High Extension Rates Research Articles

Differentiated thyroid carcinoma in children: A retrospective analysis of 125 pediatric cases from a single institution in India.

Thyroid carcinoma (TC) is extremely rare in children. We assessed the clinicopathological features, outcomes, recurrence pattern, and associated risk factors of differentiated thyroid carcinoma (DTC). Children aged ≤14years, pathologically diagnosed as DTC at a tertiary cancer institute between January 1998 and December 2015 were retrospectively analyzed. Survival outcomes were estimated using the Kaplan-Meier method. During 18years, 125 children with DTC were treated with a male:female ratio of 1:2.3. The median age was 12years (2-14years). Anterior neck swelling was the commonest presentation (72.8%). Histopathology revealed papillary thyroid carcinoma (PTC) in 123 children (98.4%). Extrathyroidal extension was seen in 32 children (25.6%). Sixty-eight children (54.4%) had nodal metastases and seven had distant metastasis. Relapse developed in 12 children. All were salvaged with subsequent surgery and radioiodine therapy. Eight children had persistent disease and one had a second malignant neoplasm. The median follow-up period was 9years 1month (1-20years). Five-year recurrence-free survival (RFS) was 94.8% and 5-year overall survival was 100%. Larger tumors (p-value=.001), extrathyroidal extension (p-value=.001), and nodal metastasis (p-value=.022) were significant predictors for RFS in univariate analysis. Pediatric DTC showed aggressive behavior characterized by a high rate of extrathyroidal extension and nodal and pulmonary metastasis. Persistent disease should be distinguished from recurrent disease as DTCs with metastatic disease remain stable for long time and usually respond well to radioiodine therapy. Our study reaffirmed favorable prognosis despite aggressive presentation and even after relapse.

Büyük Menderes Granbeni'nin Rolling Hinge (Yuvarlanan Reze) Modelinde Supra-Detachment (Sıyrılma Üstü) Havzadan Rift Havzasına Evrimi

Two types of basins developed in the Western Anatolian extensional tectonic system during the Miocene- Quaternary interval, supra-detachment and rift basins, in the form of a rolling-hinge mechanism. In this study, stratigraphic and structural data on the presence of a rolling-hinge model in the area between Buharkent-Buldan on the northern edge of the Buyuk Menderes Graben are presented for the first time and the geological evolution of the graben is discussed. In the light of obtained field data, the Miocene-Quaternary sequences deposited on the northern edge of the Buyuk Menderes Graben were evaluated under 4 main sedimentary packages, which are separated from each other by angular and/or intrabasinal unconformities. These are the Lower-Middle Miocene (1st Package) and the Middle-Upper Miocene (2nd Package) which were deposited in the supra-detachment basin, and the Plio- Quaternary 3rd and 4th packages formed in the rift basin. The structural elements that provide the basin formation and deformation of the region are the Miocene Buyuk Menderes Detachment Fault, the Pio-Quaternary Gokdere Fault, and the Holocene Buharkent Fault Segment that cuts the youngest graben basin-fill located in the most eastern part of the Buyuk Menderes Fault System. The main fault contacts of the supra-detachment basins characterizing the Miocene period are represented by a structural boundary of gneisses and schists belonging to the Menderes Massif, which is a relict of the effective compressional tectonic products of the Eocene–Oligocene interval. Due to the effectiveness of low-angle faults in the Menderes Massif until the end of Pliocene, a high rate of extension occurred; because of this, the crust thickness was reduced. As a result of cooling of the crust during Quaternary, the supra-detachment basin system was replaced by a rift system and the Menderes Massif was divided into blocks along the high-angle boundary faults of the rift basin. Field observations and kinematic analysis reveal that tectonic structures on the northern margin of the Buyuk Menderes Graben evolved from low-angle to high-angle normal faulting, and were rejuvenated southward parallel to the basin propagation in a rolling-hinge model. Thus, the basin formation also evolved from being supra-detachment to the rift type.

