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1.
Acta Endocrinol (Buchar) ; 19(3): 370-375, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38356978

RESUMEN

Background: Pheochromocytoma, the great masquerader, can have a varied spectrum of clinical manifestations. It can often cause a diagnostic challenge despite the availability of modern investigation modalities. Case: We present the case of a 38-year-old male who presented with uncontrolled hypertension for the past 10 years and heart failure for one year. The diagnosis of pheochromocytoma was missed in the initial setting, leading to a biopsy of the retroperitoneal mass. Fortunately, the patient survived the procedure. Subsequently, with the involvement of a multi-disciplinary team, he was optimized for surgery under strict cardiac monitoring. After the complete excision of the tumour, he showed significant improvement not only in his clinical symptoms but also in his cardiac status. Conclusions: This case emphasizes the age-old medical phrase of 'Primum non nocere or first, do no harm'. Any invasive procedure in a pheochromocytoma can lead to a massive release of catecholamines causing a hypertensive crisis, pulmonary oedema, and even cardiac arrest. Any young patient presenting with hypertension or heart failure should be investigated for secondary causes. Cardiomyopathy due to pheochromocytoma is because of catecholamine overload and usually reverses or improves after curative surgery.

2.
Ultrasound Obstet Gynecol ; 60(6): 759-765, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-35726505

RESUMEN

OBJECTIVE: Despite decades of obstetric scanning, the field of sonographer workflow remains largely unexplored. In the second trimester, sonographers use scan guidelines to guide their acquisition of standard planes and structures; however, the scan-acquisition order is not prescribed. Using deep-learning-based video analysis, the aim of this study was to develop a deeper understanding of the clinical workflow undertaken by sonographers during second-trimester anomaly scans. METHODS: We collected prospectively full-length video recordings of routine second-trimester anomaly scans. Important scan events in the videos were identified by detecting automatically image freeze and image/clip save. The video immediately preceding and following the important event was extracted and labeled as one of 11 commonly acquired anatomical structures. We developed and used a purposely trained and tested deep-learning annotation model to label automatically the large number of scan events. Thus, anomaly scans were partitioned as a sequence of anatomical planes or fetal structures obtained over time. RESULTS: A total of 496 anomaly scans performed by 14 sonographers were available for analysis. UK guidelines specify that an image or videoclip of five different anatomical regions must be stored and these were detected in the majority of scans: head/brain was detected in 97.2% of scans, coronal face view (nose/lips) in 86.1%, abdomen in 93.1%, spine in 95.0% and femur in 92.3%. Analyzing the clinical workflow, we observed that sonographers were most likely to begin their scan by capturing the head/brain (in 24.4% of scans), spine (in 23.2%) or thorax/heart (in 22.8%). The most commonly identified two-structure transitions were: placenta/amniotic fluid to maternal anatomy, occurring in 44.5% of scans; head/brain to coronal face (nose/lips) in 42.7%; abdomen to thorax/heart in 26.1%; and three-dimensional/four-dimensional face to sagittal face (profile) in 23.7%. Transitions between three or more consecutive structures in sequence were uncommon (up to 13% of scans). None of the captured anomaly scans shared an entirely identical sequence. CONCLUSIONS: We present a novel evaluation of the anomaly scan acquisition process using a deep-learning-based analysis of ultrasound video. We note wide variation in the number and sequence of structures obtained during routine second-trimester anomaly scans. Overall, each anomaly scan was found to be unique in its scanning sequence, suggesting that sonographers take advantage of the fetal position and acquire the standard planes according to their visibility rather than following a strict acquisition order. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.


