Upward Spread Research Articles

Sequential Lateral Lymphatic Metastasis Shows Similar Oncologic Outcomes to Upward Spread in Advanced Rectal Cancer After Preoperative Chemoradiotherapy.

Whether lateral pelvic node metastasis should be considered as a regional or systemic disease is a long-standing debate. Although previous Japanese studies have considered it to be locoregional disease, Western countries consider it a systemic disease and do not perform lateral pelvic node dissection after preoperative chemoradiotherapy. To evaluate whether lateral pelvic node metastasis is a systemic or regional disease that is amenable to curative resection. Retrospective analysis of a prospectively collected database. This study was conducted at a tertiary cancer center. There were 616 consecutive patients who underwent curative total mesorectal excision alone or with lateral pelvic node dissection after preoperative chemoradiotherapy for locally advanced rectal cancer between 2011 and 2019. Three-year disease-free and overall survival. A total of 360 patients underwent total mesorectal excision, and 160 patients underwent total mesorectal excision with lateral pelvic node dissection. There was no difference in the 3-year disease-free survival (DFS; p = 0.844) or overall survival rates ( p = 0.921) between the groups. Patients with lateral pelvic node metastasis showed DFS similar to those with perirectal lymph node metastasis in the total mesorectal excision group. In a subgroup analysis, patients with internal iliac pelvic node metastasis showed a disease-free survival comparable to those with perirectal node involvement, and patients with other lateral pelvic node metastasis showed a DFS similar to those with intermediate node involvement. In the lateral pelvic node dissection group, the lateral pelvic node metastatic rate was 32.5%. On multivariate analysis, fewer than 8 of the unilateral harvested lateral pelvic nodes and advanced ypT stage were significantly associated with poor disease-free survival. The retrospective design. Lateral lymphatic metastasis showed oncologic outcomes similar to those of upward spread, especially perirectal lymph nodes metastasis. Large cohort studies with long-term follow-up are required to confirm these results. See Video Abstract . ANTECEDENTES:Es un debate muy antiguo si las metástasis en los ganglios pélvicos laterales deben considerarse una enfermedad regional o sistémica. Si bien estudios japoneses anteriores las consideran como una enfermedad locorregional, en los países de occidente se las considera como una enfermedad sistémica por la cual no se realiza disección de ganglios pélvicos laterales después de una radioquimioterapia preoperatoria.OBJETIVOS:Evaluar si la metástasis en los ganglios pélvicos laterales se consideran como enfermedad sistémica o enfermedad regional susceptible de resección curativa.DISEÑO:Análisis retrospectivo de una base de datos recopilada prospectivamente.AJUSTE:Este estudio se realizó en un centro oncológico terciario.PACIENTES:616 pacientes consecutivos se sometieron a excisión total del mesorrecto curativa sola o con disección de los ganglios pélvicos laterales después de radioquimioterapia preoperatoria en casos de cáncer de recto localmente avanzado entre 2011 y 2019.PRINCIPALES MEDIDAS DE RESULTADO:Sobrevida global y libre de enfermedad a 3 años.RESULTADOS:Un total de 360 pacientes se sometieron a excisión total del mesorrecto y 160 pacientes se sometieron a excisión total del mesorrecto con disección de ganglios pélvicos laterales.No hubo diferencias en la sobrevida libre de enfermedad a 3 años (p = 0,844) ni en las tasas de sobrevida general (p = 0,921) entre los grupos. Los pacientes con metástasis en los ganglios pélvicos laterales mostraron una sobrevida libre de enfermedad similar a aquellos con metástasis en los ganglios linfáticos perirrectales que se encontraban en el grupo de excisión total del mesorrecto.En el análisis de subgrupos, los pacientes con metástasis en los ganglios pélvicos ilíacos internos mostraron una sobrevida libre de enfermedad comparable a aquellos con afección de los ganglios perirrectales y los pacientes con otras metástasis en los ganglios pélvicos laterales mostraron una sobrevida libre de enfermedad similar a aquellos con afección de los ganglios intermedios.En el grupo de disección de los ganglios pélvicos laterales, la tasa de metástasis en dichos ganglios fué del 32,5%. En el análisis multivariado, < de 8 ganglios pélvicos laterales resecados unilateralmente y el estadio ypT avanzado se asociaron significativamente con una menor sobrevida libre de enfermedad.LIMITACIÓN:El diseño retrospectivo del estudio.CONCLUSIONES:Las metástasis linfáticas laterales mostraron resultados oncológicos similares a la diseminación ascendente, especialmente las metástasis en los ganglios linfáticos perirrectales. Se requieren grandes estudios de cohortes con seguimiento a largo plazo para confirmar estos resultados. (Traducción-Dr. Xavier Delgadillo ).