Abstract TP410: Early Radiographic Recurrence or Extension Predicts Late Clinical Recurrence in Pediatric Acute Ischemic Stroke

Introduction: Pediatric AIS has a high recurrence rate of 10-25%. We observed a high rate of early radiographic recurrence or extension of stroke on repeat MRI performed within 2 weeks of index stroke and hypothesized that early radiographic extension of stroke or recurrent stroke would predict late clinical recurrence. Methods: IRB approved retrospective chart review of children ages 1 week to 18 years with AIS in our institutional pediatric stroke database who had repeat MRI within two weeks of initial acute presentation. We collected clinical and demographic data and reviewed f/u MRI studies for the presence of extension, new stroke, and hemorrhage. Results: 70 patients had early repeat MRI. 23 (33%) had early extension or new stroke on repeat MRI. Of these, 5 (21.7 %) had late clinical recurrence while only 1/47 (2.2%) who did not have early recurrence/extension went on to have late recurrence. 4/70 (5.7 %) had hemorrhagic conversion (only one was symptomatic -headache). Radiographic extension or new stroke on early repeat MRI was significantly associated with late recurrence (p=0.013). Using logistic regression, early extension/recurrence was found to be predictive of late recurrence, (OR 19.5, 95%CI 1.7-228). Conclusion: Children with AIS have a high rate of ongoing early, clinically silent, ischemic injury despite anticoagulation or antiplatelet therapy, which is associated with late clinical recurrence. This early imaging finding may serve as a biomarker that might prove useful as an endpoint in clinical trials comparing early antithrombotic therapies or to identify patients at higher risk of subsequent recurrent overt stroke who might benefit from intensified therapy. Given the high rate of early and late recurrence and low hemorrhage rates from current antithrombotic therapies, more aggressive therapy with dual antithrombotic agents should be investigated.

Dynamic Strength of Titanium Melt at Extremely High Extension Rates

The results of a study of the destruction of liquid titanium at an extremely high strain rate are presented. The value of tensile stresses leading to disruption of the continuity of the titanium melt at a strain rate of ~109 s–1 was determined. Interferometry with a frequency-modulated diagnostic pulse of a picosecond resolution was used to study the surface motion of a titanium target caused by exposure to femtosecond laser pulses.

Reliability of screen-printed conductors and resistors during fatigue cycling on flexible substrate

Abstract Scalable printing of conductor and resistor components has revolutionized the field of flexible electronics by enabling a myriad of low cost highly conformable devices. Flexible electronic devices need to exhibit reliable performance under strenuous mechanical deformations to be adopted in applications such as human and asset monitoring. The reliability of the devices is in turn affected by the microstructure of the materials, manufacturing processes, and conditions of use. In this research, the mechanical behavior and microstructural properties of stretchable silver conductor and stretchable carbon conductor inks on flexible substrate are studied. The test vehicles (such as 4- point probe structures are screen printed on thermoplastic polyurethane (TPU) and cured in a convection oven. The quality of the printed traces including the resolution and thickness profile are measured by Confocal Laser Scanning microscope. The microstructure of the sample including particle/nanoparticles morphology is studied by Scanning Electron Microscopy (SEM). The electrical resistance is measured by 4-point probes method and the sheet resistance of the printed samples is calculated. The mechanical and electrical reliability of the samples are investigated by fatigue-cycling and in-situ measuring of the electrical resistance. In terms of electrical conductivity, the silver printed traces show different behavior compared to the carbon printed samples when exposed to fatigue cycling. The electrical resistance of the printed silver trace increases during the fatigue cycling. Higher extension rate along with higher strain magnitude accelerate the rate of increase in the electrical resistance. The relative electrical resistance of the carbon trace initially drops to 0.7 after 40 cycles and remains constant for the rest of the cycles. The extension rate does not considerably change the electrical resistance of carbon trace. The stability in electrical resistance is crucial in applications where electrical shielding is concerned.