Asunto(s)
Aprendizaje Profundo , Femenino , Embarazo , Humanos , Flujo de Trabajo , Ultrasonografía Prenatal/métodos , Segundo Trimestre del Embarazo , Feto/anatomía & histología
3.
J Assoc Physicians India ; 70(4): 11-12, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35443335

RESUMEN

Male reproductive functions are governed by hypothalamic pituitary testicular axis. If any component of this axis malfunctions, then hypogonadism will develop which is characterized by ill-defined secondary sexual features and low serum testosterone. The common patterns seen are primary and secondary testicular failure in the young; and late onset hypogonadism in the elderly. All such cases can be virilized and managed by androgen supplementation. Spermatogenesis can be induced by use of appropriate gonadotropins in selected cases. The aim of the study was to find out the pattern, management and outcome of male hypogonadism. MATERIAL: It was a prospective questionnaire based observational study, carried out on infertile hypogonadic males, attending medicine outdoor at medical college hospital from January 2015 to December 2020. There were 50 males with hypogonadic features, cases of late onset of hypogonadism were excluded. Sexual maturity rating, semen analysis, serum testosterone and FSH level were estimated in all patients at baseline and at 6 months duration of treatment. Testicular biopsy, Karyotyping and MRI brain were performed in selected cases. Azoospermic patients having hypogonadotropic hypogonadism were treated with long-acting testosterones and gonadotropins. OBSERVATION: The study subjects were infertile azoospermic males. On the basis of serum FSH and testosterone levels, they were classified into two groups. Group A (n=42) cases were hypergonadotropic hypogonadism or primary testicular failure; of these 32 were Klinefelter syndrome (XXY), 7 chronic orchitis and 3 empty scrotal syndrome including one case of anorchia. These patients also developed other systemic illnesses in addition to hypogonadism. Group B (n=8) hypogonadotropic hypogonadism or secondary testicular failure; of these 2 were Kallman syndrome and the rest were idiopathic. After testosterone replacement all patients were virilized and there was marked improvement in libido and androgenization. CONCLUSION: The study brings out that primary testicular failure is more common than secondary testicular failure. Both pattern of hypogonadism should receive lifelong androgen replacement therapy; otherwise, they will be a basket of multiple systemic disorders. Presently testosterone undecanoate once in every three months is the agent of choice.


Asunto(s)
Azoospermia , Hipogonadismo , Anciano , Femenino , Hormona Folículo Estimulante , Disgenesia Gonadal 46 XY , Gonadotropinas , Humanos , Hipogonadismo/tratamiento farmacológico , India/epidemiología , Masculino , Estudios Prospectivos , Testículo/anomalías , Testosterona/uso terapéutico , Resultado del Tratamiento
4.
Health Qual Life Outcomes ; 19(1): 158, 2021 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-34059081

RESUMEN

BACKGROUND: Patient reported outcome measures (PROMs) are used to understand the impact of lower limb reconstruction surgery on patients' quality of life (QOL). Existing measures have not been developed to specifically capture patient experiences amongst adults with lower limb conditions that require reconstruction surgery. This review aimed to synthesise qualitative evidence to identify what is important to patients requiring, undergoing, or following reconstructive surgery for lower limb conditions. METHODS: MEDLINE, Embase, PsychINFO and Cinahl were searched from inception until November 2020. Studies were included if they employed qualitative research methods, involved patients requiring, undergoing or following lower limb reconstruction and explored patients' experiences of care, treatment, recovery and QOL. Mixed methods studies that did not separately report qualitative findings, mixed population studies that were not separately reported and studies in languages other than English were excluded. Included studies were analysed using thematic synthesis. The Critical Appraisal Skills Programme qualitative studies checklist was used to undertake quality assessment. RESULTS: Nine studies met the inclusion criteria. The thematic synthesis identified two overarching themes: (1) areas of living key to QOL for lower limb reconstruction patients and (2) moving towards a new normal. The way in which lower limb reconstruction affects an individual's QOL and their recovery is complex and is influenced by a range of inter-related factors, which will affect patients to varying degrees depending on their individual circumstances. We identified these factors as: pain, daily functioning and lifestyle, identity, income, emotional wellbeing, support, the ability to adapt and adjust and the ability to move forwards. CONCLUSIONS: The way patients' QOL is affected after a lower limb reconstruction is complex, may change over time and is strongly linked to their recovery. These findings will aid us in developing a conceptual framework which identifies the outcomes important to patients and those that should be included in a PROM. Further research is then required to establish whether the range of factors we identified are captured by existing PROMs. Depending on the outcome of this work, a new PROM for patients following lower limb reconstruction may be required.


