Higher Cross-sectional Area Research Articles

Is the Preoperative MRI Appearance of Lumbar Multifidus Prognostic for Outcomes of Lumbar Decompression?

Introduction Decompressive surgery for symptomatic lumbar spinal stenosis is associated with good outcomes provided that appropriate patient selection is undertaken, which has proven critical (Aalto et al 2006). It has previously been proposed that the MRI appearance of multifidus is correlated to leg and back pain symptoms (Ali et al 2011 and Kader et al 2000). Therefore, our aim was to assess whether the preoperative MRI appearance of multifidus was predictive of outcomes for lumbar spinal stenosis surgery and could be used in patient selection. Our hypothesis was that patients with fatty atrophy on MRI would have significantly poorer clinical outcomes than those without. Patients and Methods A review of patients who had undergone lumbar spinal stenosis surgery in the previous 2 years (minimum 1-year follow-up) and had completed spine tango outcomes was undertaken. Exclusion criteria were additional procedures, for example, fusion and patients without MRI scans. Individual patient comorbidities and complication profiles were also assessed. The multifidus caliber was measured for each patient on MRI using a DICOM viewer by two assessors blinded to the outcome scores. In addition to the Kader et al (2000) classification, elliptical cross-sectional area mapping of multifidus was taken as an average measurement at the axial L4/5 level. Also, measured were the posterior adipose tissue layer and dimensions of the L5 vertebral body, areas of critical stenosis and psoas muscles, respectively. Results A total of 66 patients (41 females and 25 males) met the inclusion criteria and underwent analysis. There was a significant improvement for the cohort in ODI and COMI scores following surgical intervention and 89% of patients had improvement in ODI and COMI scores. The mean age was 67 years (range, 29–86 years). Overall, 44 patients had single level decompressions while for 2 level and 3 level decompressions; there were 16 and 6 patients, respectively. Overall, 44 (84%) of single levels involved either L4/5 or L5/S1 (37/44) with L3/4 and L2/3 involved in five and two patients, respectively. Moderate or severe fatty degenerative changes (Kader grades II or III) were noted in 71% of patients while a mean CSA (cm2) of 8.4 cm2 or less for multifidus at the measured level was noted in 71% of patients. The proportions of the cohort who improved more than 40% in their COMI and ODI when comparing the cohorts of patients with CSA < 8.5 cm2 compared with ≥ 8.5 cm2 were significantly different (47 vs. 79% [ p = 0.02] and 32 vs. 68% [ p = 0.006]). For patients with a Kader grade of 0 to 2 and CSA ≥ 8.5 cm2, there was significantly more percentage improvement with ODI/COMI (mean 84, 75) compared with Kader 2 to 3 and CSA < 8.5 cm2 (mean 28, 23) ( p = 0.05). Conclusion The appearance of lumbar multifidus on preoperative MRI is predictive of outcomes of lumbar spinal stenosis surgery with better results at a minimum of 1 year in patients with less fatty degenerative changes and higher cross-sectional area. This has implications for use in the perioperative setting and further research on the value of preoperative imaging for other spinal surgery is indicated.

Relationship between pork quality and characteristics of muscle fibers classified by the distribution of myosin heavy chain isoforms1

A total of six fiber types, including four pure types (type I, IIA, IIX, and IIB) and two hybrid types (type IIAX and IIXB), were classified according to the expression of myosin heavy chain (MHC) isoforms by immunohistochemistry with MHC specific monoclonal antibodies. The comparison of the muscle fiber characteristics and pork quality between pork quality groups (DFD: dark, firm, and dry; PSE: pale, soft, and exudative; RFN: reddish pink, firm, and nonexudative; and RSE: reddish pink, soft, and exudative) classified by muscle pH, drip loss, and lightness was conducted and the relationship of myofiber characteristics to pork quality was investigated. The DFD group had the highest value of IIAX fiber density (P<0.05). The DFD group also showed the greatest fiber relative area of type I, IIA, and IIAX (P<0.05) whereas there were no significant differences in area composition for types I, IIA, and IIAX among the other groups including PSE, RFN, and RSE (P>0.05). The DFD group had the highest cross-sectional area (CSA) in types I, IIA, and IIX among the groups. The increase in density of type IIAX was related with the higher pH and the lower hue and drip loss. An increase in the fiber number composition of hybrid type IIXB increased the lightness and cooking loss and decreased sarcoplasmic protein solubility (SPS). Regarding fiber relative area, pure type I and IIA and hybrid type IIAX were greater in the DFD group and had lower lightness and drip loss. Hybrid type IIAX influences the desirability of the pork due to its association with low lightness and high pH and water-holding capacity (WHC). In contrast, type IIXB was related to poor quality pork, including pale color, low WHC in cooked meat, and low SPS.

