Static and dynamic stress heterogeneity in a multiscale model of the asthmatic airway wall

Airway hyperresponsiveness (AHR) is a key characteristic of asthma that remains poorly understood. Tidal breathing and deep inspiration ordinarily cause rapid relaxation of airway smooth muscle (ASM) (as demonstrated via application of length fluctuations to tissue strips) and are therefore implicated in modulation of AHR, but in some cases (such as application of transmural pressure oscillations to isolated intact airways) this mechanism fails. Here we use a multiscale biomechanical model for intact airways that incorporates strain stiffening due to collagen recruitment and dynamic force generation by ASM cells to show that the geometry of the airway, together with interplay between dynamic active and passive forces, gives rise to large stress and compliance heterogeneities across the airway wall that are absent in tissue strips. We show further that these stress heterogeneities result in auxotonic loading conditions that are currently not replicated in tissue-strip experiments; stresses in the strip are similar to hoop stress only at the outer airway wall and are under- or overestimates of stresses at the lumen. Taken together these results suggest that a previously underappreciated factor, stress heterogeneities within the airway wall and consequent ASM cellular response to this micromechanical environment, could contribute to AHR and should be explored further both theoretically and experimentally

Esophagogastric dissociation reduces the re-operation rate for persistent gastroesophageal reflux in severely neurologically impaired children

Purpose: In this study we want to demonstrate the effectiveness of the esophagogastric dissociation as a first level operation in treatment of the gastroesophageal reflux in severe neurologically impaired children, in term of a reduction of reoperation rate.Methods: We divided patients operated from 1998 to 2005 in a group A, composed by children treated with fundoplication, and in a group AR, composed by the patients of group A who had a recurrence of reflux and that was treated with esophagogastric dissociation. Patients operated from 2005 to 2013 were selected on the basis of the severity of the neurological impairment and were divided in a group B, treated with fundoplication, and in a group C of more severe impaired children, treated with esophagogastric dissociation. Data regarding the complications of the A and C groups were analyzed with Fisher’s test.Results: We evaluated 63 patients: 34 (54 %) in group A, 11 in group AR, 15 (23.6 %) in group B, 14 (22.4 %) in group C. The Fisher’s test showed a non significant difference with a p value of 0.2.Conclusion: Despite of statistic result we believe that TOGD is a useful procedure as the first choice of surgical management in severe neurological impaired children affected by gastroesophageal reflux

Empirical ground-motion prediction equations for Northwestern Turkey using the aftershocks of the 1999 Kocaeli earthquake

We present ground motion models for northwestern Turkey using the aftershocks of the Mw 7.4, 1999 Kocaeli earthquake. We consider 4047 velocity and acceleration records for each component of motion, from 528 earthquakes recorded by stations belonging to regional networks. The ground motion models obtained provide peak ground velocity, peak ground acceleration, and spectral accelerations for 8 different frequencies between 1 and 10 Hz. The analysis of the error distribution shows that the record-to-record component of variance is the largest contribution to the standard deviation of the calibrated ground- motion models. Furthermore, a clear dependence of inter-event error on stress drop is observed. The empirical ground-motion prediction equations, derived for both the larger horizontal and vertical components, are valid in the local magnitude range from 0.5 to 5.9, and for hypocentral distances up to 190 km. Citation: Bindi, D., S. Parolai, H. Grosser, C. Milkereit, and E. Durukal (2007), Empirical ground-motion prediction equations for northwestern Turkey using the aftershocks of the 1999 Kocaeli earthquake

Source parameters and seismic moment-magnitude scaling for Northwestern Turkey

Abstract The source parameters of 523 aftershocks (0.5 ML 5.9) of the 1999 Kocaeli earthquake are determined by performing a two-step spectral fitting procedure. The source spectrum, corrected for both site and propagation effects, is described in terms of a standard x-square model multiplied by an exponential term of frequency. The latter term is introduced to estimate the high-frequency (f 12 Hz) fall-off of the acceleration source spectra by computing the j parameter. The seismic moments obtained range between 1.05 1014 and 2.41 1017 N m, whereas the Brune stress drops are between 0.002 and 40 MPa. The j value varies between 0.00 and 0.08 sec, indicating a decay of the acceleration level at the higher frequency part of the spectrum greater than that assumed by the x 2 model. Both the stress drop and the j parameter show the tendency of increasing with aftershock magnitude. No evidence of self-similarity breakdown is observed between the source radius and M0. Finally, both the seismic moment and the moment magnitude are compared with the local magnitude to derive new moment–magnitude relationships for the area

