Composite Criteria Research Articles

Phase II trial of carboplatin and bevacizumab in patients with breast cancer brain metastases

BackgroundWe aimed to examine the safety and efficacy of bevacizumab and carboplatin in patients with breast cancer brain metastases.MethodsWe enrolled patients with breast cancer and > 1 measurable new or progressive brain metastasis. Patients received bevacizumab 15 mg/kg intravenously (IV) on cycle 1 day 1 and carboplatin IV AUC = 5 on cycle 1 day 8. Patients with HER2-positive disease also received trastuzumab. In subsequent cycles, all drugs were administered on day 1 of each cycle. Contrast-enhanced brain MRI was performed at baseline, 24–96 h after the first bevacizumab dose (day + 1), and every 2 cycles. The primary endpoint was objective response rate in the central nervous system (CNS ORR) by composite criteria. Associations between germline VEGF single nucleotide polymorphisms (rs699947, rs2019063, rs1570360, rs833061) and progression-free survival (PFS) and overall survival (OS) were explored, as were associations between early (day + 1) MRI changes and outcomes.ResultsThirty-eight patients were enrolled (29 HER2-positive, 9 HER2-negative); all were evaluable for response. The CNS ORR was 63% (95% CI, 46–78). Median PFS was 5.62 months and median OS was 14.10 months. As compared with an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0, patients with ECOG PS 1–2 had significantly worse PFS and OS (all P < 0.01). No significant associations between VEGF genotypes or early MRI changes and clinical outcomes were observed.ConclusionsThe combination of bevacizumab and carboplatin results in a high rate of durable objective response in patients with brain metastases from breast cancer. This regimen warrants further investigation.Trial registrationNCT01004172. Registered 28 October 2009.

Mode-Independent and Mode-Interactive Failure Criteria for Unidirectional Composites Based on Strain Energy Density.

The strain energy released plays a crucial role in generating macroscopic failure in unidirectional (UD) composites. This paper proposes two new strain energy-based failure criteria, regarding fiber-dominated and matrix-dominated failure mode as independent and interactive, respectively. The failure expression is formulated based on rigorous mathematical deducing, accompanied by physical interpretation. Based on the lack of experimentally feasible multi-axial strengths, a predefined assumption of infinite strength under bi-axial and tri-axial compressive stress provides the possibility for determining all coefficients only by using conventional uniaxial strengths. The failure envelopes predicted by the proposed criteria have been validated against experimental results under biaxial, off-axis and tri-axial loading cases. A better agreement with physical reality was achieved by the failure mode-interactive criterion, suggesting a wide range of applicability.

Genome-scale CRISPR screening at high sensitivity with an empirically designed sgRNA library

BackgroundIn recent years, large-scale genetic screens using the CRISPR/Cas9 system have emerged as scalable approaches able to interrogate gene function with unprecedented efficiency and specificity in various biological contexts. By this means, functional dependencies on both the protein-coding and noncoding genome of numerous cell types in different organisms have been interrogated. However, screening designs vary greatly and criteria for optimal experimental implementation and library composition are still emerging. Given their broad utility in functionally annotating genomes, the application and interpretation of genome-scale CRISPR screens would greatly benefit from consistent and optimal design criteria.ResultsWe report advantages of conducting viability screens in selected Cas9 single-cell clones in contrast to Cas9 bulk populations. We further systematically analyzed published CRISPR screens in human cells to identify single-guide (sg) RNAs with consistent high on-target and low off-target activity. Selected guides were collected in a novel genome-scale sgRNA library, which efficiently identifies core and context-dependent essential genes.ConclusionWe show how empirically designed libraries in combination with an optimized experimental design increase the dynamic range in gene essentiality screens at reduced library coverage.

Assessment of the Cheese-making Ability of Individual Cow’s Milks from the Experimental Farm of the University of Mostaganem, Algeria

Background: The cheese-making ability of milks varies due to its chemical composition and several factors related to good farming practices.Methods: Among these factors, the lactation stage was studied on a batch of 15 Prim’Holstein dairy cows under real production conditions at the experimental farm of the University of Mostaganem. The fresh milks produced were tested with simple criteria of chemical composition in protein rate, butyrous rate, mineral intake, on coagulation ability and cheese yield with a repeatability spread over 3 months. Result: The results indicated that the lactation stage has a significant effect, on the composition of milk, especially in terms of protein and mineral richness and on its ability to coagulate. In addition, the urea dosage showed a deficiency in the food ration of digestible nitrogen to the herd directly influenced the protein mass of milk and consequently on the technological processing times and cheese yields.