Relationship between the Right Internal Jugular Vein and Carotid Artery at Ipsilateral Head Rotation

Ultrasound-guided right internal jugular vein catheterization (RIJV) should be the first choice to decrease the catheter-related complications in high-risk hemodialysis patients. For this procedure, clinicians should identify the optimum positions of the RIJV, including its lower overlap with the carotid artery (CA) and high cross-sectional area of the vein. The aim of this prospective randomized study to evaluate the effects of mild ipsilateral head rotation combined with Trendelenburg position on RIJV cross-sectional area and its relation to the CA in adult patients. Forty ASA I–II patients who were undergoing elective surgery were enrolled for this study. The subjects were asked to remain supine in the 15–20° Trendelenburg position. Two-dimensional ultrasound was then used to measure the degree of overlap between the RIJV and CA, the cross-sectional area of the RIJV. These measurements were compared between head rotation to the >30° left, <30° left, neutral, and <30° right positions. When the head was in the >30° left position, overlap was seen in 38 of 40 patients (95%). As the head was rotated from >30° left to <30° right, the CA-RIJV overlap (from 95% to 57.5%), and the cross-sectional area (from 14.2 mm to 8.7 mm) significantly decreased. In conclusion, when the head was turned to <30° right, the CA-RIJV overlap significantly decreased, and the cross-sectional area also decreased. When clinicians determine the optimal head position before RIJV cannulation, it is important to consider the advantages and disadvantages of the different head positions from >30° left to <30° right.

328 PROGRAMMED DEATH 1 (PD-1) EXPRESSION OF PERIPHERAL CD4+ T LYMPHOCYTES IMPLICATES PROGRESSION OF MALNUTRITION AND HEPATIC CARCINOGENESIS IN PERSISTENT HEPATITIS C VIRAL INFECTION

Background and Aims: Persistent HCV infection leads to liver fibrosis and carcinogenesis. Expression of PD-1, an inhibitory molecule, causes T cell exhaustion and failure of HCV eradication. Furthermore, degree of PD-1 expression defines the level of T cell dysfunction (Nakamoto N et al. Gastroenterology 2008. 134: p1927–37). However, little is known about how persistent T cell exhaustion influences clinically during HCV infection. Methods: Sixty patients of chronic hepatitis C were included. Peripheral blood mononuclear cells were taken after informed consent, and were analyzed by flow cytometry before intervention. Twenty-two patients (37%) were HCC-bearing cases. Clinical laboratory parameters including serum albumin, branch-chain amino acids (BCAA) to tyrosine ratio (BTR), cross-section area of visceral fat (by electrode impedance method), METAVIR staging of recent liver biopsy (available in 29 cases), and clinical staging of HCC were also analyzed. Results: PD-1 expression of peripheral CD4 T lymphocytes was significantly elevated in HCC-bearing cases (12.1% vs 7.4%, p < 0.0001), but that of peripheral CD8 T lymphocytes was not statistically significant. To further evaluate risk factors affecting hepatic carcinogenesis, we found that PD-1 expression of CD4 T lymphocytes had no statistical correlation to fibrosis stages of liver biopsy specimen (p =0.98). Elevated PD-1 expression of CD4 T lymphocytes significantly correlated to lower serum albumin (p < 0.0001, correlation coefficient c.c.= −0.49), lower BTR (excluding BCAA supplemented cases, p = 0.016, c.c.= −0.48), and higher crosssection area of visceral fat to body surface area (BSA) ratio (p = 0.0016, c.c.= 0.55), which suggested that T cell dysfunction significantly correlated to nutritional/metabolic derangements in chronic hepatitis C. PD-1 expression of CD4+ T lymphocytes also increased accordingly to the T factor of HCC (p =0.035), TNM staging (p = 0.015), and JIS scores (p = 0.013). Furthermore, PD-L2 levels expressed on plasmacytoid dendritic cells (pDCs) were significantly increased as PD-1 expression of CD4+ T lymphocytes elevated (p =0.002, c.c.= 0.61). Conclusions: These findings suggest that T cell exhaustion may play a pathological role in carcinogenesis and HCC progression in chronic HCV infection. Correlation of PD-1 expression of CD4+ T lymphocytes and nutritional/metabolic factors also suggests an immunological rationale for nutritional intervention in these patients.