Experimental study on fire spread behavior of single 110 kV cable under different layout conditions

High-voltage cable fire accidents can cause large-scale power outages. In particular, the 110 kV large-section (diameter 10 cm) cable has complex cable structures. Therefore, based on the actual cable laying scenarios, three cable layout conditions are set, including the horizontal cable above horizontal floor structure (HCAHFS), the inclined cable above horizontal floor structure (ICAHFS), and the inclined cable above inclined floor structure (ICAIFS). The combustion behaviors and flame spread characteristics of 110 kV large-section cable are experimentally studied. It is found that the flame cannot spread on the surface of the flame-retardant outer sheath of the cable. However, when the cable-floor distance (lcf) is between 0.75 d and 2 d (d is the cable diameter) in HCAHFS, i.e. there is a floor under the cable that can catch cable melt, and the flame spread characteristics is different. After the cable is ignited, the cable fire can be divided into two parts, outer sheath flame and melt flame, and the cable fire can spread under the joint action of two flames. When lcf ≤ 0.75 d, the space under the cable is narrow. With the accumulation of melt on the floor, air entrainment is limited during cable combustion, resulting in the cable flame unsustainable. When lcf ≥ 2 d, the thermal radiation and convection from the melt and outer sheath flame to the cable preheat zone are weakened, resulting in cable flame extinction as well. In ICAHFS, the cable flame spread rate is first increased and then decreased with the increasing lcf at the fixed inclination angle; In ICAIFS, the upward spread rate of cable flame is faster than the downward spread rate at the fixed inclined angle. Moreover, the cable flame spread rate (FSR) in HCAHFS is the slowest compared to that in ICAIFS with different inclined angles. The preheating length for ICAIFS increases under both upper and lower ignition modes, while it is obviously at upper ignition, due to the melt flow. Finally, a correlation of FSR was proposed for various ignition positions and inclined angles. This study provides a reference for fire protection design and numerical simulation parameter setting of 110 kV cable fire.

Seed dispersal of a fleshy‐fruited invasive shrub is affected by changes in the frugivorous bird assemblage along an elevational gradient

AbstractSeed dispersal by birds constitutes an essential mechanism for ornithochorous exotic plants to successfully invade a new system. New biotic associations with native birds might facilitate the upward spread of exotic plants from the foothills into the high mountains. However, environmental changes associated with elevation are known to drive changes in bird assemblages, and it is not clear how elevation changes impact the seed dispersal service of ornithochorous invaders. We evaluated changes in frugivorous bird assemblages of one of the exotic shrubs (Cotoneaster franchetii, Rosaceae) with the broadest elevation range among woody invaders in the Córdoba Mountains (Argentina). We quantified frugivory interactions (including absolute and proportional fruit consumption by seed dispersers, pulp consumers, and seed predators) using 4‐h observations of focal C. franchetii shrubs distributed across low‐elevation, mid‐elevation, and high‐elevation sites (700, 1100, and 1800 m a.s.l., respectively; 15 individuals per elevational band and one site per elevation). Seed disperser richness was highest at the low‐ and mid‐elevation sites (three species vs. one at the high‐elevation site), but proportional and absolute fruit consumption of C. franchetii was highest at the high‐elevation site (39.1%, 88 seeds at high‐elevation and 7.7%, 20 seeds at low‐elevation). The Chiguanco Thrush (Turdus chiguanco, Turdidae) was the only seed disperser species found at the highest elevation site. Fruit consumption by seed dispersers was positively related to their abundance and elevation. In a high mountain system, a single abundant generalist seed disperser, rather than a high richness of seed disperser species, can uphold an effective dispersal service for an invasive ornithochorous shrub. This pattern may facilitate the spread of such plants across higher elevational ranges, thereby promoting the invasion of other exotic ornithochorous plants into upper elevations.