New therapies in oncogeriatrics

Cancer management is changing rapidly. Changes in practices are not all transferable to the elderly population, which is heterogeneous. The description of the intrinsic toxicity of anti-cancer treatments is insufficient in the elderly. Recent studies dedicated to the elderly incorporate composite evaluation criteria combining efficacy and toxicity with a broad definition including, among other things, loss of functional autonomy. These new data acquired, as well as new organisations integrating the new profession of advanced practice nurse in oncogeriatrics will enable us to better respond to the challenge of caring for elderly patients in the future.

Alveolar recruitment manoeuvre results in improved pulmonary function in obese patients undergoing bariatric surgery: a randomised trial

Perioperative ventilation is an important challenge of anaesthesia, especially in obese patients: body mass index is correlated with reduction of the pulmonary volume and they develop significantly more perioperative atelectasis and pulmonary complications. The alveolar recruitment manoeuvre is the most effective technique to reverse atelectasis. However, the clinical benefit on lung function in the perioperative period is not clear. The aim of the present study is to assess the perioperative clinical results of systematic alveolar recruitment manoeuvre associated with protective ventilation in patients undergoing laparoscopic bariatric surgery. It was a single-centre, randomised, double blind, superiority trial: control group with standard protective ventilation and recruitment group with protective ventilation and systematic recruitment manoeuvre. The primary outcome was a composite clinical criterion of pulmonary dysfunction including oxygen saturation, oxygen needs and dyspnoea in recovery room and at day 1. Secondary outcomes were recruitment manoeuvre tolerance, pulmonary and non-pulmonary complications, length of hospital stay and proportion of Intensive Care Unit admission. Two hundred and thirty patients were included: 115 in the recruitment manoeuvre group and 115 in the control group, 2 patients were excluded from the analysis in the control group. Patients in the recruitment manoeuvre group had significantly lower rate of pulmonary dysfunction in the recovery room (73% versus 84% (p = 0.043) and 77% versus 88% at postoperative day 1 (p = 0.043)). No significant differences were found for secondary outcomes. No patient was excluded from the recruitment manoeuvre group for intolerance to the manoeuvre. Recruitment manoeuvre is safe and effective in reducing early pulmonary dysfunction in obese patients undergoing bariatric surgery.

Simulation study to demonstrate biases created by diagnostic criteria of mental illnesses: major depressive episodes, dysthymia, and manic episodes

ObjectivesComposite diagnostic criteria alone are likely to create and introduce biases into diagnoses that subsequently have poor relationships with input symptoms. This study aims to understand the relationships between the...

A reclassification of Northwest Africa 2900 from CV3 to CK3 chondrite

AbstractThe similarities between CV and CK chondrites are so substantial that some studies have argued for a common parent body origin. These similarities also mean that they are susceptible to misclassification as one another. It is, therefore, important to accurately classify CV and CK chondrites to properly compare the properties of the two groups and evaluate the single parent body hypothesis. In this study, we re‐evaluate the current classification of Northwest Africa (NWA) 2900 as a CV3 chondrite. Based on chondrule abundance (~13%), average chondrule diameter (1.11 ± 0.67 mm), iron content in chondrule olivine (Fa1 to Fa35 with a peak near ~Fa31) and matrix olivine (Fa33 to Fa36), magnetite abundance (~4 vol%), elemental abundances in olivine (Cr2O3, Al2O3, TiO2, MnO, NiO, and CaO) and magnetite (Cr2O3, Al2O3, TiO2, and NiO), and comparison with previously reported data for CV and CK chondrites, we propose that the classification of NWA 2900 be changed from CV3 chondrite to CK3 chondrite, with characteristics most similar to those of the CK3.8 subtype. We additionally suggest minor modifications to the compositional criteria used to distinguish between CV and CK chondrites and demonstrate that NWA 2900 extends the range of bulk oxygen isotope compositions of CK chondrites.

Nutritional safety and suitability of a specific protein hydrolysate derived from whey protein concentrate and used in an infant and follow-on formula manufactured from hydrolysed protein by Danone Trading ELN B.V.

