Clear Specimens Research Articles

Effect of Growth Rings Per Inch and Specific Gravity on Compression Perpendicular to Grain in No. 2: 2 by 8 and 2 by 10 Southern Pine Lumber

Abstract Southern pine lumber 2 by 8s and 2 by 10s from across the Southeast were used as the parent material source for this study. Fundamental data were collected for each piece of lumber: growth rings per inch (RPI), presence of pith, and specific gravity (SG), among other information. After mechanical property evaluation through static bending, small clear specimens were cut from the lumber pieces and tested for compression perpendicular to grain (C⊥). Those values were then compared with 2 by 8 and 2 by 10 average RPI and density. The results were significant for both tests. Therefore, a segmentation of the growth ring data into groups of <3, 3 to 5, and >5 RPI was conducted. Correlations were run specific to each group, per both lumber sizes, and still significance was found. Segmentation of SG was not significant only for 2 by 8 SG <0.4. The results suggest that SG is a better predictor of C⊥ than RPI alone due to statistical significance found during these analyses.

"Agar Cell-Suspension": A Novel Technique for Processing Clear Specimens.

Context:Clear cytology specimens are processed by cytocentrifugation which is preferred over membrane filters (MF). Although both techniques are expensive, cytocentrifugation is less tedious and may cause cellular distortion.Aim:To standardize “Agar cell-suspension” (ACS) an innovative, simple, cost-effective technique to process clear specimens.Methods and Materials:About 93 clear specimens (65 urine, 15 effusion, 12 CSF, and 1 bronchial lavage) were processed by both cytocentrifugation and ACS. The sample was centrifuged in two tubes; one was used for ACS and other for cytocentrifugation. ACS smears were prepared by mixing one drop of 0.5% agar solution with the last drop of the centrifugate. Smears were fixed in methanol and stained by Papanicolaou staining method. ACS smears were compared with cytocentrifuged smears (CS) and evaluated for cellularity, cytomorphology preservation, staining quality, time, and cost.Results:As compared to CS smears, ACS smears showed better cellularity in 16.1%, comparable in 53.7%, and less in 30.1%. All ACS smears (100%) showed well-preserved cytomorphology as compared to 96.7% CS. Staining quality was optimal in 96.7% ACS smears against 91.3% CS. Both techniques took equal time. The additional cost of ACS was only 0.03 INR compared to 12.50 INR for CS.Conclusions:ACS is an innovative, simple, easy, and cost-effective technique for processing clear specimens. It gives equally good results comparable to cytocentrifugation in terms of cellularity and staining quality. ACS does not cause cell distortion or air-drying as seen in some CS. Thus, ACS is a superior alternative to cytocentrifugation.

Identifying the Strength Grade for Finger Jointed Timber Species According to BS 5268-2:2002

Off-cut wood is currently considered as waste thus is dumped by saw mills as they find no means of utilising them. Sawn timber material of furniture factories and short length of sawn timbers are also considered to be wastes in the timber industry. Finger jointing technique which interlock the end joints formed by machining a number of similar tapered symmetrical fingers are recognised in this regards as effective and sustainable means of utilisation of timber wastes. The present study was undertaken to assess the strength grade of finger jointed timber based on BS 5268-2:2002. Seven timber species which are commonly used in Sri Lanka were employed for the assessment with and without finger joints. Values of Modulus of Rupture (MOR), Modulus of Elasticity (MOE), Compression parallel to grain and Compression perpendicular to grain strength of the specimens were measured. Finger jointing was performed with constant geometry (finger length 19 mm, tip width 1 mm and finger pitch 4 mm) using polyvinyl acetate (PVA, P-SWR) adhesive at normal exposure conditions. The strength properties were evaluated by Universal Testing Machine (UTM) according to BS 373:1957. Strength classes relevant to the grade stresses were not significant for finger jointed and clear specimens of Satin, Mahogany, Jack and Grandis. Both clear and finger jointed timber specimens obtained D40 for Satin and Teak, D30 for Jack, Mahogany and Grandis. Teak shows properties similar to both D35 and D40 when used as finger jointed timber. Kumbuk was shown to change from D40 to D30 while using as finger jointed timber. Finger jointed Pine showed stress grade of C22, C24 and C27.