Semantic Context Can Mask Intelligibility Declines at Above-Conversational Speech Levels in Normal-Hearing Listeners.

While speech audibility generally improves with increasing level, declines in intelligibility are inconsistently observed at above-conversational levels, even in listeners with normal audiograms (NAs). The inconsistent findings could be due to different types of speech materials, ranging from monosyllabic words to everyday sentences, used across studies. Here, we hypothesized that semantic context can "mask" intelligibility declines at high levels by constraining plausible response options. Intelligibility was assessed in speech-shaped noise with monosyllabic words, sentences without semantic context, and sentences with semantic context. Two presentation levels were used: 80 and 95 dB SPL broadband. Bandpass filtering was applied to minimize upward spread of masking. Twenty-two young adults with NAs were tested. Poorer performance at the higher level was found with the monosyllabic words and context-free sentences but not with the context-rich sentences. The scores obtained at the higher level with the two context-free materials were strongly correlated. The correlation was independent of the lower-level scores, suggesting that the high-level performance declines reflect "normal" auditory functioning. Young adults with NAs show intelligibility decreases at above-conversational levels when tested with speech materials without semantic context. Top-down processing as facilitated by context information can mask such declines.

Congenital Nonprofound Bilateral Sensorineural Hearing Loss in Children: Comprehensive Characterization of Auditory Function and Hearing Aid Benefit.

A prospective cross-sectional design was used to characterize congenital bilateral sensorineural hearing loss (SNHL). The underlying material of >30,000 consecutively screened newborns comprised 11 subjects with nonprofound, alleged nonsyndromic, SNHL. Comprehensive audiological testing was performed at ≈11 years of age. Results showed symmetrical sigmoid-like median pure-tone thresholds (PTTs) reaching 50–60 dB HL. The congenital SNHL revealed recruitment, increased upward spread of masking, distortion product otoacoustic emission (DPOAE) dependent on PTT (≤60 dB HL), reduced auditory brainstem response (ABR) amplitude, and normal magnetic resonance imaging. Unaided recognition of speech in spatially separate competing speech (SCS) deteriorated with increasing uncomfortable loudness level (UCL), plausibly linked to reduced afferent signals. Most subjects demonstrated hearing aid (HA) benefit in a demanding laboratory listening situation. Questionnaires revealed HA benefit in real-world listening situations. This functional characterization should be important for the outline of clinical guidelines. The distinct relationship between DPOAE and PTT, up to the theoretical limit of cochlear amplification, and the low ABR amplitude remain to be elucidated. The significant relation between UCL and SCS has implications for HA-fitting. The fitting of HAs based on causes, mechanisms, and functional characterization of the SNHL may be an individualized intervention approach and deserves future research.

МСКТДИАГНОСТИКА ОСТЕОМИЕЛИТА ВЕРХНЕЙ ЧЕЛЮСТИ У ПАЦИЕНТОВ, ПЕРЕНЕСШИХ COVID-19

Abstract. Introduction. COVID-19 is widely known as a disease that causes respiratory dysfunction, however, it is also associated with a mass of extrapulmonary manifestations and complications, gastrointestinal, hepatocellular complications, neurological diseases, as well as complications in the maxillofacial region. Aim. The aim of this study was to diagnose osteomyelitis of the upper jaw in post COVID-19 patients using multispiral computed tomography. Material and methods. We retrospectively evaluated radiation imaging and clinical data of 37 patients, aged 28 to 52 years with osteomyelitis of the upper jaw, who underwent COVID-19. The male sex prevailed among the patients. Results and discussion. All patients had sinusitis and ophthalmic symptoms. The pattern of anatomical lesions of the upper jaw, nasal cavity, maxillary sinus, orbit, and lattice cells was consistently observed in all patients. Conclusion. Progressive and rapid course, involvement of the cavernous sinus, vascular structures, and further upward spread (intracranial) complications may be the usual evolution of rhinophthalmocerebral mucormycosis. Multiplanar tomographic imaging shows the localization, nature, as well as relationship of the surrounding structures, helping in turn to plan the operation. However, the prognosis remains difficult, despite radical surgery and, in particular, antifungal treatment.