The European Commission asked EFSA to deliver an opinion on the nutritional safety and suitability of a specific protein hydrolysate. It is derived from whey protein concentrate and used in an infant and follow‐on formula by Danone Trading ELN B.V, which submitted a dossier to the European Commission to request an amendment of Regulation (EU) 2016/127 with respect to the protein sources that may be used in the manufacture of infant and/or follow‐on formula. This opinion does not cover the assessment of the safety of the food enzymes used in the manufacture of the protein hydrolysate. The protein hydrolysate under evaluation is sufficiently characterised with respect to the fraction of the hydrolysed protein. In the pertinent intervention study provided, an infant formula manufactured from the protein hydrolysate with a protein content of 2.3 g/100 kcal and consumed as the sole source of nutrition by infants for 3.5 months led to growth equivalent to a formula manufactured from intact cow's milk protein (2 g protein/100 kcal). No experimental data have been provided on the nutritional safety and suitability of this protein source in follow‐on formula. However, given that it is consumed with complementary foods and the protein source is considered nutritionally safe and suitable in an infant formula that is the sole source of nutrition of infants, the Panel considers that the protein hydrolysate is also a nutritionally safe and suitable protein source for use in follow‐on formula. The Panel concludes that the protein hydrolysate under evaluation is a nutritionally safe and suitable protein source for use in infant and follow‐on formula, as long as the formula in which it is used contains a minimum of 2.3 g/100 kcal protein and complies with the compositional criteria of Commission Delegated Regulation (EU) 2016/127 and the amino acid pattern in its Annex IIIA.

Automated computed tomography quantification of fibrosis predicts prognosis in combined pulmonary fibrosis and emphysema in a real-world setting: a single-centre, retrospective study

BackgroundCombined pulmonary fibrosis and emphysema (CPFE) is a heterogeneous clinico-radiological syndrome without a consensus definition. There are limited data on the relation between the amount of parenchymal fibrosis and prognosis. In this study, we assessed the prognostic implications of the extent of fibrosis assessed by an automated quantitative computed tomography (CT) technique and the radiological and functional change over time in patients with a broad spectrum of fibrotic interstitial lung diseases (ILDs) encountered in a real-world setting.MethodsWe conducted a single-centre, retrospective study of 228 consecutive patients with CPFE, encountered from 2007 to 2015 at Kameda Medical Center, Chiba, Japan. We investigated the prognostic value of automated CT fibrosis quantification and the subsequent course of CPFE.ResultsAmong 228 patients with CPFE, 89 had fibrosis affecting < 5% of their lungs, 54 had 5 to < 10% fibrosis, and 85 had ≥ 10% fibrosis at the time of diagnosis. Lower volume of fibrosis correlated with lower rates of mortality and acute exacerbation (p < 0.001). In particular, among those with < 5% fibrosis, only 4.5% died and none experienced acute exacerbation during follow-up, whereas 57.6% and 29.4% of those with ≥ 10% fibrosis experienced death and acute exacerbation, respectively. Although, the ≥ 10% fibrosis group had the poorest overall survival as well as the highest incidence of acute exacerbation, the incidence of decline in pulmonary function tests, change per year in total lung volume, and progression of fibrosis on chest CT was highest in the 5 to < 10% fibrosis group. The Cox proportional hazard model for CPFE progression (defined by composite criteria of death, acute exacerbation, and decline in forced vital capacity or diffusing capacity) showed fibrosis proportion was a risk factor independent of age, sex, smoking pack-years, the Charlson Comorbidity Index, lung cancer, connective tissue disease, and idiopathic pulmonary fibrosis.ConclusionsLess severe (< 5%) fibrosis at baseline was associated with disease stability and better prognosis compared to more severe fibrosis in CPFE occurring with fibrotic ILDs. Further studies including a validation cohort will be needed.Trial Registration Retrospectively registered.

Assessing Quality of Life Inequalities. A Geographical Approach

This study proposes an integrated methodology for evaluating and mapping quality of life (QoL) and the quality of a place as residence area, at local level. The QoL assessment was based on the development of composite criteria, using geographical variables that evaluate QoL, and geographic information systems. The composite criteria are related to the natural and the socioeconomic environment, the housing conditions, the infrastructure and services, and the cultural and recreational facilities. Each criterion was evaluated by a set of variables and each variable was weighted based on the residents’ preferences and the analytical hierarchy process. The criteria were also weighted and combined to assess overall QoL. The methodology was implemented in the Municipality of Katerini, Greece, and QoL mapping led to the zoning of the study area and the identification of areas with low and high QoL. The results revealed the highest level of overall QoL in three out of twenty-nine communities, which provide better housing conditions and access to public services and infrastructures, combining also qualitative natural environment, whereas five mountainous and remote communities scored the lowest level. Mapping QoL may support decision making strategies that target to improve human well-being, increase QoL levels and upgrade living conditions.