Polymer extrudate-swell: From monodisperse melts to polydispersity and flow-induced reduction in monomer friction

This paper describes finite-element simulations and associated experimental studies of extrudate swell for near-monodisperse and polydisperse polystyrenes. The tube-model based Rolie-Poly constitutive model, when extended to include a reduction of monomeric friction at high extension rates, makes much-improved predictions of extrudate swell at high Weissenberg number. This is especially significant for near-monodisperse polymers where rheological features are unchanged by the effects of polydispersity. Extension of this molecular rheology scheme to a polydisperse constitutive model addresses extrusion experiments on polydisperse polystyrenes inside a multipass rheometer, accounting for experimental data up to Rouse Weissenberg numbers of 50. We, therefore, show that from a measurement of polymer molecular weight distribution, it is possible to predict extrudate swell over a broad range of processing conditions for polydisperse polymers and realistic extrusion processes. Small changes in the capillary length to diameter ratio have little effect on extrudate swell in this range of Weissenberg number. This is because the capillary residence time is sufficiently long for a steady state to be reached within the polymer stretch relaxation time, which controls the most decisive physics responsible for extrudate swell.

Root growth and dental eruption in modern human deciduous teeth with preliminary observations on great apes

Recent studies of dental development have indicated that root growth rates are linked to the eruption of some permanent tooth types in modern humans and Pan troglodytes. Little is known about the potential links between these aspects of dental development in deciduous teeth of any primate species. This histology study calculates the rate at which roots extend in length for human deciduous maxillary teeth and a small sample of deciduous canines and premolars from P. troglodytes and Pongo pygmaeus. Links are sought between root extension rates and previously published data for deciduous tooth emergence in each of these species. Results reported here provide the first evidence that the roots of human deciduous incisors, canines, and premolars extend in length at an accelerated rate as these teeth emerge. Accelerated extension rates in a deciduous canine from Pan coincided with the age that this tooth type emerged in captive chimpanzees. High extension rates in a canine from Pongo preceded emergence age. Preliminary observations indicate that deciduous canine and premolar roots of Pan and Pongo extend in length rapidly when compared to these tooth types from modern human children. This study provides a starting point from which to investigate new links between the incremental development of deciduous roots and tooth emergence in primates.

Coulomb stress evolution along the Kongur Extensional System since 1895 and present seismic hazard

The present-day tectonic activities on the northeastern margin of the Pamir Plateau are mainly E-W oriented extensions, among which the Kongur Extensional System (KES) plays an important role in the internal expansion of the Pamir. As the largest earthquake since Taxkorgan earthquakes in 1895 and 1896, the Aketao earthquake occurred on the Muji fault on the northern portion of the KES in 2016. Since then, the trend of seismic activities along the KES has been paid much attention to. Based on the visco elastic layered lithosphere model, we calculate the co-seismic and post-seismic stress changes caused by five historical earthquakes on the KES and its adjacent areas since 1895, and analyze the interaction among strong earthquakes. The results show that all of the historical earthquakes after 1895 occurred in the areas where the co-seismic and post-seismic Coulomb stress increased. Coulomb stress loading at the hypocenters of the 1896 Taxkorgan earthquake, the 1974 Markansu earthquake and the 2016 Aketao earthquake were 0.251 MPa, 0.013 MPa and 0.563 MPa, respectively. The three earthquakes were catalyzed by such variations. The historical earthquakes increased the stress state on most segments of the Southern Kungai Mountain fault and Kongur fault along the KES. In particular, we can identify 2 visible earthquake gaps with increasing seismic hazard formed on the Qimugan segment and Bulunkou segment of the KES. The Qimugan section and the Bulunkou section are located at the fault transition zone with concentrated stress and high extension rate, so great attention should be paid to their seismic hazard at present day.

