Larger Mean Diameter Research Articles

Exploration of splash function and lateral velocity based on three-dimensional mixed-size grain/bed collision

Based on the discrete element method, the three dimensional mixed-size grain/bed collision process has been investigated in this paper. By considering the influence of lateral impact angle on the mean ejection velocity and ejection number, we obtain that the mean lateral ejection velocity increases with the lateral impact angle at large mean diameter cases and also increases with the impact velocity, while decreases with impact angle. The simulation results indicate that although the lateral impact affects the mean ejection velocity, its effect on the mean ejection number is very limited. Moreover, the mean lateral ejection velocity is influenced by the impact angular velocity. Based on these studies, a more comprehensive three dimensional mixed-size splash function is given. It is of great significance to the particle motion based on turbulence in aeolian sand landform.

Reconstruction of redox conditions during deposition of organic-rich shales of the Upper Triassic Yanchang Formation, Ordos Basin, China

The concentration and distribution of organic matter, phosphate nodules, and framboidal pyrite preserved in shales are controlled by organic matter decomposition and the cycles of phosphorus, sulfur, and iron, which, in turn, are controlled by bottom-water redox conditions. The organic-rich shale in the 7th member of the Upper Triassic Yanchang Formation (Ch7) contains high organic carbon concentrations and abundant phosphate nodules and pyrite framboids, providing an opportunity to better understand the redox conditions at the time of deposition. Framboidal pyrite in the Ch7 organic-rich shales are composed of octahedral, pyritohedral, and spherulitic microcrystals with uniform crystal size. SEM photographs and statistical data suggest that pyrite framboids have large mean diameters (10.0 to 18.1μm) and standard deviations (2.8 to 5.9μm). This may indicate that the organic-rich shale was deposited under oxic-suboxic bottom-water conditions. The Corg:P ratios of the organic-rich shale exhibit considerable variation, ranging from 7.2 to 216, but the majority of them (83.2%) belong to the lower-intermediate range (<130), suggesting that the redox conditions were predominantly oxic-suboxic and intermittently anoxic. The Corg:P ratios also show periodic vertical variation, which suggests that redox conditions fluctuated between oxic-suboxic and anoxic. Additional support for the trends based on Corg:P ratios is provided by DOPT values, which show similar vertical variation and redox patterns. All evidence shows that the redox conditions during deposition of the Ch7 organic-rich shale was predominantly oxic-suboxic accompanied by intermittent anoxic environments. The result of this study will be helpful in better understanding the formation mechanism of the Ch7 organic-rich shale.

LINKING LUNG AIRWAY STRUCTURE TO PULMONARY FUNCTION VIA COMPOSITE BRIDGE REGRESSION.

The human lung airway is a complex inverted tree-like structure. Detailed airway measurements can be extracted from MDCT-scanned lung images, such as segmental wall thickness, airway diameter, parent-child branch angles, etc. The wealth of lung airway data provides a unique opportunity for advancing our understanding of the fundamental structure-function relationships within the lung. An important problem is to construct and identify important lung airway features in normal subjects and connect these to standardized pulmonary function test results such as FEV1%. Among other things, the problem is complicated by the fact that a particular airway feature may be an important (relevant) predictor only when it pertains to segments of certain generations. Thus, the key is an efficient, consistent method for simultaneously conducting group selection (lung airway feature types) and within-group variable selection (airway generations), i.e., bi-level selection. Here we streamline a comprehensive procedure to process the lung airway data via imputation, normalization, transformation and groupwise principal component analysis, and then adopt a new composite penalized regression approach for conducting bi-level feature selection. As a prototype of composite penalization, the proposed composite bridge regression method is shown to admit an efficient algorithm, enjoy bi-level oracle properties, and outperform several existing methods. We analyze the MDCT lung image data from a cohort of 132 subjects with normal lung function. Our results show that, lung function in terms of FEV1% is promoted by having a less dense and more homogeneous lung comprising an airway whose segments enjoy more heterogeneity in wall thicknesses, larger mean diameters, lumen areas and branch angles. These data hold the potential of defining more accurately the "normal" subject population with borderline atypical lung functions that are clearly influenced by many genetic and environmental factors.