Impact of pulmonary artery catheter hemodynamic monitoring on post-operative morbidity and mortality in elective bentall procedures

Introduction Because of debated effectiveness and safety, the perioperative use of pulmonary artery catheter (PAC) has decreased in cardiac surgery (1). However, PAC keeps some specifics indications in high risk cardiac surgery (2). This study evaluates the impact of perioperative PAC monitoring on postoperative morbidity and mortality after Bentall procedures. Methods We designed a single center retrospective observational study comparing patients undergoing Bentall procedure with or without perioperative CAP monitoring. Patients included had no major risk of hemodynamic complications (Left ventricular ejection fractions (LVEF) > 40%, no pulmonary arterial hypertension, no history of cardiac surgery). Primary endpoint was a composite criteria of postoperative morbidities and mortality defined by the occurrence of any the following: death in hospital, cardiac dysfunction (myocardial infarction or congestive heart failure), cerebral dysfunction (stroke or encephalopathy), renal dysfunction (acute kidney injury or dialysis), or pulmonary dysfunction (acute respiratory distress syndrome). Epidemiology of CAP use, others postoperative complications, biological markers (lactates, troponin), hemodynamic management and length of stay in intensive care unit (ICU) and hospital were also assessed. Results Among the 134 patients enrolled between 2012 and 2019, the primary endpoint occurred in 29 of 59 PAC patients vs. 17 of 75 patients without PAC (49.2%, 95% confidence interval (CI), 37-62, vs 22.7%, 95% CI, 15-33; P The PAC group had an increased risk of cardiac (22% vs 2.7%, P In multivariate logistic regression analysis, with independent factors (CAP use, length of cardiopulmonary bypass, EuroSCORE 2), CAP use was not associated with the occurrence of primary endpoint (adjusted odds ratio 2.07, 95% CI [0.9-4.7], P=0.08). Discussion In our study, a PAC was used in a highest risk group. The use of PAC was associated with increased postoperative mortality and morbidity in univariate but not in multivariate analysis. A randomized clinical trial is needed to clarify the link between CAP use and postoperative complications.

First Principles Density Functional Theory Prediction of the Crystal Structure and the Elastic Properties of Mo2ZrB2 and Mo2HfB2

The Molybdenum rich ternary alloys Mo-M-B (M = Zr, Hf) contain, next to the Mo solid solution (bcc Mo with small amounts of Zr or Hf as substitutional atoms), the binary borides Mo2B, MB and MB2. Recently, it was found that there is also ternary Mo2MB2, but the crystal structure and further properties are currently unknown. Density functional theory (DFT) calculations were used not only to predict the crystal structure of the Mo2MB2 phases, but also to estimate the isotropic and anisotropic elastic properties like bulk, shear and Young’s modulus, as well as the Vickers hardness of these new borides. Several known crystal structures that fulfill the criterion of the chemical composition were investigated, and the AlMn2B2 type structure seems to be the most stable crystal structure for Mo2HfB2 and Mo2ZrB2 as there are no signs of electronic or dynamic instability. Regarding the elastic properties, it was found that Mo2HfB2 shows higher elastic moduli and is less elastically anisotropic than Mo2ZrB2.

The cause of birth is associated with neonatal prognosis in late preterm singletons

