Fixation Characteristics Research Articles

Effect of design on the initial stability of press-fit cups in the presence of acetabular rim defects: experimental evaluation of the effect of adding circumferential fins

This experimental study was undertaken to examine the fixation characteristics of a six-finned acetabular cup in both primary and revision arthroplasty in comparison with two other commonly used cup designs without fins. All three cup designs (Ananova® [Intraplant], Plasmacup® NSC [Aesculap]; Exceed ABT™ [Biomet]) were implanted into validated models of normal and revision acetabula. The defect models were designed to simulate a dorso-cranial rim defect of 90° width and 10 mm in depth (moderate rim defect) and a dorso-cranial rim defect of 130° width and 15 mm in depth (severe rim defect). The fixation strength of the three cup designs was tested by cyclically edge-loading the implanted cups using a mechanical testing machine. The six-finned Ananova implant exhibited greater resistance to foam-cup interface motion than both the Plasmacup and Exceed ABT implants. The largest average differences were observed in the resistance to ultimate spin-out, with Ananova outperforming Exceed ABT and Plasmacup by 26% and 17% in the moderate and by 36% and 38% in the severe defect models, respectively. The six-finned Ananova cup was significantly more resistant to edge loading both in the normal acetabulum and in acetabula with moderate to severe dorso-cranial rim defects than cup designs without fins, indicating that it may cover a wider range of clinical indications than conventional press-fit cups and provide clinicians with the confidence that, in primary and simple revision arthroplasty, adequate fixation strength can be obtained.

Anterior Transpedicular Screw Technique for Failed Anterior Cervical Internal Fixation in Revision Surgery: a Case Report

Anterior Transpedicular Screw Technique for Failed Anterior Cervical Internal Fixation in Revision Surgery: a Case Report

Strength of Suture Anchor Versus Transosseous Tunnel in Anatomic Reconstruction of the Ankle Lateral Ligaments: A Biomechanical Study

The purpose of this study was to compare the biomechanical characteristics of fixation with 2-suture anchors versus transosseous tunnel fixation in anatomic reconstruction of the ankle lateral ligaments. Six matched pairs of human cadaveric ankles underwent anatomic lateral ankle reconstruction, and fixation of the graft on the talus was achieved with 2 suture anchors or a transosseous tunnel. Ankles for the transosseous tunnel group were chosen at random, with the paired contralateral ankles used for the 2-suture anchor group. Half of the peroneus brevis tendon was harvested as a graft. For each technique, one end of the tendon was secured to the original insertion point of the anterior talofibular ligament (ATFL) at the talus, whereas the other end was armed with 2 No. 5 nonabsorbable sutures (Ethicon, Somerville, NJ) and passed through the bone tunnel in the fibula. Biomechanical testing was performed by applying the force in line with the graft. Load to failure was determined at a displacement rate of 50 mm/min. The load-displacement curve, maximum load at failure (N), and stiffness (N/mm) were recorded and compared between the 2 techniques. There was no difference between constructs in the 2-suture anchor group and the transosseous tunnel group in terms of the ultimate load and stiffness (161.8 ± 47.6 N v 171.9 ± 76.0 N; P= .92; 4.59 ± 1.85 N/mm v 5.77 ± 1.98 N/mm; P= .35). Most constructs failed because of anchor pullout in the 2-suture anchor group (5 of 6) and fracture of the bony bridge in the transosseous tunnel group (6 of 6). The strength of fixation with suture anchors in anatomic reconstruction of the ankle lateral ligaments was equivalent to transosseous tunnel fixation as determined with biomechanical testing. However, this study did not prove that one is advantageous over the other. Both techniques showed excellent biomechanical results. Therefore, the 2-suture anchor fixation approach can be safely used in anatomic reconstruction of the ankle lateral ligaments.

Characteristics of CO2 fixation by chemical conversion to carbonate salts

We propose a new method of CO2 removal by combining carbon dioxide capture and storage (CCS) and CO2 fixation processes. In this study, amine solutions were used to make carbonates and calcium ions were used for CO2 fixation. Primary (MEA), secondary (DEA), and tertiary (MDEA) amines were selected for use in a 10 or 30wt% amine solution with H2O and Ca2+ in a CO2 saturated solution. CO2 fixation was verified and the carbonate was formed under normal temperature and pressure conditions. As a result, most of the CO2 was converted to a precipitate (more than 84% by weight). The molar yield of MDEA was higher than that of the other amines (MEA and DEA). We believe that this is due to the fact that tertiary amines (MDEA) do not have H+ in their structure. Therefore, MDEA does not produce carbamate when CO2 is absorbed in solution. Further, we measured the residual CO2 in each solution through a desorption process. These results also demonstrate less residual CO2 in the MDEA than in the other amines. Product carbonates were analyzed by X-ray diffractometry (XRD) and were found to consist of calcite, aragonite, and vaterite with various compositions depending on the particular amine solution used for the CO2 conversion. Therefore, we conclude that CO2 fixation is possible using amine solutions and metal ions. We believe that this process can be applied to CO2 emission capture techniques where no external energy is required.