Raindrop Size Distribution in a Midlatitude Continental Squall Line Measured by Thies Optical Disdrometers over East China

AbstractDisdrometer data measured by ground-based optical disdrometers during a midlatitude continental squall line event on 18 August 2012 in Shandong Province, eastern China, are analyzed to study characteristics of raindrop size distribution (DSD). Four disdrometers simultaneously performed continuous measurements during the passage of the convective line. The convective line was partitioned into three regions: the convective center, leading edge, and trailing edge. Results show distinct differences in DSDs and integral rainfall parameters between the convective-center and the edge regions. The convective center has higher drop concentrations, larger mean diameters, and wider size distributions when compared with the edge regions. The leading and trailing edges have similar drop concentrations, but the latter has larger mean diameters and wider size distributions. The shape of DSD for the convective center is convex down, whereas it is convex upward in tropical continental squall lines, as reported in the literature. There is also spatial variability of the DSD and its integral rainfall parameters in the along-convective-line direction.

Preparation and characterization of mesoporous electrospun (SiO2)0.59(CaO)0.36−x(P2O5)0.05(TiO2)x glasses (x = 0 and 0.05 mol%)

In this study, mesoporous glass nanotubes in both systems of 59SiO2–36CaO–5P2O5 (mol%) and 59SiO2–31CaO–5P2O5–5TiO2 (mol%) were successfully prepared using polyvinylpyrrolidone (PVP) via coaxial electrospinning process. Then, the significant effects of TiO2 addition on nanotubes morphology and adsorption were investigated. The PVP was extracted through calcination at 600 °C with heating rate of 2 °C/min for 5 h in the air. The characteristics of the samples were identified by field emission scanning electron microscopy, simultaneous thermal analysis, X-ray powder diffraction, Fourier transform infrared spectroscopy, and nitrogen sorption porosimetry (BET). The results indicated that the sample with additive TiO2 had larger mean diameter with non-smooth surface rather than without TiO2. After calcination at 600 °C for 5 h, the sample with TiO2 had aggregation and the particles stuck together, while without TiO2 presence a homogeneous structure without any agglomeration was observed. TiO2 addition was also effective on the adsorption; the BET surface area, pore volume, and pore size from 167 m2/g, 0.5 cm3/g, and 11.9 nm were modified to 127 m2/g, 0.23 cm3/g, and 8.2 nm respectively.

The Pfannenstiel scar and its implications in DIEP flap harvest: a clinical anatomic study

Despite the utility of the deep inferior epigastric artery perforator (DIEP) flap, the presence of abdominal wall scars can limit flap perfusion. Pfannnstiel scars are among the most common abdominal scars, during which undermining at either a subfascial or suprafascial level can damage perforators. There is an anecdotal belief that raising a DIEP flap in the presence of a Pfannenstiel scar may be less reliable due to vascular disruption. A clinical prospective analysis of retrospectively recorded imaging from 150 patients (300 hemi-abdominal walls) was undertaken. Preoperative imaging, with two computer software programmes used to reconstruct three dimensional (3-D) volume-rendered images and analyse vasculature, was used to accurately identify and measure perforators. A total of 959 perforators were identified, with 319 perforators identified in the ‘Pfannenstiel scar’ group and 640 perforators in the ‘no abdominal scar’ group. All patients, except for one patient with a Pfannenstiel scar, had one or more perforators that were larger than 1.0 mm in diameter. There were no differences in the number of DIEA perforators (6.81 vs 6.22, p = 0.2819); however, perforators of the ‘Pfannenstiel scar’ group were of larger mean diameter than the ‘no abdominal scar’ group (0.96 vs 0.85 mm (p = 0.0027). The presence of a Pfannenstiel scar is associated with larger perforator size than controls and no diminution in overall perforator number. As such, a Pfannenstiel scar may in fact aid DIEP flap harvest, a finding consistent with anecdotal outcomes. Level of Evidence: Level III, risk / prognostic study.

