system prepared by using tri-n-butyl phosphate (TBP)-constructed reversed micelles at ambient temperature and pressure. According to the titration result, the molar ratio of H+ to H2O (denoted as nH+/nH2O) in the super-concentrated HCl range from 0.50 to 1.50 which are higher than that in saturated aqueous HCl bulk solution (0.28). Significant a moment of hydrochloric acid is confined in W/O reversed micelles. Therefore, the behavior and status of HCl are different from those of conventional bluk solution. FTIR spectroscopic results demonstrate that a significant amount of HCl remains in the molecular form rather than being ionized into H+ and Cl-. Thus, super-concentrated HCl provides an extraordinary chemical environment which may have significant influence on certain substances. We found that the color of the solution is reddish brown when copper ion is dissolved in super-concentrated HCl, while the color of the saturated HCl aqueous solution (37 Wt%) containing copper ion is green. That is to say, the copper ions exist in a special state under the unique chemical environment of super-concentrated HCl. UV-Vis-NIR spectra indicate that both d-d transition band and charge transfer transition band of copper ions in super-concentrated HCl solution underwent significant variations. In addition, copper ions also have obvious influence on the hydrogen bond network among HCl in the super-concentrated HCl solution. Remarkable variation is introduced in the H-Cl stretching band in FTIR spectra.

8.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(8): 2017-20, 2014 Aug.
Artículo en Zh | MEDLINE | ID: mdl-25474926

RESUMEN

Qinghai caesious nephrite is discovered in the 1990s in the Golmud area of Qinghai Province. The conventional gemological testing methods, electron microprobe, infrared absorption spectroscopy and Raman spectroscopy were used in this study to analyze the chemical composition and infrared spectra characteristics of the caesious nephrite, selected from the jade mine of Xiaozhaohuo river in Golmud area. The results show that, the gemological physical properties of the Qinghai caesious nephrite are similar to other origin nephrite. Electron microprobe analysis indicates that the MgO, CaO and SiO2 are the major and stable composition for the caesious nephrite. The content of MgO and CaO are 18. 572%-23.603% and 12.333%-12.807% respectively. Moreover, the content of SiO2 is 56.799%-59.926%. In addition, it also contains a higher content of FeOr(Wt%: 1.924%-8.699%) and an amount of Al2O3, TiO2 and Na2O. Infrared absorption and Raman spectra show that the Qinghai caesious nephrite has a characteristic spectral features of tremolite indicating it is mainly composed of tremolite. The different frequency of the infrared absorption bands is due to the difference of Mg--Fe2+ isomorphous substitutionand Fe2+ content of the caesious nephrite. Comprehensive analysis of chemical composition and vibrational spectroscopy indicate that the color of dark gray blue for the Qinghai nephrite is mainly related to its high content of FeOr, and the Fe is a main coloring element.

9.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(9): 2346-50, 2014 Sep.
Artículo en Zh | MEDLINE | ID: mdl-25532323

RESUMEN

The authors tried to establish an approach to use acids to convert biomass into a fuel with higher carbon content and lower oxygen content in a zero-energy-consumption fashion. Considering that biomass is composed of monosaccharide, we used aqueous solutions of variation acids including hydrochloric acid, sulfuric acid and perchloric acid to treat 2-deoxy-ribose and fructose at ambient temperature and pressure. Black substances were produced after a period of time when 2-deoxy-ribose and fructose were mixed with aqueous solutions containing 8 mol · L(-1) acids. The black substance was collected and characterized by using elemental analysis, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Elemental analysis results indicate that the contents of carbon increases significantly in the black substances in comparison with 2-deoxy-ribose and fructose. Moreover, XPS results indicate that the content of oxygen in the black substance undergoes a significant decrease compared with pure 2-deoxy-ribose and fructose. In the XPS spectra, the is peaks of 2-deoxy-ribose, strong sub peak at 286. 05 eV, which is assigned to carbon linked to oxygen directly, dominate in the C is peak envelop. After treatment by HClO4, the peak decreased dramatically. This result also supports the conclusion that the content of oxygen in mono-saccharide is significantly reduced after treatment by acids. In the FTIR spectra of the black substances, strong peaks can be observed around 1 600 cm(-1), indicating that C==C bond is formed in the product. The above results suggest that treatments with acids may be developed as a new zero-energy-consumption approach to convert biomass in a new fuel with improved energy output efficiency.