IntroductionRecent studies have shown that the cause of very preterm births may be related to neonatal morbidity and mortality. Even though these risks are lower among late preterm births, this group accounts for the vast majority of all preterm births. The objective of this study was to evaluate the relation of neonatal morbidity and mortality to the cause of late preterm birth. Materials and methodsThis retrospective observational cohort study included all women who gave birth to liveborn singletons from 34 to 36 weeks+6 days of gestation in a French level III maternity hospital in the 5-year period 2013–2017. The causes of preterm delivery were divided into 6 mutually exclusive groups. The main outcome was a composite neonatal morbidity criterion, defined by at least one among the following criteria: neonatal respiratory distress, neurological complications, neonatal sepsis, severe necrotizing enterocolitis, and neonatal hypoglycemia. We analyzed the association between cause of preterm delivery and neonatal morbidity after adjustment for gestational age and antenatal corticosteroid therapy. The reference group was preterm labor, defined by spontaneous preterm labor with intact membranes. ResultsDuring the study period, there were a total of 27 110 births, including 1114 singleton births at 34 to 36 weeks of gestation + 6 days (4.1%). Among the 968 late preterm births included, the risk of neonatal morbidity in the group with preterm premature rupture of membranes (PPROM) was similar to that in the preterm labor (reference) group: adjusted odds ratio (aOR) 1.2 (95% CI, 0.8-1.8). All the other causes of late preterm birth were associated with a higher risk of neonatal morbidity than the reference group: aOR 2.0 [95% CI, 1.1–3.5] for hypertensive disorders without suspected fetal growth restriction (FGR) (9.1% of cases), aOR 2.4 [95% CI, 1.4–4.2] for hypertensive disorders with suspected FGR (8.9%), aOR 4.2 [95% CI, 2.2-8.0] for suspected FGR without hypertensive disorders (5.8%), and aOR 4.4 [95% CI, 2.2-8.8] for vaginal bleeding related to abnormal placental insertion (4.7%). ConclusionAmong infants born from 34 to 36 weeks + 6 days of gestation, PPROM and preterm labor had similar risks of neonatal morbidity, while the other causes were associated with a risk of neonatal morbidity at least twice that with preterm labor.

Size- and strain rate-dependence of nickel and Ni–Co micropillars with varying stacking fault energy

The effect of the specimen size on the mechanical characteristics of material, a phenomenon commonly referred to as the “size effect”, becomes increasingly important at micron and sub-micron dimensions of the specimen. However, the majority of size effect studies on face-centered cubic (fcc) metals have focused on pure elements, where deformation is accomplished by dislocation glide. In this work, single crystalline Ni – x at. % Co (with x = 0, 30, 50) solid solution micropillars were studied by mechanical testing and transmission electron microscopy (TEM) to elucidate the role of stacking fault energy on the size effect in Ni as a function of Co-addition. In situ strain rate jump (SRJ) microcompression testing allowed the evaluation of strain rate sensitivity and activation volumes for all pillar sizes at different strain rates, spanning over three orders of magnitude. TEM analysis showed that for an increase in Co content up to 50%, the SFE decreased from ~85 to ~28 mJ/m2. We observed all Ni – x at. % Co micropillars to exhibit consistent size effect trends (n=~−0.7), independent of composition and yield criterion, and similar trends between activation volume and different sizes: activation volume increases with grain size/pillar size.

Validation of Puck\u2019s failure criterion for CFRP composites in the cryogenic regime

For future launch vehicles, lightweight cryogenic pressure vessels are required for storage of the liquid hydrogen fuel. For their structural assessment, reliable and validated failure criteria are required. The present contribution provides an overview over the results of an ongoing research activity concerned with the validation of Puck’s composite failure criterion in the cryogenic regime. In a first step, an experimental investigation on unidirectionally fiber reinforced materials on coupon level has been performed. This test campaign has been complemented by tests on small breadboard-type specimens with an angle-ply stacking sequence. The specimens were featuring holes and tapered sections to provide stress gradients and concentrations. Test were performed at ambient temperature and in a liquid Helium environment. Puck’s failure criterion has been applied and found to provide a good prediction of first ply failure in both environments.

Optimization of machining parameters of aluminum alloy 6026-T9 under MQL-assisted turning process

The lower lead time and increasing demand for good quality parts require the industries to produce the parts manufactured sustainably with higher precision, improved productivity, and low cost using new techniques. Minimum quantity lubricant (MQL) is one of these techniques, which is economical and eco-friendly. This paper deals with the analysis and multi-response optimization of cutting process parameters of Aluminum alloy 6026-T9 in MQL and dry conditions using an integrated approach of composite desirability function and criteria importance through inter-criteria (CRITIC). The cutting parameters considered for the study are cutting speed, feed rate, depth of cut, and positive rank angle, while the responses are surface roughness profile (Ra, Rq, Rz), tool life and material removal rate. The type of insert used was a tungsten carbide, while the coolant was minimum quantity lubricant (MQL) vegetable oil (olive oil) performed at 150mL/hr. Taguchi orthogonal array (L16) using sixteen experimental runs are designed for machining. Based on analysis of variance (ANOVA) it is identified that the most significant cutting process parameters for surface roughness profile (Ra, Rq, Rz) under both dry and MQL conditions are the feed rate, while for the tool life are cutting speed and feed rate and for material removal rate is cutting speed followed by depth of cut and feed rate. Under dry conditions the optimized levels obtained are cutting speed of 500m/min, the feed rate of 0.3mm/rev, depth of cut of 2mm, and positive rake angle of 15°. However for MQL condition are cutting speed of 500m/min, the feed rate of 0.4mm/rev, depth of cut of 2mm, and positive rake angle of 15°. Finally, the machined worked piece surface and inserts are morphologically characterized at different cutting parameters using scanning electron microscopy (SEM) and Energy Dispersive X-Ray Analysis (EDX).