A guild-based approach to assessing the influence of beech forest structure on bird communities

The advantages of using birds as indicators of biodiversity and/or habitat quality in forest habitats rely principally (1) on their relative ease of detection and (2) on their strong association with many forest features. Here we investigate how forest structure can shape a bird community at the stand level (ca. 30hectares), using an expeditious sampling protocol and a simple but reasoned guild approach. We focused on three beech (Fagus sylvatica) forests in Italy with different structures resulting from different management histories: Cansiglio, Chiarano-Sparvera and Marchesale. We hypothesise that the abundance of the selected guilds varies in relation to forest structure as a result of forest management; to test this hypothesis we modelled guild abundance along a latitudinal transect in a similar habitat (i.e. beech forest) in order to offset the geographical and environmental sources of variability. Birds were surveyed through replicated aural/visual point counts. Thus we identified four guilds: generalist cavity nesters (TIT), generalist canopy nesters (WAR), insectivorous cavity nesters (INS) and granivorous canopy nesters (FIN). Forest structure and deadwood were estimated for each of the 27 sampling points. Guild abundance was estimated using the N-mixture models approach, which allows the mean abundance at each sampling location and the detectability to be estimated. Both the mean abundance and detectability were constrained to forest structure and time variables. Guild-estimated abundance was tested for differences among sites using ANOVA. Mean guild abundance proved different only for two guilds. INS was more abundant in Cansiglio than in Chiarano and Marchesale while between Chiarano and Marchesale there was no significant difference. Also WAR abundance was greater in Chiarano, followed by Marchesale and Cansiglio. Shelterwood management may result in a higher abundance of specialist guilds (i.e. insectivorous cavity nesters), compared to other management options. Our results highlight this pattern in the Cansiglio forest, where the age and the applied treatments resulted in a lower tree density and in a larger mean diameter. Such features are often correlated with a larger amount of dead wood which, in turn, promotes the presence of cavity nesters, otherwise rare-to-absent in the bird community. Forest structure is largely influenced by forest management that can be guided to benefit specific bird assemblages by applying specific treatments focused at increasing structural diversity and at multi-functionality.

Hexafluoroisopropanol-modified cetyltrimethylammonium bromide/sodium dodecyl sulfate vesicles as a pseudostationary phase in electrokinetic chromatography

A novel catanionic surfactant vesicle system, formulated from hexafluoroisopropanol (HFIP), cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), was developed as pseudostationary phase (PSP) in electrokinetic chromatography (EKC). HFIP, as an organic modifier with the prominent properties of ionization, hydrogen bond donor and hydrophobicity, was used to effectively promote the spontaneous vesicle formation from CTAB/SDS mixed aqueous solutions, where precipitates are easy to occur due to long carbon chains, and adjust the performance of CTAB/SDS vesicles. The physical features (size and viscosity) and electrophoretic parameters (electroosmotic mobility, electrophoretic mobility and elution range) of HFIP-modified CTAB/SDS vesicles were characterized as HFIP volume content (0–4%, v/v), CTAB/SDS molar ratio (2:8–7:3mol/mol) and total surfactant concentration (10–50mM) varying, respectively. The 3% v/v HFIP-modified CTAB/SDS (3:7mol/mol, 50mM) vesicle system proves to have the largest mean diameter (288.20nm) and the widest elution range (12.41), which is also much wider than that of the corresponding other four PSP systems including trifluoroethanol (TFE)-modified CTAB/SDS vesicles (5.69), isopropanol-modified CTAB/SDS micelles (2.03), HFIP-modified SDS micelles (4.86) and unmodified SDS micelles (3.12). The chromatographic performance of the HFIP-modified vesicle system was evaluated by separating eight polycyclic aromatic hydrocarbons, nitrotoluene positional isomers, five positively charged and five negatively charged/neutral drugs, respectively. Baseline or near-baseline separation was achieved for each series of solutes. Compared with the TFE-modified vesicle system, as well as the HFIP-modified and unmodified SDS micelle systems, the HFIP-modified vesicle system shows the best separation selectivity, the highest or comparable efficiency, and the lowest retention.

The effect of the particle size distribution on the mechanics of fibre-reinforced sands under one-dimensional compression

Seven reconstituted sands of different mineralogies and different particle size distributions, from uniform to well-graded and coarse to fine, were tested under one-dimensional compression, with and without reinforcement by discrete fibres. The compressibility, the particle breakage and the associated change in particle shape were examined in the sands with and without reinforcement. Each reconstituted sand was found to have a unique normal compression line. The compressibility increased with increasing uniformity and with larger mean diameters, thus coarse uniform sands were found to be the most compressible. They also underwent more breakage of particles, which was more significant in the weaker carbonate sands. At the grain scale, the addition of fibres seemed to reduce the amount of particle breakage in the soil, more significantly in well-graded sands. A unique NCL was found for each fibre-reinforced sand, parallel to that of the corresponding non-reinforced sand. A strong correlation was found between the ability of the fibres to prevent particle breakage and their ability to limit changes in particle shape.