Preconcentration of trace amounts of copper(II) on octadecyl silica membrane disks modified with indane-1,2,3-trione 1,2-dioxime prior to its determination by flame atomic absorption spectrometry

Oximes are a group of complexing agents with good affinity towards transition metal ions; The major advantages of SPE disks are: faster sample processing due to the high cross sectional area of the disk and decrease in pressure drop, allowing higher sample flow rates; less chance of plugging by particulate matter due to wide bed; reduced channeling and improved mass transfer because of small packing particles.

Effects of fibre type and kefir, wine lemon, and pineapple marinades on texture and sensory properties of wild boar and deer longissimus muscle

Fibre type percentage and changes in textural parameters, sensory properties as well as mean fibre cross sectional area (CSA), fibre shape, endomysium and perimysium thickness of wild boar and deer longissimus (L) muscle subjected to ageing with kefir, dry red wine, lemon and pineapple juice marinades for 4days were studied. Among the non-marinated and non-aged samples of muscles it was found that wild boar meat with its higher percentage of red fibres, higher CSA, thicker connective tissue as compared with deer meat, was harder, more springy and stringy.Muscles ageing, regardless of methods, resulted in a decrease in both the CSA and thickness of the connective tissue, and improve in fibre shape. As a consequence ageing caused a reduction in hardness, cohesiveness, springiness, and stringiness as well as in augmentation of tenderness, juiciness and general attractiveness of the muscles studied.As demonstrated by obtained data, regardless of ageing methods, deer L muscle contained more white fibres compared to wild boar muscle, were more susceptible to tenderization. The highest structural and textural changes, but the worst general attractiveness was found in muscles marinated with pineapple juice addition. Insignificantly lower changes in both quality traits were found in muscles aged with kefir marinade which at the same time were characterized by the high tenderness, the highest juiciness and general attractiveness.

Preoperative iris configuration and intraocular pressure after cataract surgery

To determine predictors of long-term intraocular pressure (IOP) after cataract surgery. Hunter Holmes McGuire Veterans Administration Hospital, Richmond, Virginia, USA. Case series. Clinical variables, IOP by applanation tonometry, anatomic features on anterior segment optical coherence tomography (AS-OCT), and gonioscopy were assessed before and after uneventful cataract surgery in eyes with open filtration angles. Multivariate linear regression of preoperative measurements was used to predict the mean IOP from 2 to 18 months postoperatively. The study enrolled 77 eyes (77 patients). Prediction of the mean postoperative IOP improved when up to 4 preoperative IOP values were averaged (r(2) = 0.20) compared with using the final preoperative IOP value only (r(2) = 0.13). The mean iris cross-sectional area decreased after surgery, from 3.84 mm(2) to 3.70 mm(2) (P=.01). The mean convex hull of the iris segments also decreased, from 5.05 mm(2) to 4.19 mm(2) (P<.001). The mean postoperative IOP was independently predicted by the preoperative average IOP, primary open-angle glaucoma, and the convex hull of cross-sectional iris segments (P=.001, model r(2) = 0.38) or iris cross-sectional area (P=.003, model r(2) = 0.36). Phacoemulsification parameters, incision type, and anterior chamber angle and depth did not predict postoperative IOP. Averaging up to 4 preoperative IOP values improved postoperative IOP predictions. A high iris cross-sectional area or convex hull of the iris segments on AS-OCT was associated with lower postoperative IOP. These findings might help identify patients who are likely to have the largest IOP drop after cataract surgery.