Giant hydatid lung cyst in non-endemic area

Abstract Echinococcosis is a parasitic zoonosis in which humans are involved as an intermediate host. It is a very common pathology in the areas of Eastern Europe and Asia, where the main activity is represented by pastoralism and animal breeding. In humans, the most frequently affected sites are the liver (60–70%) and lungs (20–30%), manifesting themselves with symptoms such as abdominal pain, coughing, dyspnea, hemoptysis, up to cases of anaphylactic shock. In Italy it is not a common disease with an incidence of 2:100.000 inhabitants, and it's extremely rare in pediatric population. In this work we presented a case of a 11-years male patient came for a persistent cough, to whom was found a giant cystic mass in the thorax. Serological tests confirmed the diagnosis of echinococcosis. Patient underwent to thoracotomy to remove the cyst and he begun the antiparasitic therapy. Post-operative outcome was good and the patient is, until now, free of problems. Echinococcosis is a challenging problem for a pediatric surgeon, especially in non-endemic area, not only because it is not a common disease in pediatric population, but also for the surgical management that can presents some difficulties and complications in the post-operative course

Herlyn–Werner–Wunderlich syndrome: An “early” onset case report and review of Literature

AbstractHerlyn–Werner–Wunderlich syndrome (HWWS) is a rare congenital mullerian anomaly consisting of uterus didelphys, hemivaginal septum, and unilateral renal agenesis [1,2]. Most authors reported cases of Herlyn–Werner–Wunderlich syndrome with prepuberal or postpuberal onset with cyclical abdominal pain and a vaginal mass (3–8). Only six cases are reported in Literature with early onset of this syndrome under 5 years (9–14). Our case is about 3 years old girl, with all the features of this syndrome who came to our attention for lower abdominal mass. The aim of this article is to share our experience and focus the attention on the importance of high level of suspicion of HWWS in neonatal period to early diagnosis and treatment. The possible early presentation of this syndrome should be suspected in all neonates (females) with renal agenesia confirmed postnatally or with prenatal diagnosis. It is common, in fact, an error of evaluation with planning of removal of mass, that can damage patients in term of chance for a successful reproductive outcome. For all these reasons, our team consider HWWS as differential diagnosis in newborn with prenatal ultrasonography of a cystic mass behind the urinary bladder in the absence of a kidney and plan a pelvic ultrasound (with aim to identify an uterus, normal or dydhelfus, and presence or absence of pelvic mass), an examination under anesthesia and cystoscopy and vaginoscopy, if it is necessary. A high level of suspicion, indeed, is the key to early diagnosis

New compositional and structural data validate the status of jamborite

Jamborite was originally described with the formula (Ni2+,Ni3+,Fe)(OH)2(OH,S,H2O) from Ca' de' Ladri and Monteacuto Ragazza near Bologna, and Castelluccio di Moscheda near Modena, Italy. Re-examination of the mineral from the type localities and Rio Vesale, Sestola, Val Panaro (Emilia-Romagna, Italy), led to the discovery of a crystal suitable for study by single-crystal and powder X-ray diffraction, SEM-EDS, and Raman spectroscopy. Jamborite crystallizes in the space group REmbedded Imagem, with the unit-cell parameters a 3.068(4) Å, c 23.298(11) Å, and Z = 3. The structure refinement (R1 = 0.0818) showed that jamborite contains brucite-like sheets of edge-sharing octahedra (Ni2+,M3+)(O,OH)6 with a distinctive double layer of partially occupied H2O molecules between them. Raman data indicate that the sulfur is present as sulfate rather than sulfide. The new analytical data were recalculated on the basis of 1 (Ni+Ca+Co+Fe) to give the formula [(Ni2+0.902Ca2+0.002)(Co3+0.072Fe3+0.024)]Σ1.000(OH)1.884Cl0.012(H2O)0.004(SO4)0.100·0.900H2O. The sulfur occupancy was too low to be located in the refinement, but the ≈1:1 ratio of M3+:S from the chemical analysis implies that SO42− replaces OH− in the brucite sheet rather than sitting in the interlayer space. The splitting of the H2O layer allows avoidance of short SO42−···H2O distances. Thus, jamborite is not a member of the hydrotalcite supergroup. Jamborite is redefined as M2+1−xM3+x(OH)2−x(SO4)x·nH2O, where M2+ is dominantly Ni, M3+ is dominantly Co, x ≤ 1/3 and probably ≤ 1/7 (x = 0.10 for the neotype sample), and n < (1−x). The low M3+/M2+ ratio relative to honessite and hydrohonessite and high Co content may explain the rarity of jamborite as an early alteration product of millerite. The redefinition of jamborite and designation of the neotype specimen from Rio Vesale have been approved by the Commission on New Minerals, Nomenclature and Classification (CNMNC), voting proposal 14-E