Biomechanical Comparison of Interference Screws and Combination Screw and Sheath Devices for Soft Tissue Anterior Cruciate Ligament Reconstruction on the Tibial Side

Background: The tibial fixation site has been reported to be the weakest point in anterior cruciate ligament (ACL) reconstructions. Numerous interference screws and combination screw and sheath devices are available for soft tissue fixation, and a biomechanical comparison of these devices is necessary. Hypothesis: Combination screw and sheath devices would provide superior soft tissue fixation properties compared with interference screws in a porcine model. Study Design: Controlled laboratory study. Methods: Eight different intratunnel tibial soft tissue fixation devices were biomechanically tested in a porcine model with bovine tendons, with 10 specimens per group. The soft tissue fixation devices included 3 interference screws—the Bio-Interference Screw, BIOSURE PK, and RCI Screw—and 5 combination screw and sheath devices (combination devices)—the AperFix II, BIOSURE SYNC, ExoShape, GraftBolt, and INTRAFIX. The specimens were subjected to cyclic (1000 cycles, 50-250 N, 0.5 Hz) and pull-to-failure loading (50 mm/min) with a dynamic tensile testing machine. Ultimate failure load (N), cyclic displacement (mm), pull-out stiffness (N/mm), displacement at failure (mm), load at 3 mm displacement (N), and mechanism of failure were recorded. Results: The ultimate failure loads were highest for the GraftBolt (1136 ± 115.6 N), followed by the INTRAFIX (1127 ± 155.0 N), AperFix II (1122 ± 182.9 N), BIOSURE PK (990.8 ± 182.1 N), Bio-Interference Screw (973.3 ± 95.82 N), BIOSURE SYNC (829.5 ± 172.4 N), RCI Screw (817.7 ± 113.9 N), and ExoShape (814.7 ± 178.8 N). The AperFix II, GraftBolt, and INTRAFIX devices were significantly stronger than the BIOSURE SYNC, RCI Screw, and ExoShape. Although the 3 strongest devices were combination screw and sheath devices, no significant differences were observed between the ultimate failure strengths of the screw and combination devices when compared as groups. The least amount of cyclic displacement after 1000 cycles was observed for the GraftBolt (1.38 ± 0.27 mm), followed by the AperFix II (1.58 ± 0.21 mm), Bio-Interference Screw (1.61 ± 0.22 mm), INTRAFIX (1.63 ± 0.15 mm), ExoShape (1.68 ± 0.30 mm), BIOSURE PK (1.72 ± 0.29 mm), BIOSURE SYNC (1.92 ± 0.59 mm), and RCI Screw (1.97 ± 0.39 mm). The GraftBolt allowed significantly less displacement than did the BIOSURE SYNC and RCI Screw. Similarly, no significant differences were observed between the cyclic displacements of the screws and combination devices when compared as groups. Conclusion: The combination screw and sheath devices did not provide superior soft tissue fixation properties compared with the interference screws alone in a porcine model. Although the highest ultimate failure loads and least amounts of cyclic displacement were observed for combination devices, group comparisons of screw and combination devices did not result in any significant differences for ultimate failure load and cyclic displacement. Clinical Relevance: It is important to consider that these results represent device performance in an in vitro animal model and are not directly transferrable to an in vivo clinical situation. The combination of a sheath and screw did not consistently result in improved fixation characteristics compared with interference screw fixation.

Long-term effect of pulses and nutrient management on soil carbon sequestration in Indo-Gangetic plains of India

Venkatesh, M. S., Hazra, K. K., Ghosh, P. K., Praharaj, C. S. and Kumar, N. 2013. Long-term effect of pulses and nutrient management on soil carbon sequestration in Indo-Gangetic plains of India. Can. J. Soil Sci. 93: 127–136. As an important component of crop diversification, pulses/legumes are known to improve soil quality through their unique characteristics of biological N2 fixation, root exudates, leaf litter fall and deep root system. Changes in the soil organic carbon pool due to the inclusion of pulses in an upland maize-based cropping system were evaluated after seven cropping cycles. The results indicate that inclusion of pulses in an upland maize-based cropping system improved the total soil organic carbon content, being greater in surface soil (0–0.2 m) and declining with soil depth. Of the four carbon fractions of total soil organic carbon (C frac 1 –C frac 4 ) measured in the upland maize-based system, the most labile C fraction (C frac 1 ) was dominant. Distribution of the carbon pool varie...

