Total Rotation Research Articles

Posterior C1-2 Temporary Fixation without Fusion for Recent Odontoid Fractures

ABSTRACT BACKGROUND: Posterior C1-2 fusion techniques are the commonly used treatment for odontoid fracture. But this is usually associated with limitation in the cervical spine range of motion especially the rotational motion. Posterior C1-2 temporary-fixation technique can spare the range of motion (ROM) of the atlantoaxial joint after odontoid fracture healing. OBJECTIVE: To assess the clinical and radiological outcome of the posterior C1-2 temporary fixation technique in the treatment of a new odontoid fracture. STUDY DESIGN: It is a retrospective study with clinical and radiological evaluation before and after instrumentation removal. PATIENTS AND METHODS: 12 consecutive patients, suffering from Type II odontoid fracture. The age ranged between 15-43 years old with a mean age was 24±11.6 years old, eight were male and four females. All cases were post traumatic. Eight patients were dislocated and four cases were in place. Only two patients were suffering from partial neurologic deficit pre-operative. The second surgery was done after a mean 15.5 weeks from the first surgery. RESULTS: The radiological outcome showed partial restoration of the rotation after removal of instrumentations with a mean total rotation restoration of 30±8°, using multi slice thin cuts CT scan. Significantly better functional outcomes were observed after the temporary-fixation removal using visual analog scale score (VAS) for neck pain (P=0.0033), neck stiffness and the patient satisfaction. CONCLUSION: Posterior atlanto-axial temporary fixation is a good salvage approach in dealing with odontoid fracture, especially when anterior odontoid screw is contraindicated. By regaining partial ROM, the functional outcome of the patients improved.

Development of 3D method to assess intramuscular spatial distribution of fat infiltration in patients with rotator cuff tear: reliability and concurrent validity

BackgroundIntramuscular fat infiltration is a critical factor in surgical decision-making and is the most important factor used to prognosticate surgical repair outcomes in patients with rotator cuff tears. Quantitative 3D assessment of total rotator cuff fat infiltration in patients with rotator cuff tears has been realized. However, a reproducible method to evaluate 3D spatial distribution of rotator cuff intramuscular fat has not been established. The objective of this study was to establish the reproducibility, change detectable beyond error, and concurrent validity of a semi-automated method to evaluate the 3D spatial distribution of fat infiltration and muscle volume in patients with rotator cuff tears.MethodsThirteen consecutive patients diagnosed with symptomatic rotator cuff pathology and 3.0 T MRI confirmation at a single center were included. Fat-water imaging was used to quantify 3D intramuscular fat (%fat) in sagittal oblique sequences and intramuscular spatial distribution with the semi-automated technique. Each rotator cuff muscle was manually segmented yielding %fat in four axial intramuscular quartile-regions (superior-inferior; Q1–4) and three sagittal (medial/ intermediate/ lateral) regions. Reliability and concurrent validity of %fat and whole muscle volume were calculated with intraclass correlation coefficients (ICC).ResultsIntra-rater reliability for intramuscular sagittal divisions (ICC = 0.93–0.99) and axial divisions (ICC = 0.78–0.99) was good/excellent. Inter-rater reliability for %fat (ICC = 0.82–0.99) and volume (ICC = 0.92–0.99) was good/excellent. Concurrent validity with commercialized software showed good/excellent agreement (ICC = 0.66–0.99).ConclusionsA new semi-automated method to assess 3-dimensional intramuscular distribution of fat infiltration in patients with rotator cuff tears using advanced MR imaging demonstrates high intra and inter-rater reliability and good concurrent validity. Minimal detectable change thresholds established facilitate clinical interpretation for future clinical application of this technique to assess change and treatment efficacy in patients with rotator cuff tears.