Asunto(s)
Extremidad Inferior/cirugía , Medición de Resultados Informados por el Paciente , Satisfacción del Paciente/estadística & datos numéricos , Procedimientos de Cirugía Plástica/psicología , Calidad de Vida/psicología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Investigación Cualitativa
5.
J Appl Microbiol ; 129(6): 1589-1597, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32594558

RESUMEN

AIM: Presently, N-hydroxy-N'-phenyloctanediamide (vorinostat) which is an effective histone deacetylase inhibitor, is being synthesized chemically. Hence, present study aims to develop an eco-friendly approach for the synthesis of vorinostat from N'-phenyloctanediamide through biotransformation. METHODS AND RESULTS: Using the amidase of Bacillus smithii IIIMB2907 in time course conversion and organic solvent compatibility, maximum bioconversion was observed at 12 h of reaction time and in presence of ethanol, respectively. Potassium phosphate buffer of pH 7·0 supported maximum bioconversion of N'-phenyloctanediamide (10 mmol l-1 ) into N-hydroxy-N'- phenyloctanediamide at 40°C. Bench scale study was successfully carried out with 83% yield of purified vorinostat. CONCLUSION: In this study, an eco-friendly approach for the biotransformation of N'-phenyloctanediamide into vorinostat was developed by using cell free extract of thermophilic strain B. smithii IIIMB2907. SIGNIFICANCE AND IMPACT OF THE STUDY: Microbial amidase has achieved remarkable attention in the field of biotransformation for the green synthesis of hydroxamic acids. Utilization of amidase from B. smithii IIIMB2907, specifically in the synthesis of vorinostat drug is a foremost attempt in the development a novel process and can also be employed in the synthesis of its derivatives as well.


Asunto(s)
Amidohidrolasas/metabolismo , Inhibidores de Histona Desacetilasas/síntesis química , Vorinostat/síntesis química , Bacillus/enzimología , Biotransformación , Tecnología Química Verde , Ácidos Hidroxámicos/síntesis química , Temperatura
6.
J Food Sci Technol ; 56(3): 1641-1648, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30956345

RESUMEN

Indian gooseberry (Emblica officinalis) commonly known as amla is one of the important fruit of Ayurveda. Nutritional and medicinal properties of amla make it a well known fruit. It is an excellent source of vitamin C, phytochemicals and minerals. Several cultivars of amla are grown throughout different parts of India. Physical characteristics are imperative for designing the equipments for processing, handling and storage. Processing of fruit into value added products is governed by chemical composition of fruit. The current work was aimed to examine the various physical and chemical characteristics of fruits of six cultivars viz. NA-7, NA-9, NA-10, Chakaiya, Balwant and Hathijhool. Characteristics namely height, diameter, geometric mean diameter, sphericity, surface area, aspect ratio, volume, density, rolling resistance, color, textural characteristics, proximate composition, ascorbic acid and polyphenol content was studied. Results showed that the highest fruit size was obtained in NA-7 and the lowest in Hathijhool cultivars while the highest density in Hathijhool and lowest in NA-10 cultivar. The fruit volume of different cultivars varied from 15.00 to 44.93 cm3. Moisture content was highest in Chakaiya followed by NA-7 cultivar. No significant difference was observed in surface hardness and moisture content of the fruit of different cultivars. The highest ascorbic acid and polyphenols content were found in Chakaiya cultivar. In the different cultivars, ash content ranged between 2.08 and 2.97% and NA-10 cultivar had the highest value followed by Chakaiya cultivar.

