Desarrollo de un métode para identificación de guantes con policloruro de vinilo (pvc)

En un cuerpo hallado en una casa, en las cavidades de la oreja se encontraron ``motas'' plásticas provenientes de guantes de algodón moteados. Asimismo, se encontraron motas del mismo tipo en los alrededores del cuerpo. En la casa de un sospechoso, se encontraron guantes a los cuales les faltaban algunas motas. La pregunta es si podemos evaluar si los guantes hallados en la casa del sospechoso tienen un origen común con las motas encontradas en la escena del crimen. Se hizo un estudio comparativo de los diferentes tipos de PVC utilizados para hacer guantes moteados, utilizando diferentes guantes habituales en el mercado. Se evalúa la capacidad discriminatoria del análisis químico por la técnica de EDS (utilizando un SEM) y térmico con técnicas calorimétricas (DSC). Se analizan además las características morfológicas y cómo varían las texturas dependiendo del proceso de fabricación. Finalmente, se sugiere una secuencia de análisis para hacer la identificación del plástico, de manera de ir confirmando progresivamente la posibilidad de un origen común. La secuencia implica realizar estudios progresivamente más complejos. La utilidad de este esquema es poder detenerse a tiempo en el caso de que la incompatibilidad de las fuentes esté demostrada. Esto permite reducir costos y evitar la redundancia.In the ears of a corpse found in a house, were found PVC dots of the kind present in a common type of cotton gardening gloves. These dots were also found in the area surrounding the corpse. On the other hand, cotton gardening gloves whith some PVC dots missing were found at the house of a suspect. The question raised was whether it could be ascertained if the gloves found at the suspect's house had a common origin with the PVC dots found at the crime scene. A comparative study was made of different kinds of PVC used for manufacturing cotton gardening gloves, using different gloves available on the market. The discrimination capacity of the techniques used for chemical and thermal analysis, using EDS (with a SEM) and DSC, was analyzed. The morphological and texture characteristics depending on the fabrication process were also analyzed. An sequence of analyses is suggested for indentifying the plastics, in a way such that the common origin is progressively confirmed. The sequence implies the realization of studies of increasing complexity. The usefulness of this scheme is the feature it offers of stopping the tests in cases when the incompatibility of the samples has already been demonstrated. This reduces both costs and time spent on the analyses, avoiding redundant studies

Revealing hidden information in osteoblast’s mechanotransduction through analysis of time patterns of critical events

Background Mechanotransduction in bone cells plays a pivotal role in osteoblast differentiation and bone remodelling. Mechanotransduction provides the link between modulation of the extracellular matrix by mechanical load and intracellular activity. By controlling the balance between the intracellular and extracellular domains, mechanotransduction determines the optimum functionality of skeletal dynamics. Failure of this relationship was suggested to contribute to bone-related diseases such as osteoporosis. Results A hybrid mechanical and agent-based model (Mech-ABM), simulating mechanotransduction in a single osteoblast under external mechanical perturbations, was utilised to simulate and examine modulation of the activation dynamics of molecules within mechanotransduction on the cellular response to mechanical stimulation. The number of molecules and their fluctuations have been analysed in terms of recurrences of critical events. A numerical approach has been developed to invert subordination processes and to extract the direction processes from the molecular signals in order to derive the distribution of recurring events. These predict that there are large fluctuations enclosing information hidden in the noise which is beyond the dynamic variations of molecular baselines. Moreover, studying the system under different mechanical load regimes and altered dynamics of feedback loops, illustrate that the waiting time distributions of each molecule are a signature of the system’s state. Conclusions The behaviours of the molecular waiting times change with the changing of mechanical load regimes and altered dynamics of feedback loops, presenting the same variation of patterns for similar interacting molecules and identifying specific alterations for key molecules in mechanotransduction. This methodology could be used to provide a new tool to identify potent molecular candidates to modulate mechanotransduction, hence accelerate drug discovery towards therapeutic targets for bone mass upregulation

Analysis of mechanotransduction dynamics during combined mechanical stimulation and modulation of the extracellular-regulated kinase cascade uncovers hidden information within the signalling noise

Osteoporosis is a bone disease characterized by brittle bone and increased fracture incidence. With ageing societies worldwide, the disease presents a high burden on health systems. Furthermore, there are limited treatments for osteoporosis with just two anabolic pharmacological agents approved by the US Food and Drug Administration. Healthy bones are believed to be maintained via an intricate relationship between dual biochemical and mechanical (bio-mechanical) stimulations. It is widely considered that osteoporosis emerges as a result of disturbances to said relationship. The mechanotransduction process is key to this balance, and disruption of its dynamics in bone cells plays a role in osteoporosis development. Nonetheless, the exact details and mechanisms that drive and secure the health of bones are still elusive at the cellular and molecular scales. This study examined the dual modulation of mechanical stimulation and mechanotransduction activation dynamics in an osteoblast (OB). The aim was to find patterns of mechanotransduction dynamics demonstrating a significant change that can be mapped to alterations in the OB responses, specifically at the level of gene expression and osteogenic markers such as alkaline phosphatase. This was achieved using a three-dimensional hybrid multiscale computational model simulating mechanotransduction in the OB and its interaction with the extracellular matrix, combined with a numerical analytical technique. The model and the analysis method predict that within the noise of mechanotransduction, owing to modulation of the bio-mechanical stimulus and consequent gene expression, there are unique events that provide signatures for a shift in the system's dynamics. Furthermore, the study uncovered molecular interactions that can be potential drug targets