Combination of high-resolution and color Doppler ultrasound in diagnosis of carpal tunnel syndrome

Ultrasound has recently emerged as a diagnostic tool in carpal tunnel syndrome (CTS). To evaluate the utility of a combination of high-resolution and color Doppler ultrasound as an alternative to electrodiagnostic tests (EDT), in CTS diagnosis, and to define an ultrasonographic prediction model for CTS. A total of 85 patients with certain clinical diagnosis of CTS and 49 healthy controls were enrolled. High-resolution and color Doppler ultrasound were performed and the cross-sectional area (CSA), hypoechogenicity, and hypervascularity of the median nerve were evaluated. Receiver-operating characteristic curves were used to determine the optimal cut-off point of median nerve CSA in diagnosis of CTS. Multivariate logistic regression analysis was used to formulate a prediction model for CTS. The optimal cut-off point of median CSA in wrist was 10.5 mm(2). Hypervascularity (OR = 37.95), hypoechogenicity (OR = 12.30), and high CSA (OR = 34.79) of median nerve were significantly (P < 0.001) higher in CTS patients than in controls. No significant difference was found between the sensitivity and specificity of EDT and any of the above indices in prediction of CTS. An ultrasonographic model for prediction of CTS, comprised hypervascularity and/or high CSA of median nerve, could predict the CTS probability between 87-99%. The sensitivity and specificity of this model (86% and 84%) was not different from EDT (80% and 84%). A combination of high-resolution and color Doppler ultrasound can be used as a non-invasive alternative to EDT in diagnosis of CTS.

Morpho-functional patterns and zonation of South Chilean seaweeds: the importance of photosynthetic and bio-optical traits

We address the question of whether seaweed zonation can be characterized in terms of light absorption, pigmentation, photosynthetic parameters, photoinhibition, and thallus structure. Based on 32 seaweed species from the Pacific coast of southern Chile, intertidal assemblages exhib- ited higher light requirements for photosynthesis (Ek) and lower thallus light absorptances than sub- tidal algae. Ek values were lower than the highest measured irradiances at the corresponding natural depths, suggesting that photosynthesis in these organisms could potentially occur at lower depths. During summer, 1% of photosynthetically active radiation (PAR) reached a depth of 23 m, while UV- B and UV-A wavelengths were completely attenuated at <3 and 6 m, respectively. Overall, the pho- tobiological adaptations were associated with depth, morphology, and taxonomic group. Photoinhibi- tion was similar in algae from different depths, although recovery was higher in upper littoral algae than in infra- and sublittoral species. The characteristics conferring competitive abilities in light use and light stress tolerance were not, or only partially, related to the classical Littler form-function model. The filamentous and foliose forms were able to acclimate rapidly to changing light and phys- ical stress in the supralittoral zone. For infralittoral kelps living in a highly dynamic environment, higher cross-sectional area and enhanced in vivo light absorption were coupled with morphological features (e.g. massive thallus) that are advantageous in withstanding e.g. water movement. By con- trast, the rapid physiological adjustments that allow algae to endure solar stress (e.g. photochemical down-regulation) were strongly dependent on the position on the shore but not on gross morphology.

Architectural Analysis and Intraoperative Measurements Demonstrate the Unique Design of the Multifidus Muscle for Lumbar Spine Stability