Transmission electron microscopy investigations of bubble formation in He-implanted polycrystalline SiC

The formation of He bubbles observed in the hot-pressed polycrystalline SiC samples implanted with 230 keV He ions with fluences ranging from 5 × 1015/cm2 to 1 × 1017/cm2 at room temperature and subsequently annealed at 1000 °C for 30 min was investigated. The morphology and density of the bubbles in grain interiors (GIs) and at grain boundaries (GBs) are related to the implantation fluence. After a fluence of 5 × 1015/cm2 implantation, the distribution of the bubbles is heterogenous in the damage region. Disk-shaped arrangements of the bubbles associated with dislocation loops and stacking faults are observed in GIs. A high density of triangle-shaped bubbles is observed at GBs. After a fluence of 1 × 1016/cm2 implantation, the distribution of the bubbles is homogenous in the damage region. A high density of circular bubbles associated with dislocation loops is observed in GIs. After fluences of (2.5–10) × 1016/cm2 implantation, the results show a low density but a large mean diameter of the bubbles at GBs as compared to the GIs cases. In GIs, the buried layer of the bubbles broadens as compared to that observed in the sample implanted with a fluence of 1 × 1016/cm2. The distributions of the density and diameter of the bubbles are discussed.

Pollen Morphology and Viability Relates to Seed Production in Hybrid Roses

ABSTRACTFertility of hybrid tea roses is often reduced due to their interspesific origin but also to intensive inbreeding. New genotypes used as pollen donors represent an economic risk for a breeding program, as their influence on seed production is unknown. In this study 9 garden rose genotypes were selected from a company database as high fertile or low fertile male parents, according to the number of seeds per hybridization. Pollen morphology and in vitro germination of the selected genotypes were characterized. Pollen was either small (mean diameter = 30 urn), shrunken, and irregular (abnormal), or large (mean diameter = 30 urn), elliptical and crossed by furrows (normal). High correlations were found between the number of seeds produced per hybridization and the pollen diameter (r = 0.94) or the percentage of normal pollen (r = 0.96). In order to evaluate the predictive power of the models, we conducted regression analyses and performed a validation experiment on genotypes not present in the database and without background information on fertility. Pollen diameter and percentage of normal pollen were characterized and fitted in the regression models for seed set predictions. Validation with an independent dataset gave a good prediction for 83.3% of the data. This indicates that using either the mean pollen diameter or the percentage of normal pollen resulted in effective fertility prediction. Moreover cluster analysis of the data classified all the cultivars into various groups with varying fertility. This tool could enhance the genetic variability in crossings between hybrid tea roses, thus creating possibilities for less economically risky exploitation of new tetraploid genotypes as male parents.

Native trees show conservative water use relative to invasive trees: results from a removal experiment in a Hawaiian wet forest.

While the supply of freshwater is expected to decline in many regions in the coming decades, invasive plant species, often 'high water spenders', are greatly expanding their ranges worldwide. In this study, we quantified the ecohydrological differences between native and invasive trees and also the effects of woody invasive removal on plot-level water use in a heavily invaded mono-dominant lowland wet tropical forest on the Island of Hawaii. We measured transpiration rates of co-occurring native and invasive tree species with and without woody invasive removal treatments. Twenty native Metrosideros polymorpha and 10 trees each of three invasive species, Cecropia obtusifolia, Macaranga mappa and Melastoma septemnervium, were instrumented with heat-dissipation sap-flux probes in four 100 m(2) plots (two invaded, two removal) for 10 months. In the invaded plots, where both natives and invasives were present, Metrosideros had the lowest sap-flow rates per unit sapwood, but the highest sap-flow rates per whole tree, owing to its larger mean diameter than the invasive trees. Stand-level water use within the removal plots was half that of the invaded plots, even though the removal of invasives caused a small but significant increase in compensatory water use by the remaining native trees. By investigating the effects of invasive species on ecohydrology and comparing native vs. invasive physiological traits, we not only gain understanding about the functioning of invasive species, but we also highlight potential water-conservation strategies for heavily invaded mono-dominant tropical forests worldwide. Native-dominated forests free of invasive species can be conservative in overall water use, providing a strong rationale for the control of invasive species and preservation of native-dominated stands.

