689 research outputs found
A new system to measure leather shrinkage temperature
Content:
A characteristic of leather is that if it is gradually heated in aqueous solution it reaches a temperature where sudden and irreversible shrinkage occurs. This phenomenon is related to the denaturalization of the collagen protein that conforms the hide and is known as leather shrinkage. Specifically, the internal bonds break thus causing a shortening of the skin that can be up to a 35% from its original length.
Accordingly, one of the most used methods to check the quality of the leather tanning process is the determination of the contraction temperature according to the ISO 3380:2015 standard. This method measures the leather shrinkage when constantly increasing the sample temperature. The shrinkage temperature corresponds to the temperature when the sample suddenly contracts. The value of this temperature indicates the degree of collagen stability and therefore, when higher, the leather will have better quality and resistance.
The process of leather shrinkage can be divided in different stages. Several authors discriminate temperature A1 (when the first fibre starts to shrinkage), temperature C (when there is a massive shrinkage) and finally temperature A2 (when the last fibres are contracted individually).
The method that describes the ISO 3380:2015 standard uses a device where the determination of the shrinkage temperature is performed visually by the laboratory technician. Consequently, the method tends to be imprecise and subjective. It should also be noticed that the device proposed by the standard does not allow differentiation between the different stages of the contraction process.
There are other methods to determine leather shrinkage temperature including differential scanning calorimetry, microscopic hot table, thermogravimetric analysis, differential thermal analysis and thermomechanical analysis. All these methods involve complex devices and are only suitable for specialized personnel.
In this work, a new device is developed to precisely measure the leather shrinkage temperature and to distinguish the different contraction stages. In addition, the proposed device is simple, easy to use and inexpensive, which facilitates its use in any industry. The developed system consists basically of a load cell to measure the strength produced by the shrinkage of the leather. With the logged data during the test a strength versus temperature graph is built. By means of its interpretation, the different stages of shrinkage can be determined. Different mathematical analysis of the logged data is proposed to determine the shrinkage stages temperatures, thus achieving a high degree of certainty and repeatability.
Take-Away:
A new device, simple and inexpensive, is developed to precisely measure the leather shrinkage temperature and to distinguish the different contraction stages
Bound states of dark solitons and vortices in trapped multidimensional Bose-Einstein condensates
We report on the existence and stability of multidimensional bound solitonic states in harmonically trapped scalar Bose-Einstein condensates. Their equilibrium separation, as a measure of the strength of the soliton- soliton or the solitonic vortex-vortex interaction, is provided for varying chemical potential μ. Static bound dark solitons are shown to be dynamically stable in elongated condensates within a range of intermediate (repulsive) interparticle-interaction strength. Beyond this range the snaking instability manifests during the time evolution of the planar solitons and produces the decay into nonstationary vortex states. A subsequent dynamical recurrence of solitons and vortices can be observed at low μ. At equilibrium, the bifurcations of bound dark solitons are bound solitonic vortices. Among them, both two-open and two-ring vortex lines are demonstrated to exist with both counter- and co-rotating steady velocity fields. The latter flow configurations evolve, for high chemical potential, into a stationary three-dimensional (3D)-chain-shaped vortex and a three vortex-antivortex-vortex ring sequence that arrest the otherwise increasing angular or linear momentum respectively. As a feature common to the bifurcated families of vortex states, their excitation spectra present unstable modes with associated oscillatory dynamics. In spite of this, the family of two-open counter-rotating vortices support dynamically stable 3D states
All night analysis of time interval between snores in subjects with sleep apnea hypopnea syndrome