Muscular instability is an important risk factor for lumbar spine injury and chronic low-back pain. Although the lumbar multifidus muscle is considered an important paraspinal muscle, its design features are not completely understood. The purpose of the present study was to determine the architectural properties, in vivo sarcomere length operating range, and passive mechanical properties of the human multifidus muscle. We hypothesized that its architecture would be characterized by short fibers and a large physiological cross-sectional area and that it would operate over a relatively wide range of sarcomere lengths but would have very stiff passive material properties. The lumbar spines of eight cadaver specimens were excised en bloc from T12 to the sacrum. Multifidus muscles were isolated from each vertebral level, permitting the architectural measurements of mass, sarcomere length, normalized fiber length, physiological cross-sectional area, and fiber length-to-muscle length ratio. To determine the sarcomere length operating range of the muscle, sarcomere lengths were measured from intraoperative biopsy specimens that were obtained with the spine in the flexed and extended positions. The material properties of single muscle fibers were obtained from passive stress-strain tests of excised biopsy specimens. The average muscle mass (and standard error) was 146 +/- 8.7 g, and the average sarcomere length was 2.27 +/- 0.06 microm, yielding an average normalized fiber length of 5.66 +/- 0.65 cm, an average physiological cross-sectional area of 23.9 +/- 3.0 cm(2), and an average fiber length-to-muscle length ratio of 0.21 +/- 0.03. Intraoperative sarcomere length measurements revealed that the muscle operates from 1.98 +/- 0.15 microm in extension to 2.70 +/- 0.11 microm in flexion. Passive mechanical data suggested that the material properties of the muscle are comparable with those of muscles of the arm or leg. The architectural design (a high cross-sectional area and a low fiber length-to-muscle length ratio) demonstrates that the multifidus muscle is uniquely designed as a stabilizer to produce large forces. Furthermore, multifidus sarcomeres are positioned on the ascending portion of the length-tension curve, allowing the muscle to become stronger as the spine assumes a forward-leaning posture.

Effect of Gonadal Hormones on the Cross‐Sectional Area of Pubococcygeus Muscle Fibers in Male Rat

Effects of gonadal hormones on dimorphic striated muscles such as the bulbocavernosus/levator ani complex related to male penile erection have been widely studied. However, the action of these hormones on pelvic nondimorphic muscles is not known. In the present study, the sensitivity of the male rat pubococcygeus muscle (Pcm) to gonadal hormones was studied measuring the cross-sectional area (CSA) of its fibers. For this, two experiments were done: in the first, the effect of castration, and in the second the effect of gonadal hormone administration was analyzed. We found that castration after 6 weeks significantly reduced the average CSA of the fibers of this muscle and that castration after 2 or 6 weeks reduced the percentage of fibers with higher CSAs, but only castration after 6 weeks increased the percentage of fibers with the lowest CSA. In comparison with castrated animals implanted with an empty Silastic capsule, Silastic implants of testosterone propionate or dihydrotestosterone significantly increased the average CSA of Pcm fibers, and the treatment with testosterone propionate, estradiol benzoate, or dihydrotestosterone decreased the percentage of fibers with low CSAs and increased the percentage with larger CSAs. Our results could be considered for therapy in patients with damage of the Pcm, and suffering urinary incontinence or ejaculatory dysfunctions.

Sonographic findings of the median nerve and prevalence of carpal tunnel syndrome in patients with Parkinson's disease

Purpose Parkinson's disease (PD) is a chronic progressive disorder which is characterized by rest tremor, akinesia or bradykinesia and rigidity. Carpal tunnel syndrome (CTS) is caused by compression of median nerve and can occur as a result of repetitive trauma. The aim of this study was to estimate the prevalence of CTS in PD and evaluate the median nerve sonographically. Materials and methods Fifty-three wrist of 29 patients with PD were included in the study according to Hoehn and Yahr (H&Y) clinical stage and divided into two groups. The first group consisted of 29 wrists of patients with mild PD (H&Y stage I–II). The second group consisted of 24 wrists of patients with severe PD (H&Y stage III–IV). Thirty-six wrists of 20 age-matched patients were used as control group. Both of the patients with PD and control group underwent sonography and electromyography (EMG). Axial sonograms of the median nerve were obtained at the level of distal radioulnar joint (level 1) and at the level of pisiform bone in the carpal tunnel (level 2). At each level, the cross-sectional area of the median nerve and flattening ratio were calculated. Results There was no significant difference for all parameters, except one parameter, between the patients with PD and control group, and also among mild and severe groups of PD and control group ( p > 0.05). Interestingly, amplitude of median nerve in the second finger was significantly lower in PD patients than control group within normal limits ( p = 0.010). Of all wrists of PD patients, 13 (24.4%) have been diagnosed as CTS and 7 (19.4%) control wrists had CTS. Median nerve cross-sectional area of CTS patients were more than 10 mm 2 in 6 (46%) wrists of PD patients but in only 1 (14%) control wrist at each level. Although it was not statistically significant, there was higher cross-sectional area at each level in patients with severe PD (level 1: 10.43 ± 2.30 mm 2, level 2: 10.35 ± 3.19 mm 2) than patients with mild PD (level 1: 9.93 ± 2.61 mm 2, level 2: 9.51 ± 2.83 mm 2) and control group (level 1: 9.69 ± 3.19 mm 2, level 2: 9.07 ± 3.61 mm 2). Conclusion PD may pose a risk for the development of CTS due to the repetitive movement of tremor. Although sonography is not an ideal method of diagnosis for CTS, it may take our attention for indicating CTS in patients with PD especially in severe ones.