Primary Gliosarcoma of the Brain: Radiologic and Histopathologic Features

Gliosarcoma is a rare central nervous system (CNS) neoplasm with biphasic glial and non-glial malignant components. Here we describe the radiologic and histopathologic features observed in five cases of primary gliosarcoma. The mean age at diagnosis in the studied patients was 54.2 years; these patients were predominantly males (male:female ratio = 4:1). At diagnosis all patients had several clinical deterioration. The most common symptoms of presentation were: headache (5/5 cases), seizures (4/5 cases) and hemiparesis (1/5 cases). All the tumors were large (mean major diameter= 4.12±1.64 cm) at diagnosis as evidenced in computer tomography (CT) scans and magnetic resonance images (MRIs), with preferential involvement of the temporal lobe and frequent associated deviation of the midline structures. Other common characteristics identified on CT scans and MRIs were partial contrast medium uptake with annular pattern (5/5 cases), peripheral edema (5/5 cases), and central calcification (3/5 cases). In additional a peak of dye uptake was observed (4/5 cases) on MRI spectrometry. In the histopathology, the glial component showed malignant astrocytes, with high Ki67 (>60%) and p53 positivity; the sarcomatous components displayed pleomorphic spindle cells similarly with p53 positivity and high Ki67 (75-90%) in all cases. Dedifferentiation to pleomorphic sarcoma (two cases), fibrosarcoma (one case), leiomyosarcoma (one case) and MPNST (one case) were documented. All patients received radiotherapy/chemotherapy and had a median overall survival of ten months. The study of radiologic and histopathologic features in primary gliosarcomas of the brain is a priority to achieve early diagnosis that can be translated to better outcomes. Here we describe the radiologic and histopathologic features observed in a group of gliosarcoma patients with variable histopathologic dedifferentiation.

Spectrum of Surgically Treated Thyroid Carcinoma in Latvia

Abstract Introduction Health care statistics provides a solid evidence of increasing thyroid cancer prevalence in Latvia. However, in order to characterise the problem of thyroid cancer more completely, histological type and stage of carcinomas as well as demographic characteristics of the affected patients would be as important as the total burden of new cases. Aim of the study was to provide detailed characteristics of the spectrum of surgically treated primary thyroid carcinoma. Materials and methods. The study was designed as retrospective research. Archives of a single university hospital were searched for consecutive, surgically treated or histologically proved cases of primary thyroid carcinoma (2008 - 2012). Each case was characterised by histological type, local tumour spread, largest diameter of the carcinoma, patient’s age and sex as well as extent of surgical treatment. Descriptive statistics was carried out by CIA software. Results. Archive search yielded 323 primary thyroid carcinoma cases, including 255 cases (78.9%; 95% confidence interval (CI) = 74.2 - 83.0) of papillary carcinoma, 54 cases (16.7%; 95% CI = 13.1 - 21.2%) of follicular carcinoma and 7 cases (2.2%; 95% CI = 1.1 - 4.4%) of medullary and anaplastic carcinoma. Although the youngest cases (aged 18 and 20 years) were diagnosed with papillary and follicular carcinoma, respectively, the mean age did not show statistically significant differences between the groups. Strong female predominance was observed regardless of cancer type. Regarding local tumour spread, pT1a was significantly more frequent in papillary carcinoma: 50.2% (95% CI = 44.1 - 56.3) in contrast to 18.5% (95% CI = 10.4 - 28.9) in case of follicular carcinoma. Total thyroidectomy was the most frequent type of operation that was applied for 28.6 - 71.4% cases in relation to histological type. Conclusions. This is the first research work in Latvia that comprehends the overall review of the morphological spectrum of thyroid carcinoma in the surgical material. Papillary and follicular carcinomas are the most frequently identified types in accordance with the global data. Much less common morphological forms of thyroid tumours were also diagnosed - medullary carcinoma and anaplastic thyroid carcinoma. The large mean diameter of follicular carcinoma in the surgery material and the fact that more than half of follicular carcinomas are revealed as pT2-T3 tumours highlights the necessity for up-to-dated diagnostics and elaboration of reliable novel molecular tests.