Origin of basin-scale syn-extensional synclines on the southern margin of the Northern Carnarvon Basin, Western Australia

Fault geometry exerts a dominant structural control on the deformation of hanging wall sequences during extension and contraction. Numerical, kinematic and sandbox modelling studies have demonstrated that characteristic anticline–syncline pairs are produced during the extension of ramp-flat faults. These features are commonly recognized in smaller fault-scale structures, but remain underappreciated in larger, basin-scale settings. The Lewis Trough, situated within the Northern Carnarvon Basin, Western Australia, is a basin-scale, largely unfaulted syncline with an associated anticline along its western flank, rather than the fault-related graben typical of the region. We present kinematic models demonstrating that a SE-dipping, ramp-flat fault geometry can produce relative highs and lows in Jurassic strata as well as honouring the asymmetrical onlap pattern within the Lewis Trough. This study indicates that the Lewis Trough formed during the Early Jurassic, a period typically associated with high rates of extension and not during the Late Triassic Fitzroy Compression Event. This study also highlights the importance of the Locker Shale in partitioning deformation of the Permian and Mesozoic fault systems and as a diffuse zone that variably partitions displacement between stacked Permian and Mesozoic fault systems.

Attitude and Practice of Breast Self-Examination in Women in Morocco

Background: Breast cancer is characterized in Morocco, by the delay in diagnosis, with a high rate of metastatic extension which leads to the difficulty of treatment and an increasement of mortality. It is often the woman who detects breast abnormalities through self-examination. Self-examination alone does not diagnose the breast cancer. Despite it is accessible method in developing countries because it is easy, convenient, private, safe and requires no specific equipment. Aim: The objective was to study the practice of breast self-examination in women in Morocco. Methods: This was a cross-sectional observational study that was conducted in July 2011 based on early detection programs in basic health centers. A total of 1444 women aged from 17 to 86 years were included on the eligibility basis for early detection of breast and cervical cancer in Morocco. For each participant we collected sociodemographic data, information on breast cancer factors, data on the level of knowledge of breast cancer, and information on breast self-examination practice. Results: The average age was 41 years old. The information on breast self-examination came mainly from the media (57, 28%). The practice of the breast self-examination in 56.9%. In our study population, we had 76.6% multiparous, 7.8% nulliparous and 15.6% primiparous. Among the 36 participants, 3% were illiterate, 23% had primary education, 26.4% secondary education and 201 (14%) had a higher education level. The breast self-examination practice was associated with participants´ level of education (OR = 1.69) ( P = 0.000). Membership in the different age groups had no effect on the practice of breast self-examination ( P = 0.182). Conclusion: It is imperative to increase awareness of the practice of breast self-examination and its methods through health education campaigns.

Steady-state extensional viscosity of a linear polymer solution using a differential pressure extensional rheometer on a chip

In our earlier theoretical work [Lee and Muller, J. Rheol. 61, 1049–1059 (2017)], we proposed a design for a differential pressure extensional rheometer (DPER) on a chip. Here, we implement the DPER to evaluate the steady-state viscosity of a semidilute poly(ethylene oxide) solution at high and low extension rates. At low extension rates, the extensional viscosity exhibits strain thinning behavior with a power-law exponent of −0.5. At intermediate extension rates, the extensional viscosity exhibits strain thickening. At high extension rates, the extensional viscosity plateau has been estimated, and the corresponding finite extendable nonlinear elastic (FENE) constant is evaluated as 482. A novel method to determine the FENE constant and the extensional relaxation time distribution is presented, which are key parameters for the understanding of the extensional flow of a linear polymer solution.

A Novel Technique for Fiber Formation: Mechanotropic Spinning-Principle and Realization.

We present basic experimental data and the theoretical background of a novel technique for fiber spinning from polymer solutions. The principal feature of the advanced process is realization of phase separation with detachment of a solvent, accompanied by the orientation of macromolecules, under the action of high extension rates. This is similar in some respects to dry spinning, though the driving force is not diffusion with subsequent evaporation of a solvent but redistribution of polymer-solvent interactions in favor of polymer-polymer and solvent-solvent ones governed by mechanical stresses. A promise of this approach has been demonstrated by experiments performed with polyacrylonitrile solutions in different solvents and solutions of the rigid-chain aromatic polyamide. We examined mechanotropic fiber spinning in model experiments with stretching jets from a drop of polymer solution in different conditions, and then demonstrated the possibility of realizing this process in the stable long-term continuous mode. During extension, phase separation happens throughout the whole section of a jet, as was confirmed by visual observation. Then a solvent diffuses on a jet surface, forming a liquid shell on the oriented fiber. Instability of this cover due to surface tension leads either to formation of separate solvent drops “seating” on the fiber or to the flow of a solvent down to the Taylor cone. The separate liquid droplets can be easily taken off a fiber. The physics underlying this process is related to the analysis of the influence of macromolecule coil-to-stretched chain transition on the intermolecular interaction.