Ultrasonography shows increased cross-sectional area of the median nerve in patients with arthritis and carpal tunnel syndrome

To examine whether patients with arthritic diseases and carpal tunnel syndrome (CTS) have increased cross-sectional areas of the median nerves measured by ultrasonography (US). Enlarged cross-sectional areas have previously been found in non-arthritic patients with idiopathic CTS. During 1 yr, all 12 patients with rheumatoid arthritis (RA) or other arthritic diseases hospitalized in our department for surgery for CTS were included. Nine of the patients had bilateral CTS, giving a total of 21 pathological nerves. The median duration of CTS symptoms was 9.5 months. The controls were 30 randomly selected RA patients without symptoms of CTS and 30 healthy persons. Both CTS patients and controls were examined bilaterally by use of US at the entrance of the carpal tunnel, and the cross-sectional areas of the median nerves were calculated. Cross-sectional areas of the median nerves were significantly higher in the CTS patients compared with the RA controls and healthy persons; median (range) areas were 15.7 mm(2) (11.1-21.8), 8.5 mm(2) (5.8-11.0) and 8.0 mm(2) (4.9-12.0), respectively (P<0.0001). No significant differences in cross-sectional areas were observed between the two control groups, or between the right and left hand in the control groups. Higher cross-sectional areas were found in the arthritic patients with CTS than in RA patients and healthy persons without CTS. This supports previous studies of idiopathic CTS in which increased cross-sectional areas have been found. Thus, as in idiopathic CTS, arthritic patients may be examined by US of the median nerve when CTS is suspected.

Tensile properties of polyethylene-layered silicate nanocomposites

The sodium ions of clays with different cation exchange capacities (CEC) have been exchanged with alkyl ammonium ions, in which 1–4 octadecyl chains are attached to the nitrogen atom. Due to the different cation cross-sectional area to available area per cation ratio, the resulting organo-montmorillonites (OMs) have different organic surface coverage and alkyl chain packing density. Nanocomposites of these OMs and HDPE were prepared and the influence of the organic monolayer structure on the exfoliation of montmorillonite and the tensile properties of the composites was studied. A high cation cross-sectional area to available area ratio led to complete surface coverage and large d-spacing, favoring the dispersion of the filler. In spite of the identical chemical structure of the polymer and the organic monolayer, complete exfoliation was not attained. Partial exfoliation was achieved without a compatiblizer, which often adversely affect the mechanical properties of the composites. Enhanced exfoliation increased the elastic modulus and yield stress but decreased the yield strain and stress at break of the nanocomposites. Increased filler loading enhanced the elastic modulus but decreased all other tensile properties. The tensile properties were correlated to the volume fraction of the inorganic part of the OMs and not to the total volume of the OM. Fitting the elastic modulus data to the Halpin-Tsai equation showed that the fitting parameter in this equation is not only related to the aspect ratio of the inclusions.

Quadrupled bone-semitendinosus ACL reconstruction: a prospective clinical investigation in 100 patients