Asunto(s)
Ácidos/química , Biocombustibles , Carbohidratos/química , Carbono/química , Espectroscopía Infrarroja por Transformada de Fourier , Biomasa , Oxígeno , Espectroscopía de Fotoelectrones
10.
Appl Spectrosc ; : 37028241245136, 2024 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-38646741

RESUMEN

Two-dimensional correlation spectroscopy is used to investigate the intermolecular interaction between two substances dissolved in the same solutions, where the intermolecular interaction is described by two reversible reactions producing two supramolecular aggregates. The severe overlappings expected among the characteristic peaks of the original solute and aggregates make conventional one-dimensional spectra difficult to accurately reflect the physiochemical nature of the intermolecular interaction. The double asynchronous orthogonal sample design (DAOSD) approach is utilized to analyze the simulated data for proof-of-principle demonstration. The patterns of cross-peaks are much more complex compared with the intermolecular interaction described by only a single reaction. Four major groups of cross-peaks with characteristic patterns observed in the pair of DAOSD asynchronous spectra are systematically analyzed and classified. Further analysis of the spectral feature of the cross-peaks of the DAOSD asynchronous spectra is helpful to exact additional information concerning the variation of the peak position and peak width of the aggregates compared with those of the original solute. The result is important to reveal the physicochemical nature of intermolecular interaction between the solutes (e.g., changes in conformation, dynamical behavior, etc.). The pattern of cross-peaks in the corresponding 2D asynchronous spectra may become rather complex when the peak position, peak width, and peak intensity of two supramolecular aggregates change simultaneously. Further work using artificial intelligence techniques to interpret the complex cross-peaks is still being carried out.

12.
Front Surg ; 9: 819519, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35433810

RESUMEN

Background: Solitary cecal ulcer is a rare disease. Its etiology is unknown and there are no pathognomonic symptoms. There are rare reports mimicking carcinoma as seen in this case. Case Presentation: A 64 year-old woman presented with a history of intermittent right lower abdominal pain for 20 years and worsening for 1 year. Colonoscopy revealed an enormous cecal ulcer. The PET-CT showed increased metabolism of the lesion. She underwent a right hemicolectomy. Histopathological examination revealed chronic non-specific inflammation. A rare diagnosis of the solitary cecal ulcer was ultimately made. Conclusion: Solitary cecal ulcer is a rare, idiopathic entity. It mimics inflammatory bowel disease, malignancy, infection, etc. The comprehensive images of this case describe the characteristics of the disease.

13.
Int J Ophthalmol ; 15(10): 1691-1698, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36262861

RESUMEN

AIM: To investigate the behaviors of smartphone usage and parental knowledge of vision health among primary students in the rural areas of China. METHODS: In this school-based, cross-sectional study, a total of 52 606 parents of students from 30 primary schools in the Xingguo County were investigated through an online questionnaire from July 2020 to August 2020. The self-designed questionnaire contained three parts: the demographic factors of both children and parents, parental knowledge and attitude toward myopia, and the preventive treatment of myopia. RESULTS: A total of 52 485 appropriately answered questionnaires were received, showing an effective response rate of 95.1%. The average age of the primary students was 10.1±0.98y and the prevalence of myopia among the primary students was 40.3%. The age of myopia occurrence in elementary students was significantly correlated with the parents' educational level (95%CI: 0.82-0.98, P=0.013), children's gender (95%CI: 1.08-1.20, P<0.001), school location (county or countryside) (95%CI: 0.59-0.66, P<0.001), children's smartphone ownership (95%CI: 1.09-1.26, P<0.001), and the average time spent on smartphone per day (95%CI: 0.78-0.88, P<0.001). School location in the county town, high family income, and high parents' educational level significantly affected both parents' myopia awareness and children's vision-threatening behaviors (P<0.01). Left-behind children showed a higher incidence of vision-threatening habits than those who lived with their parents (P<0.01). CONCLUSION: The results reveal the current situation of myopia development among rural primary school students and their parents. This survey will serve as a guidance for designing myopic prevention policies in the rural areas of China.

