The entomopathogenicbacterium Bacillus thuringiensis is the most widely used biopesticide. In this study, to find and identify the more toxic B. thuringiensis strains against coleopteran pests, we ...isolated a B. thuringiensis strain (Xd3) from European shot-hole borer, Xyleborus dispar (Coleoptera: Scolytidae), a higly damaging pest of hazelnut. Based on various morphological, physiological, biochemical, and molecular characteristics, the bacterial isolate was identified as B. thuringiensis subsp. tenebrionis (morrisoni) serovar H8a8b. This isolate was compared with the reference strains by scanning electron microscopy, SDS-PAGE analysis, cry gene content, and insecticidal activity. Isolate Xd3 forms a flat-square inclusion containing a protein component of c. 70 kDa. PCR analysis showed that the Xd3 has a cry gene, cry3. Toxicity tests were performed against coleopteran species. One hundred percent mortality was observed against larvae of Agelastica alni (Coleoptera: Chrysomelidae). The others were 90% for Amphimallon solstitiale (Coleoptera: Scarabaeidae), and Melolontha melolontha (Coleoptera: Scarabaeidae). Our results indicate that B. thuringiensis subsp. tenebrionis (Xd3) may be valuable as biological control agent for coleopteran insects.
•A recombinant insect iridovirus was constructed.•The CIV 157L gene, putatively encoding a non-functional inhibitor of apoptosis (IAP), was chosen as target for foreign gene insertion.•The gfp open ...reading frame preceded by the viral mcp promoter was inserted into the 157L locus by homologous recombination in Anthonomus grandis BRL-AG-3A cells.•One-step growth curves for recombinant and wild-type CIV were similar.•Consequently, the CIV 157L locus can be used as a site for insertion of foreign DNA, e.g. to modify viral properties for insect biocontrol.
Chilo iridescent virus (CIV), officially named Insect iridescent virus 6 (IIV6), is the type species of the genus Iridovirus (family Iridoviridae). In this paper we constructed a recombinant CIV, encoding the green fluorescent protein (GFP). This recombinant can be used to investigate viral replication dynamics. We showed that homologous recombination is a valid method to make CIV gene knockouts and to insert foreign genes. The CIV 157L gene, putatively encoding a non-functional inhibitor of apoptosis (IAP), was chosen as target for foreign gene insertion. The gfp open reading frame preceded by the viral mcp promoter was inserted into the 157L locus by homologous recombination in Anthonomus grandis BRL-AG-3A cells. Recombinant virus (rCIV-Δ157L-gfp) was purified by successive rounds of plaque purification. All plaques produced by the purified recombinant virus emitted green fluorescence due to the presence of GFP. One-step growth curves for recombinant and wild-type CIV were similar and the recombinant was fully infectious in vivo. Hence, CIV157L can be inactivated without altering the replication kinetics of the virus. Consequently, the CIV 157L locus can be used as a site for insertion of foreign DNA, e.g. to modify viral properties for insect biocontrol.
Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), is an important pest on solanaceous crops worldwide. CPB has developed resistance to insecticides used for its control. In this study, ...in order to find a more effective and safer biological control agent against L. decemlineata, we studied the bacterial flora of CPB, and tested them for insecticidal effects on it. The highest insecticidal effect determined on L. decemlineata within 5 days was 100% and this effect was exhibited by Ld1 isolate. According to the morphological, physiological and biochemical tests, and 16S rRNA sequence homologies, Ld1 was identified as Leclercia adecarioxylata. This is the first time that this bacterium has been isolated from any insect pests. Our results indicate that Lecl. adecarboxylata may be valuable as a biological control agent for L. decemlineata.
During accelerating aging, experimental uncertainty may arise due to variability in the oxidation process, or due to limitations in the technique that is ultimately used to measure oxidation. The ...purpose of the present interlaboratory study was to quantify the repeatability and reproducibility of standard accelerated aging methods for ultra-high molecular weight polyethylene (UHMWPE). Sections (200
μm thick) were microtomed from the center of an extruded rod of GUR 4150 HP, gamma irradiated in air or nitrogen, and circulated to 12 institutions in the United States and Europe for characterization of oxidation before and after accelerated aging. Specimens were aged for 3 weeks at 80°C in an air circulating oven or for 2 weeks at 70°C in an oxygen bomb (maintained at 503
kPa (5 atm.) of O
2) in accordance with the two standard protocols described in ASTM F 2003-00. FTIR spectra were collected from each specimen within 24
h of the start and finish of accelerated aging, and oxidation indices were calculated by normalizing the peak area of the carbonyl region by the reference peak areas at 1370 or 2022
cm
−1. The mean relative interlaboratory uncertainty of the oxidation data was 78.5% after oven aging and 129.1% after bomb aging. The oxidation index measurement technique was not found to be a significant factor in the reproducibility. Comparable relative intrainstitutional uncertainty was observed after oven aging and bomb aging. For both aging methods, institutions successfully discriminated between air-irradiated and control specimens. However, the large interinstitutional variation suggests that absolute performance standards for the oxidation index of UHMWPE after accelerated aging may not be practical at the present time.