The hypothesis of our study was that a quadrupled bonesemitendinosus tendon graft could combine the advantage of bone-tobone healing with the high cross-sectional area of a quadrupled hamstring graft in ACL reconstruction. ACL reconstruction with a semitendinosus tendon graft was performed on 100 patients with isolated ACL injury from January 1996 to December 1999: femoral fixation was obtained with Endobutton and tibial fixation with Fastlok. Patients were evaluated for standard knee scores and functional strength tests, postoperative pain rating, knee radiographs taken after surgery and at final follow-up, magnetic resonance images at 3 and 6 months, isokinetic flexion-extension and internal-external rotation tests at 3, 6, and 12 months. Computerized laxity analysis was performed at final evaluation. Average surgical time was 85 minutes, including 13 minutes for graft preparation; 90% of the patients were discharged within 24 h. Subjective knee rating was 80%; kneeling test was positive in 7% and Werner score was 44 (range, 30–48). Lachman test was negative in 90% at final evaluation (mean follow-up, 38 months). Sensory changes at the anterior part of the proximal tibia were present in 30% at 3 months and 10% had definite hyposthesia. MRI showed graft incorporation at 3 months. Computerized laxity analysis revealed 90% with less than 3-mm side-to-side differences. Isokinetic testing showed normal hamstring and quadriceps peak torques at 12 months. The functional strength tests were normal by 6 months. Average Noyes score was 87.9, Lysholm score 93, and Tegner activity rating 6.0 (pre-injury, 6.1). IKDC score showed 90 normal or nearly normal knees, 9 abnormal, and one severely abnormal knee. Quadrupled bone-semitendinosus is a viable graft for ACL reconstruction and should be considered, especially in patients with pre-existing extensor mechanism problems.

Iron oxide-based honeycomb catalysts for the dehydrogenation of ethylbenzene to styrene

Corning has recently developed a novel extrusion method to make bulk transition metal oxide honeycomb catalysts. One area of effort has been iron oxide-based catalysts for the dehydrogenation of ethylbenzene to styrene, a major chemical process that yields worldwide 20MM tons/yr. In industry, the monomer is synthesized mostly in radial-flow fixed-bed reactors. Because of the high cross-sectional area for flow and shallow depth of the catalyst bed in these reactors, low reactor pressure gradients are maintained that favors the yield and selectivity for styrene formation. However, the radial-flow design has inherent detractions, including inefficient use of reactor volume and large temperature gradients that decrease catalyst service life. The overall economics of the process can be improved with parallel-channel honeycomb catalysts and axial flow reactors. The simple axial flow design of honeycomb catalysts provides low-pressure drop, while making more efficient use of reactor volume, with better heat and mass transfer characteristics compared to a conventional radial packed bed. An important part of this concept is the ability to fabricate a wide family of dehydrogenation catalyst compositions into honeycombs with the requisite chemical, physical, mechanical, and catalytic properties for industrial use. The ethylbenzene dehydrogenation (EBD) honeycomb catalysts developed by Corning have compositions similar to those commonly used in industry and are prepared with the same catalyst and promoter precursors and with similar treatments.However, to enable extrusion of catalyst precursors into honeycomb shapes, especially at cell densities above 100cell/in.2, Corning’s process compensates for the high salt concentrations and the high pH of the batch material that would otherwise prevent or impede honeycomb extrusion. The improved rheological characteristics provide the necessary plasticity, lubricity, and resiliency for honeycomb extrusion with sufficient binder strength needed before calcination to the final product. Iron oxide-based honeycombs after calcination are strong and possess macroporosity and high surface area. In bench-scale testing, particular honeycomb catalyst compositions exhibited 60–76% ethylbenzene conversion with styrene selectivity of 95–91%, respectively, under conventional reaction conditions without apparent deactivation or loss of mechanical integrity.

Effect of nursing mixtures on stem form, crown size, branching habit and wood properties of Sitka spruce ( Picea sitchensis (Bong.) Carr.)