14.
Guang Pu Xue Yu Guang Pu Fen Xi ; 31(7): 1767-71, 2011 Jul.
Artículo en Zh | MEDLINE | ID: mdl-21942020

RESUMEN

In situ TLC/FTIR technique has tremendous potential in the analysis of complex mixtures. However, the progress in this technique was quite slow. The reason is that conventional stationary phase such as silica gel etc. has strong absorption in FTIR spectrum and thus brings about severe interference in the detection of samples. To solve the problem, the authors propose to use barium fluoride fine particles as stationary phase of TLC plate. The reasons are as follows: Barium fluoride wafer has been extensively used as infrared window in FTIR experiments and it has no absorbance in an IR region between 4 000 and 800 cm'. As a matter of fact, the atomic mass of barium and fluoride is quite large, thus the normal vibration of BaF2 lattice is limited in far-IR region and low frequency part of mid-IR region. Therefore, the interference caused by IR absorption of stationary phase can be resolved if BaF2 is used as stationary phase of TLC plate. Moreover, BaF2 is quite stable and insolvable in water and most organic solvents and it will not be dissolved by mobile phase or react with samples in TLC separation. Additionally, decreasing the particle size of BaF2 is very important in TLC/FTIR analysis technique. The reason is two-fold: First, decreasing the particle size of stationary phase is helpful to improving the efficiency of separation by TLC plate; second, decreasing the size of BaFz particle can improve the quality of FTIR spectra by alleviating the problem of light scattering. By optimizing the synthetic conditions, fine particles of barium fluoride were obtained. SEM results indicate that the size of the BaF2 particles is around 500 nm. FTIR spectrum of the BaF2 particles shows that no absorption of impurity was observed. Moreover, the elevation of baseline caused by light scattering is insignificant. The authors have developed a new technique named "settlement volatilization method" to prepare TLC plate without polymeric adhesive that may bring about significant interference in FTIR analysis. Preliminary TLC experiments proved that the TLC plate using BaF2 fine particles as stationary phase can separate rhodamine B from methylene blue successfully. Applications of barium fluoride fine particles as stationary phase have bright perspective in the development of new in-situ TLC/FTIR analysis techniques.

15.
J Gastrointest Surg ; 25(6): 1524-1533, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-32424688

RESUMEN

BACKGROUND: Pouchitis is a common complication after ileal pouch-anal anastomosis (IPAA) in patients with ulcerative colitis. However, an ideal model remains lacking. Therefore, we aimed to establish an appropriate model resembling human pouchitis. METHODS: Sprague-Dawley rats were randomly assigned to five groups: TNBS group, DSS group, NS group (following IPAA procedure, administrated with TNBS enema, DSS orally, normal saline enema, respectively), NI group (underwent IPAA), and sham group (underwent switch abdominal surgery). General status, weight change, hematochezia, and fecal scores were recorded. Fecal microbiota were counted under a microscope and analyzed by 16S rRNA gene high-throughput sequencing. Specimens of ileal pouch and small intestine (proximal, mid, distal) were collected to evaluate myeloperoxidase and occludin expression by immunohistochemistry and mRNA expression of pro-inflammatory markers by PCR. RESULTS: General status, hematochezia, fecal score, and increased mRNA expression of interleukin-6 and TNF-α in the TNBS group were similar to those in the DSS group, whereas the TNBS-induced model displayed a more stable weight change and more serious dysbacteriosis, not only was fecal bacterial diversity reduced, the dominant microbiota was altered. Histopathology scores of the distal small intestine in the TNBS group were lower compared with those in the DSS group (P < 0.05). A significant difference in myeloperoxidase and occludin expression in the small intestine was also detected between the TNBS and DSS groups. CONCLUSIONS: Our model mimicked the characteristics of human pouchitis and avoided potential side effects in the small intestine, and thus could be employed for further research.