Cystatin C and Urine Albumin to Creatinine Ratio Predict 5-Year Mortality and Cardiovascular Events in People Living With HIV.

Identifying people with HIV (PWH) at risk for chronic kidney disease, cardiovascular events, and death is crucial. We evaluated biomarkers to predict all-cause mortality and cardiovascular events, and measured glomerular filtration rate (mGFR) slope. Biomarkers were measured at enrollment. Baseline and 5-year mGFR were measured by plasma iohexol clearance. Outcomes were a composite criterion of all-cause mortality and/or cardiovascular events, and mGFR slope. Of 168 subjects, 146 (87.4%) had undetectable HIV load. Median follow-up was 59.1 months (interquartile range, 56.2-62.1). At baseline, mean age was 49.5 years (± 9.8) and mean mGFR 98.9 mL/min/1.73m2 (± 20.6). Seventeen deaths and 10 cardiovascular events occurred during 5-year follow-up. Baseline mGFR was not associated with mortality/cardiovascular events. In multivariable analysis, cystatin C (hazard ratio [HR], 5.978; 95% confidence interval [CI], 2.774-12.88; P < .0001) and urine albumin to creatinine ratio (uACR) at inclusion (HR, 1.002; 95% CI, 1.001-1.004; P < .001) were associated with mortality/cardiovascular events. Area under receiver operating curve of cystatin C was 0.67 (95% CI, .55-.79) for mortality/cardiovascular event prediction. Biomarkers were not associated with GFR slope. uACR and cystatin C predict all-cause mortality and/or cardiovascular events in PWH independently of mGFR.

Experimental procedures for the mechanical characterization of composite reinforced mortar (CRM) systems for retrofitting of masonry structures

Fiber-reinforced composites can be arranged in the form of bi-dimensional grids and employed as internal reinforcement of mortar plasters to realize composite reinforced mortar (CRM) systems. Recently, CRM were applied as externally bonded reinforcement of existing masonry members showing promising improvements of load-carrying and deformation capacities. However, since CRM systems are still in their infancy, limited research is available regarding their mechanical properties and their bond behavior with respect to masonry substrates. In this paper, a series of experimental tests are performed on a CRM system comprising a glass fiber-reinforced composite grid and a lime-based matrix. Namely, tensile tests of bare grid yarns and of CRM coupons, shear tests of grid joints, and single-lap direct shear tests of CRM-masonry joints were performed. These tests are aimed at providing a comprehensive mechanical characterization of the CRM, which results can be used to design strengthening applications with this system. Namely, the tensile properties of bare grid yarns in warp and weft direction are obtained and compared with those of CRM coupons tested following the indications of the Italian and U.S. acceptance criteria for inorganic-matrix composites. Furthermore, the grid joints are subjected to shear tests to determine if the yarns orthogonal to the applied load direction provide a contribution to the system load-carrying capacity. Finally, CRM-masonry joints are subjected to single-lap direct shear tests to study the CRM bond behavior. This work provides an insight on the behavior of CRM that can be useful to formulate reliable design procedures for these systems.

First-order anisotropic beam model and failure criterion for flexural parallel bamboo strand lumbers

To investigate the anisotropic behavior of parallel bamboo strand lumbers (PBSLs), flexural properties of seven kinds of PBSL beams with different fiber orientations were tested. It is found that the bending strength and stiffness decreases with the increase of the angle between the fibers and the beam axis. When the fibers are not parallel to the beam axis, the PBSL beam has an interfacial failure judged from the crack evolution. To reveal the coupling effect between the shear deformation and the axial tension/compression deformation induced by the anisotropy, first-order anisotropic beam model is proposed. Based on the tensile-shear failure of fibers or matrix, composite failure criteria for PBSLs were proposed to predict the ultimate load. The research also suggests a method to get material properties of PBSLs based on flexural experiments and failure analyses.