962 research outputs found
Sensory hypoinnervation in club foot
Abstract
We have compared the density of nerve fibres in the synovium in club foot with that of specimens obtained from the synovium of the hip at operations for developmental dysplasia. The study focused on the sensory neuropeptides substance P; calcitonin gene-related peptide; protein gene product 9.5, a general marker for mature peripheral nerve fibres; and growth associated protein 43, a neuronal marker for new or regenerating nerve fibres. In order to establish whether there might be any inherent difference we analysed the density of calcitonin gene-related peptide-positive nerve fibres in the hip and ankle joints in young rats. Semi-quantitative analysis showed a significant reduction in the number of sensory and mature nerve fibres in the synovium in club foot compared with the control hips. Calcitonin gene-related peptide (CGRP) positive fibres were reduced by 28%, substance P-positive fibres by 36% and protein gene product 9.5-positive fibres by 52% in club foot. The growth associated protein 43-positive fibres also seemed to be less in six samples of club foot. No difference in the density of CGRP-positive nerve fibres was observed in the synovium between ankle and hip joints in rats. The lack of sensory input may be responsible for the fibrosis and soft-tissue contractures associated with idiopathic club foot
Muscle healing and nerve regeneration in a muscle contusion model in the rat
The nervous system is known to be involved in inflammation and repair. We aimed to determine the effect of physical activity on the healing of a muscle injury and to examine the pattern of innervation. Using a drop-ball technique, a contusion was produced in the gastrocnemius in 20 rats. In ten the limb was immobilised in a plaster cast and the remaining ten had mobilisation on a running wheel. The muscle and the corresponding dorsal-root ganglia were studied by histological and immunohistochemical methods.In the mobilisation group, there was a significant reduction in lymphocytes (p = 0.016), macrophages (p = 0.008) and myotubules (p = 0.008) between three and 21 days. The formation of myotubules and the density of nerve fibres was significantly higher (both p = 0.016) compared with those in the immobilisation group at three days, while the density of CGRP-positive fibres was significantly lower (p = 0.016) after 21 days.Mobilisation after contusional injury to the muscle resulted in early and increased formation of myotubules, early nerve regeneration and progressive reduction in inflammation, suggesting that it promoted a better healing response
Ordering of droplets and light scattering in polymer dispersed liquid crystal films
We study the effects of droplet ordering in initial optical transmittance
through polymer dispersed liquid crystal (PDLC) films prepared in the presence
of an electrical field. The experimental data are interpreted by using a
theoretical approach to light scattering in PDLC films that explicitly relates
optical transmittance and the order parameters characterizing both the
orientational structures inside bipolar droplets and orientational distribution
of the droplets. The theory relies on the Rayleigh-Gans approximation and uses
the Percus-Yevick approximation to take into account the effects due to droplet
positional correlations.Comment: revtex4, 18 pages, 8 figure
Behavior of thin-walled tubes with combined cross-sectional geometries under oblique loading
Hollow tubes are the most important part of any structure because of their load-bearing capacity, lightweight and inexpensive manufacturing cost. One of the methods for improving the performance under quasi-static loading is to vary the cross-sectional shapes. In the real case, structures are seldom subjected to pure axial or pure bending rather they are subjected to a combination of two load cases i.e. oblique loading. In this paper, the circular cross-section was combined with four different polygonal cross-sections namely tetragon, hexagon, octagon and decagon and a total of 13 geometries were obtained. The buckling behavior of each tube was investigated numerically at various angles of inclination. Each tube was modeled in SOLIDWORKS and then was analyzed in ANSYS. Linear buckling code was used for finding the critical load at various angles ranging from 0° to 14°. The overall result was then compared and it was found that the proposed geometry can be a good alternative over conventional circular tubes in terms of load-bearing capacity at angular load
Wind Farms and Flexible Loads Contribution in Automatic Generation Control: An Extensive Review and Simulation
With the increasing integration of wind energy sources into conventional power systems, the demand for reserve power has risen due to associated forecasting errors. Consequently, developing innovative operating strategies for automatic generation control (AGC) has become crucial. These strategies ensure a real-time balance between load and generation while minimizing the reliance on operating reserves from conventional power plant units. Wind farms exhibit a strong interest in participating in AGC operations, especially when AGC is organized into different regulation areas encompassing various generation units. Further, the integration of flexible loads, such as electric vehicles and thermostatically controlled loads, is considered indispensable in modern power systems, which can have the capability to offer ancillary services to the grid through the AGC systems. This study initially presents the fundamental concepts of wind power plants and flexible load units, highlighting their significant contribution to load frequency control (LFC) as an important aspect of AGC. Subsequently, a real-time dynamic dispatch strategy for the AGC model is proposed, integrating reserve power from wind farms and flexible load units. For simulations, a future Pakistan power system model is developed using Dig SILENT Power Factory software (2020 SP3), and the obtained results are presented. The results demonstrate that wind farms and flexible loads can effectively contribute to power-balancing operations. However, given its cost-effectiveness, wind power should be operated at maximum capacity and only be utilized when there is a need to reduce power generation. Additionally, integrating reserves from these sources ensures power system security, reduces dependence on conventional sources, and enhances economic efficiency
Synthesis of ferric-manganese doped tungstated zirconia nanoparticles as heterogeneous solid superacid catalyst for biodiesel production from waste cooking oil
The solid superacid catalyst ferric-manganese doped tungstated zirconia (FMWZ) nanoparticles was prepared by impregnation reaction followed by calcination at 600°C for 3 hr and had been characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), temperature programmed desorption of NH3 (TPD-NH3), X-ray fluorescence (XRF), transmission electron microscopy (TEM), and Brunner-Emmett-Teller (BET) surface area measurement. The transesterification reaction was used to determine the optimum conditions of methanolysis of waste cooking oil with FMWZ nanoparticles as heterogeneous solid superacid catalyst. The reactions variables such as reaction temperatures, catalyst loading, molar ratio of methanol/oil and reusability were also assessed which effects the waste cooking oil methyl esters (WCOME’s) production yield. The catalyst was reused ten times without any loss in activity and maximum yield of 96% was achieved at the optimized conditions of reaction temperature of 200°C; stirring speed of 600 rpm, 1:25 molar ratio of oil to alcohol and 4% w/w catalyst loading. The fuel properties of the WCOME’s were discussed in light of ASTM D6751 biodiesel standard
Ankle Arthrodesis using Ilizarov Ring Fixator: A Primary or Salvage Procedure? An Analysis of Twenty Cases
Introduction: Ankle arthrodesis using the Ilizarov technique
provides high union rate with the added benefits of early
weight-bearing, and the unique advantage of its ability to
promote regeneration of soft tissue around the bone,
including skin, muscle and neuro-vascular structures, and its
versatility to allow correction of the position of the foot by
adjusting the frame post-operatively as needed. We describe
our experience with this technique and the functional
outcomes in our patients.
