Volumetric Loss Research Articles

Investigation of wear and friction characteristic of Al/(Si3N4)np nano composites under as-cast and heat-treated conditions

Several automotive components, such as clutch plate, piston and cylinder liner, etc., require excellent wear characteristics. The current study focused on fabricating nano Si3N4 reinforced Al alloy composites through a stir casting route with ultrasonic assistance, then performing T-6 heat treatment to alter their properties. Dry sliding wear tests were performed to investigate the frictional and wear characteristics at various applied loads and sliding distances. Results reveal that the coarse grain of α-Al was significantly refined after incorporating nano Si3N4 particles in it, and their structure was transformed from coarse columnar to rosette-like dendrites. The hardness and wear resistance increase with nano Si3N4 addition and T-6 heat treatment. The formation of SiO2 and Fe2O3 layers at the interacting interface significantly reduces the coefficient of friction of nanocomposites. The volumetric loss increased with load (15 N to 45 N) and sliding distance (500 m to 3000 m) for cast and heat-treated samples. The maximum volumetric loss was found in the case of as-cast alloy and the minimum for heat-treated Al/2wt.% Si3N4 nanocomposites. The SEM investigation of worn surfaces shows that the adhesive mechanism is more dominant in alloys, whereas the abrasive wear mechanism was associated with nanocomposites.

Wear behavior and abrasiveness of monolithic CAD/CAM ceramics after simulated mastication

ObjectivesTo evaluate the wear resistance and abrasiveness of monolithic CAD/CAM ceramics.Materials and methodsRectangular-shaped specimens (12 mm × 6.5 mm × 1.5 mm) were sectioned from the following CAD/CAM blocks (n = 10); partially crystallized lithium disilicate (PLD), experimental fully crystallized lithium disilicate (FLD), zirconia-reinforced lithium silicate (ZLS), super-translucent monolithic zirconia (SMZ), and ultra-translucent monolithic zirconia (UMZ). Silicon carbide papers were used to mechanically flatten and polish the surfaces. PLD specimens were subjected to a combined crystallization/glazing firing cycle. Ceramic specimens were mounted to the wear device and tested for 200,000 cycles against human premolars at 20 N force and 2 mm sliding distance. Artificial saliva was used as a lubricant. The teeth were scanned using micro-CT before and after the wear test and the generated models were overlapped to determine the volumetric tooth loss. Before and after the test, specimens’ weights and surface roughness (Ra) values were measured, and the differences were calculated. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were utilized for microstructural and chemical analysis. Statistical analysis was performed using one-way ANOVA or an equivalent test for non-parametric results. Significance level was set at P ≤ 0.05.ResultsThe type of ceramic material affected the ceramic and antagonist wear rates (P < 0.001). PLD and ZLS had the highest ceramic and antagonist wear, whereas UMZ and SMZ demonstrated the lowest wear values. The FLD group showed comparable antagonist wear and significantly less ceramic wear than PLD and ZLS.ConclusionsMonolithic zirconia demonstrated the best wear resistance and least abrasiveness to the antagonist. The experimental lithium disilicate was more wear-resistant than other glass–ceramic groups.Clinical relevanceMonolithic zirconia is wear-resistant and gentle on the antagonist. In contrast, glass–ceramics are more abrasive to enamel.

Cerebrospinal Fluid sTREM2 Has Paradoxical Association with Brain Structural Damage Rate in Early- and Late-Stage Alzheimer's Disease.

Recently it has been proposed that microglial response has a stage-dependent effect on the progression of Alzheimer's disease (AD). Cerebrospinal fluid (CSF) sTREM2 has emerged as a promising microglial activation marker. To test the stage-dependent role of microglia by studying the association between baseline sTREM2 and dynamic brain structural changes in AD and mild cognitive impairment (MCI) patients. 22 amyloid-β-positive (A+) and tau-positive (T+) AD and 24 A+T+MCI patients were identified from the Alzheimer's Disease Neuroimaging Initiative. The patients had baseline CSF amyloid-β, phosphorylated-tau, and sTREM2, and were followed up for at least one year by T1-weighted and diffusion tensor imaging scans. Gray matter volumes and white matter microstructural integrity were evaluated. Linear mixed models were applied to analyze how baseline sTREM2 may influence the rate of brain structural changes while adjusting for the effects of age, APOE4 status, and the CSF core markers. In A+T+AD patients, baseline CSF sTREM2 was associated with faster mean diffusivity increase in the bilateral posterior corona radiata and right superior longitudinal fasciculus. In A+T+MCI patients, baseline CSF sTREM2 was associated slower gray matter volumetric loss in parahippocampal gyrus, left fusiform cortex, left middle temporal gyrus, and left lateral occipital cortex. Baseline CSF sTREM2 also had a protective effect against mean diffusivity increase in right inferior fronto-occipital fasciculus, left superior longitudinal fasciculus, left forceps minor, and left uncinate fasciculus. Microglial activation at early stage might have a protective effect against neurodegeneration, while at late stage it might facilitate AD. Future efforts on modulating microglial activation could be promising, given a carefully selected time window for intervention.