Endocytic recycling via the TGN underlies the polarized hyphal mode of life.

Intracellular traffic in Aspergillus nidulans hyphae must cope with the challenges that the high rates of apical extension (1μm/min) and the long intracellular distances (>100 μm) impose. Understanding the ways in which the hyphal tip cell coordinates traffic to meet these challenges is of basic importance, but is also of considerable applied interest, as fungal invasiveness of animals and plants depends critically upon maintaining these high rates of growth. Rapid apical extension requires localization of cell-wall-modifying enzymes to hyphal tips. By combining genetic blocks in different trafficking steps with multidimensional epifluorescence microscopy and quantitative image analyses we demonstrate that polarization of the essential chitin-synthase ChsB occurs by indirect endocytic recycling, involving delivery/exocytosis to apices followed by internalization by the sub-apical endocytic collar of actin patches and subsequent trafficking to TGN cisternae, where it accumulates for ~1 min before being re-delivered to the apex by a RAB11/TRAPPII-dependent pathway. Accordingly, ChsB is stranded at the TGN by Sec7 inactivation but re-polarizes to the apical dome if the block is bypassed by a mutation in geaAgea1 that restores growth in the absence of Sec7. That polarization is independent of RAB5, that ChsB predominates at apex-proximal cisternae, and that upon dynein impairment ChsB is stalled at the tips in an aggregated endosome indicate that endocytosed ChsB traffics to the TGN via sorting endosomes functionally located upstream of the RAB5 domain and that this step requires dynein-mediated basipetal transport. It also requires RAB6 and its effector GARP (Vps51/Vps52/Vps53/Vps54), whose composition we determined by MS/MS following affinity chromatography purification. Ablation of any GARP component diverts ChsB to vacuoles and impairs growth and morphology markedly, emphasizing the important physiological role played by this pathway that, we propose, is central to the hyphal mode of growth.

Pediatric differentiated thyroid carcinoma: The clinicopathological features and the coexistence of Hashimoto's thyroiditis

The purpose of this study is to assess outcomes and the detailed clinicopathological features of differentiated thyroid carcinoma (DTC), including the relation of Hashimoto's thyroiditis and postoperative pathological features in child under 18 years old. We reviewed patients with DTC under 18 years old (pediatric DTC patients) seen during recent 16 years. The clinicopathological features and outcomes of pediatric DTC were analyzed by comparison with patients of 19-20 years old or 21-44 years old. Sixty four children with DTC [median age 16 years (range, 5-18)] were studied. The ratio of female to male was 5:1, but no difference was found by comparison with adult of 21-44 years old. No difference was found in multifocality, but DTC in child showed lager tumor size (P<0.001), higher rate of extrathyroidal extension (P=0.017), more local or pulmonary metastasis (P<0.001, P<0.001 respectively) than adult thyroid carcinoma. High rate of Hashimoto's thyroiditis (19/43) without influence on pathological features was found in patients under 18 years old. No differences, except for distant metastasis, were found by comparison of clinicopathological features between patients under 18 years old and 19-20 years old. Pediatric patients possessed highest rates of persistent/recurrent disease, though only one child died. Pediatric DTC has more aggressive behavior characterized by a high rate of extrathyroidal extension, local and pulmonary metastasis. Pediatric DTC has low mortality, but active treatments are needed for the high risk of persistent or recurrent diseases. Hashimoto's thyroiditis may be associated with the pathogenesis or mechanism of pediatric DTC.

Fusion of Taq DNA polymerase with single-stranded DNA binding-like protein of Nanoarchaeum equitans-Expression and characterization.

