278 research outputs found
Is Laser Additive Manufacturing Sustainable?
No full textLaser Additive Manufacturing (LAM) has revolutionized industrial manufacturing by enabling the fabrication of lighter, stronger, complex and customized metallic parts. LAM is attractive mainly due to the various freedoms offered by the technology, like—shape design freedom, material design freedom, logistic freedom and post-processing freedom. LAM technology is considered as a green technology due to two major attributes: minimum material wastage as compared to conventional manufacturing techniques and direct conversion of 3D models to 3D components eliminating intermediate development stages. In addition, LAM possess significant potential to build highly efficient functional components with minimal life cycle impact. Thus, the wider adaptation of LAM is dependent on the sustainability of the technology, which is primarily dependent on economic, environmental and societal effects of LAM. Although LAM paves a way towards sustainability in manufacturing, achieving complete sustainability is challenging due to the use of support structures, higher energy consumption, need for post-processing, etc. Thus, assessing the environmental impact and cost-effectiveness at each stages of the life cycle of LAM built components play a significant role in wider adoption of the technology. This chapter compiles an overview of LAM technology and the various associated processes. It discusses the need for sustainability in manufacturing, the factors governing and challenging the sustainability of LAM technology. A comprehensive comparative assessment of LAM with other conventional manufacturing techniques is compiled and the various theoretical models are discussed in detail. At the end, the suggestions and future directions to improve the sustainability of LAM is deliberated. This chapter is a quick-start for novices to understand this novel technology and a reference document for researchers in the field
Erratum: Retracted Article: Determination of sulpha drugs and ascorbic acid, individually or in mixture, with N-chlorosuccinimide by A. Srivastava, R. Abbi, A. Gupta, S. Bindra, and S. K. Singh (Microchim Acta, Vol 99/1-2 (1989), 81-89; DOI 10.1007/BF01242793)
No full textLong term outcomes of open reduction internal fixation versus external fixation of distal radius fractures: A meta-analysis
No full textDistal radius fractures are among the most common fractures encountered in the clinical setting. Of these common fractures, it has been said that up to 60% are intraarticular in nature. Intra-articular or unstable and comminuted fractures represent severe and high energy injuries. Despite a large amount of literature, it is surgeon preference which determines the fixation method employed. There are only a few randomised control trials that report 2-year outcomes. There has yet to be a meta-analysis comparing the long-term outcomes of open reduction internal fixation (ORIF) and external fixation (EF). The aim of this metaanalysis is to identify any difference in the outcomes of either fixation method in the long term. We pooled the data of all the available randomised control trials that followed the patients for a minimum of 2 years and compared outcomes of ORIF against EF of distal radius fractures as per PRISMA guidelines from inception of the databases to December 2016. We then performed our meta-analysis using RevMan 5.3 software. Flexion/extension arcs were significantly improved in ORIF, and 7 of the 10 analysed outcomes supported ORIF, although most not to a significant degree. The meta-analysis indicated that there is no difference in outcomes with either form of treatment. Even though the flexion extension arc was statistically better in the ORIF group, the difference is not clinically meaningful.Full Tex
BMP2 and GDF5 for Compartmentalized Regeneration of the Scapholunate Ligament
No full textBackground: Chronic injuries to the scapholunate ligament (SLIL) alter carpal kinematics and may progress to early degenerative osteoarthritis. To date, there is no consensus for the best method for SLIL reconstruction. This study aims to assess the use of growth factors (bone morphogenetic protein [BMP]2 and growth and differentiation factor 5 [GDF5]) for compartmentalized regeneration of bone and ligament in this multiphasic scaffold in a rabbit knee model. Case Description: A total of 100 µg of BMP2 and 30 µg of GDF5 were encapsulated into a heparinized gelatin–hyaluronic acid hydrogel and loaded into the appropriate compartment of the multiphasic scaffold. The multiphasic scaffold was implanted to replace the native rabbit medial collateral ligament (n = 16). The rabbits were randomly assigned to two different treatment groups. The first group was immobilized postoperatively with the knee pinned in flexion with K-wires for 4 weeks (n = 8) prior to sacrifice. The second group was immobilized for 4 weeks, had the K-wires removed followed by a further 4 weeks of mobilization prior to sample harvesting. Literature Review: Heterotopic ossification as early as 4 weeks was noted on gross dissection and confirmed by microcomputed tomography and histological staining. This analysis revealed formation of a bony bridge located within and over the ligament compartment in the intra-articular region. Biomechanical testing showed increased ultimate force of the ligament compartment at 4 weeks postimplantation consistent with the presence of bone formation and higher numbers of scaffold failures at the bone–tendon junction. This study has demonstrated that the addition of BMP2 and GDF5 in the bone–ligament–bone (BLB) scaffold resulted in heterotopic bone formation and failure of the ligament compartment. Clinical Relevance: The implantation of a three-dimensional-printed BLB scaffold alone demonstrated superior biomechanical and histological results, and further investigation is needed as a possible clinical reconstruction for the SLIL.No Full Tex