Asunto(s)
Colitis Ulcerosa , Reservorios Cólicos , Reservoritis , Proctocolectomía Restauradora , Anastomosis Quirúrgica/efectos adversos , Animales , Colitis Ulcerosa/cirugía , Reservorios Cólicos/efectos adversos , Humanos , Reservoritis/etiología , Proctocolectomía Restauradora/efectos adversos , ARN Ribosómico 16S , Ratas , Ratas Sprague-Dawley , Trinitrobencenos , Ácido Trinitrobencenosulfónico/toxicidad
16.
Spectrochim Acta A Mol Biomol Spectrosc ; 251: 119427, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33461134

RESUMEN

Terbium acetylsalicylate has been prepared, and the ethanol solution of the complex exhibits strong luminescence under the excitation of ultraviolet radiation. When a small amount of bilirubin solution is introduced into the solution containing a high concentration of terbium acetylsalicylate, a remarkable diminution of the luminescence of the terbium complex was observed. Investigations on the behavior and life-time of luminescence indicate that the quenching is not caused by forming a stable non-luminescent product via a reaction between terbium acetylsalicylate and bilirubin. A π-π interaction between the chromophore of bilirubin and the aromatic moiety of ligand was revealed via the pattern of cross peaks in the 2D asynchronous spectrum generated using the DAOSD (double asynchronous orthogonal sample design) approach. Such an interaction paves a route for energy transfer in the quenching process. The combination of a high concentration of the terbium complex and a long life-time of luminescence in the lanthanide complex/bilirubin system forms a special scenario: a bilirubin molecule by diffusion may visit and deactivate dozens of excited terbium complexes within the half-life period of the lanthanide complex. This is why a small amount of bilirubin can bring about the significant reduction of luminescence on the solution containing a high concentration of the terbium complex.

17.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(10): 2706-9, 2010 Oct.
Artículo en Zh | MEDLINE | ID: mdl-21137404

RESUMEN

Gels are gaining extensive interest owing to their versatile applications in fields such as drug delivery, tissue engineering, cosmetics, templated materials and food industry. Surfactants have an ability to self-assemble into a variety of supramolecular aggregate structures and morphologies. Of particular interest in resent years are surfactant-based gels, one special class of materials due to surfactant assemblies resulting in viscoelastic solid-like rheological behaviors. Up to now, there is only limited understanding on the mechanism of gel formation, especially on the interaction among water, organic solvents and surfactant during thegel formation. In this study we prepare a Low-molecule-gel that is composed of cetyl trimethyl ammonium bromide (CTAB), water and carbon tetrachloride. Based on the experimental result of XRD and titration, the authors find that CTAB in gel are more than in saturated CTAB solution but CTAB is not solide in gel. CTAB is not solvented in CCl4. The solubility of CTAB in saturated CTAB solution is limited. So the authors suppose that CTAB is a synergistically solubilized by water and CCl4 in the gel. In addition, both NMR and FTIR spectroscopic results demonstrate that CTAB cations form a quasi-ordered structure in the gel.


Asunto(s)
Tetracloruro de Carbono , Compuestos de Amonio Cuaternario , Tensoactivos , Agua , Cationes , Geles , Micelas , Solubilidad , Soluciones , Solventes
18.
World J Clin Cases ; 8(16): 3553-3559, 2020 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-32913863