Superior Capsular Reconstruction for Massive Rotator Cuff Tears

» A massive rotator cuff tear is defined as a tear involving >2 tendons or >5 cm of retraction.» Superior capsular reconstruction is done with either a folded fascia lata autograft (6 to 8 mm in thickness) or acellular dermal allograft (3 to 4 mm in thickness). The graft is secured arthroscopically with anchors on the superior glenoid rim and multiple anchors on the humeral head with use of a transosseous-equivalent repair technique.» Superior capsular reconstruction is indicated for younger patients with massive and irreparable rotator cuff tears involving the supraspinatus and infraspinatus with minimal arthritis, intact subscapularis, and a functional deltoid. Contraindications include bone defects, stiffness, and moderate to severe arthropathy.» Arthroscopic superior capsular reconstruction with fascia lata autograft or humeral dermal allograft is a surgical option, with multiple studies showing statistically significant improvement in short-term outcomes for both pain and function among younger patients with massive irreparable rotator cuff tears. The long-term clinical effectiveness and value have yet to be determined.» Biomechanical data suggest improved restoration of superior glenohumeral stability with decreased subacromial contact pressures in association with the use of the 8-mm fascia lata graft as compared with the 4-mm acellular humeral dermal allograft. In addition, fascia lata graft has shown less elongation and thinning than humeral dermal graft.» Either fascia lata autograft or humeral dermal allograft may be used clinically for arthroscopic superior capsular reconstruction; however, a graft thickness of at least 3 mm is recommended to decrease the risk of radiographic and clinical failure.» No comprehensive quality-of-life or cost-comparison analyses are available to compare superior capsular reconstruction, reverse total shoulder arthroplasty (rTSA), tendon transfer, and partial rotator cuff repair for the treatment of massive irreparable rotator cuff tears. However, the potential higher cost of superior capsular reconstruction and the lack of long-term clinical outcomes or revision data suggest that either an attempt at repair or primary arthroplasty may be more cost-effective than superior capsular reconstruction.» Long-term outcome data are essential to determine the role of superior capsular reconstruction for young patients with massive irreparable rotator cuff tears.» Superior capsular reconstruction using fascia lata autograft may provide a different biomechanical and biological healing environment compared to acellular dermal allograft. Thus, the clinical outcome data between the 2 graft methods should not be generalized.

Dynamic Ultrasonography of Anterior Femoral Translation: Comparison to Ballet Turnout and Hip Symptoms in Dancers

PURPOSE: To determine if there is a relationship between turnout, self-reported hip symptoms, and femoral head anterior translational motion under dynamic ultrasound in a population of adolescent ballet dancers. METHODS: Cross-sectional cohort study. Population: 25 ballet academy students, 17 females and 8 males, ages 14-18 yrs. Dynamic ultrasound of the bilateral hips was performed on each study participant in supine position. With the low frequency linear ultrasound probe in sagittal oblique plane, the distance between the femoral head and acetabular rim was measured in 3 positions: both hips in neutral position, ipsilateral hip in neutral and contralateral hip hyperflexed, and with the ipsilateral hip in extension and external rotation and the contralateral hip hyperflexed. Compensated turnout was defined as difference between functional turnout angle in first position and total bilateral hip passive external rotation in prone. Each participant completed the Hip Osteoarthritis and Outcome Score (HOOS) questionnaire. RESULTS: Spearman’s rho correlation coefficient (r) was used to test strength of association between variables, defined as <0.3 = poor, 0.3-0.5 = fair/moderate, 0.5-0.7 = good, >0.7 = strong. P=0.05 was used as threshold for statistical significance. IBM SPSS software (version 23, SPSS, Chi, IL) was used for all analyses. Mean maximal femoral translation distance for the right hip: 0.66mm (+/- 1.74mm), and the left hip: 1.56mm (+/- 1.93mm). Mean compensated turnout: 62.8° (+/- 14.8 °). There was no significant correlation between femoral translation and HOOS scores, nor between femoral translation and compensated turnout (right: p=.56, r=0.123, left: p=.203, r= -0.64). There was a significant correlation between greater compensated turnout and higher mean bilateral HOOS scores, with strongest association in the domains: symptoms (p=.02, r=.463), quality of life (p=.003, r=.561) and activities of daily living (p=.034, r=.426). CONCLUSIONS: In this population of adolescent ballet dancers, there was no significant correlation between femoral head translational motion on ultrasound and compensated turnout or self-reported symptoms. There was significant correlation between degree of compensated turnout and more favorable self-reports on hip symptoms and function.

Multiple-twisted spiral beams.

We propose a method to construct paraxial light fields whose transverse intensity rotates as a whole during the field propagation (spiral beams), and the total rotation angle is an integer multiple of π/2 (multiple-twisted beams). We derive analytical expressions for the field complex amplitude by utilizing an integral description of Laguerre-Gaussian beams. This method provides a straightforward way to obtain multiple-twisted spiral beams of various intensity shapes and rotation rates.