Graphene‐Assisted Epitaxy of High‐Quality GaN Films on GaN Templates

AbstractGraphene (Gr)‐assisted epitaxy of semiconductors has been demonstrated as a revolutionary strategy for the fabrication of nitride materials and flexible devices. However, till now, most of the GaN epitaxy assisted by Gr is performed on thermally stable foreign substrates because Gr suffers obvious deterioration due to the decomposition of GaN substrate. Thus, large lattice and thermal mismatches still exist and inevitably lead to a high density of dislocations in nitrides. To address this issue, here, the Gr‐assisted epitaxy of high‐quality GaN films on GaN templates is demonstrated by constructing specially designed self‐organized defective (SOD) Gr as a buffer layer. The SOD Gr allows for the spontaneous relaxation of strain in GaN epilayers by weakening the interfacial interactions; and thus, blocks the upward spread of threading dislocations in GaN templates. Therefore, screw and edge dislocation densities in GaN epilayers show reductions of 51% and 62%, respectively, compared to that in homoepitaxy. Based on the GaN film grown on SOD Gr, the as‐fabricated blue light‐emitting diode exhibits a 17% enhancement of light output power and a better emission wavelength stability than that without Gr. This work opens a practical pathway for the growth of high‐quality nitrides and manufacturing of high‐performance nitride‐based devices.

Exploring the brachistochrone (shortest-time) path in fire spread

The brachistochrone (shortest-time) curve is the path connecting two points that enables the shortest travel time. This work explores the “brachistochrone path” of fire spread connecting two points at the same altitude and with a fixed path length. The starting and ending points are connected by both thermally thin fuels (thin wires) and thermally thick fuels (PMMA bars). Flame-spread paths of triangular, rectangular, and circular shapes with different heights and inclinations are explored. Results show that having a local maximum flame-spread rate does not result in the shortest overall travel time. For thin-wire paths, the fastest overall-path fire spread occurs, when the upward spread path is vertical, and the path height reaches a maximum, as demonstrated by the theoretical analysis. Differently, for thick PMMA-bar paths, the brachistochrone condition occurs when the path length of the vertical upward spread reaches the maximum, because the upward spread is about ten times faster than the downward spread. This study extends the conventional problem of the fastest fire spread to the shortest-time problem of the whole fire path, and it may help optimize the fuel distribution inside the built environment and estimate available safe egress time in building and wildland fires.

Tonotopic Selectivity in Cats and Humans: Electrophysiology and Psychophysics

We describe a scalp-recorded measure of tonotopic selectivity, the “cortical onset response” (COR) and compare the results between humans and cats. The COR results, in turn, were compared with psychophysical masked-detection thresholds obtained using similar stimuli and obtained from both species. The COR consisted of averaged responses elicited by 50-ms tone-burst probes presented at 1-s intervals against a continuous noise masker. The noise masker had a bandwidth of 1 or 1/8th octave, geometrically centred on 4000 Hz for humans and on 8000 Hz for cats. The probe frequency was either − 0.5, − 0.25, 0, 0.25 or 0.5 octaves re the masker centre frequency. The COR was larger for probe frequencies more distant from the centre frequency of the masker, and this effect was greater for the 1/8th-octave than for the 1-octave masker. This pattern broadly reflected the masked excitation patterns obtained psychophysically with similar stimuli in both species. However, the positive signal-to-noise ratio used to obtain reliable COR measures meant that some aspects of the data differed from those obtained psychophysically, in a way that could be partly explained by the upward spread of the probe’s excitation pattern. Our psychophysical measurements also showed that the auditory filter width obtained at 8000 Hz using notched-noise maskers was slightly wider in cat than previous measures from humans. We argue that although conclusions from COR measures differ in some ways from conclusions based on psychophysics, the COR measures provide an objective, noninvasive, valid measure of tonotopic selectivity that does not require training and that may be applied to acoustic and cochlear-implant experiments in humans and laboratory animals.