Sleep apnea–hypopnea syndrome (SAHS) is a serious sleep disorder, and snoring is one of its earliest and most consistent symptoms. We propose a new methodology for identifying two distinct types of snores: the so-called non-regular and regular snores. Respiratory sound signals from 34 subjects with different ranges of Apnea-Hypopnea Index (AHI = 3.7–109.9 h−1) were acquired. A total number of 74,439 snores were examined. The time interval between regular snores in short segments of the all night recordings was analyzed. Severe SAHS subjects show a shorter time interval between regular snores (p = 0.0036, AHI cp: 30 h−1) and less dispersion on the time interval features during all sleep. Conversely, lower intra-segment variability (p = 0.006, AHI cp: 30 h−1) is seen for less severe SAHS subjects. Features derived from the analysis of time interval between regular snores achieved classification accuracies of 88.2 % (with 90 % sensitivity, 75 % specificity) and 94.1 % (with 94.4 % sensitivity, 93.8 % specificity) for AHI cut-points of severity of 5 and 30 h−1, respectively. The features proved to be reliable predictors of the subjects’ SAHS severity. Our proposed method, the analysis of time interval between snores, provides promising results and puts forward a valuable aid for the early screening of subjects suspected of having SAHS
Land degradation and mitigation policies in the mediterranean region. A brief commentary
Land degradation is more evident where conditions of environmental vulnerability already exist because of arid climate and unsustainable forms of land exploitation. Consequently, semi-arid and dry areas have been identified as vulnerable land, requiring attention from both science and policy perspectives. In some regions, such as the Mediterranean region, land degradation is particularly intense, although there are no extreme ecological conditions. In these contexts, a wide range of formal and informal responses is necessary to face particularly complex and spatially differentiated territorial processes. However, the fit of responses has been demonstrated to be different over time and space according to the underlying socioeconomic context and the specific ecological conditions. The present commentary discusses this sort of \u201centropy\u201d in the policy response to land degradation in Southern Europe, outlining the intrinsic complexity of human\u2013nature dynamics at the base of such processes. Reflecting the need of differentiated regional strategies and more specific national measures to combat desertification, three policy frameworks (agro-environmental, economic, social) with an indirect impact on fighting land degradation have been considered, delineating the importance of policy assemblages. Finally, the importance of policy impact assessment methodologies was highlighted, focusing on the possible responses reinforcing a continental strategy against land degradation. By evidencing the role of participatory planning, developmental policies indirectly addressing land degradation reveal to be an important vector of more specific measures abating desertification risk, creating, in turn, a favorable context for direct interventions of mitigation or adaptation to climate change
Genetic Evidence Supports the Multiethnic Character of Teopancazco, a Neighborhood Center of Teotihuacan, Mexico (AD 200-600)
Multiethnicity in Teopancazco, Teotihuacan, is supported by foreign individuals found in the neighborhood center as well as by the diversity observed in funerary rituals at the site. Studies of both stable and strontium isotopes as well as paleodietary analysis, suggest that the population of Teopancazco was composed by three population groups: people from Teotihuacan, people from nearby sites (Tlaxcala-Hidalgo-Puebla), and people from afar, including the coastal plains. In an attempt to understand the genetic dynamics in Teopancazco we conducted an ancient DNA (aDNA) analysis based on mtDNA. Our results show that the level of genetic diversity is consistent with the multiethnicity phenomenon at the neighborhood center. Levels of genetic diversity at different time periods of Teopancazco's history show that multiethnicity was evident since the beginning and lasted until the collapse of the neighborhood center. However, a PCA and a Neighbor-Joining tree suggested the presence of a genetically differentiated group (buried at the Transitional phase) compared to the population from the initial phase (Tlamimilolpa) as well as the population