Application of block theory for evaluating face stability under disc cutters loading of TBM, case study of a water-conveyance tunnel project

Block theory has been widely used in analyzing the stability of rock blocks during engineering activities in jointed rock masses due to its simplicity and computational efficiency. This paper extended the traditional block theory to tunnels constructed using tunnel boring machine (TBM) by incorporating the disc cutter-block interaction mechanism. The rock blocks were divided into front, corner and rear blocks according to their spatial positions with respect to the cutterhead. The interaction between different blocks and the disc cutters mounted on the cutterhead were examined by estimating the forces exerted by disc cutters on the blocks relative to the location of the blocks in the face, direction of movement of the discs, and the depth of penetration. The estimated forces were then used in a subsequent analysis to calculate factor of safety for individual blocks and probability of blocks dislodging from its location. Two new evaluation parameters, eA and eη, were proposed to account for the probability of block instability. eA is the ratio of exposed area of unstable blocks to the face area and quantifies the size of unstable blocks relative to the face, and eη is the ratio of cutterhead rotation angles making a block unstable to the total rotation angles in a revolution which reflects the possibility of encountering an unstable block during a single round of revolution. This paper discussed the implementation of the idea of using fundamental concepts of block theory to determine block stability at the face and related analysis for assessment of face stability. The proposed method was used in evaluation of the stability conditions for a water-conveyance tunnel in western China that is currently under construction using a hard rock TBM.

Biomechanical analysis of latissimus dorsi tendon transfer with and without superior capsule reconstruction using dermal allograft

Irreparable rotator cuff tears (ICTs) remain a challenging treatment dilemma. Superior capsule reconstruction (SCR) acts as a static stabilizer to decrease superior humeral head migration. Latissimus dorsi tendon transfers (LDTs) dynamically decrease superior humeral head migration and improve external rotation. We hypothesized that the dynamic stabilizing effect of the latissimus transfer plus the static stabilizing effect of SCR would improve shoulder kinematics in shoulders with ICTs. Eight fresh-frozen cadaveric shoulders were tested in 5 conditions: (1) intact, (2) ICT (supraspinatus plus anterior half of infraspinatus), (3) SCR with dermal allograft, (4) SCR plus LDT, and (5) LDT alone. Rotational range of motion, superior translation, anteroposterior translation, and peak subacromial contact pressure were measured at 0°, 30°, and 60° of glenohumeral abduction in the scapular plane. Statistical analysis was performed using a repeated-measures analysis of variance test, followed by a Tukey post hoc test for pair-wise comparisons. ICTs increased total shoulder rotation, superior translation, posterior translation, and peak subacromial contact pressure. SCR plus LDT significantly decreased internal rotation only at 60° of abduction. The effect of SCR plus LDT was most evident at lower levels of abduction. At the mid range of abduction (30°), the static stabilizing effect diminishedbut the dynamic stabilizing effect remained, allowing SCR plus LDT to reduce superior translation more effectively than SCR with dermal allograft alone. Adding SCR to LDT adds static stabilization to a dynamic stabilizer. Therefore, SCR plus LDT may provide additional stability at the low to mid ranges of abduction.

Influence of welding parameters and tool geometry on the morphology and mechanical performance of ABS friction stir spot welds

In the present paper, a tool with a flat pin was designed and utilized to friction stir spot weld acrylonitrile butadiene styrene sheets. Influences of welding parameters and pin geometries on joint morphology and mechanical performance were investigated. Results showed that rotational speed during plunging and stirring phase exerted a significant influence on the joint surface appearance and cross-sectional morphology while plunge rate and dwell time showed a slight effect. Secondary extrusion ring, rough weld surface, groove defects, and pores were observed under excessive stirring rotational speed. Spot weld diameter enlarged with the increase of the total tool rotation number in the plunging and stirring phase. Joint lap-shear tensile load varied significantly with the variation of the keyhole orientation. The comparison of the joints produced by different pin geometries showed that flat pin was optimal to fabricate joints with larger bonded region and lap-shear tensile load. With the increase of rotational speed or the decrease of plunge rate, joint shear strength reduced. The proper extension of dwell time under moderate rotational speed exerted a slight influence on the joint shear strength but showed a positive effect on the joint fracture load.