Parameter optimization for enhancing tribological properties of sol–gel alumina and aluminum silicate-coated aluminum alloy: Grey–Taguchi method

The degradation of materials by wear is reduced by the wet chemical technique, where a thin film is coated over the surface susceptible to wear. The sol–gel coating method is one of the wet chemical techniques normally employed to improve tribological and anti-corrosive properties. This paper deals with evaluating tribological properties such as coefficient of friction, volumetric wear loss, and corrosive stability of alumina and aluminum silicate-coated aluminum alloy A356. The coating parameters affecting the tribological properties are identified and the experiments are designed using Taguchi orthogonal array and optimized using the Grey relation analysis technique. The tribological characteristics at room temperature are evaluated using a pin on disc tribometer. Among the sol–gel coating parameters chosen for minimizing the effect of wear and coefficient of friction between surfaces, the temperature for heat treatment and pH of the sol–gel are identified as the critical parameters that affect the tribological characteristics. The corrosive stability of the samples has been evaluated by corrosion current, corrosion potential, and corrosive stability methods. It is found that tribological properties and corrosive stability are improved for the coated sample compared with the uncoated sample. It is also observed that alumina coating provides better tribological properties and aluminum silicate coating provides better corrosive stability.

On the use of kinetic energy balance for the volumetric identification of drag sources of a blunt body. Application to road vehicles

A volumetric identification of drag sources is proposed using the Reynolds equation for the integral mean momentum and mean flow kinetic energy balance. This methodology works independently of the turbulence model used in CFD and relies on a physical interpretation. The approach, developed in the context of automotive engineering, is of general use. A road vehicle is indeed a complex multi-scale geometry and all the flow regions are interacting. As far as the kinetic energy of the mean flow is concerned, the main volumetric loss is production of turbulent kinetic energy at all relevant sub-scales of the body. The quantitative link to the power of the mean drag force is derived from first principles. For practical applications, the volume integral used to compute the volumetric losses can be decomposed in user-defined regions and integrated into optimization loops. Indeed, if losses in a given flow region are minimized, consequences can be precisely and quantitatively evidenced for all other regions. Applications to a model two-dimensional test case and a real car geometry are discussed.

Two-body wear of occlusal splint materials from subtractive computer-aided manufacturing and three-dimensional printing

ObjectivesTo investigate the two-body wear of occlusal splint materials fabricated from subtractive computer-aided manufacturing (CAM) compared to three-dimensional printing (3DP).Material and methodsForty-eight substrates (n = 12/material) in the design of a mandibular first molar were fabricated using CAM (CAM-TD, Thermeo, pro3dure medical GmbH, Iserlohn, Germany; CAM-CL, CLEARsplint, Astron Dental Corporation, Lake Zurich, USA) and 3DP (3DP-GI, GR22 flex, pro3dure medical GmbH; 3DP-KY, KeySplint soft, Keystone Industries, Gibbstown, USA). The substrates were subjected to mastication simulation (120,000 cycles, 37 °C, 50 N, 1.3 Hz) opposed to enamel antagonists. The two-body wear was measured through matching of the scanned substrates before and after aging using Gaussian best-fit method. The damage patterns were categorized and evaluated based on microscopic examinations. Data was analyzed using Kolmogorov–Smirnov test followed by 1-way analysis of variance (ANOVA). Pearson correlation was calculated between vertical and volumetric material loss. The failure types were analyzed with Chi2-test and Ciba Geigy table.ResultsNo difference in two-body wear results between all materials was found (p = 0.102). Fatigue substrates showed a perforation for CAM and a fracture for 3DP. No abrasion losses on the antagonists were detected.Conclusions3DP substrates showed no differences in two-body wear compared to CAM ones but are more likely to show a fracture. None of the tested materials caused an abrasion on human teeth structure.Clinical relevanceWhile therapies with occlusal splint materials are rising, 3DP offers a promising alternative to CAM in terms of production accuracy and therapeutic success at reduced costs.