Small intestine contrast ultrasonography vs computed tomography enteroclysis for assessing ileal Crohn's disease

Aim: To compare computed tomography enteroclysis (CTE) vs small intestine contrast ultrasonography (SICUS) for assessing small bowel lesions in Crohn's disease (CD), when using surgical pathology as gold standard. Methods: From January 2007 to July 2008, 15 eligible patients undergoing elective resection of the distal ileum and coecum (or right colon) were prospectively enrolled. All patients were under follow-up. The study population included 6 males and 9 females, with a median age of 44 years (range: 18-80 years). Inclusion criteria: (1) certain diagnosis of small bowel requiring elective ileo-colonic resection; (2) age between 18-80 years; (3) elective surgery in our Surgical Unit; and (4) written informed consent. SICUS and CTE were performed ≤ 3 mo before surgery, followed by surgical pathology. The following small bowel lesions were blindly reported by one sonologist, radiologist, surgeon and histolopathologist: disease site, extent, strictures, abscesses, fistulae, small bowel dilation. Comparison between findings at SICUS, CTE, surgical specimens and histological examination was made by assessing the specificity, sensitivity and accuracy of each technique, when using surgical findings as gold standard. Results: Among the 15 patients enrolled, CTE was not feasible in 2 patients, due to urgent surgery in one patients and to low compliance in the second patient, refusing to perform CTE due to the discomfort related to the naso-jejunal tube. The analysis for comparing CTE vs SICUS findings was therefore performed in 13 out of the 15 CD patients enrolled. Differently from CTE, SICUS was feasible in all the 15 patients enrolled. No complications were observed when using SICUS or CTE. Surgical pathology findings in the tested population included: small bowel stricture in 13 patients, small bowel dilation above ileal stricture in 10 patients, abdominal abscesses in 2 patients, enteric fistulae in 5 patients, lymphnodes enlargement (> 1 cm) in 7 patients and mesenteric enlargement in 9 patients. In order to compare findings by using SICUS, CTE, histology and surgery, characteristics of the small bowel lesions observed in CD each patient were blindly reported in the same form by one gastroenterologistsonologist, radiologist, surgeon and anatomopathologist. At surgery, lesions related to CD were detected in the distal ileum in all 13 patients, also visualized by both SICUS and CTE in all 13 patients. Ileal lesions > 10 cm length were detected at surgery in all the 13 CD patients, confirmed by SICUS and CTE in the same 12 out of the 13 patients. When using surgical findings as a gold standard, SICUS and CTE showed the exactly same sensitivity, specificity and accuracy for detecting the presence of small bowel fistulae (accuracy 77% for both) and abscesses (accuracy 85% for both). In the tested CD population, SICUS and CTE were also quite comparable in terms of accuracy for detecting the presence of small bowel strictures (92% vs 100%), small bowel fistulae (77% for both) and small bowel dilation (85% vs 82%). CONCLUSION: In our study population, CTE and the non-invasive and radiation-free SICUS showed a comparable high accuracy for assessing small bowel lesions in CD

Wireless capsule endoscopy and proximal small bowel lesions in Crohn's disease

AIM: To investigate the prevalence of proximal small bowel (SB) lesions detected by wireless capsule endoscopy (WCE) in Crohn's disease (CD). METHODS: WCE was performed in 64 patients: 32 with CD of the distal ileum, and 32 controls with iron-deficiency anemia (IDA) or diarrhea. WCE was performed using the Given SB-WCE, followed by small intestine contrast ultrasonography (SICUS). Findings compatible with CD by using WCE included erosions, aphthoid or deep ulcers, and strictures/stenosis. RESULTS: WCE detected proximal SB lesions in 16/32 (50%) patients (14 aphthoid ulcers, 2 deep ulcers, one stricture), which appeared not to be related to clinical parameters [epigastric pain, age, smoking, non-steroidal anti-inflammatory drugs (NSAIDs), IDA]. Among patients with proximal SB lesions, 6 (37%) were smokers, 3 (19%) NSAID users, 3 (19%) had epigastric pain and 4 (25%) had IDA. SICUS detected proximal SB lesions in 3/32 patients (19%) also showing lesions with WCE. No correlations were observed between proximal SB lesions assessed by WCE or by SICUS (χ2 = 1.5, P = 0.2). CONCLUSION: The use of WCE allows the detection of previously unknown upper SB lesions in a high proportion of patients with a previous diagnosis of CD involving the distal ileum. © 2010 Baishideng

Colonic phenotype of the ileum in Crohn's disease: A prospective study before and after ileocolonic resection