ML scale in Northwestern Turkey from 1999 Izmit aftershocks: updates

We present an update of the local magnitude scale previously calibrated for Northwestern Turkey by Baumbach et al. (2003). The path coverage in the westernmost part of the analysed area has been increased, as well as the number of amplitudes for distance greater than 110 km. Furthermore, a set of recordings from accelerometric stations operated by the Kandilli Observatory and Earthquake Research Institute (KOERI) has been merged with the recordings by the Sapanca-Bolu and GermanTaskForce seismological networks. In all, 4047 recordings from 528 earthquakes recorded by 31 seismometers and 23 accelerometers are considered to calibrate the local magnitude scale over a hypocentral distance range from 10 to 190 km. By analyzing the unit covariance matrix and the resolution matrix, we show how the source-to-station geometries of the seismic and strong motion networks affect the uncertainties of the computed station corrections, attenuation coefficients, and magnitudes. The assumptions made concerning the reference station correction, and the change in the amplification for the Wood-Anderson torsion seismograph from 2800 to 2080 (Uhrhammer and Collins, 1990) introduced an offset of about 0.34 in the magnitudes with respect to Baumbach et al. (2003), with the updated local magnitude scale ranges from 0.50 to 5.91. The distribution of the residuals with distance confirms that the extension of both the magnitude and distance ranges and the improved path coverage have preserved the high quality that characterized the data set analyzed by Baumbach et al. (2003)

ML scale in Northwestern Turkey from 1999 Izmit aftershock: updates

Abstract We present an update of the local magnitude scale previously calibrated for northwestern Turkey by Baumbach et al. (2003). The path coverage in the westernmost part of the analyzed area has been increased, as well as the number of amplitudes for distance greater than 110 km. Furthermore, a set of recordings from accelerometric stations operated by the Kandilli Observatory and Earthquake Research Institute (KOERI) has been merged with the recordings by the Sapanca-Bolu and German Task Force seismological networks. In all, 4047 recordings from 528 earthquakes recorded by 31 seismometers and 23 accelerometers are considered to calibrate the local magnitude scale over a hypocentral distance range from 10 to 190 km. By analyzing the unit covariance matrix and the resolution matrix, we show how the source-to-station geometries of the seismic and strong-motion networks affect the uncertainties of the computed station corrections, attenuation coefficients, and magnitudes. The assumptions made concerning the reference station correction, and the change in the amplification for the Wood–Anderson torsion seismograph from 2800 to 2080 (Uhrhammer and Collins, 1990) introduced an offset of about 0.34 in the magnitudes with respect to Baumbach et al. (2003), with the updated local magnitude scale ranges from 0.50 to 5.91. The distribution of the residuals with distance confirms that the extension of both the magnitude and distance ranges and the improved path coverage have preserved the high quality that characterized the data set analyzed by Baumbach et al. (2003)

A novel computational model predicts key regulators of chemokine gradient formation in lymph nodes and site-specific roles for CCL19 and ACKR4

The chemokine receptor CCR7 drives leukocyte migration into and within lymph nodes (LNs). It is activated by chemokines CCL19 and CCL21, which are scavenged by the atypical chemokine receptor ACKR4. CCR7-dependent navigation is determined by the distribution of extracellular CCL19 and CCL21, which form concentration gradients at specific microanatomical locations. The mechanisms underpinning the establishment and regulation of these gradients are poorly understood. Here, we have incorporated multiple biochemical processes describing the CCL19/CCL21/CCR7/ACKR4 network into our model of LN fluid flow to establish a computational model to investigate intranodal chemokine gradients. Importantly, the model recapitulates CCL21 gradients observed experimentally in B cell follicles and interfollicular regions, building confidence in its ability to accurately predict intranodal chemokine distribution. Parameter variation analysis indicates that the directionality of these gradients is robust, but their magnitude is sensitive to these key parameters: chemokine production, diffusivity, matrix binding site availability, and CCR7 abundance. The model indicates that lymph flow shapes intranodal CCL21 gradients, and that CCL19 is functionally important at the boundary between B cell follicles and the T cell area. It also predicts that ACKR4 in LNs prevents CCL19/CCL21 accumulation in efferent lymph, but does not control intranodal gradients. Instead, it attributes the disrupted interfollicular CCL21 gradients observed in Ackr4-deficient LNs to ACKR4 loss upstream. Our novel approach has therefore generated new testable hypotheses and alternative interpretations of experimental data. Moreover, it acts as a framework to investigate gradients at other locations, including those that cannot be visualized experimentally or involve other chemokines