Recellularization of Bioengineered Scaffolds for Vascular Composite Allotransplantation.

Traumatic injuries or cancer resection resulting in large volumetric soft tissue loss requires surgical reconstruction. Vascular composite allotransplantation (VCA) is an emerging reconstructive option that transfers multiple, complex tissues as a whole subunit from donor to recipient. Although promising, VCA is limited due to side effects of immunosuppression. Tissue-engineered scaffolds obtained by decellularization and recellularization hold great promise. Decellularization is a process that removes cellular materials while preserving the extracellular matrix architecture. Subsequent recellularization of these acellular scaffolds with recipient-specific cells can help circumvent adverse immune-mediated host responses and allow transplantation of allografts by reducing and possibly eliminating the need for immunosuppression. Recellularization of acellular tissue scaffolds is a technique that was first investigated and reported in whole organs. More recently, work has been performed to apply this technique to VCA. Additional work is needed to address barriers associated with tissue recellularization such as: cell type selection, cell distribution, and functionalization of the vasculature and musculature. These factors ultimately contribute to achieving tissue integration and viability following allotransplantation. The present work will review the current state-of-the-art in soft tissue scaffolds with specific emphasis on recellularization techniques. We will discuss biological and engineering process considerations, technical and scientific challenges, and the potential clinical impact of this technology to advance the field of VCA and reconstructive surgery.

Accuracy of 3D dynamic navigation system for fiber post retrival from RC treated teeth

Introduction: Removing fiber posts from root canal–treated teeth is inherent to tooth loss and time consuming. Hence in our study we aim to investigate the accuracy and efficiency of the 3-dimensional dynamic navigation system (DNS) compared with the freehand technique (FH) when removing fiber posts from root canal–treated teeth. Material and Methods: We compared the extracted single rooted teeth prepared with post and build with core. We divided 40 teeth equally as DNS &amp; FH. We compared Global coronal and apical deviations, angular deflection, operation time, and volumetric tooth loss, keeping the p&lt;0.05 as significant. Results: The DNS group showed significantly lower global coronal and apical deviations and angular deflection than the FH group (P &lt; .05). DNS required less operation time than FH. Moreover, the DNS technique had significantly less volumetric loss of tooth structure than the FH technique (P &lt; .05).Conclusions: The DNS was more precise and effective in removing fiber posts from root canal–treated teeth than the FH technique.

Structural and Functional Characterization of Gray Matter Alterations in Female Patients With Neuropsychiatric Systemic Lupus.

ObjectiveTo investigate morphological and functional alterations within gray matter (GM) in female patients with neuropsychiatric systemic lupus (NPSLE) and to explore their clinical significance.Methods54 female patients with SLE (30 NPSLE and 24 non-NPSLE) and 32 matched healthy controls were recruited. All subjects received a quantitative MRI scan (FLAIR, 3DT1, resting-state functional MRI). GM volume (GMV), fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and degree of centrality (DC) were obtained. Between-group comparison, clinical correlation, and discrimination of NPSLE from non-NPSLE were achieved by voxel-based analysis, cerebellar seed-based functional connectivity analysis, regression analysis, and support vector machine (SVM), respectively.ResultsPatients with NPSLE showed overt subcortical GM atrophy without significantly abnormal brain functions in the same region compared with controls. The dysfunction within the left superior temporal gyri (L-STG) was found precede the GM volumetric loss. The function of the nodes in default mode network (DMN) and salience network (SN) were weakened in NPSLE patients compared to controls. The function of the cerebellar posterior lobes was significantly activated in non-NPSLE patients but attenuated along with GM atrophy and presented higher connectivity with L-STG and DMN in NPSLE patients, while the variation of the functional activities in the sensorimotor network (SMN) was the opposite. These structural and functional alterations were mainly correlated with disease burden and anti-phospholipid antibodies (aPLs) (r ranges from -1.53 to 1.29). The ReHos in the bilateral cerebellar posterior lobes showed high discriminative power in identifying patients with NPSLE with accuracy of 87%.ConclusionPatients with NPSLE exhibit both structural and functional alterations in the GM of the brain, which especially involved the deep GM, the cognitive, and sensorimotor regions, reflecting a reorganization to compensate for the disease damage to the brain which was attenuated along with pathologic burden and cerebral vascular risk factors. The GM within the left temporal lobe may be one of the direct targets of lupus-related inflammatory attack. The function of the cerebellar posterior lobes might play an essential role in compensating for cortical functional disturbances and may contribute to identifying patients with suspected NPSLE in clinical practice.