7.
Clin Exp Immunol ; 193(2): 207-220, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29645082

RESUMEN

Paediatric asthma exacerbations are often caused by rhinovirus (RV). Moreover, 25(OH)-vitamin D3 (VitD3) deficiency during infancy was found associated with asthma. Here, we investigated the innate immune responses to RV and their possible modulation by 25(OH)-VitD3 serum levels in a preschool cohort of children with and without asthma. The innate lymphoid cell type 2 (ILC2)-associated marker, ST2, was found up-regulated in the blood cells of asthmatic children with low serum levels of 25(OH)-VitD3 in the absence of RV in their airways. Furthermore, in blood cells from control and asthmatic children with RV in their airways, soluble (s) ST2 (sST2) protein was found reduced. Asthmatic children with low 25(OH)-VitD3 in serum and with RV in vivo in their airways at the time of the analysis had the lowest sST2 protein levels in the peripheral blood compared to control children without RV and high levels of 25(OH)-VitD3. Amphiregulin (AREG), another ILC2-associated marker, was found induced in the control children with RV in their airways and low serum levels of 25(OH)-VitD3. In conclusion, the anti-inflammatory soluble form of ST2, also known as sST2, in serum correlated directly with interleukin (IL)-33 in the airways of asthmatic children. Furthermore, RV colonization in the airways and low serum levels of 25(OH)-VitD3 were found to be associated with down-regulation of sST2 in serum in paediatric asthma. These data indicate a counter-regulatory role of 25(OH)-VitD3 on RV-induced down-regulation of serum sST2 in paediatric asthma, which is relevant for the therapy of this disease.


Asunto(s)
Asma/inmunología , Colecalciferol/sangre , Resfriado Común/inmunología , Proteína 1 Similar al Receptor de Interleucina-1/metabolismo , Leucocitos Mononucleares/fisiología , Sistema Respiratorio/metabolismo , Rhinovirus/inmunología , Células Cultivadas , Niño , Preescolar , Estudios de Cohortes , Progresión de la Enfermedad , Femenino , Humanos , Inmunidad Innata , Proteína 1 Similar al Receptor de Interleucina-1/genética , Interleucina-33/metabolismo , Leucocitos Mononucleares/virología , Masculino , Regulación hacia Arriba
8.
J Postgrad Med ; 64(4): 226-231, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30306968

RESUMEN

In today's world when biomedical science is experiencing continuous threats from various sources, publication of research articles in predatory journals has created a major havoc. These predatory journals are publishing worthless biomedical science which will haunt genuine researchers and keen readers of authentic biomedical journals for several decades. Hence, researchers of various disciplines and academic experience should be continuously made aware of these predatory publishers and potential ways to recognize them. The main aim of this article is to discuss the issues related to predatory publishing, techniques and strategies used by these publishers to prey young inexperienced researchers, and disadvantages of publishing in predatory journals.


Asunto(s)
Investigación Biomédica/tendencias , Revisión de la Investigación por Pares/tendencias , Publicaciones Periódicas como Asunto/tendencias , Edición/tendencias , Mala Conducta Científica/tendencias , Humanos
9.
J Postgrad Med ; 64(3): 177-179, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29992912

RESUMEN

Dilated cardiomyopathy (DCM) is an idiopathic condition that results from impaired ventricular systolic function. Thyroid diseases have been known to cause myriad changes in the structure and function of the heart. Diastolic dysfunction is a common abnormality reported in hypothyroidism. However, hypothyroidism-induced DCM and systolic dysfunction is an uncommon phenomenon, especially as the initial presenting manifestation of hypothyroidism. The current article describes the case of a young female who presented with symptoms of heart failure and was diagnosed as having DCM as echocardiography revealed left ventricular global hypokinesia and severely depressed systolic function. Thyroid profile revealed a grossly elevated thyroid-stimulating hormone (TSH) value of 313 µIU/ml; free thyroxine (fT4) was 0.220 ng/dl. The present case presented with DCM as the initial presentation of hypothyroidism and improved significantly after five months of levothyroxine replacement therapy.