The combination of two-dimensional and three-dimensional analysis methods contributes to the understanding of glioblastoma spatial heterogeneity.

Heterogeneity is regarded as the major factor leading to the poor outcomes of glioblastoma (GBM) patients. However, conventional two-dimensional (2D) analysis methods, such as immunohistochemistry and immunofluorescence, have limited capacity to reveal GBM spatial heterogeneity. Thus, we sought to develop an effective analysis strategy to increase the understanding of GBM spatial heterogeneity. Here, 2D and three-dimensional (3D) analysis methods were compared for the examination of cell morphology, cell distribution and large intact structures, and both types of methods were employed to dissect GBM spatial heterogeneity. The results showed that 2D assays showed only cross-sections of specimens but provided a full view. To visualize intact GBM specimens in 3D without sectioning, the optical tissue clearing methods CUBIC and iDISCO+ were used to clear opaque specimens so that they would become more transparent, after which the specimens were imaged with a two-photon microscope. The 3D analysis methods showed specimens at a large spatial scale at cell-level resolution and had overwhelming advantages in comparison to the 2D methods. Furthermore, in 3D, heterogeneity in terms of cell stemness, the microvasculature, and immune cell infiltration within GBM was comprehensively observed and analysed. Overall, we propose that 2D and 3D analysis methods should be combined to provide much greater detail to increase the understanding of GBM spatial heterogeneity.

Mechanical characterization of clear wood from Portuguese poplar

Poplar wood is a light, soft, and fast-growing timber from a hardwood species, characteristics that make it suitable for several applications. This study focused on the mechanical characterization of Portuguese poplar species, namely white poplar (Populus alba) and black poplar (P. nigra), aiming for its structural use. Therefore, a sample of lamellae was assessed to determine its density and dynamic modulus of elasticity, using a non-destructive device, based on longitudinal vibrations. Clear wood specimens were obtained from a set of lamellae to perform tension and compression parallel-to-grain tests. These tests were used to determine the moduli of elasticity in tension and compression and the tensile and compressive strengths and strains. Also, typical stress-strain curves were identified for the sample studied. The results stressed the potential for structural applications of Portuguese poplar.

Relationships between wood properties of small clear specimens and structural-sized boards in three softwood species

Abstract Research on the mechanical and physical properties of wood is commonly carried out on either small clear specimens or structural-sized boards. The first approach was more frequently utilized in the past, while the latter is more commonly used nowadays. However, there is very little information on how the two approaches relate with one another. This study aimed to quantify the relationships between the mechanical [modulus of elasticity (MOE) and bending strength] and physical properties (density) of both specimen sizes. A total of 1376 structural-sized boards from three different species (Douglas-fir, Norway spruce and Sitka spruce) were tested in bending, after which a small clear specimen was extracted from the undamaged portion of each board and re-tested in bending. Prior to destructive testing, all boards and clear specimens were evaluated using non-destructive technology. Poor-to-moderate relationships were found between all measured mechanical and physical properties of structural-sized timber and small clear specimens. In both specimen sizes, the properties correlated with one another within the same specimen size, as well as across the two sizes. The strength of correlations appears to be somewhat species dependent. Relatively good relationships were identified when comparing the mean tree values of the properties examined, suggesting either method can be used for a tree-level comparison. The non-destructive evaluation of specimens was shown to reflect the measured properties moderately well, with the relationships changing significantly depending on which measured property was being predicted.

Genomic Alterations of Renal Cell Carcinoma and Clinical Implications in the Chinese Population.