FINANCIAL IMPLICATIONS OF STORM DAMAGE TO CONIFEROUS FORESTS IN LATVIA

INTRODUCTION&#x0D; Storms are the primary factor reducing carbon sequestration in Europe’s forests, thus negatively affecting the ability of countries to fulfil their targets related to greenhouse gas balance (emission vs. sequestration). The impact of storms is rising due to an increase in forest cover, a preference for less wind-firm species (namely the Norway spruce) as well as the aging of forests in Europe (leading to greater vulnerability). Furthermore, climate change will affect the amount of damage. The frequency of windstorms and/or high speed wind gusts is expected to increase. The largest storms in our region occur mostly in autumn/winter – in the future this is likely to increase due to conditions in which it is more likely that tree anchorage is weak, due to the soil not being frozen and being saturated with water. From a sustainable forestry perspective, it is important to note that recreational use of those forests affected by storms as well as secondary damage (e.g. by bark beetle) will also be substantially reduced. Forest owners suffer direct financial losses as a result of storms. The aim of this study is to estimate the losses caused by storms and evaluate measures that could be used to reduce storm damage.&#x0D; MATERIALS AND METHODS&#x0D; Forest owners suffer direct damage as a result of a loss of timber value from stem cracks (which is estimated to account for 20% of the volume of first (bottom) logs reduced to fire-wood quality), increased logging costs as well as additional regeneration, tending and precommercial thinning. The cost of these processes and the timber prices used in calculations are obtained from the Central Statistical Bureau of Latvia; information on the amount of timber damage during storms in the last decade is provided by the State Forest Service. To obtain information on the possibility of reducing storm damage, growth models (LSFRI Silava) are used in addition to assessments of vulnerability to storm damage (ForestGALES). The financial impact of damage-reduction measures is given as equivalent annual annuity (EAA) - interest rate 4%.&#x0D; RESULTS&#x0D; During the last decade, windstorms in Latvia alone have caused direct economic losses to forest owners of around €164 million, an average of €9 per m3 of wood from salvage logging. Vulnerability to damage increases as tree height increases (as critical wind speed decreases). Lower planting density slightly increases the critical wind speed (by 3-9%) (for Scots pine: 1500 trees ha-1vs current 3000 tree ha-1) and notably reduces the financial impact of storm damage: EAA for pine stands planted on the best soils is €15 ha-1 with sparser planting, and -€11 ha-1 with denser planting. If final harvest is planned by the stand age (101 years in majority of cases in Latvia), the financial impact of wind damage is higher in the best growing pine stands (site index Ia): in sparse stands the affect of wind damage reduces EAA by 38%, while stands with a lower site index are reduced by 25%. The reason for this is that faster-growing trees reach certain height, at which they are vulnerable to smaller (in terms of m s-1) critical wind speed, at earlier age. For example, the above-mentioned sparse Ia stand has a critical wind speed of ≤20ms-1 for 38% of its total rotation period, compared to 26% for the I stand. Thus, harvesting by constant age reduces the financial gain from the best-quality sites and silvucultural treatments aimed at increasing tree growth (e.g. planting best-growing genotypes). Therefore, harvesting by target diameter is recommended.&#x0D; CONCLUSION&#x0D; Major damage to forests mean owners are less willing to invest – thus reducing future potential wood flow for the industry. Therefore, changes in legislation concerning criteria for initial stand density and target diameter are recommended to minimize the negative economic impact of climate change (adapt).

Visibility graph analysis on time series of shield tunneling parameters based on complex network theory

Shield tunneling operation affects project scheduling, cost estimation, and safety risk during metro construction. Given the importance of this process, tunnel engineers should understand the complexities of shield tunneling parameters. This study addresses the characteristics of shield tunneling parameters by introducing a visibility graph model implemented in a complex network of shield tunneling in metro construction. Time series data are collected for the analysis of six parameters generated in each segment ring tunneling cycle. These parameters are total thrust, torque, penetration rate, rotation rate, advance speed, and working chamber pressure. Bridging time series and the complex network with visibility graph algorithm indicates that all degree distributions of the construct networks follow the power law, establishing the scale-free time series of the parameters. Small-world features and hierarchical structures also indicate that the fluctuation and variance of the parameters are attracted, limited, or affected by a previous shield operation of segment rings. In addition, findings reveal turning points in the parameters’ time series with vital node identification based on complex network analysis. Implications relevant for shield operators and managers are proposed to improve shield tunneling performance, efficiency, and safety.