Asunto(s)
Cardiomiopatía Dilatada/etiología , Hipotiroidismo/complicaciones , Adulto , Femenino , Humanos
10.
Eur J Neurol ; 24(9): 1099-1107, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28695634

RESUMEN

Multiple patient-reported outcomes (PROs) are currently being used in multiple sclerosis (MS) but their application is inconsistent and guidance on the appropriateness of each tool is lacking. The objective of our study was to identify MS-specific PROs and systematically to assess the development process and the reliability and validity of various instruments. A systematic literature search was conducted on multiple data sources, including MEDLINE, Embase (using the Ovid platform) and Google Scholar, from 1996 to March 2015. Search terms included combinations of MS, PROs and quality of life. Randomized controlled trials or observational studies conducted on patients with MS and published in English were included. In addition, the PROQOLID database was explored. The MS-specific PROs were systematically assessed using the Evaluating the Measurement of Patient-Reported Outcomes tool. In total, 8094 articles were screened and 405 PROs were identified from 1102 relevant articles. PROs were classified into MS-specific (n = 82) and non-MS-specific (n = 323). The results for the eight PROs that are most commonly used in MS clinical trials are presented here. For these eight PROs, the overall summary scores ranged between 50.1 and 68.7. The Multiple Sclerosis Impact Scale-29 had the best overall mean score (68.7), followed by the Leeds Multiple Sclerosis Quality of Life (67.0). This is the first study to provide a standardized assessment of all PROs for MS. There is a lack of data on content validity for PROs used in MS research, which indicates the need for a robust instrument in MS developed according to the US Food and Drug Administration guidelines.


Asunto(s)
Esclerosis Múltiple/tratamiento farmacológico , Medición de Resultados Informados por el Paciente , Humanos , Pacientes , Calidad de Vida , Autoinforme , Resultado del Tratamiento
12.
Nanotechnology ; 27(10): 105302, 2016 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-26867001

RESUMEN

Thermally responsive polymers present an interesting avenue for tuning the optical properties of nanomaterials on their surfaces by varying their periodicity and shape using facile processing methods. Gold bowtie nanoantenna arrays are fabricated using nanosphere lithography on prestressed polyolefin (PO), a thermoplastic polymer, and optical properties are investigated via a combination of spectroscopy and electromagnetic simulations to correlate shape evolution with optical response. Geometric features of bowtie nanoantennas evolve by annealing at temperatures between 105 °C and 135 °C by releasing the degree of prestress in PO. Due to the higher modulus of Au versus PO, compressive stress occurs on Au bowtie regions on PO, which leads to surface buckling at the two highest annealing temperatures; regions with a 5 nm gap between bowtie nanoantennas are observed and the average reduction is 75%. Reflectance spectroscopy and full-wave electromagnetic simulations both demonstrate the ability to tune the plasmon resonance wavelength with a window of approximately 90 nm in the range of annealing temperatures investigated. Surface-enhanced Raman scattering measurements demonstrate that maximum enhancement is observed as the excitation wavelength approaches the plasmon resonance of Au bowtie nanoantennas. Both the size and morphology tunability offered by PO allows for customizing optical response.


Asunto(s)
Oro/química , Nanoestructuras/química , Polímeros/síntesis química , Polímeros/química , Espectrometría Raman , Resonancia por Plasmón de Superficie , Propiedades de Superficie , Temperatura
14.
J Chem Phys ; 145(15): 154707, 2016 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-27782456

RESUMEN

Surface ordering of pentacene molecules adsorbed on an aperiodic Cu surface has been studied with density functional theory (DFT) and scanning tunnelling microscopy as a function of coverage. Below 0.73 ML (5.3 × 1013 molecules cm-2), the adsorbate structure is row-like with the molecular axes aligned with the rows in the Cu structure. Between this coverage and 1 ML (7.3 × 1013 molecules cm-2), a structural phase with a checkerboard structure is seen. At this coverage region, the molecules are very close to each other which leads to unusual bending. At higher coverages, a further phase transition to a high-density row structure is seen for most of the film. DFT with van der Waals functionals is employed to study how the molecule-molecule and molecule-surface interactions evolve as a function of coverage.

15.
Indian J Med Res ; 143(3): 348-56, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27241649

RESUMEN

BACKGROUND & OBJECTIVES: It is well documented that the Northeast state of Manipur in India has been dealing with the dual problems of injecting drug use and HIV for the last two decades, but the hepatitis C problem has not been so well characterized. The aim of this study was to assess the prevalence of hepatitis C virus (HCV) infection and HCV/HIV co-infection among people who inject drugs (PWID) in Manipur, and identify factors associated with infection. METHODS: Data were obtained from the Integrated Behavioural and Biological Assessment (2009-2010), a cross-sectional survey among 821 male PWID in two districts of Manipur (Churachandpur and Bishnupur). Information about drug use, sexual and injecting risk behaviours, and exposure to interventions was obtained, and biological specimens tested for HIV and HCV. Logistic regression analyses identified factors associated with HCV infection and HCV/HIV co-infection. RESULTS: HCV prevalence was 74 per cent (91% Churachandpur, 56% Bishnupur), and HCV/HIV co-infection was 29 per cent (38% Churachandpur, 21% Bishnupur). Among the 31 per cent of HIV positive PWID, 95 per cent were co-infected. HCV infection was associated with district, longer duration of injecting, injecting at least once daily, generally injecting with a used needle and syringe, and having had an HIV test. HCV/HIV co-infection was associated with district, older age, being employed, being widowed/divorced, longer duration of injecting, and feeling at risk of HIV infection. INTERPRETATION & CONCLUSIONS: The HCV/HIV co-infection among PWID in Manipur was very high, highlighting the urgent need for effective prevention, diagnosis and treatment.


Asunto(s)
Coinfección/epidemiología , Infecciones por VIH/epidemiología , Hepacivirus/aislamiento & purificación , Hepatitis C/epidemiología , Adolescente , Adulto , Coinfección/transmisión , Coinfección/virología , Consumidores de Drogas , Femenino , Infecciones por VIH/transmisión , Infecciones por VIH/virología , Hepacivirus/patogenicidad , Hepatitis C/etiología , Hepatitis C/transmisión , Hepatitis C/virología , Humanos , Masculino , Persona de Mediana Edad , Asunción de Riesgos , Conducta Sexual
16.
Br J Neurosurg ; 30(4): 461-3, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26488339

RESUMEN

We report a case of intractable proctalgia on a background of lower back and bilateral leg pain secondary to spinal canal stenosis and spondylolisthesis. A complete resolution was observed following spinal surgery. This case highlights consideration of a spinal aetiology when intractable proctalgia is associated with back and leg pain.


Asunto(s)
Descompresión Quirúrgica , Procedimientos Neuroquirúrgicos , Dolor/etiología , Estenosis Espinal/cirugía , Anciano , Dorso , Descompresión Quirúrgica/métodos , Femenino , Humanos , Pierna , Fusión Vertebral/métodos , Estenosis Espinal/complicaciones , Resultado del Tratamiento
17.
J Food Sci Technol ; 53(9): 3455-3464, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27777451

RESUMEN

The present study evaluated the effect of removal of polyphenols on the structural properties of protein isolates extracted from sunflower seed and kernel. The structural and thermal changes in protein upon phenolic interaction were studied using circular dichroism, differential scanning calorimetry, thermal gravimetric analysis, X-ray diffraction, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), and Fourier Transform Infrared (FT-IR) spectroscopy. Presence of phenolic compounds in proteins decreased the ordered structure content with parallel increase in unordered structure content. Denaturation temperature was higher for protein isolates with phenolic compounds while, enthalpy decreased upon phenolic interaction. In the presence of phenolic compounds, higher mass loss was observed upon heating. Crystalinity and crystal size got increased after removal of phenolic compounds. Protein isolates from kernels had higher percentage of crystalinity and crystal size as compared to seed protein isolates. Higher molecular weights were observed for protein isolates with phenolic compounds. Presence of polyphenols reduced the hydrophobicity as well the sulfhydryl content and increased the particle size of proteins.

18.
J Chem Phys ; 142(9): 094703, 2015 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-25747095

RESUMEN

The use of quasicrystals as precursors to catalysts for the steam reforming of methanol is potentially one of the most important applications of these new materials. To develop application as a technology requires a detailed understanding of the microscopic behavior of the catalyst. Here, we report the effect of leaching treatments on the surface microstructure, chemical composition, and valence band of the icosahedral (i-) Al-Cu-Fe quasicrystal in an attempt to prepare a model catalyst. The high symmetry fivefold surface of a single grain i-Al-Cu-Fe quasicrystal was leached with NaOH solution for varying times, and the resulting surface was characterized by x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The leaching treatments preferentially remove Al producing a capping layer consisting of Fe and Cu oxides. The subsurface layer contains elemental Fe and Cu in addition to the oxides. The quasicrystalline bulk structure beneath remains unchanged. The subsurface gradually becomes Fe3O4 rich with increasing leaching time. The surface after leaching exhibits micron sized dodecahedral cavities due to preferential leaching along the fivefold axis. Nanoparticles of the transition metals and their oxides are precipitated on the surface after leaching. The size of the nanoparticles is estimated by high resolution transmission microscopy to be 5-20 nm, which is in agreement with the AFM results. Selected area electron diffraction (SAED) confirms the crystalline nature of the nanoparticles. SAED further reveals the formation of an interface between the high atomic density lattice planes of nanoparticles and the quasicrystal. These results provide an important insight into the preparation of model catalysts of nanoparticles for steam reforming of methanol.

19.
Allergol Immunopathol (Madr) ; 43(1): 81-7, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-24656623

RESUMEN

BACKGROUND: Autoimmune diseases such as rheumatoid arthritis (RA) are the consequence of a persistent imbalance between pro- and anti-inflammatory immune mechanisms, leading to chronic inflammation. The objective of this study was to determine whether the high sensitive C-reactive protein (hs-CRP) and cytokines are elevated in RA patients and to investigate the relationship between these markers and disease activity in RA, measured by disease activity score 28 (DAS28). METHODS: We studied 110 RA patients according to American College of Rheumatology revised criteria for RA, and 55 controls matched by age and sex. Serum levels of hs-CRP and cytokines interleukin (IL)-6, IL-10 and tumour necrosis factor-α (TNF-α) were estimated and correlated with the DAS28. Serum hs-CRP was assayed immunoturbidimetrically and cytokines were analysed by commercially available ELISA kit. RESULTS: We found that RA patients had significantly higher levels of serum hs-CRP (p<0.001), IL-6 (p<0.001), TNF-α (p<0.001), and IL-10 (p<0.01) as compared to healthy controls. hs-CRP, IL-6 and TNF-α correlated positively (p<0.001) and IL-10 correlated negatively (p<0.01) with DAS28. CONCLUSIONS: These results demonstrate that RA patients have high levels of inflammatory markers, and these levels are correlated with the DAS28. These findings suggest a possible role of these markers in the pathogenesis of RA. Moreover, these biomarkers can be used as markers of disease activity in the diagnosis and treatment of RA.


Asunto(s)
Artritis Reumatoide/diagnóstico , Biomarcadores/metabolismo , Proteína C-Reactiva/metabolismo , Citocinas/sangre , Mediadores de Inflamación/metabolismo , Adulto , Artritis Reumatoide/inmunología , Progresión de la Enfermedad , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Masculino , Persona de Mediana Edad , Nefelometría y Turbidimetría , Índice de Severidad de la Enfermedad
20.
Nano Lett ; 14(3): 1184-9, 2014 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-24528205

RESUMEN

Quasicrystals are materials with long-range ordering but no periodicity. We report scanning tunneling microscopy (STM) observations of quasicrystalline molecular layers on 5-fold quasicrystal surfaces. The molecules adopt positions and orientations on the surface consistent with the quasicrystalline ordering of the substrate. Carbon-60 adsorbs atop sufficiently separated Fe atoms on icosahedral Al-Cu-Fe to form a unique quasicrystalline lattice, whereas further C60 molecules decorate remaining surface Fe atoms in a quasi-degenerate fashion. Pentacene (Pn) adsorbs at 10-fold symmetric points around surface-bisected rhombic triacontahedral clusters in icosahedral Ag-In-Yb. These systems constitute the first demonstrations of quasicrystalline molecular ordering on a template.

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