Improving the property of wear rate and hardness by adding hybrid nanomaterials to AA7075

Aluminum alloys have become an essential material in many modern applications, such as automobiles, marines and aviation industries. It is expected that more applications will heavily depend on aluminum alloys to reduce the weight and maintain safety standards, many previous studies have done in this regard. Numerous of these applications’ parts could be subjected to different loading and environmental conditions. This includes wearing stress and loss of the surface properties. To address these issues, intensive researches have been conducted aiming to improve aluminum wear resistance. However, there is an increasing demand to provide a comprehensive understanding of the mechanisms of enhancing wear resistance. Preparation of nano-materials combined with aluminum alloy can be made in several known metallurgical methods. One of the most important difficulties and challenges faced in the manufacture of these nano-materials is to obtain a homogeneous mixture that does not have manufacturing defects. The present work aims to process and evaluate the Nano-hybrid composites of with different ratios of (Cu+Ti) mixed with AA7075 by using the liquid stir casting method by using (pin-on-disc) wear testing apparatus. The results showed when using multiple speeds and different loads in practical experiments, that the volumetric wear loss increase from 2.8 mm3 to 29.89 mm3 for zero–Nano and from 0.889 mm3 to 3.09 mm3 for 0.8 %+0.3 % (Cu+Ti) composite at speed 100 to 300 respectively. And from 12.81 mm3 to 0.889 mm3 at 25N. The coefficient of friction is reduced with the addition of reinforced material at 0.8 %+0.3 % (Cu+Ti) composite from 0.172 to 0.05. The hardness (BH) of the prepared composites increases with increasing the amount of hybrid Nano–reinforced materials. The enhancement percentage of 25.4 % is attained compared to the matrix material. These additions, which were in certain proportions, improved the mechanical properties

Green engineered rubber process oil for passenger tire tread component and its effect on mechanical and rheological characteristics

AbstractThe rich flavonoid glycosides present in the peel of lemon has the property of anticarcinogen the need of hour. This experimental study open up way for exploring the possibilities of providing an optimal alternative in search of conventional high polycyclic aromatic hydrocarbon rubber process oils. The preliminary elastomer science test (tensile, hardness, and rheometry) conducted provided scope for replacement. The tensile test showed higher strength at minimal loading (10 phr) in comparison with controlling component aromatic oil. The hardness test exposed a gradual 3% increase for increase in loading. The elongation at break was found higher for L ‐ trials (L1‐Lemon peel oil 5 phr, L2–10, L3–15 and L4–20 phr) than A‐ trials (Controlling component aromatic oil) indicates greater resistance to change in geometric property without any crack formation attributed to uniform dispersion of N330. Around 2% of mass loss (mg) and 6% of volumetric loss were prevented with the usage of trial ‐L process oil in place of trial A process oil. The uniformity in dispersion was evident from SEM images prove to be an optimal alternative to high polycyclic aromatic hydrocarbon rubber process oil a major carcinogenic threat to environment and living creatures.

Local delivery of a CXCR3 antagonist decreases the progression of bone resorption induced by LPS injection in a murine model.

This experimental study was carried out to investigate the effects of locally delivered nanoparticles (AMG-487 NP) containing a CXCR3 antagonist in inhibiting the progression of LPS-induced inflammation, osteoclastic activity, and bone resorption on a murine model. Thirty, 7-week-old C57BL/6J male mice were used. Inflammatory bone loss was induced by Porphyromonas gingivalis-lipopolysaccharide (P.g.-LPS) injections between the first and second maxillary molars, bilaterally, twice a week for 6weeks (n = 20). AMG-487 NP were incorporated into a liposome carrier and locally delivered on sites where P.g.-LPS was injected. Control mice (n = 10) were injected with vehicle only. Experimental groups included (1) control, (2) LPS, and (3) LPS + NP. At the end of 1 and 6weeks, mice were euthanized, maxillae harvested, fixed, and stored for further analysis. Volumetric bone loss analysis revealed, at 1week, an increase in bone loss in the LPS group (47.9%) compared to control (27.4%) and LPS + NP (27.8%) groups. H&E staining demonstrated reduced inflammatory infiltrate in the LPS + NP group compared to LPS group. At 6weeks, volumetric bone loss increased in all groups; however, treatment with the CXCR3 antagonist (LPS + NP) significantly reduced bone loss compared to the LPS group. CXCR3 antagonist treatment significantly reduced osteoclast numbers when compared to LPS group at 1 and 6weeks. This study showed that local delivery of a CXCR antagonist, via nanoparticles, in a bone resorption model, induced by LPS injection, was effective in reducing inflammation, osteoclast numbers, and bone loss. CXCR3 blockade can be regarded as a novel target for therapeutic intervention of bone loss. It can be a safe and convenient method for periodontitis treatment or prevention applicable in clinical practice.