BackgroundThe aim of this study was to investigate the genomic alterations of renal cell carcinoma (RCC) in Chinese patients and to evaluate the correlations between significantly mutated genes and tumor mutation burden (TMB) levels in RCC.Material/MethodsTwo batch of specimens were collected from patients with RCC. Cohort 1 enrolled 17 RCC patients. Specimens and clinicopathological data were collected and the duration of disease-free survival were evaluated with a follow-up from 2 weeks to longer than 1 year. Cohort 2 collected 70 clear cell RCC (ccRCC) tissues and blood specimens. Next-generation sequencing were used to detect the genomic variations in those specimens in both cohorts and TMB in cohort 2. Clinicopathological features of the 2 cohorts were collected and the χ2 test or Fisher’s exact test was used for categorical variables stratified by TMB values.ResultsOur present study demonstrated that the top 3 most frequent aberrated genes in Chinese ccRCC patients were ABCB1, UGT1A1, and VHL, with percentages of 50.00%, 42.86%, and 34.52% respectively. And only 1 gene, which was ABCB1, showed statistically significant difference (P=0.047) stratified by TMB levels. In addition, 6 oncogenic pathways were involved in ccRCC cases in the 2 cohorts. Only 5 out of the 8 most common altered genes of RCC from COSMIC or TCGA databases were detected in our study.ConclusionsThe genomic alterations of Chinese RCC patients were different from that in TCGA and COSMIC. No significant genomic alterations were found correlating to TMB levels in ccRCC. Non-silent mutation of VHL may be a predictor for the outcome of ccRCC treated with axitinib.

Evaluating timber quality in larger-diameter standing trees: rethinking the use of acoustic velocity

Abstract The use of acoustic velocity for different purposes is becoming widespread in the forestry industry. However, there are conflicting reports on how well this technology reflects the mechanical properties of trees. In this study, the prediction of timber quality using acoustic technology was evaluated on mature standing trees of three softwood species. The velocity in 490 standing trees was measured in several directions (longitudinal, radial and tangential). A sub-sample of trees was felled and the acoustic velocity was measured in 120 logs which were then sawn into structural-sized timber. A total of 1383 boards were tested for bending, as were small clear specimens extracted from the structural-sized boards. The mean tree values of the timber grade-determining properties (elastic modulus, bending strength and density) of both specimen sizes were related to the acoustic velocities and tree slenderness. The correlations between the mean tree mechanical properties and acoustic velocities were relatively low, most likely due to a high ratio of diameter to measurement distance. The transverse directions showed similar correlations with mechanical properties in larger-diameter trees to the longitudinal direction, as did tree slenderness. The results suggest that while the acoustic velocity in the longitudinal direction can reflect the mean tree mechanical properties in small-diameter trees, alternatives are needed to achieve the same in larger-diameter trees.

High-resolution 3D imaging and analysis of axon regeneration in unsectioned spinal cord with or without tissue clearing.

Here we present a protocol for analyses of axon regeneration and density in unsectioned adult mouse spinal cord. This includes methods for injury and tracing of dorsal column sensory and corticospinal axons; clearing and staining of unsectioned spinal cord; visualization of axon degeneration and regeneration in cleared and uncleared specimens using two-photon microscopy; and either manual or semi-automatic analysis of axon density and regeneration in 3D space using Imaris and ImageJ software. This protocol can be used to elucidate the molecular and cellular mechanisms underlying nervous system degeneration and regeneration and to establish the therapeutic efficacy of candidate neuroregenerative treatments. Because tissue sectioning is not required, this protocol enables unambiguous evaluation of regeneration and greatly accelerates the speed at which analyses can be conducted. Surgical procedures take <30 min per mouse, with a wait period of 2 weeks between axonal injury and tracing and 2-8 weeks between tracing and tissue processing. Clearing and immunolabeling take ~1-2 weeks, depending on the size of the sample. Imaging and analysis can be performed in 1 d. All these procedures can be accomplished by a competent graduate student or experienced technician.

Development of Sample-Adaptable Holders for Lightsheet Microscopy.

Multi-user core microscopy facilities are often faced with the challenge to adapt or modify existing instruments. This is essential in order to fulfill the requirements of the user community, who wants to image a wide range of model organisms with varying stains and sample thicknesses. In recent years, lightsheet microscopy has turned into an invaluable tool for both live and cleared sample imaging of many different specimens. This brought up new challenges in terms of sample mounting as the classical approach of attachment onto a coverslip cannot be universally applied. Here we describe the development of a diversified holder which extends the range of samples which can be imaged on a Zeiss Lightsheet microscope Z1. We focus on mounting strategies of cleared specimens; however, the holder and mounting strategy can be applied to live specimens too. The proposed methodology provides very high flexibility along with numerous possibilities for adaptation based on imaging specimen size, condition and available clearing reagents. Moreover, the described mounting strategies can be applied to other light sheet microscopes that can mount 1 mL syringes.