The entomopathogenic bacterium Bacillus thuringiensis is the most widely used biopesticide. In this study, to find and identify the more toxic B. thuringiensis strains against coleopteran pests, we ...isolated a B. thuringiensis strain (Xd3) from European shot-hole borer, Xyleborus dispar (Coleoptera: Scolytidae), a higly damaging pest of hazelnut. Based on various morphological, physiological, biochemical, and molecular characteristics, the bacterial isolate was identified as B. thuringiensis subsp. tenebrionis (morrisoni) serovar H8a8b. This isolate was compared with the reference strains by scanning electron microscopy, SDS-PAGE analysis, cry gene content, and insecticidal activity. Isolate Xd3 forms a flat-square inclusion containing a protein component of c. 70 kDa. PCR analysis showed that the Xd3 has a cry gene, cry3. Toxicity tests were performed against coleopteran species. One hundred percent mortality was observed against larvae of Agelastica alni (Coleoptera: Chrysomelidae). The others were 90% for Amphimallon solstitiale (Coleoptera: Scarabaeidae), and Melolontha melolontha (Coleoptera: Scarabaeidae). Our results indicate that B. thuringiensis subsp. tenebrionis (Xd3) may be valuable as biological control agent for coleopteran insects.
Accurate and timely detection of medical adverse events (AEs) from free-text medical narratives can be challenging. Natural language processing (NLP) with deep learning has already shown great ...potential for analyzing free-text data, but its application for medical AE detection has been limited.
In this study, we developed deep learning based NLP (DL-NLP) models for efficient and accurate hip dislocation AE detection following primary total hip replacement from standard (radiology notes) and non-standard (follow-up telephone notes) free-text medical narratives. We benchmarked these proposed models with traditional machine learning based NLP (ML-NLP) models, and also assessed the accuracy of International Classification of Diseases (ICD) and Current Procedural Terminology (CPT) codes in capturing these hip dislocation AEs in a multi-center orthopaedic registry.
All DL-NLP models outperformed all of the ML-NLP models, with a convolutional neural network (CNN) model achieving the best overall performance (Kappa = 0.97 for radiology notes, and Kappa = 1.00 for follow-up telephone notes). On the other hand, the ICD/CPT codes of the patients who sustained a hip dislocation AE were only 75.24% accurate.
We demonstrated that a DL-NLP model can be used in largescale orthopaedic registries for accurate and efficient detection of hip dislocation AEs. The NLP model in this study was developed with data from the most frequently used electronic medical record (EMR) system in the U.S., Epic. This NLP model could potentially be implemented in other Epic-based EMR systems to improve AE detection, and consequently, quality of care and patient outcomes.
•Accurate and timely detection of medical adverse events (AEs) from free-text medical narratives can be challenging.•We developed deep learning based natural language processing models for efficient and accurate hip dislocation AE detection.•A convolutional neural network (CNN) model achieved the best overall performance detecting hip dislocation AE.•Such a CNN model can be used in large-scale orthopaedic registries for accurate and efficient hip dislocation AE detection.
Accurate and timely detection of medical adverse events (AEs) from free-text medical narratives is challenging. Natural language processing (NLP) with deep learning has already shown great potential for analyzing free-text data, but its application for medical AE detection has been limited. In this study, we developed deep learning based NLP (DL-NLP) models for efficient and accurate detection of hip dislocation AEs following primary total hip replacement using standard (radiology notes) and non-standard (follow-up telephone notes) free-text medical narratives. We benchmarked these proposed models with traditional machine learning based NLP (ML-NLP) models, and also assessed the accuracy of International Classification of Diseases (ICD) and Current Procedural Terminology (CPT) codes in capturing these hip dislocation AEs in a multi-center orthopaedic registry. All DL-NLP models outperformed all of the ML-NLP models, with a convolutional neural network (CNN) model achieving the best overall performance (Kappa = 0.97 for radiology notes, and Kappa = 1.00 for follow-up telephone notes). In comparison, the ICD/CPT codings of the patients who sustained a hip dislocation AE were only 75.24% accurate. We showed that a DL-NLP model can be used in large-scale orthopaedic registries for accurate and efficient hip dislocation AE detection. The NLP model in this study was developed with data from the most frequently used electronic medical record (EMR) system in the U.S., Epic. This model could be implemented in other Epic-based EMR systems for AE detection to improve the quality of care and patient outcomes.