Evaluation of semi-preloaded intraocular lens delivery system

Purpose: In this study, we aimed to evaluate the single surgeon experience of semi-preloaded intraocular lens (IOL) delivery system. Methods: Phacoemulsification was performed under topical anesthesia by temporal clear corneal incision. CT Lucia hydrophobic IOL was injected through semi- preloaded IOL system in the capsular bag. Two hundred patients (200 eyes) were included in the study. The main outcome measures were ease of implantation, intraoperative and postoperative complications, postoperative centration, and visual acuity. Data on successful implantation and complications were collected prospectively. Results: Correct IOL delivery was achieved in 193 out of 200 patients (96.5%). Four patients (2%) required intrawound rotation of the injector to place the leading haptic in the capsular bag. Two patients (1%) had anteroposterior rotation of the IOL and one patient (0.5%) had total posterior rotation of IOL. Other problems noted were trapped trailing haptic (n=2,1%), improper loading of IOL (n=3,1.5%) and stretch marks on the optic of IOL (n=4,2%). None of the patients had iris trauma or posterior capsular rupture during the implantation and manipulation of the IOL. The mean incision size after completion of implantation of IOL was 2.82 mm (+ 0.02), which achieved sutureless closure. None of the patients developed postoperative infection. Conclusion: Implantation of CT Lucia 601 PY IOL with the semi preloaded system led to minor complications and gave satisfactory visual results.

Determination of total rotation of polarization axes in polarization-maintaining fibers

A simple method is proposed to measure the total rotation of polarization axis caused by both internal and external factors during the fabrication process in polarization-maintaining fibers (PMFs). The method is suitable for any kind of PMF, and avoids the additional clamping-induced rotation of fiber with assistance of gravity. Based on this method, a polarization-maintaining photonic crystal fiber (PM-PCF) and a conventional panda PMF used in fiber-optic gyroscope (FOG) are tested. The experimental results provide foundation for the analysis of fiber quality and magnetic-induced bias error in a FOG. © 2018 The Author(s).

Low-dose low-scattering X-ray computed tomography with high-spatial-energy resolutions using a cooled cadmium telluride detector

To improve the image quality of photon-counting energy-dispersive X-ray computed tomography (CT) and to reduce the incident dose for the object, we have developed a low-dose low-scattering CT scanner with high-spatial and -energy resolutions using a cooled cadmium telluride (CdTe) detector. X-ray photons are absorbed by the CdTe crystal, and the event pulses from the shaping amplifier are input to a high-speed triple-energy (TE) counter. In the TE-CT, four 3.0-mm-thick lead (Pb) pinholes are used. The line-beam diameter is roughly reduced using the first 2.0-mm-diam pinhole. Using the second 0.5-mm-diam pinhole, the line-beam diameter is reduced again, and the 0.5-mm-diam line beam is exposed to the object. The scattering photon count was reduced using the third 0.5-mm-diam pinhole, and the only penetrating photons are absorbed by the cooled CdTe crystal through the fourth 0.3-mm-diam pinhole for improving the spatial resolution. K-edge tomograms using iodine (I) and gadolinium (Gd) media were obtained simultaneously at two energy ranges of 33–50 and 50–100 keV, respectively. Utilizing I-K-edge CT, coronary arteries filled with I medium were visible. Next, blood vessels filled with Gd medium were observed at high contrasts using Gd-K-edge CT. The maximum count rate was 30 kilocounts per second (kcps) at a tube current of 0.33 mA, and the minimum count rate after penetrating objects was approximately 2 kcps. The maximum incident dose for the object was approximately 0.3 mGy, and the exposure time for TE-CT was 19.6 min at a total rotation angle of 360°. The energy resolution of the detector was 1.1% at 59.5 keV, and the spatial resolutions had values of 0.3 × 0.3 mm2.

An Efficient Finite Element For Restrained Torsion Of Thin-Walled Beams Including The Effect Of Warping And Shear Deformation

An efficient torsion element is developed to describe the restrained torsion of thin-walled beams based on the first-order torsion theory. The element has two nodes, each with two degree of freedoms, namely, total rotation and warping function of cross section. The element stiffness matrix is directly obtained on the basis of first-order torsion theory without the assumption of interpolation function and the derivation of classical finite element method, which is more convenient and applicable than the initial parameter method. This element can consider not only the warping deformation but also the shear deformation of cross section due to restrained torsion. Finally, numerical examples are presented to demonstrate the validity and reliability of current torsion element, and the comparison between the results obtained from current method and those from other approaches is also illustrated.