Wear of Polymer-Infiltrated Ceramic Network Materials against Enamel.

Polymer-infiltrated ceramic network materials (PICNs) have high mechanical compatibility with human enamel. However, the wear properties of PICN against natural human enamel have not yet been clarified. We investigated the in vitro two-body wear behaviors of PICNs and an enamel antagonist. Two PICNs were used: Experimental PICN (EXP) prepared via the infiltration of methacrylate-based resin into the porous silica ceramic network and commercial Vita Enamic (ENA). Two commercial dental ceramics, lithium disilicate glass (LDS) and zirconia (ZIR), were also characterized, and their wear performance was compared to PICNs. The samples were subjected to Vickers hardness tests and two-body wear tests that involve the samples being cyclically impacted by enamel antagonists underwater at 37 °C. The results reveal that the Vickers hardness of EXP (301 ± 36) was closest to that of enamel (317 ± 17). The volumetric wear losses of EXP and ENA were similar to those of LDS but higher than that of zirconia. The volumetric wear loss of the enamel antagonist impacted against EXP was moderate among the examined samples. These results suggest that EXP has wear behavior similar to that of enamel. Therefore, PICNs are mechanically comparable to enamel in terms of hardness and wear and are excellent tooth-restoration materials.

Failure pressure estimation for an aged and corroded oil and gas pipeline: A finite element study

The mechanical behavior of an aged pipeline, affected by localized and generalized corrosion defects, is investigated using the finite element method. A sample of pipeline steel was aged artificially via an isothermal process (which represents the natural aging transformations), to obtain the mechanical characteristics. In real scenarios, oil and gas pipelines undergo deterioration owing to both aging and corrosion defects.Therefore, this research studies the assessment of failure pressure by combining these two types of deterioration using the finite element method. To calibrate the methodology proposed for estimating the pipeline failure pressure,data from real-scale burst tests published by the Pipeline Research Council International (PRCI) was used. Following the simulations, the initial failure region for each type of defect was determined and analyzed. Similarly, the estimated values of pipeline failure pressure were compared to assess the results obtained through finite element analysis, considering the changes in mechanical characteristics caused by the artificialartificial aging of the steel. In addition, these results were compared with those of certain well-known semiempirical models. Finally, for the different types of corrosion defects investigated in this study, the effects of volumetric loss on the estimation of pipeline failure pressure using finite elements are discussed. The main conclusion of this study is that failure pressure can be estimated more accurately by considering both corrosion defects characteristics and variations in the steel properties caused by aging.

A novel approach to assess volumetric bone loss at immediate implant sites and comparison to linear measurements: A pilot study

ObjectivesStudies have evaluated changes in hard tissue following immediate implant placement (IIP) through cone beam computed tomography (CBCT) imaging. This study compared the 3D volumetric changes of the alveolar bone at immediate implant sites with 2D linear measurement outcomes by using a novel image analysis workflow. MethodsPreoperative and 6-month postoperative CBCT images of patients who underwent IIP and bone grafting in the maxillary esthetic area were acquired. Linear and volumetric measurements of buccal bone dimensions were taken using a specially designed workflow. The 2D and 3D measurements were compared, and their correlations were determined. ResultsImages from 13 patients (13 implants) were analyzed. Linear measurements revealed that the general linear buccal bone loss was less than 1mm in all segments. The 3D volumetric bone reduction (reported as median [first quantile, third quantile]) in the vertical, cervical, middle, and apical segments was 14.27 [11.33, 30.66] mm3 (51.30 [42.78, 66.91]%), 16.20 [10.35, 30.52] mm3 (18.20 [9.88, 24.74]%), 17.48 [8.42, 21.17] mm3 (24.05 [12.39, 28.22]%), and 6.87 [3.88, 9.45] mm3 (11.34 [5.14, 22.54]%), respectively. Significant positive correlations between 2D and 3D measurements were consistently identified in the cervical and middle segments, but no significant correlation was noted in the vertical segment. ConclusionsThe results revealed that linear measurements could not fully represent volumetric bone dimensional changes. Performing volumetric measurements and 3D rendering could be valuable in presenting the actual amount and topography of peri-implant bone remodeling. Clinical SignificanceLinear measurements only partially represent the real-life event of 3D bone changes at immediate implant sites. Factors affecting hard tissue alterations following IIP should be reassessed using 3D volumetric measurement outcomes.