The influence of suture material on the strength of horizontal mattress suture configuration for meniscus repair

PurposeComparison of the mechanical characteristics of meniscal repair fixation using horizontal sutures and six different sutures under submaximal cyclic and load to failure test conditions may aid physicians in selecting a suture type. MethodsA 2-cm long anteroposterior vertical longitudinal incision was created in six groups of bovine medial menisci. Lesions were repaired using a No. 2 suture either composed of polyester or polyester and ultra high-molecular weight polyethylene (UHMWPE), or UHMWPE and polydioxanone or pure UHMWPE. Endpoints included ultimate failure load (N), pull-out stiffness (N/mm), pull-out displacement (mm), cyclic displacement (mm) after 100cycles, after 500cycles, and mode of failure. ResultsPolyester suture had lower ultimate load than all groups except the suture composed of polyester and UHMWPE (P<.05). Pure UHMWPE suture had higher ultimate failure load than sutures composed of either polyester or polyester plus UHMWPE (P<.05).Predominant failure mode was suture cutting through the meniscus for the groups except for polyester suture which failed by suture rupture. ConclusionUnder cyclic loading conditions in bovine meniscus, braided polyester suture fixation provided lower initial fixation strength than fixation with various high strength sutures composed of pure UHMWPE or a combination of absorbable monofilament polydioxanone and UHMWPE, except for combination of polyester and UHMWPE sutures. Clinical relevancePresent study does not support the usage of the braided polyester sutures instead of high strength sutures composed either partially or totally of ultra-high molecular weight polyethylene for the horizontal suture configuration of meniscus repair.

浙北地区常见绿化树种光合固碳特征

高固碳能力的树种选择是营造优质碳汇林,发展碳汇林业的重要基础工作。以浙北地区常见的30种造林绿化树种为研究材料,利用LI-6400便携式光合测定仪,测定树木光合日变化及不同光强梯度下光合作用的光响应特性,并根据实验观测值进行计算,对30个树种的日净固碳量和光合生理拟合参数进行Ward法聚类分析和因子分析。结果表明:香樟的固碳量最大((11.374±1.020) g·m^-2·d^-1),其次为碧桃、垂柳、石栎、无患子,固碳量最小的为红叶李((2.178±0.605) g·m^-2·d^-1),香樟和红叶李的日净固碳量有极显著差异(<em>P</em><0.01);树木的生理特性指标分析进一步反映了树种在浙北地区生长适应性及固碳能力大小,同时,根据树木的生理特性指标进行因子分析和聚类分析的结果,香樟、碧桃在浙北地区生长适应性较好,其次为无患子、垂柳、女贞等;根据树种固碳量及生理指标综合测定分析,建议在浙北地区造林绿化中可以优先选用香樟、碧桃、垂柳、无患子、石栎、女贞这些树种。;Development of carbon sequestration forestry has made the species choice of high carbon sequestration capacity an important measure for planting superior quality carbon sink forests. The photosynthetic rate, light saturation point, light compensation point, maximum net photosynthetic rate, apparent quantum efficiency and other physiological indicators can be used to reflect the characteristics of carbon fixation and assimilation of CO₂ capacity. This research selected thirty common afforestation tree species in northern Zhejiang province as the research materials. They are <em>Ginkgo biloba </em>L., <em>Taxodium distichum </em>(L.) Rich, <em>Podocarpus nagi </em>(Thunb.) Kuntze, <em>Populus euramevicana</em>,<em> Salix babylonica </em>L., <em>Zelkova schneideriana </em>(Hand.) Mazz, <em>Celtis julianae </em>Schneid., <em>Magnolia grandiflora </em>L., <em>Magnolia denudate </em>Desr., <em>Michelia chapensis </em>Dandy, <em>Michelia maudiae </em>Dunn, <em>Liriodendron chinense </em>(Hemsl.) Sarg, <em>Cinnamonum campora </em>(L.) Prels, <em>Machilus pauhol kanehira</em>, <em>Amygdalus persica </em>var.<em> persica </em>f. Duplex, <em>Prunus cerasifera </em>f.<em> Atropurpurea</em>,<em> Cerasus yedoensis</em>, <em>Photinia×fraseri Dress 'Red Robin'</em>, <em>Albizia julibrissin </em>Durazz., <em>Choerospondias axillaris</em>, <em>Acer buergerianum </em>Miq, <em>Ilex chinensis </em>Sims, <em>Sapindus mukorossi </em>Gaertn, <em>Koelreuteria integrifoliola </em>Merr., <em>Diospyros glaucifolia</em>, <em>Osmanthus fragrans</em>, <em>Ligustrum lucidum</em>, <em>Liquidambar formosana </em>Hance, <em>Elaeocarpus glabripetalus </em>Merr., and <em>Lithocarpus glaber</em>. A portable LI-6400 photosynthesis apparatus is used to measure the photosynthetic diurnal variation and the responses of photosynthesis to different light intensities in the tested tree species. Ward cluster analysis was used to analyze the net sequestered carbon of 30 tree species, and both factor analysis and Ward cluster analysis were used to examine the fitting physiological parameters of photosynthesis. The results showed that <em>Cinnamonum campora </em>(L.) Pres has the highest carbon fixation ((11.374±1.020) g·m^-2·d^-1), followed by <em>Amygdalus persica </em>var<em>. persica </em>f.<em> duplex</em>, <em>Salix babylonica </em>L., <em>Lithocarpus glaber</em>, <em>Sapindus mukorossi</em> <em>Gaertn</em> and others, and <em>Prunus cerasifera </em>f.<em> atropurpurea </em>has the lowest ((2.178±0.605) g·m^-2·d^-1). <em>Cinnamonum campora </em>(L.) Prels. has significantly higher net sequestered carbon (<em>P</em><0.05) than <em>Prunus cerasifera </em>f.<em> Atropurpurea.</em> The physiological characteristics of these trees further reflect their growth adaptability and carbon sequestration capacity in northern Zhejiang province. According to the results of factor analysis and Ward cluster analysis, <em>Cinnamonum campora </em>(L.) Prels. and <em>Amygdalus persica </em>var.<em> persica </em>f.<em> duplex</em> have better growth adaptability, followed by <em>Sapindus mukorossi Gaertn</em>,<em> Salix babylonica </em>L.,<em> Ligustrum lucidum. </em>Therefore, these tree species are recommended for afforestation in northern Zhejiang. Because plant photosynthesis is a complex physiological process, the photosynthetic physiological indicators only show the characteristics of tree species in one aspect, and do not represent the pros and cons of the species. The conclusion obtained from comprehensive multi-index and cluster analysis is consistent with that from diurnal net carbon sequestration analysis, implying that the integrated indicators of physiological parameters can better reflect the relative inferiority of the carbon sequestration capacity. On the view of optimal afforestation tree configuration, more research is needed to combine photosynthesis and regional growth and adaptability of species and to improve their photosynthetic capacities.