The Impact of Anatomical Characteristics on the Structural Integrity of Wood

The structural integrity of wood is closely related to its brittleness and thus to its suitability for numerous applications where dynamic loads, wear and abrasion occur. The structural integrity of wood is only vaguely correlated with its density, but affected by different chemical, physico-structural and anatomical characteristics, which are difficult to encompass as a whole. This study aimed to analyze the results from High-Energy Multiple Impact (HEMI) tests of a wide range of softwood and hardwood species with an average oven-dry wood density in a range between 0.25 and 0.99 g/cm³ and multifaceted anatomical features. Therefore, small clear specimens from a total of 40 different soft- and hardwood species were crushed in a heavy vibratory ball mill. The obtained particles were fractionated and used to calculate the ‘Resistance to Impact Milling (RIM)’ as a measure of the wood structural integrity. The differences in structural integrity and thus in brittleness were predominantly affected by anatomical characteristics. The size, density and distribution of vessels as well as the ray density of wood were found to have a significant impact on the structural integrity of hardwoods. The structural integrity of softwood was rather affected by the number of growth ring borders and the occurrence of resin canals. The density affected the Resistance to Impact Milling (RIM) of neither the softwoods nor the hardwoods.

Modified Osgood Equation for Acacia Mangium

The purpose of this study is to identify the Osgood’s coefficient of species and the Modified Osgood Equation for Acacia mangium. Acacia mangium trees were cut to produce oven-dried Small Clear Specimens that were then tested until fracture. Results were gathered from static tensile tests in the direction parallel (0° angle), perpendicular (90° angle) and at 30° angle to the wood grain. All test results confirmed that the Acacia mangium wood is brittle as there was no obvious necking observed on the test specimens. From the static testing, the Osgood’s coefficient of species for Acacia mangium, (a), is identified algebraically to be 0.49. Acacia mangium, by nature, has a significant difference in the strengths parallel and perpendicular to the grain line. The finalized results of the Ultimate Tensile Strength for 15-year old Acacia mangium demonstrated that the Ultimate Tensile Strength in parallel and perpendicular to the grain directions are 143.87 MPa and 6.32 MPa respectively, while the Ultimate Tensile Strength at 30° grain angle is 32.985 MPa. An extreme reduction of 95.6% of the Ultimate Tensile Strength was identified between 0° and 90° grain angles with a decreased value from 143.87 MPa to 6.32 MPa.

Fatigue Strength of Acacia Mangium

The works in this study is to investigate and understand the nature of Acacia mangium axial fatigue strengths under repeated stress. Acacia mangium trees were cut to produce oven-dried Small Clear Specimens that were then tested until fracture in parallel to the grain direction. This was carried out in order to discover its Ultimate Tensile Strength, which was later identified as 143.87 MPa, in parallel to the grain direction (0° grain angle). In the next phase, specimens were tested for fatigue strengths in repeated-tensile sinusoidal waveform loading at 100 Hz frequency. The stress levels for this test were at the ratios of 80, 60, 40, 30, 20 and 10% of the Ultimate Tensile Strength (0° grain angle) for the construction of Life (N) - Stress (S) plots and empirical correlation. It was observed that the Acacia Mangium N-S (Wöhler) plots have an exponential correlation with the N – intercept of vertical axis at five (5) million cycles, while the intercept of horizontal, S – axis, was at 143.87 MPa. The study also observed that Acacia mangium achieves 106 life cycles at 10% stress level. For this reason, it is concluded that the material has a fatigue endurance limit at 10% of the Ultimate Tensile Strength for 0° grain angle.

Skeletal development of the chondrocranium in the tongue sole Cynoglossus semilaevis (Pleuronectiformes: Cynoglossidae).