3D Surface Deviation Wear Analysis of Veneered PEEK Crowns and Its Correlation with Optical Digital Profilometry.

To verify whether 3D surface deviation analysis software can detect the surface changes of composite veneered polyetheretherketone posterior crowns following wear simulation compared to optical digital profilometry. Twenty dental crowns, fabricated from CAD-CAM polyetheretherketone (PEEK) and veneered with high impact polymer composite (HIPC), were subjected to wear test (50N, 5/55°C; 120,000 chewing cycles). Optical digital profilometry and 3D surface deviation using Geomagic design X software was used before and after the wear test to measure volumetric wear loss (mm3 ). The data were statistically analyzed with Wilcoxon signed-rank test to compare the two methodologies. The significance level was set at p ≤ 0.05. There was no statistically significant difference between the two assessment methods (p-value = 0.075, Effect size = 0.854). Regarding the optical digital profilometry analysis, HIPC veneered PEEK crowns showed 0.01686 (0.018-0.02155) mm3 as a median volumetric wear loss value. While the crowns analyzed by 3D surface deviation showed -0.0398 (-0.0913 to -0.0042) mm3 as a median volumetric loss value (p-value = 0.075, Effect size = 0.854). In addition, there was no statistically significant correlation between wear measurements by optical digital profilometry and 3D surface deviation analyses (ρ = -0.177, p-value = 0.685). There was no significant difference or correlation between optical digital profilometry and 3D surface deviation analyses for volumetric wear loss of veneered PEEK crowns.

Ultrasound Analyses of the Dorsal Hands for Volumetric Rejuvenation

Volumetric hand rejuvenation of the dorsal hands is increasingly applied for aged, skeletonized dorsal hand skin, with prominent veins, tendons, and joints due to volumetric loss of subcutaneous fat. However, the aging process of the fatty laminae remains unexplored. The aim of this study was to investigate the impact of aging and potential determinants on the fatty laminae to improve the therapeutic effect of volumetric injection. This cross-sectional study enrolled 105 Taiwanese participants aged ≥20 years, divided into 5 decade-based age groups. A single blinded practitioner measured the thicknesses of the dorsal superficial lamina (DSL), dorsal intermediate lamina (DIL), and dorsal deep lamina (DDL) by ultrasonography. The potential determining factors of the laminae thickness (age, sex, BMI, and hand dominance) were analyzed. The thicknesses of the 3 laminae decreased with age, with the mean decrease in thickness from the 20s to >60 years of the DSL, DIL, and DDL being 0.21 mm (30.0%), 1.38 mm (63.89%), and 0.31 mm (20.95%), respectively. The decrease in DIL thickness was the greatest and most significant in subjects aged >30 years. Multiple linear regression analysis showed age to be the only determinant of thickness for the 3 laminae (all P < 0.001), although the DIL was significantly thicker in men (P < 0.001). Volumetric fat loss was noted in the 3 fatty laminae of dorsal hands during aging; the DIL showed the greatest progressive fat loss after the age of 30. Volumetric rejuvenation of the 3 laminae may result in the most aesthetic appearance, especially in women.