This study investigated the effects of Alaskan lodgepole pine ( Pinus contorta Loud.) and hybrid larch ( Larix × eurolepis Henry) nurses, planted in triplet mixture with Sitka spruce ( Picea sitchensis (Bong.) Carr.), on growth rate, stem form, branching habit and wood properties of the spruce. These mixtures were compared with pure stands of Sitka spruce which had been regularly and periodically fertilised with nitrogen. Hybrid larch promoted diameter increments in Sitka spruce greater than those achieved by the other treatments over the last 12 years of the experiment (current age 30 years). Growth of regularly fertilised pure Sitka spruce was not significantly greater than that of periodically fertilised pure spruce, suggesting that regular applications of nitrogen fertiliser did not result in increased stem growth. The greatest increase in growth of the larch-nursed spruce occurred during the period immediately following canopy closure, thus demonstrating the failure of the larch to compete with the spruce crowns. This period of high growth was associated with a high branch, cross-sectional area and deep knots within the wood on the lower part of the spruce stems in comparison with other treatments. While each treatment was associated with a similar number of branches, lodgepole pine-nursed spruce had more small branches (0–10 mm diameter) and fewer big branches (>20 mm diameter) compared with other treatments, highlighting the capacity of lodgepole pine to control branch development of the spruce. Spruce trees nursed by larch had deeper and more imbalanced living crowns with longer lived branches in comparison with lodgepole pine-nursed spruce, and both the pure spruce treatments, suggesting that more juvenile wood may have formed within the stem. Larch-nursed spruce also had the highest stem taper and lodgepole pine-nursed spruce the lowest. Basic wood density was not influenced by treatments. Overall, the evidence from this study suggests that the use of larch as a nursing species on deep peats is inadvisable and that Alaskan lodgepole pine is better able to control the branching habit of Sitka spruce with the prospect of better quality sawlogs in the future, albeit with a lower average tree size. Periodically fertilised pure spruce appears to maintain a growth rate consistently above that of the lodgepole pine-nursed spruce but without many of the disadvantages linked with the regularly fertilised pure spruce, particularly the development of large branches and an irregular pattern of annual rings within the wood.

Development of an Automated Remote Inspection System for the Interior of the Primary Containment Vessel of a Nuclear Power Plant.

An automated remote inspection system has been developed for the interior of the primary containment vessel of a nuclear power plant. This system consists of an inspection robot and an operator's console. The inspection robot travels along a monorail provided in the interior of the primary containment vessel. The operator's console is located in the central control room of the power plant. We have made efforts to downsize the robot and automate the inspection and monitoring machinery. As for downsizing the robot, a 152mm wide, 290mm high cross-sectional area and 15kg weight can be realized usingcommercially available small sensors and rearranging the parts in those sensors. As for automating the inspection and monitoring, several monitoring functions are developed using image processing, frequency analysis and other techniques applied to signals from sensors such as an ITV camera, an infrared camera and a microphone, which are mounted on the robot. Endurance tests show resistance of the robot to radiational and thermal conditions is adequate for actual use in actual power plants.

Controlled polymerization of methyl methacrylate using lithium aluminum alkyls

It is shown that certain combinations of lithium and aluminum alkyl enable polymerizations of alkyl methylmethacrylate to be carried out at elevated temperatures. Both the lithium and aluminum components must contain alkyl groups which have cross-sectional areas as large as possible. Moreover, these initiators are only effective in hydrocarbon solvents in which they are soluble. In hydrocarbon solvents the separation between the anionic and cationic components are minimized and the high cross-sectional area of the latter screens the propagating terminus of the polymer chain from side reactions. Molecular weights in the range 2000-150000 were obtained with dispersions close to that described by the Poisson distribution

Ultrasound speed in the metacarpal cortex--a survey of 347 thoroughbreds in training.

Transmission ultrasound speed was determined in the third metacarpal bone of 347 Thoroughbred racehorses in training. In addition to direct measurement of apparent ultrasound speed and lateral bone diameter, several derived parameters were estimated (cortical ultrasound speed, corticomedullary ratio and cortical cross-sectional area). Multiple regression equations were developed for each ultrasound measurement using the explanatory variables: sex, age, duration and intensity of training, preparation number and previous shin soreness. The horses (114 females, 82 entire males and 151 geldings ranging in age from 20 to 116 months) had been in continuous training for an average of 10.0 weeks when measurements were made. All measurements except corticomedullary ratio were influenced by the sex of the horse. Geldings had significantly lower ultrasound transmission speed than entire males and females, reflecting a lower bone density. However, the geldings had larger cross-sectional areas (ie bone size). We suggest that the relationship between low ultrasound speed (ie low bone density) and large cross-sectional area maintains the overall mechanical integrity of the metacarpus. This relationship (high ultrasound speed and low cross-sectional area) was also found in each sex group. Ultrasound speed and corticomedullary ratio, but not cross-sectional area, were affected by age. Both duration and intensity of training influenced the ultrasound speed measurements. This study indicated that sex, age and state of training affect ultrasound results, but this explained only about 30% of the variance in the data. Other factors, ie genetic variation in bone density and size, differences in soft tissue thickness and distal limb temperature, presumably account for most of the variance.