from the final phase (Xolalpan) of the history of Teopancazco. Genetic studies showed no differences in genetic diversity between males and females in the adult population of Teopancazco, this data along with ample archaeological evidence, suggest a neolocal post-marital pattern of residence in Teopancazco. Nevertheless, genetic analyses on the infant population showed that the males are significantly more heterogeneous than the females suggesting a possible differential role in cultural practices by sex in the infant sector. Regarding interpopulation analysis, we found similar indices of genetic diversity between Teopancazco and heterogeneous native groups, which support the multiethnic character of Teopancazco. Finally, our data showed a close genetic relationship between Teopancazco and populations from the "Teotihuacan corridor" and from Oaxaca and the Maya region, in agreement with previous archaeological evidence
Human infection by Angiostrongylus costaricensis in Venezuela: first report of a confirmed case
(-)-Epigallocatechin-3-gallate and hydroxytyrosol improved antioxidative and anti-inflammatory responses in bovine mammary epithelial cells
(-)-Epigallocatechin-3-gallate and hydroxytyrosol improved antioxidative and anti-inflammatory responses in bovine mammary epithelial cells
L. Basiricò1, P. Morera1, D. Dipasquale1, R. Bernini1, L. Santi1, A. Romani2, N. Lacetera1 and U. Bernabucci1†
1Dipartimento di Scienze Agrarie e Forestali (DAFNE), Università degli Studi della Tuscia, via San Camillo de Lellis, 01100, Viterbo, Italy; 2Dipartimento di Statistica, Informatica, Applicazioni (DiSiA) “Giuseppe Parenti”, Università degli Studi di Firenze, via Morgagni 59, 50134, Firenze, Italy
(-)-Epigallocatechin-3-gallate (EGCG), the major phenolic compound of green tea, and hydroxytyrosol (HTyr), a phenol found in
olive oil, have received attention due to their wide-ranging health benefits. To date, there are no studies that report their effect
in bovine mammary gland. Therefore, the aim of this study was to evaluate the anti-oxidative and anti-inflammatory effects of
EGCG and HTyr in bovine mammary epithelial cell line (BME-UV1) and to compare their antioxidant and anti-inflammatory in
vitro efficacy. Sample of EGCG was obtained from a commercially available green tea extract while pure HTyr was synthetized in
our laboratories. The mammary oxidative stress and inflammatory responses were assessed by measuring the oxidative stress
biomarkers and the gene expression of inflammatory cytokines. To evaluate the cellular antioxidant response, glutathione (GSH/
GSSH), γ-glutamylcysteine ligase activity, reactive oxygen species and malondialdehyde (MDA) production were measured after
48-h incubation of 50 μM EGCG or 50 μM of HTyr. Reactive oxygen species production after 3 h of hydrogen peroxide (50 μM
H2O2) or lipopolysaccharide (20 μM LPS) exposure was quantified to evaluate and to compare the potential protection of EGCG
and HTyr against H2O2-induced oxidative stress and LPS-induced inflammation. The anti-inflammatory activity of EGCG and HTyr
was investigated by the evaluation of pro and anti-inflammatory interleukins (tumor necrosis factor (TNF)-α, interleukin (IL)-1β,
IL-6 and IL-10) messenger RNA abundance after treatment of cells for 3 h with 20 μM of LPS. Data were analyzed by one-way
ANOVA. (-)-Epigallocatechin-3-gallate or HTyr treatments induced higher concentrations of intracellular GSH compared to control
cells, matched by an increase of γ-glutamylcysteine ligase activity mainly in cells treated with HTyr. Interestingly, EGCG and HTyr
prevented oxidative lipid damage in the BME-UV1 cells by a reduction of intracellular MDA levels. (-)-Epigallocatechin-3-gallate
and HTyr were able to enhance cell resistance against H2O2-induced oxidative stress. It was found that EGCG and HTyr elicited a
reduction of the three inflammatory cytokines TNF-α, IL-1β, IL-6 and an increase of the anti-inflammatory cytokine IL-10.
Hydroxytyrosol has proved to be a strong antioxidant compound, and EGCG has shown mainly an anti-inflammatory profile.
These results indicated that EGCG and HTyr may provide dual protection because they were able to attenuate oxidative stress
and inflammatory responses, suggesting that these phenolic compounds are potential natural alternatives to be used in dairy
cattle as feed supplement for reducing the development of oxidative and inflammatory processes related to parturition or as
topical treatments for the control of bovine intramammary inflammation.