Simultaneous measurement of human auditory nerve and brainstem potentials: Effects of upward spread of excitation

Acoustic clicks evoke strong synchrony of auditory-nerve (AN) fibers, thereby eliciting a compound action potential (CAP); however, synchrony is reduced by the delay of the cochlear traveling wave. Upward-frequency chirps compensate for this delay, resulting in larger CAPs evoked by chirps than clicks. Our model simulations of CAPs suggest that chirps presented at high intensities (100 dB peSPL) adapt basal AN fibers via upward spread of excitation of low-frequency chirp components. This adaptation results in less-than-or-equal-to CAP amplitudes and distorted CAP morphology compared to CAPs evoked by clicks. Simulations show that these effects on CAP amplitude and morphology can be avoided by reducing the amplitude of the low-frequency components of the chirp (i.e., modified chirp). Here we present CAPs from 12 young adults with NH, which for high stimulus intensities, exhibit reduced amplitudes and broader CAP morphology for chirps than clicks, whereas CAP amplitudes for modified chirps exceed those for clicks, consistent with model simulations. The distorted CAP morphology in response to high-level chirps is consistent with adaptation of AN responses and broad cochlear excitation. Interestingly, the deleterious effects of high-level chirps on CAP amplitude and morphology are reduced or absent in simultaneous recordings of the auditory brainstem response.

Influence of top water on SAGD steam chamber growth in heavy oil reservoirs: An experimental study

Steam-assisted gravity drainage (SAGD) is one efficient and mature technology for recovering heavy oil and bitumen resources. The key underlying mechanism is the growth of the steam chamber after injecting steam. However, due to the complex geological environment, the thief zones exist and have a prejudicial effect on the development of the steam chamber, thus impacting the ultimate heavy-oil recovery. In this work, our objective is to investigate the effect of a top-water thief zone (i.e., water zone overlies the oil sand) on SAGD performance and further to understand the crucial mechanisms that control the heat loss during steam injection. A large-scale three-dimensional experimental apparatus is used to carry out the SAGD process with a top aquifer. Based on the similarity criterion, the field-scale model is transformed into a laboratory elemental model. To evaluate the SAGD performance quantitatively, the dynamic growth of the steam chamber is measured using the thermal detectors and the production data is recorded. The results show that the steam chamber exhibits three distinguished stages, that is, upward spread, lateral extension, and downward development in the presence of top-water zone. The bottom-water zone has less impact on the steam-chamber growth. The existence of a confined top-water zone, however, significantly affects SAGD performance, especially the lateral expansion of the steam chamber. The lateral propagation of the steam front is hindered by the top thief zone due to the heat exchange with the top water. Once the steam chamber reaches the boundary, the accumulation of energy in the water thief zone, in turn, can reduce the remaining oil saturation along the topwater–oil interface. This study provides us some key insights into the development of heavy oil resources with top thief zones when implementing SAGD technology.

An experimental study on upward flame spread over corrugated cardboard used in underground logistic transportation: Influence of grain orientation and thickness

Corrugated cardboard is widely used in underground logistic transportation and warehousing and it has become an important fire hazard source. According to previous warehouse fire studies, upward flame spread on corrugated cardboard plays an important role during the initial stage of warehouse fires and can decide the occurrence of subsequent increasing fire hazards. However, the wavy structural effect of corrugated cardboard on fire spread still lacks enough attention. This work studies the fire spread behavior of vertically-set corrugated cardboard with thicknesses of 1.5 mm, 3.0 mm and 4.0 mm. The cardboard inner hollow gaps are set either parallel (defined as along grain direction) or perpendicular (defined as across grain direction) to buoyancy direction. Experimental results show that: (1) along grain sample has better flammability than across grain sample; (2) the relationship between flame height (or pyrolysis height) and time has a best fit with power law, and the difference of the exponents between two grain orientations decreases with the increasing of the sample thickness; (3) for cardboard of different grain orientations and thickness, the ratio of average flame height to average pyrolysis height is a constant. The hollow gaps inside along grain sample, working as passage, are beneficial for the transportation of heated pyrolysis gases and preheating of upper virgin area, hence increasing burning rate and flame upward spread. However, it is observed that the phenomenon (flame luminance, delamination of front layer, extinguishment of flame base, etc.) difference between different grain orientations decreases as sample thickness increases. This study reveals the effects of grain orientation and sample thickness on the corrugated cardboard fire spread behavior which is common in commodity fire in underground logistic transportation and warehousing. The conclusions are beneficial for fire risk assessment as well as the improvement of related codes and regulations.