Intraoperative findings and procedures in culturally and geographically different patient and surgeon populations

Background and purpose Patient and implant registries are important clinical tools in monitoring and benchmarking quality of care. For comparisons amongst registries to be valid, a common data set with comparable definitions is necessary. In this study we compared the patients in the Norwegian Knee Ligament Registry (NKLR) and the Kaiser Permanente Anterior Cruciate Ligament Reconstruction Registry (KP ACLRR) with regard to intraarticular findings, procedures, and graft fixation characteristics reported by the operating surgeon for both primary and revision anterior cruciate ligament reconstructions (ACLRs).Methods We performed a cross-sectional comparison of the NKLR and KP ACLRR cohorts registered between 2005 and 2010. Aggregate-level data including patient characteristics (age, sex, and laterality), meniscal and cartilage injury patterns and corresponding treatment procedures, choice of graft, and fixation characteristics (type and component material) were shared between registries. Descriptive analyses were then conducted.Results During the study period, 11,217 ACLRs were registered in the NKLR and 11,050 were registered in the KP ACLRR. In the NKLR, hamstring autograft was used more (68% vs. 30%) for primary ACLRs and allograft was used less (0.2% vs. 41%) than in the KP ACLRR. The KP ACLRR reports more meniscal tears among both primary and revision ACLRs (63% and 50% vs. 49% and 36%). The NKLR reports less use of biodegradable fixation devices.Conclusions Baseline findings between the NKLR and the KP ACLRR were congruent regarding patient characteristics and most injury patterns, adding to the evidence that comparisons and collaborations between these registries will provide generalizable information to the international orthopedic community. The variation in the treatment, including graft and implant selection and meniscus procedures, between the 2 registries provides opportunities to explore the impact of treatment choices on the outcomes of ACLRs.