DNA polymerases are present in all organisms and are important enzymes that synthesise DNA molecules. They are used in various fields of science, predominantly as essential components for in vitro DNA syntheses, known as PCR. Modern diagnostics, molecular biology and genetic engineering need DNA polymerases which demonstrate improved performance. This study was aimed at obtaining a new NeqSSB-TaqS fusion DNA polymerase from the Taq DNA Stoffel domain and a single-stranded DNA binding-like protein of Nanoarchaeum equitans in order to significantly improve the properties of DNA polymerase. The DNA coding sequence of Taq Stoffel DNA polymerase and the nonspecific DNA-binding protein of Nanoarchaeum equitans (NeqSSB-like protein) were fused. A novel recombinant gene was obtained which was cloned into the pET-30 Ek/LIC vector and introduced into E. coli for expression. The recombinant enzyme was purified and its enzymatic properties including DNA polymerase activity, PCR amplification rate, thermostability, processivity and resistance to inhibitors, were tested. The yield of the target protein reached approximately 18 mg/l after 24 h of the IPTG induction. The specific activity of the polymerase was 2200 U/mg. The recombinant NeqSSB-TaqS exhibited a much higher extension rate (1000 bp template in 20 s), processivity (19 nt), thermostability (half-life 35 min at 95°C) and higher tolerance to PCR inhibitors (0.3–1.25% of whole blood, 0.84–13.5 μg of lactoferrin and 4.7–150 ng of heparin) than Taq Stoffel DNA polymerase. Furthermore, our studies show that NeqSSB-TaqS DNA polymerase has a high level of flexibility in relation to Mg2+ ions (from 1 to 5 mM) and KCl or (NH4)2SO4 salts (more than 60 mM and 40 mM, respectively). Using NeqSSB-TaqS DNA polymerase instead of the Taq DNA polymerase could be a better choice in many PCR applications.

A differential pressure extensional rheometer on a chip with fully developed elongational flow

A method is presented to construct a fully developed elongational flow at a nearly constant extension rate in a converging microchannel. For a Giesekus–Leonov fluid, we show that under appropriate conditions, the first normal stress difference in a fluid element flowing along the channel centerline reaches its steady-state value early in the converging region, so that the time-averaged normal stress difference is approximately equal to the spatially averaged normal stress along the converging section. We demonstrate that the averaged normal stress in the converging region (with contraction ratios of 4.9 or 10.343) maintains greater than 90% of the steady value up to an extension rate of 100 s−1. At higher extension rates, the averaged normal stress becomes significantly smaller than the steady value. A differential pressure elongational rheometer is proposed where the pressure difference between the converging channel and a reference channel can be monitored. The reference channel is a straight channel geometry in which the viscous contribution to the pressure drop equals that in the converging channel.

RECENT SEDIMENTARY PROCESSES IN THE WESTERN GULF OF CORINTH, GREECE: SEISMIC AND ASEISMIC TURBITIDES

The Corinth rift is counted among the most active tectonic grabens in the world, with extension rates up to 15 mm/yr (Western part). These high extension rates are associated with very strong seismic events that are, occasionally, responsible for submarine mass movements. These movements, their consequential bottom currents, and the differential river-discharging sediment accumulation in the whole gulf, strongly affect the modern marine sedimentary processes. The definition and understanding of these processes is the main aim of this project. This is attempted through via sedimentological, mineral and geochemical analyses on sediment samples from two ~1.1 m long, sediment cores from a WE submarine canyon (10 km long, 3 km wide) that lies in the Western tip of the gulf. The general sedimentation motif reveals the presence of hemipelagic deposits which are occasionally interrupted by sandy turbidites. Occasionally, these turbidites seem to have seismic origin. The sedimentation rates range between 2.57 mm/yr in the western part and 0.67 mm/yr in the eastern part.