Animal (2019), 13:12, pp 2847–2856Ministry for education, University and Research of Italy (MIUR) for financial support (Law 232/216, Departments of Excellence)
Mitochondrial DNA control region typing from highly degraded skeletal remains by single-multiplex next-generation sequencing
Altres ajuts: acords transformatius de la UABPoor nuclear DNA preservation from highly degraded skeletal remains is the most limiting factor for the genetic identification of individuals. Mitochondrial DNA (mtDNA) typing, and especially of the control region (CR), using next-generation sequencing (NGS), enables retrieval of valuable genetic information in forensic contexts where highly degraded human skeletal remains are the only source of genetic material. Currently, NGS commercial kits can type all mtDNA-CR in fewer steps than the conventional Sanger technique. The PowerSeq CRM Nested System kit (Promega Corporation) employs a nested multiplex-polymerase chain reaction (PCR) strategy to amplify and index all mtDNA-CR in a single reaction. Our study analyzes the success of mtDNA-CR typing of highly degraded human skeletons using the PowerSeq CRM Nested System kit. We used samples from 41 individuals from different time periods to test three protocols (M1, M2, and M3) based on modifications of PCR conditions. To analyze the detected variants, two bioinformatic procedures were compared: an in-house pipeline and the GeneMarker HTS software. The results showed that many samples were not analyzed when the standard protocol (M1) was used. In contrast, the M3 protocol, which includes 35 PCR cycles and longer denaturation and extension steps, successfully recovered the mtDNA-CR from highly degraded skeletal samples. Mixed base profiles and the percentage of damaged reads were both indicators of possible contamination and can provide better results if used together. Furthermore, our freely available in-house pipeline can provide variants concordant with the forensic software
Soil degradation and socioeconomic systems’ complexity: Uncovering the latent nexus
Understanding Soil Degradation Processes (SDPs) is a fundamental issue for humankind. Soil degradation involves complex processes that are influenced by a multifaceted ensemble of socioeconomic and ecological factors at vastly different spatial scales. Desertification risk (the ultimate outcome of soil degradation, seen as an irreversible process of natural resource destruction) and socioeconomic trends have been recently analyzed assuming “resilience thinking” as an appropriate interpretative paradigm. In a purely socioeconomic dimension, resilience is defined as the ability of a local system to react to external signals and to promote future development. This ability is intrinsically bonded with the socio-ecological dynamics characteristic of environmentally homogeneous districts. However, an evaluation of the relationship between SDPs and socioeconomic resilience in local systems is missing in mainstream literature. Our commentary formulates an exploratory framework for the assessment of soil degradation, intended as a dynamic process of natural resource depletion, and the level of socioeconomic resilience in local systems. Such a framework is intended to provide a suitable background to sustainability science and regional policies at the base of truly resilient local systems
Adaptation of the person centered therapeutic relationship patient version (PCTR‐PT) to a version for physiotherapists (PCTR‐PHYS) and evaluation of its psychometric properties
[EN] Background and Purpose
The therapeutic relationship is a central component for developing person-centered care within physiotherapy services. However, it is necessary to understand how this relationship is perceived by both parties involved. The Person Centered Therapeutic Relationship-Patient scale (PCTR-PT) was constructed to identify patients' perceptions. No instruments are currently available to correlate patients' and physiotherapists' perceptions of the therapeutic relationship. This study sought to adapt the PCTR-PT to develop a version for physiotherapists, the Person Centered Therapeutic Relationship Scale for Physiotherapists (PCTR-PHYS) and to determine its psychometric properties.
Methods
A three-stage study was performed: (1) item generation, (2) pretesting of the questionnaire, (3) analysis of psychometric properties. Factor validity and psychometric properties were analyzed by confirmatory factor analysis (CFA). Convergent validity was calculated. Internal consistency was verified using the Cronbach's alpha coefficient. The intraclass correlation coefficient (ICC) was used to examine temporal stability.
Results
Thirty-three physiotherapists participated in two rounds of cognitive interviews and 343 participated in the analysis of psychometric properties. The CFA confirmed the four-structure model. Reliability of the tool was confirmed by Cronbach's alpha (α = 0.863) for all four dimensions, as all were above 0.70, ranging from 0.704 (relational bond) and 0.898 (therapeutic communication). Test-retest was performed with 2-week intervals, indicating an appropriate stability for the scale (ICC = 0.908).
Discussion
The Person Centered Therapeutic Relationship Scale for Physiotherapists is a useful, valid and applicable instrument to evaluate the person-centered therapeutic relationship during physiotherapy interventions. It will enable the comparison of patients' and physiotherapists' perceptions. To provide person-centered care in physiotherapy services, there is a clear need to incorporate specific resources into clinical practice to evaluate the quality of the therapeutic relationship from the perspective of both the persons being treated and the professionals providing care.SIPublicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL
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