Superior fixation and less periprosthetic stress-shielding of tibial components with a finned stem versus an I-beam block stem: a randomized RSA and DXA study with minimum 5 years’ follow-up

Background and purpose — The stem on the tibial component of total knee arthroplasty provides mechanical resistance to lift-off, shear forces, and torque. We compared tibial components with finned stems (FS) and I-beam block stems (IS) to assess differences in implant migration.Patients and methods — In a patient-blinded RCT, 54 patients/knees (15 men) with knee osteoarthritis at a mean age of 77 years (70–90) were randomly allocated to receive tibial components with either a FS (n = 27) or an IS (n = 27). Through 5 to 7 years’ follow-up, implant migration was measured with RSA, periprosthetic bone mineral density (BMD) was measured with DXA, and surgeons reported American Knee Society Score (AKSS).Results — At minimum 5 years’ follow-up, maximum total point motion (MTPM) was higher (p = 0.04) for IS (1.48 mm, 95% CI 0.81–2.16) than for FS (0.85 mm, CI 0.38–1.32) tibial components. Likewise, total rotation (TR) was higher (p = 0.03) for IS (1.51˚, CI 0.78–2.24) than for FS (0.81˚, CI 0.36–1.27). Tibial components with IS externally rotated 0.50° (CI –0.06 to 1.06) while FS internally rotated 0.09° (CI –0.20 to 0.38) (p = 0.03). Periprosthetic bone stress-shielding was higher (p < 0.01) up to 2 years’ follow-up for IS compared with FS in the regions medial to the stem (–13% vs. –2%) and posterior to the stem (–13% vs. –2%). Below the stem bone loss was also higher (p = 0.01) for IS compared with FS (–6% vs. +1%) up to 1-year follow-up. Knee score improved similarly in both groups up to 5 years’ follow-up.Interpretation — Periprosthetic bone stress-shielding medial and posterior to the stem until 2 years, and tibial component migration at 5 years, was less for a finned compared with an I-shaped block stem design.Trial registration: ClinicalTrials.gov identifier: NCT00175136.

Assessment of ultrasonography as a diagnostic tool in shoulder pain and alterations in glenohumeral range of motion in tennis players.

IntroductionShoulder pain and alterations in the range of motion are common disorders in tennis players. However, the relation between shoulder structures and these conditions is unknown.AimTo evaluate whether, using ultrasonography, one can identify tennis players with shoulder pain and those having specific changes of the range of rotation of the glenohumeral joint.Material and methodsA total of 66 subjects were assessed through examination of the range of rotation of the glenohumeral joint and ultrasonography.ResultsThe study group consisted of 37 people with shoulder pain (24.2 ±8.6 years) and the control group included 29 subjects without shoulder pain (21.9 ±10.8 years). The prevalence of pathologies of the supraspinatus (SSP), infraspinatus (ISP) or subscapularis (SSC) was significantly higher in the study group than in the control group (p = 0.044) but solely for the combined pathologies. The incidence rate of pathological shoulder changes (the SSP, ISP, SSC and the subacromial bursa) was not correlated with the ranges of rotations or intensity of pain. Glenohumeral internal rotation deficit (GIRD), total rotational motion (TROM) deficit and external rotation deficiency (ERD) were independent of pathological shoulder changes, except the significantly higher prevalence of SSP pathologies among subjects with ERD.ConclusionsUltrasonography could be helpful in identifying tennis players with painful shoulder having rotator cuff pathologies. However, the ability of the method to identify players having specific changes of the range of rotation of the glenohumeral joint is limited, with the exception of tennis players with ERD having SSP pathologies.

Protocatechuic acid ameliorates neurobehavioral deficits via suppression of oxidative damage, inflammation, caspase-3 and acetylcholinesterase activities in diabetic rats