Genetic profile of ductal adenocarcinoma of the prostate

Despite being discovered almost 50 years ago, little is known regarding the genetic profile of ductal adenocarcinoma of the prostate (DAC). In recent years, progress has been made in the understanding of the genetics of acinar adenocarcinomas, and at least 7 genetically different subtypes have been identified. DAC is known to present at an advanced stage with a high rate of extraprostatic extension and seminal vesicle invasion, and a decreased interval to biochemical recurrence and the development of metastatic disease when compared with acinar adenocarcinoma. Our aim was to investigate the genetic profile of DAC to determine whether there is a genomic rationale for the aggressive behavior associated with this tumor type. Frozen tissue from 11 cases of DAC with paired benign tissue was analyzed. After DNA extraction, copy-number alteration analysis was performed, as well as identification of mutations and indels. We compared the fraction of the DAC genome with copy-number alteration to previous results from 74 primary acinar adenocarcinomas of the prostate. The alteration rate in DAC was comparable to that of acinar adenocarcinoma of high Gleason score. DAC harbored somatic changes seen in advanced and/or metastatic castration-resistant acinar adenocarcinoma, which likely accounts for its aggressive biological behavior.

Experimental evaluation and modified Weibull characterization of the tensile behavior of tri-component elastic-conductive composite yarn

In order to clarify the effects of the extension rate and gauge length upon the distribution of tensile strength of tri-component elastic-conductive composite yarn (t-ECCY), experimental as well as theoretical studies have been performed in this paper. Influences of the extension rate and gauge length are highlighted. The yarn exhibits an extension-rate strengthening effect, and the higher extension rate results in a higher strength and fracture strain, irrespective of the gauge length considered, and vice versa. Expressed in terms of gauge length, yarn tenacity shows a drop for a longer testing length at all extension rates, based on the weakest-link theory. A modified two-parameter Weibull strength distribution model, taking into account the effects of extension rate and gauge length, can be reasonably used to quantify the degree of variability in tensile strength and to obtain the individual Weibull parameters for practical applications. Different fracture mechanisms of the t-ECCY are demonstrated at lower and higher extension rates. A “cascade-like” break happens at lower extension rates due to inner sliding, weaker interactive transverse force of individual fibers, and sufficient time available for the fiber realignment. Nevertheless, a “chimney-like” break dominates at higher extension rates by virtue of the reduced reorientation of some disordered fibers and intensive instant impact force of the stainless steel filament component along the load direction.

Moderate-Grade Germinal Matrix Haemorrhage Activates Cell Division in the Neonatal Mouse Subventricular Zone

Precise temporal and spatial control of the neural stem/progenitor cells within the subventricular zone (SVZ) germinal matrix of the brain is important for normal development in the third trimester and the early postnatal period. The high metabolic demands of proliferating germinal matrix precursors, coupled with the flimsy structure of the germinal matrix cerebral vasculature, are thought to account for the high rates of haemorrhage in extremely- and very-low-birth-weight preterm infants. Germinal matrix haemorrhage can commonly extend to intraventricular haemorrhage (IVH). Because neural stem/progenitor cells are sensitive to microenvironmental cues from the ventricular, intermediate, and basal domains within the germinal matrix, haemorrhage has been postulated to impact neurological outcomes through aberration of normal neural stem/progenitor cell behaviour. We developed an animal model of neonatal germinal matrix haemorrhage using stereotactic injection of autologous blood into the mouse neonatal germinal matrix. Pathological analysis at 4 days postinjury showed high rates of intraventricular extension and ventricular dilatation but low rates of parenchymal disruption outside the germinal zone, recapitulating key features of human “Papile grade III” IVH. At 4 days postinjury we observed proliferation in the wall of the lateral ventricle with significantly increased numbers of transient amplifying cells within the SVZ and the corpus callosum. Analysis at 21 days postinjury revealed that cortical development was also affected, with increased neuronal and concomitant reduced oligodendroglial differentiation. At the molecular level, we showed downregulation of the expression of the transmembrane receptor Notch2 in CD133^+ve cells of the SVZ, raising the possibility that the burst of precocious proliferation seen in our experimental mouse model and the skewed differentiation could be mediated by downregulation of the Notch pathway within the proximal/ventricular domain. These findings raise the possibility that Notch regulation plays a critical role in mediating the response of the neonatal SVZ to ischaemic and haemorrhagic insults.