Materials and Methods: This retrospective study was
conducted in 20 ankle fusion cases using the Ilizarov method
between the years 2007 and 2017. We defined success in
treatment by loss of preoperative symptoms and radiological
union on plain radiographs of the ankle.
Results: Fusion was achieved in all patients (100%).
Immediate post-operative ambulation was with full weight
bearing (FWB) in 16 (83%) of the participants and
non-weight bearing (NWB) in 3 patients (17%). Postprocedure
11 patients (67%) of the participants who were full
weight bearing required some form of support for walking
for 2-3 weeks. Post-operatively three patients had pin tract
infection requiring intravenous antibiotics. Radiological
union took range of 6-12 weeks, mean union time was 8
weeks. Only one patient required bone grafting due to bone
loss. Average follow-up period was 10-45 months.
Conclusion: The Ilizarov technique has a high union rate
and leads to general favourable clinical outcome and may be
considered for any ankle arthrodesis but is especially useful
in complex cases such as for revisions, soft-tissue
compromise, infection and in patients with risk for
non-union. Early weight bearing is an extra benefit
Enhanced mechanical and corrosion protection properties of pulse electrodeposited NiP-ZrO2 nanocomposite coatings
Pulse electrodeposition is a technique of particular interest, which offers promising advantages such as ease of processing, compositional control, uniformity in structure, and grain refinement. In the present study, NiP-ZrO2 nanocomposite coatings containing various concentrations of ZrO2 nanoparticles (ZONPs) were deposited on low alloy steel (30CrMnSi) through pulse electrodeposition technique. The ZONPs in concentration of 0.0, 0.25, 0.50, 0.75, and 1.0 g/L were added in the electrolyte bath to obtain NiP-ZrO2 nanocomposite coatings. Furthermore, to elucidate the role of ZONPs in the NiP matrix, the structural, morphological, mechanical, and electrochemical properties of NiP-ZrO2 nanocomposite coatings were studied thoroughly. FESEM and EDX results reveal the successful incorporation of ZONPs into the NiP matrix. XRD and XPS analysis confirm the formation of a pure phase NiP structure without any noticeable defects. A considerable improvement in the mechanical response was observed with an increasing amount of ZONPs, reaching to highest values (hardness 6.7 GPa, modulus of elasticity 21.72 GPa) for NiP-1.0 ZrO2 coating composition. Similarly, the electrochemical results show a gradual increase in corrosion protection behavior of the NiP-ZrO2 coatings with increasing ZONP concentration, reaching an eventual value ~5.8 kΩ cm−2 at NiP-1.0 ZrO2 coating composition, which is six times greater than the pure NiP coatings. These improvements in the mechanical and electrochemical response of NiP-ZrO2 nanocomposite coatings highlight their suitability for applications such as oil and gas pipelines
A surrogate FRAX model for Pakistan
Summary
A surrogate FRAX® model for Pakistan has been constructed using age-specific hip fracture rates for Indians living in Singapore and age-specific mortality rates from Pakistan.
Introduction
FRAX models are frequently requested for countries with little or no data on the incidence of hip fracture. In such circumstances, the International Society for Clinical Densitometry and International Osteoporosis Foundation have recommended the development of a surrogate FRAX model, based on country-specific mortality data but using fracture data from a country, usually within the region, where fracture rates are considered to be representative of the index country.
Objective
This paper describes the development and characteristics of a surrogate FRAX model for Pakistan.
Methods
The FRAX model used the ethnic-specific incidence of hip fracture in Indian men and women living in Singapore, combined with the death risk for Pakistan.
Results
The surrogate model gave somewhat lower 10-year fracture probabilities for men and women at all ages compared to the model for Indians from Singapore, reflecting a higher mortality risk in Pakistan. There were very close correlations in fracture probabilities between the surrogate and authentic models (r ≥ 0.998) so that the use of the Pakistan model had little impact on the rank order of risk. It was estimated that 36,524 hip fractures arose in 2015 in individuals over the age of 50 years in Pakistan, with a predicted increase by 214% to 114,820 in 2050.
Conclusion
The surrogate FRAX model for Pakistan provides an opportunity to determine fracture probability within the Pakistan population and help guide decisions about treatment
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