This study provides a comprehensive description of chondrocranial development before, during and after larval metamorphosis in the tongue sole Cynoglossus semilaevis, a commercially valuable flatfish in China. Samples were collected at regular intervals ranging from 1 to 23 days post hatching (dph). Based on observations of cleared and double-stained specimens and images from sections stained with safranin O-fast green, major morphological events during early development were described. No cartilaginous structure was visible at hatching. From 2 dph onwards, cartilaginous structures such as the trabecular bar and some elements of the mandibular, hyoid and branchial arches appeared. At this time also, cartilaginous structures of the neurocranium started to form. Hypertrophic chondrocytes could be observed in many splanchnocranium elements at 5 dph. The start of ossification was indicated by alizarin red stain visible at 14 dph. At 17 dph, most of the cartilaginous skeleton was ossified. Soon after, the right eye started to migrate and pass through a slit beneath the dorsal-fin base and above the skull. Metamorphosis was complete at 20 dph, at which time the dorsal-fin base cartilage extended onto the anterior region of the head. Meanwhile, extremities of the hyoid and branchial arch elements remained cartilaginous. At 23 dph, endochondral ossification of the splanchnocranium was nearly complete. Unlike previous observations of other Pleuronectiformes, our study indicates that endochondral ossification of C. semilaevis skull cartilage occurs before metamorphosis.

Effect of finger joining on flexural strength of commonly used timber species in Sri Lanka

The variation of flexural strength of seven timber species mainly used for furniture industry in Sri Lanka was studied. Modulus of Rupture (MOR) and Modulus of Elasticity (MOE) were measured without finger joint and with finger joint specimens of timber species. Finger joint technique is used to eliminate wood defects which weaken the strength of sawn wood plank and used. This paper gives comparison study of finger jointed and un-jointed seven wood species, tested under three point bending test. BS 373: 1957 and BS EN 15497:2014 were used as standards for tests. Vertical finger joint orientation and 13 mm finger joint length were used in this study. The tests for mechanical properties were performed by using a Universal Testing Machine (UTM 100 PC). The parameters were analyzed by using ANOVA and means were separated by Duncan's Multiple Range Test at 0.05 significant levels in SAS. It was found that control (un-jointed solid wood) samples gave the highest flexural strength than finger-jointed specimens and it was also observed that Kumbuk timber species was showed the highest MOE in 13 mm finger-jointed specimens comparing control specimens. The highest flexural strength loss percentage was obtained from Satin species. The MOE of finger-jointed Kumbuk was higher than clear Kumbuk specimens and least strength loss percentage of MOR (46.08 %) was obtained from Mahogany species.

The influence of crown and stem characteristics on timber quality in softwoods

The relationships between several crown and tree properties and timber quality were examined on three softwood species: Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), Norway spruce (Picea abies (L.) H. Karst) and Sitka spruce (Picea sitchensis (Bong.) Carr). Crown and stem characteristics were collected on 487 standing trees, and their acoustic velocity measured using a stress-wave device. Of the trees measured, 60 were chosen for further testing, stratified by crown social class and cut into structural sized boards (N = 1342). Each board was assessed with regard to knots using a grading X-ray machine, after which all boards were destructively tested in four-point bending and their mechanical properties (elastic modulus, bending strength and density) evaluated. To exclude the effect of branchiness across the crown social classes, mechanical properties were also examined on small clear samples cut from the undamaged section of the tested boards, a total of 1303 specimens were tested destructively in bending. Multi-level models based on Bayesian data analysis were used to evaluate the relationships between recorded characteristics, acoustic velocities and mechanical properties. Considerable differences in acoustic velocities were found between crown social classes, with suppressed trees having the highest velocities. This trend was also confirmed in mechanical properties of structural-sized boards and small clear specimens, suggesting that branchiness is not the primary cause of differences. Results indicate that slenderness affects both tree stiffness and the properties of sawn timber differently across the crown social classes. The relationship is negative in suppressed trees (increasing slenderness leads to a decrease in velocity or mechanical properties) and positive in dominant and co-dominant trees. The effect of crown projection area on either tree acoustic velocity or mechanical properties differs between social classes. In general, it was found to be positive, therefore an increase in crown projection area leads to an increase in either tree acoustic velocity or wood properties of timber. This trend is more evident in sawn timber than in acoustic velocities. The effects appear to be species dependant. No evidence was found of the effect of crown ratio, crown eccentricity or crown roundness on either the examined wood properties or acoustic velocities. Results confirm that there is a link between crown/stem development and timber quality. They indicate that in order to increase the overall quality of timber produced, the proportions of crown social classes in final stand composition should be adjusted with thinning.