Erosion behavior of aluminum by an inclined cavitating jet

The erosion behavior of pure aluminum by an inclined cavitating jet in the acceleration period was experimentally investigated for potential applications in peening and cleaning. The mass loss and surface topography of the eroded specimens were investigated to unravel the erosion mechanism under inclined impingement with various feeding pressure. The cavitation cloud motion was numerically investigated in various erosion stages with two-phase CFD calculation. Results show that at the first optimum standoff distance of mass loss l1 close to the nozzle bottom, erosion occurs in two ring-like areas, whereas the erosion at the downstream second optimum standoff distance l2 appears as a single ring at inclined angles αi∈ [0∘, 15∘] and as separated crescent-shaped areas at αi = 30∘ and 45∘. The increasing αi induces a higher cumulative erosion ratio in the acceleration period at Pin = 15 MPa and 13 MPa, whereas the aggressive ability of inclined impingement is attenuated at Pin = 11 MPa due to the low cavitation intensity. An obvious transition from plastic deformation to erosion damage is found on the boundary of the main erosion area. Under the inclined impingement, the upper side of the main erosion area shows much more severe erosion damage than the lower side due to the blocking effect, where the upward spread of the cavitation clouds is blocked and their collapse primarily occurs in the erosion valley. The erosion develops with the a ring-shaped pattern at αi∈ [0∘, 5∘]. At higher inclined impingement angles αi∈ [15∘, 45∘], the erosion primarily develops along the surface normal direction in the part of the main erosion area closer to the nozzle exit.

Dominant synoptic patterns associated with the decay process of PM&amp;lt;sub&amp;gt;2.5&amp;lt;/sub&amp;gt; pollution episodes around Beijing

Abstract. The variation in the concentrations of ambient PM2.5 (particles with an aerodynamic diameter less than 2.5 µm) generally forms a continuous sawtooth cycle with a recurring smooth increase followed by a sharp decrease. The episode of abrupt decay of pollution is mostly meteorological in origin and is controlled by the passage of synoptic systems. One affordable and effective measure for quickly reducing PM2.5 concentrations in northern China is to wait for a strong wind to arrive. However, it is still unclear how strong the wind needs to be and exactly what kind of synoptic system most effectively results in the rapid decay of air pollution episodes. PM2.5 variations over the 28 pollution channel cities of the Beijing region are investigated to determine the mechanisms by which synoptic patterns affect the decay processes of pollution episodes. This work shows more obvious day-to-day variations in PM2.5 concentration in winter than in summer, which implies that wintertime PM2.5 variations are more sensitive to meteorological factors. There were 365 decay processes from January 2014 to March 2020, and 97 of them were related to the effective wet deposition. In total, 26 %–43 % of PM2.5 pollutant is removed by the wet deposition in different seasons. Two dominant circulation patterns are identified in summer. All the other three seasons have three circulation types (CTs), respectively. The three CTs in spring show the same patterns as those in autumn and winter. The circulation patterns beneficial to the decay processes all exhibit a higher-than-normal surface wind speed, a negative relative humidity anomaly and net outflow of PM2.5 from the domain. In addition, CT1 in spring, autumn and winter is controlled by northeasterly wind and features the most significant horizontal net outflow of air pollutants and effective upward spread of air pollutants to the free atmosphere. CT2 is the most frequent CT in autumn and winter, with the highest wind speed from the northwest, highest boundary layer height (BLH) and lowest relative humidity among the three CTs, all of which are favorable for the reduction of PM2.5 concentrations. In CT3, strong vertical wind shear within the boundary layer enhances the mixing of surface air pollutants, which is the extra cleaning mechanism besides dry and clean air mass inflow. PM2.5 concentrations show significant decreases of more than 37 %, 41 % and 27 % after the passage of CT1, CT2 and CT3, respectively. A dry airflow with a positive BLH anomaly and the effective horizontal outflow of air pollutants are the main reasons for the abrupt decay phase in summer. PM2.5 concentrations after the decay process show a significant decreasing trend from 2014 to 2020, reflecting successful emission mitigation. Emission reductions have led to a 4.3–5.7 µgm-3yr-1 decrease in PM2.5 concentrations in the 28 pollution channel cities of the Beijing region.