Lengthened proximal femoral nail antirotation for femoral shaft fractures combined with ipsilateral femoral neck fractures

Objective To investigate the methods and results of lengthened proximal femoral nail antirotation (PFNA) in the treatment of femoral shaft fractures combined with ipsilateral femoral neck fractures. Methods Of the 21 patients with femoral shaft combined with ipsilateral femoral neck fractures treated by lengthened PFNA from 2006 to 2009,16 patients with complete follow-up were retrospectively studied.There were 15 males and 1 female,at mean age of 35 years (range,21-51 years).Injury causes were all high-energy trauma including traffic injuries in 11 patients and fall injuries in five.According to Garden classification,there were seven patients with type Ⅰ femoral neck fractures,six with type Ⅱ and three with type Ⅲ.Femoral shift fractures contained six superior part fractures and nine medial part fractures and one inferior part fracture.According to Winquist classification,there were two patients with type Ⅰ femoral shaft fractures,four with type Ⅱ,six with type Ⅲ and four with type Ⅳ.Two patients had open fractures belonging to type Ⅰ Gustilo-Anderson.Harris hip score was used to evaluate functional outcomes at the last follow-up postoperatively. Result The mean follow-up time was 2.4years (range,1-4 years ).The mean period for healing of femoral neck and shaft fractures was 4.2months ( range,3-6 months) and 5.1 months ( range,3-8 months) respectively.Four patients showed delayed diagnoses of femoral neck fractures ; two patients had delayed union of femoral shaft fractures ; one suffered from avascular necrosis of the femoral head ; one patient presented 3 cm of extension of the affected limb and was accompanied by active pain of the knee joint for over four months.According to Harris score,function of hip joints was excellent in seven patients,good in six and fair in three,with excellence rate of 82％. Conclusions It is relatively few that the femoral shaft fracture is combined with ipsilateral femoral neck fracture.The rate of missed diagnosis of femoral neck fractures is high and the patients with high energy trauma hould be highly paid attention to.Lengthened PFNA conforms to characteristics of biomechanical fixation and presents short operation time and solid fixation. Lengthened PFNA achieves affirmatory effects for treatment of femoral shaft fractures combined with ipsilateral femoral neck fractures. Key words: Femoral fractures; Femoral neck fractures; Fracture fixation,internal

Identification and validation of reference genes to study the gene expression in Gluconacetobacter diazotrophicus grown in different carbon sources using RT-qPCR

Gluconacetobacter diazotrophicus strain PAL5 is a nitrogen-fixing endophytic bacterium originally isolated from sugarcane and later on was found to colonize other plants such as rice, elephant grass, sweet potato, coffee, and pineapple. Currently, G. diazotrophicus has been considered a plant growth-promoting bacterium due to its characteristics of biological nitrogen fixation, phytohormone secretion, solubilization of mineral nutrients and antagonism to phytopathogens. Reverse transcription followed by quantitative real-time polymerase chain reaction (RT-qPCR) is a method applied for the quantification of nucleic acids because of its specificity and high sensitivity. However, the decision about the reference genes suitable for data validation is still a major issue, especially for nitrogen-fixing bacteria. To evaluate and identify suitable reference genes for gene expression normalization in the diazotrophic G. diazotrophicus, mRNA levels of fourteen candidate genes (rpoA, rpoC, recA, rpoD, fabD, gmk, recF, rho, ldhD, gyrB, gyrBC, dnaG, lpxC and 23SrRNA) and three target genes (matE, omp16 and sucA) were quantified by RT-qPCR after growing the bacteria in different carbon sources. The geNorm and Normfinder programs were used to calculate the expression stabilities. The analyses identified three genes, rho, 23SrRNA and rpoD, whose expressions were stable throughout the growth of strain PAL5 in the chosen carbon sources. In conclusion our results strongly suggest that these three genes are suitable to be used as reference genes for real-time RT-qPCR data normalization in G. diazotrophicus.

MEASURING RETINAL SENSITIVITY WITH THE MICROPERIMETER IN PATIENTS WITH DIABETES

To evaluate the retinal sensitivity and fixation characteristics in participants with diabetes mellitus, using the microperimeter (MP-1) and to correlate the MP-1 values with the severity of diabetic retinopathy (DR). We performed complete ophthalmic examinations, including best-corrected visual acuity, slit-lamp examination, indirect ophthalmoscopy, and microperimetry (central 20° of macula) on 210 eyes of 160 participants. Participants included healthy individuals, individuals with diabetes but no retinopathy, and individuals with different stages of DR. The mean age of participants was (mean ± SD) 49.83 ± 7.43 years for healthy individuals, 53.20 ± 5.7 years for participants with diabetes but no retinopathy, and 55.39 ± 7.81 years for participants with DR. Retinal sensitivity was significantly (P = 0.001) decreased with severity of DR. The mean foveal sensitivity (retinal sensitivity in the central 2°) was 16.68 ± 2.13 dB in healthy individuals, 14.73 ± 3.64 dB in participants with diabetes but no DR, and 11.60 ± 5.76 dB in participants with DR. There was significant loss of retinal sensitivity in participants with diabetes but no retinopathy when compared with healthy individuals. Participants with severe nonproliferative DR showed more significant loss of retinal sensitivity in the central 20° than those with other stages of DR. The MP-1 is a useful tool to quantify retinal sensitivity in DR. Using the MP-1, we can detect early loss of retinal sensitivity in patients with diabetes but no retinopathy. Patients with severe nonproliferative DR will have less retinal sensitivity than those with other stages of DR. Scotoma mapping using the MP-1 provides details of functional vision in patients with DR.