Use of particle tracking velocimetry in timber material and connection testing

Particle tracking velocimetry (PTV) is a quantitative field measuring technique originally developed to track and measure the velocity of individual particles in fluid flows. In this study, PTV was applied for the first time in three different experimental studies in the field of structural timber engineering: (1) dowel embedment testing in cross laminated timber (CLT), (2) large-scale dowelled CLT connection testing, (3) material testing of small clear wood and laminated veneer lumber (LVL). The suitability of PTV was first assessed by comparing the PTV displacements to those obtained by potentiometers. Furthermore, the behaviour of the timber substrate was analysed with PTV in both embedment and large-scale connection tests. It was found that PTV was able to not only accurately measure dowel displacements, but also capture crack growth in the timber and compute the resulting displacement and strain fields in the dowel embedment area. Lastly, PTV was applied to small clear specimen testing to capture brittle fracture in shear, tension perpendicular to the grain, and in cleavage. This study demonstrated that PTV is able to provide reliable contact-free high-resolution measurements of displacement and strain fields on exposed timber surfaces and capture failure mechanisms such as brittle fractures and crack growth.

In-situ density estimation by four nondestructive techniques on Norway spruce from built-in wood structures

AbstractNeedle penetration resistance (NPR), screw withdrawal resistance (SWR), core drilling (CD) and drilling chips extraction (DCE) are nondestructive and semi-destructive techniques used to estimate density in timber structures. In most of the previous studies, these techniques were tested in clear sawn timber and clear specimens. The goal of the present paper is to study the relationship between density and these techniques by means of five different devices in whole pieces of timber from built-in engineering structures, which are from 12 4.5-m long structural timber joists of Norway spruce from a 19thcentury building in Barcelona (Catalonia, Spain). Although determination coefficients (R2) for density estimation models were lower than those from clear timber, the results obtained confirmed that these four techniques are suitable forin-situdensity estimation of woods in buildings. The best results were obtained by CD (the bigger the bit, the higher the correlation), followed by DCE, and SWR. The worst correlation was found for NPR devices, but the results could be probably improved with more measurements.

Effects of moisture content on elastic constants of fir wood

In this study, the effect of moisture on elastic properties of fir wood (Abies cilicica Carr.) was investigated. Three moduli of elasticity in principal directions (EL, ER, ET), six Poisson’s ratios (υLR, υLT, υRT, υTR, υRL, υTL) and three shear moduli (GLR, GRT, GLT) were determined using compression tests. Compression strength in principal directions was also determined. Clear and small wood specimens were conditioned at 20 °C and 45, 65 and 85% relative humidity. Stress–strain curves of the samples were obtained using bi-axial extensometer in order to calculate elastic constants. Test results indicated that moisture content significantly reduced the measured properties except for Poisson’s ratio. The elastic modulus in the three principal directions is significantly different. Well-known order of EL > ER > ET for elasticity, and L > T > R for compression strength is valid. Shear modulus obeys the GLR > GLT > GRT rule. The results of this study can provide sufficient data for modeling of the elements or system’s behavior under load using fir wood.

A further modification of Dioni’s mounting media to allow staining, clearing and mounting of Acari

Modified Dioni’s media has previously been presented as an alternative to tradition Gum Chloral mounting media for microscopical specimens. This paper aims to explore a further modification of Dioni’s mounting media with the objective to provide a simple solution to clear, stain and mount Acari specimens in regions where obtaining Chloral Hydrate based media is problematic.