Experimental investigation of upward spread forced smoldering phenomenon

Systematic experimental study is carried out to fundamentally understand the governance of external energy source(s) on upward smoldering. Appreciable work had been done on downward spreading smoldering however, upward spread smoldering represents complexity of higher order and is more difficult to suppress. In most of the practical cases, the phenomenon is governed by external flow, thermal, acoustic source(s) and have been a source of enormous mutilation which imposes more scientific research activities in this domain to study this phenomenon. In the present work, upward smoldering phenomenon is investigated for singular and coupled effect(s) of external energy source(s) in the form of regression rate variation. Thorough experimentation was carried out with distinct linear configurations depending on varying forced flow effects on upward spread smoldering under cases of (i) in presence of external heat source (ii) in presence of external alternative energy sources (acoustic energy). Additionally, the role of ash removal was also observed and studied. The results highlight significant effects of different external energy source(s) which varies singularly and as coupled effect on upward smoldering. The complexity is clearly highlighted with continuously varying definitive effect of a particular external source under varying subjective conditions. The results provides better understanding of the coupled external energy source(s) effect and can be utilized effectively for testing, designing and validation of effective fire prevention in both cases of stationary and propagating fires.

An uphill battle? The elevational distribution of alien plant species along rivers and roads in the Austrian Alps

Ever-increasing international trade and anthropogenic activity has led to the relocation of thousands of plant species worldwide. So far, the harsh climate of the European Alps historically has restricted the establishment of alien plants. However, new opportunities created by rising temperatures and increasing human activity might allow alien plants to spread further upwards. Here, the distribution of alien plants along an altitudinal gradient in two Austrian valleys is analyzed. Specifically, the distribution along two contrasting corridors (roads, rivers) and the spread of alien plants into adjacent habitats is examined. Following the MIREN sampling protocol, 20 transects composed of three plots along each river and main road, were established in each study region. Plant species cover and a range of site-specific factors were collected. In total, 641 plant species were recorded, of which 20 were alien. Alien species richness along roads was slightly higher compared to rivers, and the composition of the alien flora differed markedly between roads and rivers. Further, alien plant species richness decreases with distance to roads and rivers (indicating that adjacent habitats are less invaded), as well as with increasing elevation. Mowing along roadsides resulted in lower alien plant species cover, but higher alien plant species richness. Finally, compositional dissimilarity between sites showed that elevation, proximity of a plot to a river or road, and alien plant cover are important factors for higher dissimilarity. This study demonstrates that both natural (rivers) and man-made (roads) corridors play an essential role in the upward spread of different alien plants in mountains.

Image analysis of flame behavior for polyolefins and polystyrene in vertical flame test

AbstractAlthough the UL‐94 vertical flame test is often used to evaluate the flammability of polymers based on ignition time and combustion duration parameters, a significant amount of information regarding the time course of combustion is difficult to analyze in detail. Herein, image analysis of the time course of the upper and lower end heights, total area, and color division of flame was performed for polyolefins and polystyrene with different molecular weights in the vertical flame test. The combustion process was classified into two stages: before and after the first drip. In the first stage, the upward spread velocity, oscillation, and color of flame were analyzed. It was assumed that the difference in the fuel production rates or thermal decomposition products depends on the molecular structure. In the second stage, the melt flowability, flame position, and combustion continuity differed vastly depending on the molecular structure or molecular weight.