Quality, yield and nitrogen fixation of faba bean seeds as affected by sulphur fertilization

Faba bean (Vicia faba L.) is an important source of plant protein for humans and animals; however, nutritional value of seeds is notoriously deficient in sulphur (S)-containing amino acids. In this article, the effect of S fertilization on faba bean's capability of N2 fixation, grain yield and chemical characteristics in terms of protein fractions, fatty acids and minerals composition is reported. A randomized, complete block design with three replicates was used, and three S applications (0, 30 and 60 kg ha−1, respectively) for faba bean were performed. The S fertilization was split into two applications: 50% before sowing and 50% in the beginning of March as K2SO4. At the same time, both the legume and oat crops were fertilized uniformly with 10 kg N ha−1 as 15N NH4 15NO3 (10% 15N atomic excess) in solution form. In a Mediterranean climate under optimal spring rainfall situations, faba bean produced high yield of grain and protein. Sulphur application resulted in an increase in overall plant yield and N2 fixation. In addition, S fertilization enhanced the protein quality, increasing its degradable fraction. Fertilizing faba bean with 30 kg ha−1 of S resulted in a more appropriate dose in order to obtain a quantitative and qualitative crop improvement. From our findings, it can be concluded that S fertilization to faba bean should be recommended to soils with suboptimal S levels to obtain maximum seed and protein yields.

Horizontal suture placement influences meniscal repair fixation strength

This in vitro biomechanical study investigated the influence of horizontal suture placement distance from the medial meniscal lesion repair site on fixation characteristics during submaximal cyclic and load to failure test conditions. Eighteen cadaveric (20-45years of age) medial menisci with intact joint capsules were harvested within 24-48h after death and divided into two groups of 9 specimens each for biomechanical testing. A 2.0-cm-long antero-posterior vertical longitudinal lesion was created with a #15 scalpel 2.0-3.0mm from the outer edge of each meniscus. Menisci were repaired using #2-0 suture material with two horizontal suture loops placed either 1.0mm (Group 1) or 3.0mm (Group 2) from the lesion site. Following repair, the lesion was extended completely through the meniscal horns so that no tissue secured the repair, only the two horizontal suture loops representing a "worst-case" testing scenario. Following repair, specimens were placed in a servo hydraulic device using a pair of 1.2-mm-diameter steel wire loops and underwent submaximal cyclic loading between 5 and 50N (1Hz) for 500 cycles prior to load to failure testing (5mm/min crosshead speed, 20Hz data collection). An alpha level of P<0.05 was selected to indicate statistical significance. Five of nine (55.6%) Group 1 specimens did not complete submaximal cyclic testing. All Group 2 specimens completed submaximal cyclic testing (Fisher's exact test P=0.029). Statistically significant mean group differences were not observed for displacement during submaximal cyclic loading (Group 1=5.0±1.5mm and Group 2=5.7±1.6mm) or for construct stiffness during load to failure testing (Group 1=50.1±6.3N/mm and Group 2=52.6±11.9N/mm). Group 2 displayed greater mean load at failure (112.1±40.8N vs. 72.7±11.2N, P=0.02) and mean displacement at failure (11.1±2.2mm vs. 7.6±1.4mm, P=0.03) than Group 1. Horizontal sutures placed slightly farther away from the meniscus lesion displayed superior repair fixation than sutures placed closer to the lesion. The superior biomechanical meniscal repair fixation provided by capturing greater tissue volume may enable safe earlier participation in functional exercise activities. Studies are needed to verify these findings in vivo.

Influence of Snowy Pavement on Driver’s Characteristics of Fixation and Saccade

For driving safety on snowy pavement, it is necessary to study on the influence of snowy pavement on driver’s visual characteristics. Based on reasonable partition of driver’s visual field, the data of the number of driver’s fixation and fixation time were surveyed. And driver’s characteristics of fixation were compared on good pavement and snowy pavement. Based on the data of driver’s saccade distance and speed, driver’s characteristics of saccade were compared on good and snowy pavement. It shows that snowy pavement make drivers’ visual field become narrow and it is easy to cause drivers’ visual fatigue which is adverse to driving safety.