Biodegradable PEG-poly(ω-pentadecalactone- co - p -dioxanone) nanoparticles for enhanced and sustained drug delivery to treat brain tumors
Get PDFIntracranial delivery of therapeutic agents is limited by penetration beyond the blood-brain barrier (BBB)
and rapid metabolism of the drugs that are delivered. Convection-enhanced delivery (CED) of drugloaded
nanoparticles (NPs) provides for local administration, control of distribution, and sustained
drug release. While some investigators have shown that repeated CED procedures are possible, longer
periods of sustained release could eliminate the need for repeated infusions, which would enhance
safety and translatability of the approach. Here, we demonstrate that nanoparticles formed from
poly(ethylene glycol)-poly(u-pentadecalactone-co-p-dioxanone) block copolymers [PEG-poly(PDL-co-
DO)] are highly efficient nanocarriers that provide long-term release: small nanoparticles (less than
100 nm in diameter) continuously released a radiosensitizer (VE822) over a period of several weeks
in vitro, provided widespread intracranial drug distribution during CED, and yielded significant drug
retention within the brain for over 1 week. One advantage of PEG-poly(PDL-co-DO) nanoparticles is that
hydrophobicity can be tuned by adjusting the ratio of hydrophobic PDL to hydrophilic DO monomers,
thus making it possible to achieve a wide range of drug release rates and drug distribution profiles. When
administered by CED to rats with intracranial RG2 tumors, and combined with a 5-day course of fractionated
radiation therapy, VE822-loaded PEG-poly(PDL-co-DO) NPs significantly prolonged survival
when compared to free VE822. Thus, PEG-poly(PDL-co-DO) NPs represent a new type of versatile
nanocarrier system with potential for sustained intracranial delivery of therapeutic agents to treat brain
tumors
Predictive Factors for Patient Recovery Following Triangular Fibrocartilage Foveal Repair Surgery: A Retrospective Case-Series
Get PDFBackground:
There are many factors that may influence patient recovery following triangular fibrocartilage complex (TFCC) foveal repair surgery. This study aimed to retrospectively analyze patient records following TFCC foveal repair surgery to identify characteristics that predict patient outcomes.
Methods:
A multicenter, retrospective case-series was conducted. Informed written consent was obtained from participating hand therapy clinics, who provided deidentified patient records for adult patients following TFCC foveal repair surgery between January 1 2015 and December 31 2020. Predictors of outcomes were identified using Linear Mixed Effects Regression and Logistic Regression models.
Results:
A total of 210 patients were included. The most notable improvements in range of motion (ROM) and grip strength, and pain reduction, were observed in the first 10 weeks postsurgery. Longer forearm immobilization duration predicted poorer ROM for pronation, flexion, and extension. Workcover (compensable) patients demonstrated poorer ROM progression compared with private patients. Forty-two patients (20%) required further surgery, of which was due to postoperative TFCC rupture for 22 patients (10%). Patients who received a shorter wrist immobilization period were more likely to experience TFCC rupture. The duration of time between injury and operative treatment did not predict ROM, grip strength, or pain progression.
Conclusions:
Longer forearm immobilization predicted poorer ROM and grip strength progression, whereas shorter wrist immobilization predicted an increased risk of TFCC rupture. These findings support a staggered commencement of wrist and forearm ROM exercises, whereby forearm rotation exercises could commence earlier than wrist exercises. The duration of time between injury and operative treatment did not predict ROM, grip strength, or pain progression.Full Tex
Reproductive Patterns of Captive Lesser Bandicoot Rat (Bandicota Bengalensis Gray) in the Punjab
Get PDFAuthor Institution: Department of Entomology, Punjab Agricultural UniversityDevelopment of the lesser bandicoot rats was studied under caged conditions. Early development of both sexes was similar. Walking started (14 days) at about the time sensory organs became functional. Body weight in males continued to increase for about 9 months. After about 5 months, weights of females fluctuated with pregnancies. Sexual maturity was attained by 60 days in females, slightly earlier in males (51 days). A female might produce 9 litters annually; mean litter size was 5.4 Sex ratio was 41% males
Effect of plant density on vine growth, yield, fruit quality and nutrient status in Perlette grapevines
Get PDFStudies on the effect of plant density on vine growth, nutrient status, yield and quality of the grape cv. Perlette were carried out during 1980, 1981 and 1982. Vine growth measured in terms of shoot length, trunk girth and pruning weight as weil as the level of the nutrient elements N, P, K, Fe, Mn, Zn and carbohydrates were highest at the maximum spacing i. e. 3.0 x 3.0 m and decreased with an increase in the plant density. Most of the nutrients were high either in early spring or during the rainy season. The average yields per vine and per ha were highest at 3.0 x 3.0 m and 2.0 x 2.0 m spacing, respectively. No significant differences were observed in the various quality parameters of the fruit under various plant densities. Under the prevailing agro-climatic conditions optimum yield per ha of Perlette grapes trained on head system can be obtained by planting the vines at 2.0 x 2.0 m spacing
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