Effects of Ambient Parameters and Sample Width on Upward Flame Spread over Thermally Thin Solids

Upward flame spread is the most rapid and hazardous of the different modes of flame spread. Moreover, studies on the effects of ambient parameters on flame spread are very important for fire safety on spacecraft systems. Therefore, the effects of pressure (0 kPa to 70 kPa), oxygen mole fraction (0.30 to 0.90) and sample width (0.3 cm to 2 cm) on upward flame spread over thin papers were studied. A flame break-off phenomenon over papers was firstly observed, which occurred more likely at high oxygen and high pressure conditions. Upward flame spread reached a steady state by varying the ambient parameters and using narrow samples. The smaller sample width narrowed the flammability limits. Differences in upward and downward flame spread were discussed. We found that a power law relationship between flame spread rate and pressure remained valid near the extinction limit for upward spread, while the power law broke down in the extinction region for downward spread. The controlling mechanism of upward spread was revealed by a pressure modeling method showing that the upward flame spread rate was proportional to the Grashof number raised to an exponent of 0.257. For upward flame spread over narrow solids, the gas phase kinetics and radiation effects are less important compared to the heat convection in the flame spread process, which is quite different from the downward spread. This study contributes to the fire safety of space vehicles and enhances the understanding of the controlling mechanism of flame spread.

Morphological and molecular correlates of altered hearing sensitivity in the genetically audiogenic seizure-prone hamster GASH/Sal

Rodent models of audiogenic seizures, in which seizures are precipitated by an abnormal response of the brain to auditory stimuli, are crucial to investigate the neural bases underlying ictogenesis. Despite significant advances in understanding seizure generation in the inferior colliculus, namely the epileptogenic nucleus, little is known about the contribution of lower auditory stations to the seizure-prone network. Here, we examined the cochlea and cochlear nucleus of the genetic audiogenic seizure hamster from Salamanca (GASH/Sal), a model of reflex epilepsy that exhibits generalized tonic–clonic seizures in response to loud sound. GASH/Sal animals under seizure-free conditions were compared with matched control hamsters in a multi-technical approach that includes auditory brainstem responses (ABR) testing, histology, scanning electron microscopy analysis, immunohistochemistry, quantitative morphometry and gene expression analysis (RT-qPCR). The cochlear histopathology of the GASH/Sal showed preservation of the sensory hair cells, but a significant loss of spiral ganglion neurons and mild atrophy of the stria vascularis. At the electron microscopy level, the reticular lamina exhibited disarray of stereociliary tufts with blebs, loss or elongated stereocilia as well as non-parallel rows of outer hair cells due to protrusions of Deiters’ cells. At the molecular level, the abnormal gene expression patterns of prestin, cadherin 23, protocadherin 15, vesicular glutamate transporters 1 (Vglut1) and -2 (Vglut2) indicated that the hair-cell mechanotransduction and cochlear amplification were markedly altered. These were manifestations of a cochlear neuropathy that correlated to ABR waveform I alterations and elevated auditory thresholds. In the cochlear nucleus, the distribution of VGLUT2-immunolabeled puncta was differently affected in each subdivision, showing significant increases in magnocellular regions of the ventral cochlear nucleus and drastic reductions in the granule cell domain. This modified inputs lead to disruption of Vglut1 and Vglut2 gene expression in the cochlear nucleus. In sum, our study provides insight into the morphological and molecular traits associated with audiogenic seizure susceptibility in the GASH/Sal, suggesting an upward spread of abnormal glutamatergic transmission throughout the primary acoustic pathway to the epileptogenic region.

Dichotic integration of acoustic-phonetic information: Competition from extraneous formants increases the effect of second-formant attenuation on intelligibility.

Differences in ear of presentation and level do not prevent effective integration of concurrent speech cues such as formant frequencies. For example, presenting the higher formants of a consonant-vowel syllable in the opposite ear to the first formant protects them from upward spread of masking, allowing them to remain effective speech cues even after substantial attenuation. This study used three-formant (F1+F2+F3) analogues of natural sentences and extended the approach to include competitive conditions. Target formants were presented dichotically (F1+F3; F2), either alone or accompanied by an extraneous competitor for F2 (i.e., F1±F2C+F3; F2) that listeners must reject to optimize recognition. F2C was created by inverting the F2 frequency contour and using the F2 amplitude contour without attenuation. In experiment 1, F2C was always absent and intelligibility was unaffected until F2 attenuation exceeded 30 dB; F2 still provided useful information at 48-dB attenuation. In experiment 2, attenuating F2 by 24 dB caused considerable loss of intelligibility when F2C was present, but had no effect in its absence. Factors likely to contribute to this interaction include informational masking from F2C acting to swamp the acoustic-phonetic information carried by F2, and interaural inhibition from F2C acting to reduce the effective level of F2.