Background: Colonic metaplasia has been described in pouchitis. In a prospective study, we investigated whether colonic phenotype may develop in Crohn's disease (CD) ileum. The expression of sulfomucins (colonic mucin), sialomucins, and CD10 (small intestine mucin and phenotype) was evaluated before and after ileocolonic resection for CD. Methods: From February 2007 to March 2010, 22 patients with CD undergoing surgery were enrolled. Clinical (Crohn's Disease Activity Index >150) and endoscopic recurrence (Rutgeerts score ≥1) rates were assessed at 6 and 12 months. Ileal samples were taken at surgery (T0), at 6 (T1), and 12 months (T2) for histology, histochemistry (High Iron Diamine-Alcian Blue), and immunohistochemistry (anti-CD10). Results: In 22 patients, recurrence was assessed at 6 and 12 months (clinical recurrence 9% and 18%; endoscopic recurrence 73% and 77%). In all 22 patients, ileal samples were taken at 6 and 12 months (involved area in patients with recurrence). In 19 of 22 (86.3%) patients, the involved ileum was also studied at surgery. At T0, T1, and T2, the expression of sialomucins and CD10 (small intestine mucin and phenotype) was comparable and higher (P < 0.0001) than the expression of sulfomucins (colonic mucin) (mean [range], T0:82 [35-100] versus 75 [0-100] versus 16 [0-50]; T1:96 [60-100] versus 94.7 [50-100] versus 3.89 [0-40]; T2:93.3 [60-100] versus 88.1 [25-100] versus 6.6 [0-40]). The expression of small-intestine mucin and phenotype was higher at T1 (P = 0.025) versus T0 (P = 0.026). Differently, the expression of colonic mucin was lower at T1 versus T0 (P = 0.027). Conclusions: In CD, the ileum involved by severe/established lesions develops a "metaplastic" colonic mucosa phenotype. Differently, CD ileum with no lesions or with early recurrence maintains the "native" small intestine type mucin secretion and phenotype

ELECTRONIC-STRUCTURE OF AMORPHOUS SI-N COMPOUNDS

We have measured valence-band photoemission spectra and dark conductivity of a-SiN(x):H compounds for compositions between x = 0 and x = 1.35. The photoemission spectra have been measured with Zr Mzeta and Al Kalpha radiation of 151.4 and 1486.6 eV, respectively. At hnu = 151.4 eV the spectra resemble directly the total density-of-states (DOS) of the system; the most important change with x is the shift of spectral weight from near the valence-band maximum (VBM) toward the center of the band, indicating the change from a band of Si-Si bonding states to a band of Si-N bonding states. At hnu = 1486.6 eV the spectra are dominated by the contribution of the Si-3s partial DOS; this contribution is located at the bottom of the band and shifts toward higher binding energies with increasing x. We compare our results at x = 0.36 and x = 1.35 with those of two recent calculations. Combining results of the dark-conductivity measurements and the photoemission spectra with a previous determination of the optical gaps we make a plot of the VBM, Fermi-level position, and conduction-band minimum (CBM) versus x. It is shown that the sudden opening of the gap at x approximately 1 is due mainly to the recession of the CBM.4919134461345

Outcomes of COVID-19 in 79 patients with IBD in Italy : an IG-IBD study

COVID-19 has rapidly become a major health emergency worldwide. Patients with IBD are at increased risk of infection, especially when they have active disease and are taking immunosuppressive therapy. The characteristics and outcomes of COVID-19 in patients with IBD remain unclear. Design: This Italian prospective observational cohort study enrolled consecutive patients with an established IBD diagnosis and confirmed COVID-19. Data regarding age, sex, IBD (type, treatments and clinical activity), other comorbidities (Charlson Comorbidity Index (CCI)), signs and symptoms of COVID-19 and therapies were compared with COVID-19 outcomes (pneumonia, hospitalisation, respiratory therapy and death). Results: Between 11 and 29 March 2020, 79 patients with IBD with COVID-19 were enrolled at 24 IBD referral units. Thirty-six patients had COVID-19-related pneumonia (46%), 22 (28%) were hospitalised, 7 (9%) required non-mechanical ventilation, 9 (11%) required continuous positive airway pressure therapy, 2 (3%) had endotracheal intubation and 6 (8%) died. Four patients (6%) were diagnosed with COVID-19 while they were being hospitalised for a severe flare of IBD. Age over 65 years (p=0.03), UC diagnosis (p=0.03), IBD activity (p=0.003) and a CCI score >1 (p=0.04) were significantly associated with COVID-19 pneumonia, whereas concomitant IBD treatments were not. Age over 65 years (p=0.002), active IBD (p=0.02) and higher CCI score were significantly associated with COVID-19-related death. Conclusions: Active IBD, old age and comorbidities were associated with a negative COVID-19 outcome, whereas IBD treatments were not. Preventing acute IBD flares may avoid fatal COVID-19 in patients with IBD. Further research is needed

Modelling collective cell behaviour

The classical mean-field approach to modelling biological systems makes a number of simplifying assumptions which typically lead to coupled systems of reaction-diffusion partial differential equations. While these models have been very useful in allowing us to gain important insights into the behaviour of many biological systems, recent experimental advances in our ability to track and quantify cell behaviour now allow us to build more realistic models which relax some of the assumptions previously made. This brief review aims to illustrate the type of models obtained using this approach