Clinical and experimental data have demonstrated that diabetes is associated with neurological complications. Protocatechuic acid (PCA) is a phenolic phytochemical widely reported to possess antidiabetic property. However, there is no scientific information on the influence of PCA on diabetes-induced neurotoxicity. The present study aimed at investigating the neuroprotective mechanism of PCA in streptozotozin (STZ)-induced type 1 diabetic rats orally treated with PCA (50 mg/kg body weight) or glibenclamide (5 mg/kg body weight) for 45 consecutive days. Locomotor behavior was analyzed using video-tracking software during the 8-min trial in a novel environment whereas the pancreas, cerebrum and cerebellum of the rats were processed for biochemical analyses. Results showed that treatment of diabetic rats with PCA at 50 mg/kg significantly (p < 0.05) improved the locomotor and motor activities including the average speed, total time mobile, distance travelled, body rotation, turn angle, forelimb grip and grooming when compared with untreated diabetic rats. Moreover, the prevention of diabetes-mediated increase in acetylcholinesterase activity, biomarkers of inflammatory and oxidative stress as well as caspase 3 activity by PCA treatment was accompanied by improved pancreatic, cerebral and cerebellar architectures. Collectively, the neuroprotective mechanisms of PCA is related to its antioxidant, anti-inflammatory and anti-apoptotic activities.

Liver Transplant From a Donor With Situs Inversus Totalis Using Orthotopic and Retroversus Technique: A Case Report

Situs inversus totalis is an infrequent genetic malformation affecting 0.01% of the population and consists of the total rotation of the organs 180 degrees, generating the so-called mirror-image reversal. For many years donors with this pathology were discouraged from organ donation. We present a case of hepatic and renal transplantation using the 2 techniques described, orthotopic and retroversus. The recipient was a 69-year-old man with end-stage liver and kidney disease due to alcoholism and diabetes, respectively, and a Model for End-Stage Liver Disease score of 32. There was no mismatch between recipient and donor. The implant started with the piggy-back technique using the retroversus technique, generating a tense portal vein anastomosis due to the superior situation of the elements of the hepatic hilum, so it was decided to undo suprahepatic anastomosis with the orthotopic technique, rotating the liver on its axis, without complications. Roux-en-Y hepaticojejunoanastomosis was carried out. The patient was discharged 15 days after surgery with normalization of renal function. Although both techniques must be taken into account, the one that fits best for a particular recipient should be used, given the particularities of size and shape of the liver graft. This can take some art and creativity from the surgical team.

Matrix WKB solution for electromagnetic waves in an inhomogeneous gyrotropic layer

A matrix solution 4x4 was obtained using the Wenzel-Kramers-Brillouin method for inclined incidence of a plane electromagnetic wave on an inhomogeneous gyrotropic torsion layer. The medium is affected by an external nonhomogeneous magnetic field reverses direction within the layer. Solutions for fields in the form of a fundamental matrix of the solution and the Cauchy matrix are obtained. The absolute values of the reflectance matrix coefficients and the reflection energy coefficients for the s and p polarized waves are calculated. The dependence of the cross-polarization coefficients of the reflection matrix of the total rotation angle of the external magnetic field vector within the layer is shown.

Effects of lumbo-pelvic rhythm on trunk muscle forces and disc loads during forward flexion: A combined musculoskeletal and finite element simulation study

Previous in-vivo studies suggest that the ratio of total lumbar rotation over pelvic rotation (lumbo-pelvic rhythm) during trunk sagittal movement is essential to evaluate spinal loads and discriminate between low back pain and asymptomatic population. Similarly, there is also evidence that the lumbo-pelvic rhythm is key for evaluation of realistic muscle and joint reaction forces and moments predicted by various computational musculoskeletal models. This study investigated the effects of three lumbo-pelvic rhythms defined based on in-vivo measurements on the spinal response during moderate forward flexion (60°) using a combined approach of musculoskeletal modeling of the upper body and finite element model of the lumbosacral spine. The muscle forces and joint loads predicted by the musculoskeletal model, together with the gravitational forces, were applied to the finite element model to compute the disc force and moment, intradiscal pressure, annular fibers strain, and load-sharing. The results revealed that a rhythm with high pelvic rotation and low lumbar flexion involves more global muscles and increases the role of the disc in resisting spinal loads, while its counterpart, with low pelvic rotation, recruits more local muscles and engages the ligaments to lower the disc loads. On the other hand, a normal rhythm that has balanced pelvic and lumbar rotations yields almost equal disc and ligament load-sharing and results in more balanced synergy between global and local muscles. The lumbo-pelvic rhythm has less effect on the intradiscal pressure and annular fibers strain. This work demonstrated that the spinal response during forward flexion is highly dependent on the lumbo-pelvic rhythm. It is therefore, essential to adapt this parameter instead of using the default values in musculoskeletal models for accurate prediction of muscle forces and joint reaction forces and moments. The findings provided by this work are expected to improve knowledge of spinal response during forward flexion, and are clinically relevant towards low back pain treatment and disc injury prevention.