All-Nanoporous fiber sorbent with a Non-Sacrificial polymer of intrinsic microporosity (PIM) matrix

Microporous materials are highlighted with regard to low-energy and low-carbon adsorptive separation processes, where the interests have evolved simple microporous powders into a structured sorbent platform of fiber sorbent to tackle the technical challenges of large-scale applications. However, the challenge of sorption capacity loss in a limited footprint due to the addition of non-adsorbing binder materials still remained. Polymers of intrinsic microporosity (PIMs) are promising advanced materials for gas separation and capture due to their unique textural properties and processability. This article reports an efficient but straightforward blend of organic and inorganic materials, PIM-1 and zeolite NaY, forming “all-nanoporous” fiber sorbents. The combination of the two nanoporous materials resulted in a structured platform for a sorption-based separation system for volatile organic compounds (VOCs). It is differentiated from other sorption platforms as it presents minimal volumetric sorption loss from the “binder” material by allowing the microporous substrate to work as a VOC sorbent. The “all-nanoporous” fiber sorbent of NaY/PIM-1 shows feasible sorption performance capabilities under both dry and humid conditions while maintaining a minimal pressure drop due to its hierarchical porous structure.

Quantitative Gradient Echo MRI Identifies Dark Matter as a New Imaging Biomarker of Neurodegeneration that Precedes Tisssue Atrophy in Early Alzheimer's Disease.

Background: Currently, brain tissue atrophy serves as an in vivo MRI biomarker of neurodegeneration in Alzheimer’s disease (AD). However, postmortem histopathological studies show that neuronal loss in AD exceeds volumetric loss of tissue and that loss of memory in AD begins when neurons and synapses are lost. Therefore, in vivo detection of neuronal loss prior to detectable atrophy in MRI is essential for early AD diagnosis.Objective: To apply a recently developed quantitative Gradient Recalled Echo (qGRE) MRI technique for in vivo evaluation of neuronal loss in human hippocampus.Methods: Seventy participants were recruited from the Knight Alzheimer Disease Research Center, representing three groups: Healthy controls [Clinical Dementia Rating® (CDR®) = 0, amyloid β (Aβ)-negative, n = 34]; Preclinical AD (CDR = 0, Aβ-positive, n = 19); and mild AD (CDR = 0.5 or 1, Aβ-positive, n = 17).Results: In hippocampal tissue, qGRE identified two types of regions: one, practically devoid of neurons, we designate as “Dark Matter”, and the other, with relatively preserved neurons, “Viable Tissue”. Data showed a greater loss of neurons than defined by atrophy in the mild AD group compared with the healthy control group; neuronal loss ranged between 31% and 43%, while volume loss ranged only between 10% and 19%. The concept of Dark Matter was confirmed with histopathological study of one participant who underwent in vivo qGRE 14 months prior to expiration.Conclusion: In vivo qGRE method identifies neuronal loss that is associated with impaired AD-related cognition but is not recognized by MRI measurements of tissue atrophy, therefore providing new biomarkers for early AD detection.

Effects of rainfall characteristics and contour tillage on ephemeral gully development in a field in Northeastern China

Contour tillage can be an effective measure for increasing infiltration, reducing runoff volumes and velocities, and protecting against soil erosion. However, ephemeral gullies often occur when contours are overtopped because gradients of the contoured row slopes exceed critical values, causing the runoff to collect along furrows and be transported to low-lying areas, often in natural drainages. This study aims to determine the main factors that influence ephemeral gully development on a contour tilled slope in the black soil region of northeastern China by investigating development of ephemeral gullies after each heavy rainfall during the rainy season. Cross-sectional measurements were used to obtain estimates of volumetric soil loss from the ephemeral gullies. An Unmanned Aerial Vehicle (UAV) was used to collect photogrammetric data to create DEMs with a resolution of 0.08 m for monitoring morphologic changes of the ephemeral gullies. Data was collected six times during the season. After a 24 mm rainfall event at the beginning of the rainy season, three ephemeral gullies developed on the contoured slopes, with initial rapid length extension, followed by deepening during subsequent heavy rainfall events. Gully heads formed in positions with steep slopes and large drainage areas. The volumetric soil loss from the gullies under one heavy rainfall event accounted for an estimated 29–45% of the total erosion on the field. We found that the contour ridges changed drainage patterns in the field from their natural state, effectively reducing the size of the areas that contributed runoff to the gullies. Contours were overtopped and broken when the row slopes were greater than approximately 2°. The relationship between the volumetric gully erosion (ESL) and estimated surface runoff volume (VQ) was: ESL = 0.707 *VQ0.598 (R2 = 0.84). The critical relationship between gully runoff volume (VQ) and critical slope gradient (S) for ephemeral gully heads and deep gullies was SEG = 0.043 *VQ0.232 and SDG = 0.078 *VQ−0.050. This study provides a reference for the prediction and prevention of gully erosion on contoured tillage areas.