Longevity of total joints has been compromised by wear and fatigue of ultrahigh molecular weight polyethylene (UHMWPE) components. Crosslinking reduces UHMWPE wear, but combined with postirradiation ...melting, also reduces its fatigue strength, therefore limiting its use in high-stress applications. We hypothesized that a lipophilic antioxidant (
α-tocopherol,
α-T) can protect UHMWPE against oxidation eliminating the need for postirradiation melting of crosslinked UHMWPE and improve its fatigue strength. To test these hypotheses, 65- and 100-kGy irradiated,
α-T-doped and subsequently
γ-sterilized UHMWPE were used. (I)
α-T-doped irradiated UHMWPEs showed significantly lower oxidation levels (0.48±0.25 and 0.44±0.06) compared to 100-kGy irradiated UHMWPE (3.74±0.16) after 5 weeks of accelerated aging at 80°C in air. (II) Wear rate of
α-T-doped irradiated UHMWPE (1.9±0.5, and 0.9±0.1
mg/million cycles (MC) for 65- and 100-kGy irradiated UHMWPE, respectively) were comparable to that of 100-kGy irradiated/melted UHMWPE (1.1±0.7
mg/million cycles). (III) The stress intensity factor at crack inception (Δ
K
i) of 100-kGy irradiated UHMWPE increased significantly upon doping with
α-T from 0.74 to 0.87
MPa
m
1/2 (
p<0.01). The Δ
K
i for the 100-kGy irradiated and melted UHMWPE, currently in clinical use, was 0.55
MPa
m
1/2. Doping with
α-T eliminated the need for postirradiation melting to protect irradiated UHMWPE against long-term oxidation. The fatigue strength was improved by 58% for
α-T-doped 100-kGy irradiated UHMWPE compared to irradiated and melted UHMWPE. The increase in oxidative stability of
α-T-doped UHMWPE is attributed to the ability of
α-T to react with peroxy free radicals on lipid chains and arrest the oxidation reactions. The improved fatigue strength is attributed to the increase in plasticity of UHMWPE due to the lipophilic nature of
α-T.
Abstract Recent in vitro findings suggest that UHMWPE wear particles containing vitamin E (VE) may have reduced biologic activity and decreased osteolytic potential. We hypothesized that particles ...from VE-stabilized, radiation cross-linked UHMWPE would cause less osteolysis in a murine calvarial bone model when compared to virgin gamma irradiated cross-linked UHMWPE. Groups received equal amount of particulate debris overlaying the calvarium for 10 days. Calvarial bone was examined using high resolution micro-CT and histomorphometric analyses. There was a statistically significant difference between virgin (12.2% ± 8%) and VE-UHMWPE (3% ± 1.4%) groups in regards to bone resorption ( P = 0.005) and inflammatory fibrous tissue overlaying the calvaria (0.48 vs. 0.20, P < 0.0001). These results suggest that VE-UHMWPE particles have reduced osteolytic potential in vivo when compared to virgin UHMWPE.
Abstract Poly(vinyl alcohol) (PVA) has been advanced as a biomaterial for the fabrication of medical devices to be used as synthetic articular cartilage because of its viscoelastic nature, high water ...content, and biocompatibility. Key material requirements for such devices are high creep resistance to prevent mechanical instability in the joint and high water content to maintain a lubricious surface to minimize wear and damage of the cartilage counterface during articulation. The creep resistance of PVA hydrogels can be increased by high temperature annealing; however this process also collapses the pores, reducing the water content and consequently reducing the lubricity of the hydrogel surface Bodugoz-Senturk H, Choi J, Oral E, Kung JH, Macias CE, Braithwaite G, et al. The effect of polyethylene glycol on the stability of pores in polyvinyl alcohol hydrogels during annealing. Biomaterials 2008;29(2):141–9.. We hypothesized that polymerizing acrylamide (AAm) in the pores of the PVA hydrogel would minimize the loss of lubricity during annealing by preventing the collapse of the pores and loss of water content. Increasing AAm content increased porosity and equilibrium water content and decreased the coefficient of friction, tear strength, crystallinity, and creep resistance in annealed PVA hydrogels.
Crosslinking has been shown to improve the wear resistance of ultra-high molecular weight polyethylene in both in vitro and clinical in vivo studies. The molecular mechanisms and material properties ...that are responsible for this marked improvement in wear resistance are still not well understood. In fact, following crosslinking a number of mechanical properties of UHMWPE are decreased including toughness, modulus, ultimate tensile strength, yield strength, and hardness. In general, these changes would be expected to constitute a precursor for lower wear resistance, presenting a paradox in that wear resistance increases with crosslinking. In order to understand better and to analyze this paradoxical behaviour of crosslinked UHMWPE, we investigated the wear behavior of (i) radiation-crosslinked GUR 1050 resin, (ii) peroxide-crosslinked GUR 1050 resin and (iii) peroxide-crosslinked Himont 1900 resin using a bi-directional pin-on-disk (POD) machine. Wear behavior was analyzed as a function of crystallinity, ultimate tensile strength (UTS), yield strength (YS), and molecular weight between crosslinks (
M
c). The crosslink density increased with increasing radiation dose level and initial peroxide content. The UTS, YS, and crystallinity decreased with increasing crosslink density. While these variations followed the same trend, the absolute changes as a function of crosslink density were different for the three types of crosslinked UHMWPE studied. There was no unified correlation for the wear behavior of the three types of crosslinked UHMWPE with the crystallinity, UTS and YS. However, the POD wear rate showed the identical linear dependence on
M
c with all three types of crosslinked UHMWPEs studied. Therefore, we have strong evidence to propose that
M
c or crosslink density is a fundamental material property that governs the lubricated adhesive and abrasive wear mechanisms of crosslinked UHMWPEs, overriding the possible effects of other material properties such as UTS, YS and crystallinity on the wear behavior.
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