Phylogenetic diversity and symbiotic functioning in mungbean ( Vigna radiata L. Wilczek) bradyrhizobia from contrast agro-ecological regions of Nepal

Nepal consists wide range of climatic and topographical variations. Here, we explored the phylogeny of native mungbean bradyrhizobia isolated from different agro-ecological regions of Nepal and accessed their nodulation and nitrogen fixation characteristics. Soil samples were collected from three agro-ecological regions with contrasting climate and topography. A local mungbean cultivar, Kalyan, was used as a trap plant. We characterized isolates based on the full nucleotide sequence of the 16S rRNA, ITS region, and nodA genes; and partial sequences of nodD1 and nifD genes. We found 50% of isolates phylogenetically related to B. yuanmingense, 13% to B. japonicum, 8% to B. elkanii, and 29% to novel phylogenetic origin. Results of the inoculation test suggested that expression of different symbiotic genes in isolates resulted in different degrees of symbiotic functioning. Our results indicate B. yuanmingense and novel strains are more efficient symbiotic partners than B. elkanii for the local mungbean cv. Kalyan. We also found most mungbean rhizobial genotypes were conserved across agro-ecological regions. All the strains from tropical Terai region belonged to B. yuanmingense or a novel lineage of B. yuanmingense, and dominance of B. japonicum related strains was observed in the Hill region. Higher genetic diversity of Bradyrhizobium strains was observed in temperate and sub-tropical region than in the tropical region.

소나무와 낙엽송 스킨팀버의 ACQ, CUAZ, CuHDO 가압처리를 위한 처리용 목재의 적정 함수율 및 처리목재의 정착 특성 평가

본 연구에서는 소나무와 낙엽송 스킨팀버의 ACQ-2, CUAZ-2, CuHDO-1 가압처리 특성을 평가하기 위해 소나무 변재부와 낙엽송 심재부 시험편을 대상으로 처리용 목재의 함수율이 방부제 처리도에 미치는 영향과 방부제 유효성분인 구리의 처리목재 내 정착 특성을 조사하였다. 본 연구 결과에 의하면 소나무 변재부는 방부제 종류에 관계없이 함수율 30%부터 사용환경 범주 H3용 처리목재의 침윤도와 흡수량 기준을 모두 만족하였다. 완벽한 방부제 침투가 가능한 소나무 변재부에서 깊이에 따른 방부제 흡수량 경사를 조사한 결과, 방부제 종류에 따른 차이가 관찰되었다. CuHDO-1 처리 시험편에서 발생한 경사가 ACQ-2와 CUAZ-2 처리 시험편에서의 경사보다 심했는데, 특히 고함수율(25, 30%) 시험편에서 경사가 저함수율(15, 20%) 시험편에서보다 심함을 알 수 있었다. 그러나 난주입성인 낙엽송 심재부는 처리용 목재의 함수율 조건 및 방부제 종류에 관계없이 처리도 가 매우 불량하였다. 낙엽송 심재부의 처리도 개선을 위해 증기 전처리(<TEX>$121^{\circ}C$</TEX>의 포화수증기 조건에서 12시간 처리)를 실시한 결과, 낙엽송 심재부의 침윤도와 흡수량 모두 사용환경 범주 H3용 처리목재 기준에 부합하게 처리도가 개선됨을 확인할 수 있었다. 소나무 변재부와 낙엽송 심재부 시험편에서 공히 방부제 유효성분인 구리의 정착이 비건조 양생에 비하여 건조 양생에서 빨리 진행되었다. 소나무 변재부는 양생 초기 3~6일, 낙엽송 심재부는 양생 1일 이내에 3주간 정착된 구리 양의 95% 이상이 정착되었다. 양생 3주 후 처리목재 내에 미정착 상태로 남아있는 구리의 양은 ACQ-2, CuHDO-1, CUAZ-2 순으로 많았는데, 이는 처리용 작업액에 존재하는 구리의 양과 비례하였다. This study was conducted to evaluate the pressure treatment characteristics of Japanese red pine and Japanese larch skin timber with ACQ-2, CUAZ-2 and CuHDO-1. The effect of moisture content (MC) on preservative treatability was investigated for Japanese red pine sapwood and Japanese larch heartwood, and fixation characteristics of CCA alternatives was also evaluated. Japanese red pine sapwood, which was dried below 30 percent MC, was fully penetrated with preservatives, and minimum requirement of preservative retention for the hazard class H3 was achieved. Through measuring preservative retention gradient in Japanese red pine sapwood, it was confirmed that the retention gradient of CuHDO-1 was steeper than that of both ACQ-2 and CUAZ-2. In particular, it was intensified at a higher MCs of wood samples (25∼30%). Japanese larch heartwood did not meet the minimum requirement of penetration and retention for the hazard class H3 over the range of pretreatment MCs tested. With presteaming under <TEX>$121^{\circ}C$</TEX> for 12 hours, the treatability of Japanese larch heartwood was enhanced to meet the minimum requirement for the hazard class H3. The fixation rate of copper was much more faster under drying condition compared with nondrying condition; more than 95% of copper were fixed in 3~6 days and 1 day under drying conditions in Japanese red pine sapwood and Japanese larch heartwood, respectively. After 3-week fixation period at ambient temperature, the amount of mobile copper in treated wood sample that remains available for leaching from treated wood was the highest in the wood samples treated with ACQ-2, followed by CuHDO-1 and CUAZ-2. It was proportional to the amount of copper in treating solution.