RESUMEN

BACKGROUND: Reverse rotation of the midgut is a rare type of intestinal malrotation. Volvulus of the right colon or entire midgut, stenosis of the transverse colon and obstruction of the duodenojejunal junction are common complications of reverse rotation. In this study, we report the first case of intestinal obstruction associated with reverse rotation in pregnancy. CASE SUMMARY: A 31-year-old woman at 36+2 wk gestation presented to the emergency department with progressive abdominal cramping, nausea and bilious vomiting. Abdominal ultrasound scanning showed dilatation of the bowel. Computed tomography scanning revealed features of reverse rotation of the midgut with intestinal volvulus. After consultation with the obstetrician, the pregnancy was terminated and exploratory abdominal surgery was performed. Intra-operatively, it was found that the mesentery of the colon and small intestine was insufficiently attached. The right colon and the small intestinal mesentery was twisted, and intestinal necrosis was observed. The duodenum and duodenojejunal junction were curved in front of the transverse colon, and the transverse colon passed through the tunnel behind the mesenteric root. Intestinal reverse rotation with volvulus was confirmed. The |necrotic intestine was resected and small intestine mesenteric reconstruction was performed. The patient recovered after surgery. After leaving the hospital, the patient and her daughter remained well during an 8-month follow-up period. CONCLUSION: We report the diagnosis, treatment and etiology of a pregnant patient with intestinal obstruction due to reverse rotation of the midgut. For similar cases, appropriate diagnosis and treatment should be carried out according to the condition of the fetus and pregnant woman.

19.
Ann Clin Transl Neurol ; 7(9): 1692-1701, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32857484

RESUMEN

OBJECTIVE: The objective of this study was to assess the relationship between white matter hyperintensities (WMH) and the occurrence and progression of apathy in Parkinson's disease (PD). METHODS: We recruited patients with PD who underwent baseline evaluation, which included apathy assessment and magnetic resonance imaging (MRI) head scans. After 2.5 years of follow-up, we re-evaluated patient apathy symptoms. The severity and location of WMH were assessed with fluid-attenuated inversion recovery (FLAIR) sequences using the Fazekas visual rating scale. Logistic regression and linear regression analyses of baseline WMH characteristics were conducted to explore the potential association between apathy and WMH. RESULTS: A total of 141 PD patients were recruited. The apathy group had a higher proportion of male patients, advanced disease, and depression, which was coupled with a lower quality of life. Morever, higher WMH severity was significantly associated with apathy. Logistic regression analyses demonstrated that WMH severity was a risk factor for apathy. In addition, linear regression analysis also suggests that apathy severity is positively correlated with baseline WMH Fazekas scales (ϐ = 0.959, P < 0.001). Baseline WMH severity was also a risk factor for apathy progression. INTERPRETATION: WMH is associated with apathy and could be a promising marker to predict apathy progression in PD.


Asunto(s)
Apatía/fisiología , Leucoaraiosis/patología , Enfermedad de Parkinson/patología , Enfermedad de Parkinson/fisiopatología , Factores de Edad , Anciano , Anciano de 80 o más Años , Progresión de la Enfermedad , Femenino , Humanos , Leucoaraiosis/diagnóstico por imagen , Estudios Longitudinales , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Enfermedad de Parkinson/diagnóstico por imagen , Factores de Riesgo , Índice de Severidad de la Enfermedad
20.
Spectrochim Acta A Mol Biomol Spectrosc ; 243: 118789, 2020 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-32799191

RESUMEN

Systematic Absence of Cross Peaks (SACPs) in a two-dimensional (2D) asynchronous spectrum, a sensitive indicator of the signal purity, is very important in analyzing bilinear data. However, identification of SACPs in practice remains a challenge because of noise in the corresponding 2D asynchronous spectrum. We firstly show that SACP can be identified via a statistical test using a large amount of 2D asynchronous spectra. To meet the practical demand that SACPs must be identified based on a single 2D asynchronous spectrum in many cases, we use a 2D quotient spectrum (Q (x, y)) as an effective auxiliary tool to recognize SACPs. The expectation of Q(x, y) is zero when (x, y) is within SACP or background regions in the corresponding 2D asynchronous spectrum. When (x, y) is in a cross-peak region, the expectation of the absolute value of Q(x, y) is a constant regardless of whether the cross-peak in a 2D asynchronous spectrum is strong or weak. Thus, a unified threshold can be set up to differentiate the SACP region from cross-peak region via the auxiliary 2D quotient spectrum. We have applied this approach on two real-world examples and satisfactory results have been obtained. This result demonstrates that the statistical test with a 2D quotient spectrum is applicable in real-world systems.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA