411 research outputs found
Twin-induced plasticity of an ECAP-processed TWIP steel
The TWIP steels show high strain hardening rates with high ductility which results in high ultimate tensile strength. This makes their processing by equal channel angular pressing very difficult. Up to now, this has only been achieved at warm temperatures (above 200 °C). In this paper, a FeMnCAl TWIP steel has been processed at room temperature and the resulted microstructure and mechanical properties were investigated. For comparison, the material has also been processed at 300 °C. The TWIP steel processed at room temperature shows a large increase in yield strength (from 590 in the annealed condition to 1295 MPa) and the ultimate tensile strength (1440 MPa) as a consequence of a sharp decrease in grain size and the presence within the grains of a high density of mechanical twins and subgrains. This dense microstructure results also in a loss of strain hardening and a reduction in ductility. The material processed at 300 °C is more able to accommodate deformation and has lower reduction in grain size although there is a significant presence of mechanical twins and subgrains produced by dislocation activity. This material reaches an ultimate tensile strength of 1400 MPa with better ductility than the room temperature material.Postprint (published version
Stress-strain response and microstructural evolution of a FeMnCAl TWIP steel during tension-compression tests
© 2016.
The stress-strain response of a Fe-17.5Mn-0.7C-2Al TWIP steel during cyclic loading has been investigated by means of tension-compression tests within the strain limits of ±2%, ±5% and ±10%. In addition, the microstructural evolution during the ±5% cyclic test has also been studied. The difference between the forward and reverse stress for each pre-strain has been analyzed at 0.2% offset strain and at the strains in which forward and reverse curves were parallel in order to study the Bauschinger effect (BE) and permanent softening, respectively. The evolution of the BE with pre-strain for this steel is similar to other FeMnC TWIP steels, that is, increasing values of BE are obtained as the pre-strain increases. However, its absolute values are half those reported in the literature on other FeMnC steels. This diminution of the BE is related to the lower activity of mechanical twinning in FeMnCAl TWIP steels at the pre-strains herein investigated, which promotes less polarized stresses in the matrix due to the lower dislocation storage capacity.Regarding permanent softening, the evolution is similar to that of the BE and the same analysis can be applied. During reverse compression, a slight increase of twin thickness and twin spacing with respect to the first tensile stage took place. This fact might be linked to the lower flow stress observed in the permanent softening period during reverse straining.Peer ReviewedPostprint (author's final draft
Equal channel angular pressing of a TWIP steel: microstructure and mechanical response
A Feâ20.1Mnâ1.23Siâ1.72Alâ0.5C TWIP steel with ultrafine grain structure was successfully processed through equal channel angular pressing (ECAP) at warm temperature up to four passes following the BC route. The microstructure evolution was characterized by electron backscattered diffraction to obtain the grain maps, which revealed an obvious reduction in grain size, as well as a decrease in the twin fraction, with increasing number of ECAP passes. The texture evolution during ECAP was analyzed by orientation distribution function. The results show that the annealed material presents brass (B) as dominant component. After ECAP, the one pass sample presents A1* and A2* as the strongest components, while the two passes and four passes samples change gradually toward B/BÂŻB/BÂŻ components. TEM analysis shows that all samples present twins. The twin thickness is reduced with increasing the number of ECAP passes. Nano-twins, as a result of secondary twinning, are also observed in the one and two passes samples. In the four passes sample, the microstructure is extensively refined by the joint action of ultrafine subgrains, grains and twins. The mechanical behavior was studied by tensile samples, and it was found that the yield strength and the ultimate tensile strength are significantly enhanced at increasing number of ECAP passes. Although the ductility and strain hardening capability are reduced with ECAP process, the present TWIP steel shows significant uniform deformation periods with positive work hardening rates.Postprint (author's final draft
Application of catalytic hydrodechlorination for the fast removal of chlorinated azole pesticides in drinking water
Catalytic hydrodechlorination (HDC) is regarded as a promising purifying technology for drinking water treatment. So far, it has proved to be highly effective for the removal of different groups of chlorinated micropollutants including pharmaceuticals, neonicotinoid pesticides, personal care products or chloroacetic acids. The
azole pesticides, recently included in the EU Watch Lists (Decisions 2020/1161 and 2022/1307), are a group of
micropollutants of particular concern for drinking water given their high toxicity, persistence, and bioaccumulation potential. In this work, the feasibility of HDC for the removal of a representative group of chlorinated azole pesticides tebuconazole (TEB), tetraconazole (TET), prochloraz (PCZ), penconazole (PEN),
metconazole (MET) and imazalil (IMZ)) is demonstrated, and their reactivity is compared with that observed for
other halogenated micropollutant groups. Notably, all the pesticides investigated in this work (100 ÎŒg Lâ 1
) were
completely dechlorinated within 30 min under ambient conditions using a 1 wt% Pd/Al2O3 catalyst concentration of 0.25 g Lâ 1 and a H2 feeding of 50 mL N minâ 1
. The experimental data were accurately described by a
pseudo-first order kinetic equation and rate constant values in the range from 1.08 to 2.60 L gcat
â 1 minâ 1 were
obtained. These values are quite close to those achieved for the most reactive neonicotinoid pesticides and
significantly higher than the obtained for chloroacetic acids and most pharmaceuticals (e.g. diclofenac, sertraline
or chlorpromazine). From the identification of the generated reaction intermediates and the final nonchlorinated products, sequential reaction pathways were proposed for each pollutant. Remarkably, despite the
high toxicity exhibited by the azole pesticides tested, with LC50 values within the 0.4â7.0 mg Lâ 1 range using
A. salina, HDC effluents were non-toxic in all cases. Furthermore, the catalyst showed a remarkable stability upon
three consecutive runs. Finally, the versatility of the process was demonstrated in the treatment of real aqueous
matrices such as DWTP and tap water, where no significant differences were found either in terms of activity or
stabilityThis research has been supported by the Spanish MINECO through
project PID2019-105079RB-I00 and by the CM through project P2018/
EMT-4341. J. Nieto-Sandoval and M. Munoz thanks the MINECO for the
FPI contract (BES-2017-081346) and the Ramon ÂŽ y Cajal postdoctoral
contract (RYC-2016-20648), respectively. R. B. del Olmo thanks the
Operational Program for Youth Employment and the Youth Employment
Initiative (YEI) of the CM for his contract as Research Assistant (PEJ2020-AI/AMB-19161
Surveillance of imported malaria in Spain: The useful tool of the Semi-Nested Multiplex PCR
The use of a new PCR-based method for the diagnosis of malaria in the Spanish Malaria Reference Laboratory has promoted an increase in confirmed cases of malaria. From August 1997 to July 1998, a total of 192 whole-blood samples and 71 serum samples from 168 patients were received from the hospitals of the Spanish National Health System. Most of the patients came from west-central African countries (85%). This molecular method showed more sensitivity and specificity than microscopy, detecting 12.4% more positive samples than microscopy and 13% of mixed infections undetectable by Giemsa stain. Plasmodium falciparum was the main species detected, with 68% of the total positive malaria cases, followed by Plasmodium malariae (29%), Plasmodium vivax (14%), and Plasmodium ovale (7%), including mixed infections in all cases. This report consists of the first wide, centralized survey of malaria surveillance in Spain. The reference laboratory conducted the analysis of all imported cases in order to detect trends in acquisition. The use of a seminested multiplex PCR permitted confirmation of the origins of the infections and the Plasmodium species involved and confirmation of the effectiveness of drug treatments. This PCR also allowed the detection of the presence in Spain of primaquine-tolerant P. vivax strains from west-central Africa, as well as the detection of a P. falciparum infection induced by transfusion.This work was supported by the Fondo de Investigaciones Sanitarias (FIS) (contract number 96/0216) and the Spanish Agency of International Cooperation (AECI). J. M. Rubio was granted a postdoctoral fellowship from the Comunidad AutĂłnoma de Madrid, Madrid, Spain. J. Alvar was supported by a B.A.E. from the FIS (contract number 99/5038) and by the Christâs College, University of Cambridge, Cambridge, United Kingdo
High Plasma sTNF-R1 Level Is Related to Loss of Natural HIV Control in Long-Term Elite Controllers
Human immunodeficiency virus-1 (HIV-1) elite controllers are heterogeneous due to different immunovirological features. We aimed to identify plasma biomarkers associated with loss of spontaneous HIV-1 control in long-term elite controllers (HIV-LTECs). We performed a retrospective study in 60 HIV-LTECs [36 true-LTECs and 24 LTECs losing control (LTECs-LC)]. We selected a plasma sample from true-LTECs (towards the middle of the follow-up period) and two samples from LTECs-LC (one far from the loss of control and another close to loss of control). Plasma biomarkers were evaluated using multiplex immunoassays. The partial least squares-discriminant analysis provided the variable importance in projection (VIP), and the adjusted Generalized Linear Model provided the adjusted arithmetic mean ratio (aAMR). At the moment of the first LTECs-LC samples, the only plasma biomarker with a VIPâ„1.5 was sTNF-R1, which showed higher values in LTECs-LC than true-LTECs [aAMR=1.62 (95%CI=1.20-2.19); p=0.001]. After a median of 3.9 (IQR=4.5) years of follow-up from the first sample, we also had access to a second plasma sample from 10 LTECs-LC patients. At the moment of this second LTECs-LC sample, the only plasma biomarker with VIPâ„1.5 was also sTNF-R1, which showed higher values in LTECs-LC than true-LTECs [aAMR=1.93 (95%CI=1.41-2.65); p<0.001]. The difference between the first and second samples of LTECs-LC was significant (Îx= 6.58 (95%=0.3; 12.88); p=0.040). In conclusion, high plasma values of sTNF-R1 appear to discriminate HIV-LTECs that lose the natural control of HIV-1, helping to define a specific phenotype that may be useful for the clinical management of these patients.The study was also funded by the Spanish AIDS Research Network (RD16/0025/0013, RD16/0025/0019, and RD16CIII/0002/0002) and Centro de InvestigacioÌn BiomeÌdica en Red (CIBER) en Enfermedades Infecciosas (CB21/13/00044). NR is a âMiguel Servetâ researcher from the ISCIII (grant number CPII19/00025). DS-C is a âSara Borrellâ researcher from the ISCIII (grant number CD20CIII/00001).S
Interaction with touchscreen smartphones in patientswith essential tremor and healthy individuals.
tremorAbstractIntroduction: Smartphone use in biomedical research is becoming more prevalent in differ-ent clinical settings. We performed a pilot study to obtain information on smartphone use bypatients with essential tremor (ET) and healthy controls, with a view to determining whetherperformance of touchscreen tasks is different between these groups and describing touchscreeninteraction factors.Method: A total of 31 patients with ET and 40 sex- and age-matched healthy controls com-pleted a descriptive questionnaire about the use of smartphones. Participants subsequentlyinteracted with an under-development Android application, and performed 4 tests evaluatingtypical touchscreen interaction gestures; each test was performed 5 times.Result: The type of smartphone use and touchscreen interaction were not significantly differ-ent between patients and controls. Age and frequency of smartphone use are key factors intouchscreen interaction.Conclusion: Our results support the use of smartphone touchscreens for research into ET,although further studies are required.pre-print1030 K
Eliminando la divisiĂłn cualitativo-cuantitativo en estudios sobre transferencia de conocimiento: el uso de QCA en la exploraciĂłn de las relaciones universidad-empresa
This article uses Qualitative Comparative Analysis (QCA) to study knowledge-transfer processes that are difficult to observe due to the absence of standardized data sources. It examines universityâindustry relationships and focuses on firmsâ chances of developing R&D projects and services within a local innovation system. The article makes methodological and substantive contributions. First, micro- and meso-level qualitative approaches move towards the tradition of quantitative studies on science through a process that illustrates the construction of quantifiable dimensions and their possibilities of analysis. Second, analysis reveals the conditioning factors that influence non-R&D-intensive small and medium-sized enterprises (SMEs) into using university knowledge. The conclusions highlight the possibilities of this methodologyâs cross-fertilization with other approaches in the empirical study of science and innovation.Este artĂculo utiliza el AnĂĄlisis Cualitativo Comparado (QCA) para estudiar procesos de transferencia de conocimiento difĂciles de observar debido a la ausencia de fuentes de datos estandarizados. Estudia las relaciones entre universidad y empresa focalizando en las posibilidades de las empresas de contratar proyectos y servicios de I+D en un sistema local de innovaciĂłn. El artĂculo realiza contribuciones de carĂĄcter metodolĂłgico y sustantivo. En primer lugar, las aproximaciones cualitativas de carĂĄcter micro y meso se acercan a la tradiciĂłn de los estudios cuantitativos sobre la ciencia a travĂ©s de un proceso que ilustra la construcciĂłn de dimensiones cuantificables y sus posibilidades de anĂĄlisis. En segundo lugar, el anĂĄlisis muestra los condicionantes que influyen en que las pequeñas y medianas empresas no intensivas en I+D utilicen conocimiento de la universidad. Las conclusiones resaltan las posibilidades de fertilizaciĂłn cruzada de esta metodologĂa con otros enfoques en el estudio empĂrico de la ciencia y la innovaciĂłn
National validation of the Nursing Intensive-Care Satisfaction Scale: research protocol
Aim: Validate the Nursing Intensive-Care Satisfaction Scale in ICUs throughout Spain. Identify the improvement strategies recommended by the patients and professionals. Design: Quantitative psychometric methodology and a cross-sectional descriptive correlational design.Methods: The study population will be all patients discharged from 19 participating ICUs in Spain. Consecutive sampling (n= 564). Once discharged from the ICUs, they will receive the questionnaire and then, after 48 hours it will be given to them again to analyse the temporal stability. To validate the questionnaire, the internal consistency (Cronbach's Alpha) and temporal stability (test-retest) will be analysed. Results: Improve the quality of nursing care by modifying, changing or strengthening behaviours, skills, attitudes or areas for improvement involved in the proces
HIV-reservoir size is not affected either by HCV coinfection or by direct acting antivirals (DAAs) therapy
The role of HCV on the HIV reservoir is controversial since the reduction on HIV-DNA levels after HCV eradication with IFNα/RBV treatment seems to be the result of drugs instead of HCV clearance. We assessed whether HCV eradication can decrease HIV-DNA content in HIV/HCV-coinfected patients treated with direct-acting antivirals, DAAs (IFNα/RBV-free regimens). Cell-associated HIV-DNA was measured by ddPCR in 25 HIV-monoinfected and 25 HIV/HCV-coinfected patients. There were no differences in HIV-DNA levels between groups neither at baseline nor at 12 weeks after DAAs treatment completion. Our results indicate that HCV does not appear to influence the HIV reservoir size and suggest the lack of an anti-HIV action for DAAs.This work was supported by projects PI14/00518, RD16/0025/0013 integrated into the State Plan for Scientific and Technical Research and Innovation from the General Sub-Directorate for research assessment and promotion, Spanish Carlos III Institute of Health (ISCIII) co-funded by the European Regional Development Fund (ERDF). Maria A Navarrete-Muñoz was funded by the Spanish Directorate General for Research and Technological of the âComunidad de Madridâ [grant: IND2018/BMD9651]. Norma RallĂłn is supported by the Miguel Servet program funded by the Spanish Health Institute Carlos III [grant: CPII19/00025].S
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