Determinants of Fixation in Eyes With Neovascular Age-Related Macular Degeneration Treated With Intravitreal Ranibizumab

To correlate the anatomic features of the macula with functional parameters like location and stability of fixation in patients with neovascular age-related macular degeneration treated with intravitreal ranibizumab injections. Retrospective analysis. The location and stability of fixation were determined in 41 eyes of 41 patients treated with ranibizumab for neovascular age-related macular degeneration for at least 12 months. All patients underwent 3 injections of ranibizumab 1 month apart and were retreated according to predefined criteria. The fixation parameters measured with microperimetry were correlated to visual acuity, qualitative measures on optical coherence tomography, and patterns of autofluorescence. The location of fixation was predominantly central in 68.29%, poor central in 2.4%, and predominantly eccentric in 29.27%. The fixation was stable in 80.5%, relatively unstable in 7.3%, and unstable in 12.2%. The factors that determined central and stable location of fixation were better visual acuity (P = .004), absence of subretinal thickening (P = .003), intact subfoveal third hyperreflective band (P = .006), and intact external limiting membrane (P = .036). Autofluorescence pattern within the 4-degree circle of fovea did not correlate with fixation characteristics. However, complete absence of autofluorescence in this area was a poor prognostic indicator for central fixation. Anatomic characteristics of the macula determine fixation patterns in patients with neovascular age-related macular degeneration treated with intravitreal ranibizumab injections. Further studies focused on eyes with complete absence of autofluorescence in the central 4-degree circle of fovea may help to define the disease characteristics in this group.

Biomechanical analysis of pedicle screw thread differential design in an osteoporotic cadaver model

BackgroundPedicle screw fixation, the standard surgical care for posterior stabilization in the thoraco-lumbar spine has a high rate of failure in osteoporotic individuals. Screw design factors and insertion techniques have been shown to influence the biomechanical performance of pedicle screws. Our objective was to investigate the biomechanical characteristics of pedicle screw fixation in osteoporotic bone by comparing standard screws with newly designed differential crest thickness dual lead screws. MethodsAn in-vitro spinal-level paired factorial study design was used to examine thoraco-lumbar spine biomechanical outcomes for differential pedicle screw thread designs. Six cadaveric human spines (T8-L5) were tested for six groups (n=20) consisting of 2 different crest thickness and 3 different insertion techniques. Bone mineral density was assessed and peak insertion torque measured while placing one screw of new design and control on the contralateral side. Screw pullout properties were measured from classical American Society for Testing and Materials protocols. FindingsThe screws designed specifically for osteoporotic bone showed significantly larger insertion torque compared with the standard screw design irrespective of insertion technique. Much of the variability in pullout failure and stiffness was explained by bone mineral density. The osteoporotic screws of different crest thickness were statistically similar to each other in all outcome measures. InterpretationCompared with standard pedicle screws, the dual lead osteoporotic-specific pedicle screws demonstrated significantly larger insertion torques and similar pullout properties. Non-significant increased biomechanical strength was observed for thin crest compared to thick crest dual lead pedicle screws indicating their enhanced purchase in osteoporotic bone.

Quality of fixation in eyes with neovascular age-related macular degeneration treated with ranibizumab

To define factors that determine the location and stability of fixation in patients with neovascular age-related macular degeneration (NV-AMD) treated with intravitreal ranibizumab injections. The location and stability of fixation using microperimetry were determined in 77 eyes treated with ranibizumab for NV-AMD for at least 12 months. All patients were treated with three injections of ranibizumab 0.5 mg, 1 month apart and retreated according to predefined criteria. The fixation parameters were correlated to the visual acuity, and quantitative measures on OCT. The location of fixation was predominantly central in 52.6%, poor central fixation in 9.2%, and predominantly eccentric fixation in 38.2%. The fixation was stable in 65%, relatively unstable in 25%, and unstable in 10%. Visual acuity was the only factor that determined the stability and location of fixation. The characteristics of fixation were not related to the macular thickness or volume as measured by OCT. Better visual outcome ensures central and stable fixation. Quantitative measures of OCT parameters do not determine fixation. Further studies on morphological features of the macula may provide some insight into the determinants of fixation.