Surgical management of isolated superficial femoral artery degenerative aneurysms

To investigate the mode of presentation, diagnosis, association with other aneurysms, operative management, and outcomes of superficial femoral artery (SFA) aneurysms. Records of all patients who underwent surgery for isolated, true SFA aneurysms (not due to infection, vasculitis, or tissue disorders) from 2002 to 2012 in two European centers were retrospectively analyzed. Demographic (sex, age), clinical (cardiovascular risk factors, location of the aneurysm, symptoms, presentation, emergency setting), surgical and radiological data (diameter, surgical technique, runoff vessels patency, presence of aneurysms elsewhere) were obtained for analysis. Follow-up was undertaken with clinical and ultrasound examinations at 1 month, 3 months, 6 months, 12 months, and yearly thereafter. The patency of the graft and the status of the anastomoses and inflow and outflow vessels were assessed. Main end points were represented by 30 days and long-term mortality and amputation-free survival. A total of 27 cases of SFA aneurysm were analyzed. Mean age at operation was 78 years ± 8.5. At presentation, SFA aneurysms were often symptomatic (rupture was present in 7/27 cases and acute distal ischemia in 6/27 cases), large (mean diameter, 54 mm ± 33.1 mm), bilateral (38% of the cases), and associated with aneurysms elsewhere (84%). Sixteen patients underwent resection of the aneurysm and polytetrafluoroethylene interposition graft, seven patients exclusion of the aneurysm with a femoropopliteal bypass (autogenous bypass in five cases, prosthetic in two), three patients simple ligation, and one patient underwent primary amputation. Mean follow-up was 41.47 months (range, 0.43-128.67 months). Early (<30 days) mortality and amputation rate were 4% and 7%, respectively. Estimated 5-year survival, limb salvage, and graft patency rates were 62%, 88%, and 85%, respectively. Degenerative aneurysms of the SFA display peculiar characteristics (in terms of clinical onset, diagnostic timing, and clinical behavior) so that they differ from other peripheral aneurysms. In fact, they often grow to reach a considerable diameter before medical attention is sought, presenting with rupture or ischemia at diagnosis. SFA aneurysms preferentially affect elderly men and are often associated with aneurysms elsewhere. However, despite their rarity, the treatment is usually feasible, and long-term outcomes are good.

Technique for delivering large tumors in video-assisted thoracoscopic lobectomy

The optimal technique for delivering large tumors during video-assisted thoracoscopic lobectomy remains uncertain. In 258 patients receiving video-assisted thoracoscopic lobectomy for lung cancer, techniques for delivering the resected lobe included complete video-assisted thoracoscopic lobectomy without rib spreading (n = 206, 80%), resection of a short rib segment (n = 9, 3%), brief rib spreading (n = 12, 5%), and conversion to a minithoracotomy (n = 21, 8%). In 10 (4%) patients, a novel anterior rib cutting technique was used: one rib at the utility port was cut near its anterior end to widen the intercostal space without forcible rib spreading for lobe delivery. There was no mortality or major morbidity using the anterior rib cutting technique, and it delivered tumors of a larger mean diameter than complete video-assisted thoracoscopic lobectomy (5.4 ± 3.4 vs. 2.3 ± 1.4 cm, p = 0.017) whilst yielding a similar mean operation time and blood loss to the other non-complete video-assisted thoracoscopic lobectomy techniques. The anterior rib cutting technique gave similar postoperative patient pain scores and analgesic use to complete video-assisted thoracoscopic lobectomy, and shorter mean hospital stay than the other non-complete video-assisted thoracoscopic lobectomy techniques (5.6 ± 2.8 vs. 10.0 ± 7.1 days, p = 0.003). In video-assisted thoracoscopic lobectomy, the anterior rib cutting technique is a safe and feasible procedure for delivering large tumors, causing no more pain than complete video-assisted thoracoscopic lobectomy, and allowing faster recovery than other non-complete video-assisted thoracoscopic lobectomy techniques.

Intratumoral Gas in Hepatocellular Carcinoma following Transarterial Chemoembolization: Associated Factors and Clinical Impact

PurposeTo determine the frequency and factors associated with the presence of intratumoral gas-containing areas in hepatocellular carcinoma (HCC) on computed tomography (CT) scans obtained 4–6 weeks after transarterial chemoembolization. Materials and MethodsFrom June 2010 to December 2011, 201 patients underwent 286 chemoembolization procedures for HCC (n = 497 tumors) and were retrospectively included. The presence of intratumoral gas was assessed on CT 4–6 weeks after chemoembolization. Clinical and biologic data and tumoral and chemoembolization procedure characteristics were noted. Factors associated with the presence of intratumoral gas were evaluated. Tumor response was assessed by using European Society for the Study of the Liver criteria. Tumors containing gas or not containing gas were compared by univariate and multivariate analysis. ResultsIntratumoral gas was found in 26 tumors (5%) after 26 chemoembolization procedures (9.1%) in 26 patients (13%). Gas was related to abscess formation in three patients (11.5%). On multivariate analysis, a large mean tumor diameter at baseline (72.4 mm vs 40.2 mm; P = .003), chemoembolization with drug-eluting beads (P = .033), and superselective approach (P = .024) were independently associated with the presence of gas. Tumors that exhibited gas-containing areas at 1 month had a significantly higher objective response rate than those that did not (P < .0001). ConclusionsIntratumoral gas-containing areas after chemoembolization are rarely related to the formation of abscesses. The presence of intratumoral gas on CT 4–6 weeks after chemoembolization could be a surrogate marker for marked tumor necrosis.

A Comparative Analysis of the Flow Properties between Two Alumina-Based Dry Powders

We measured and compared the flow properties of two alumina-based powders. The alumina powder (AP) is irregularly shaped and has a smooth surface and moisture content of 0.16% (d.b.), and the ceramic powder (CP), obtained after atomization in a spray dryer, is spherical and has a rough surface and moisture content of 1.07%. We measured the Hausner ratio (HR), the static angle of repose (AoR), the flow index (FI), the angle of internal friction, and the wall's friction angle. The properties measured using aerated techniques (AoR and HR) demonstrated that AP presents true cohesiveness (and therefore a difficult flow), while CP presents some cohesiveness and its flow might be classified as half way between difficult and easy flow. Their FI values, which were obtained using a nonaerated technique, enable us to classify the alumina as cohesive and the ceramic powder as an easy-flow powder. The large mean diameter and morphological characteristics of CP reduce interparticle forces and improve flowability, in spite of the higher moisture content of their granules. The angles of internal friction and of wall friction were not significantly different when comparing the two powders.

Evolution of Aerosol Particles in the Rainfall Process via Method of Moments

The method of moments is employed to predict the evolution of aerosol particles in the rainfall process. To describe the dynamic properties of particle size distribution, the population balance equation is converted to moment equations by the method of moments and the converted equations are solved numerically. The variations of particle number concentration, geometric mean diameter, and geometric standard deviation are given in the cases that the Brownian diffusion and inertial impaction of particles dominate, respectively. The effects of raindrop size distribution on particle size distribution are analyzed in nine cases. The results show that the particle number concentration decreases as time goes by, and particles dominated by Brownian diffusion are removed more significantly. The particle number concentration decreases much more rapidly when particle geometric mean diameter is smaller, and the particle size distribution tends to be monodisperse. For the same water content, the raindrops with small geometric mean diameters can remove particles with much higher efficiency than those with large geometric mean diameters. Particles in the “Greenfield gap” are relatively difficult to scavenge, and a new method is needed to remove it from the air.

Nest-Site Characteristics of Three Woodpecker Species in Managed Ponderosa Pine Forests of the Eastern Cascade Range

Abstract In order to conserve populations of woodpeckers in managed forests of the inland Northwest, managers require information about the nest substrates (for example, trees and snags) in which woodpeckers excavate cavities and the habitat characteristics surrounding those substrates. I describe and compare the nest-site characteristics of the White-headed Woodpecker (Picoides albolarvatus), Hairy Woodpecker (Picodes villosus), and Northern Flicker (Colaptes auratus) in burned and unburned logged Ponderosa Pine (Pinus ponderosa) stands of the eastern Cascade Range of Washington, 2003 to 2010. All 3 woodpecker species most frequently excavated cavities in well-decayed snags. In burned stands, Northern Flickers used nest substrates that had a larger mean diameter at breast height (dbh) than those used by Hairy Woodpeckers, and that were shorter in height than those used by Hairy and White-headed Woodpeckers. Northern Flickers also excavated cavities lower in height than Hairy Woodpecker cavities. In unbur...