Flame-Retarded and Heat-Resistant PP Compounds for Halogen-Free Low-Smoke Cable Protection Pipes (HFLS Conduits).

Conduits are plastic tubes extensively used to safeguard electrical cables, traditionally made from PVC. Recent safety guidelines seek alternatives due to PVC's emission of thick smoke and toxic gases upon fire incidents. Polypropylene (PP) is emerging as a viable alternative but requires modification with suitable halogen-free additives to attain flame retardancy (FR) while maintaining high mechanical strength and weathering resistance, especially for outdoor applications. The objective of this study was to develop two FR systems for PP: one comprising a cyclic phosphonate ester and a monomeric N-alkoxy hindered amine adjuvant achieving V0, and another with hypophosphite and bromine moieties, along with a NOR-HAS adjuvant achieving V2. FR performance along with mechanical properties, physicochemical characterization, and dielectric behavior were evaluated prior to and after 2000 h of UV weathering or heat ageing. The developed FR systems set the basis for the production of industrial-scale masterbatches, from which further optimization to minimize FR content was performed via melt mixing with PP towards industrialization of a low-cost FR formulation. Accordingly, two types of corrugated conduits (ø20 mm) were manufactured. Their performance in terms of flame propagation, impact resistance, smoke density, and accelerated UV weathering stability classified them as Halogen Free Low Smoke (HFLS) conduits; meanwhile, they meet EU conduit standards without significantly impacting conduit properties or industrial processing efficiency.

Additional data on the investigation of the reaction mechanisms for the production of silica hyperbranched polyethylene imine silver nanoparticle composites.

Silica-organic matrix-silver, nano-catalysts, were synthesized employing four different hyperbranched poly(ethylene imines) (MW 2000 to 750,000) to reduce Ag+ to metal nanoparticles and the formation of formation SiO2 shells. The latter is performed at pH 7,5 employing three different pH regulating agents Hepes, Trizma, and Phosphate Salts. Characterization of the resulting materials with spectroscopy (FTIR), thermogravimetry (TG), scanning electron microscopy (SEM), and ζ-potential is reported. Kinetic studies of standard reactions, 4-nitrophenol and 4-nitroaniline reduction to 4-aminophenol and p-phenylenediamine, respectively by UV-Visible spectroscopy are also included. This data in brief article is related to the "Investigation of two Bioinspired Reaction Mechanisms for the Optimization of Eco Composites-Nano Catalysts Generated from Hyperbranched Polymer Matrices" manuscript submitted to reactive & functional polymers.

Solid-State Polymerization as a Vitrimerization Tool Starting from Available Thermoplastics: The Effect of Reaction Temperature.

In the current work, solid-state polymerization (SSP) was studied for the synthesis of poly(butylene terephthalate), PBT-based vitrimers. A two-step process was followed; the first step involved alcoholysis reactions and the incorporation of glycerol in the polymer chains. The second step comprised transesterification reactions in the solid state (SSP) in the presence of zinc(II) catalyst resulting in the formation of a dynamic crosslinked network with glycerol moieties serving as the crosslinkers. The optimum SSP conditions were found to be 3 h at 180 °C under N2 flow (0.5 L/min) to reach high vitrimer insolubility (up to 75%) and melt strength (2.1 times reduction in the melt flow rate) while increasing the crosslinker concentration (from 3.5 to 7 wt.%) improved further the properties. Glass transition temperature (Tg) was almost tripled in vitrimers compared to initial thermoplastic, reaching a maximum of 97 °C, whereas the melting point (Tm) was slightly decreased, due to loss of symmetry perfection under the influence of the crosslinks. Moreover, the effect of the dynamic crosslinked structure on PBT crystallization behavior was investigated in detail by studying the kinetics of non-isothermal crystallization. The calculated effective activation energy using the Kissinger model and the nucleating activity revealed that the higher crosslinker content impeded and slowed down vitrimers melt crystallization, also inducing an alteration in the crystallization mechanism towards sporadic heterogeneous growth.

Halogen-Free Flame-Retardant Compounds. Thermal Decomposition and Flammability Behavior for Alternative Polyethylene Grades.

The effect of six halogen-free flame retardant (FR) formulations was investigated on the thermal stability of two low-density polyethylenes (LDPE) and one linear low-density polyethylene (LLDPE), by means of thermogravimetric analysis (TGA) under nitrogen and air atmosphere. The relative data were combined with flammability properties and the overall performance of the FRs was correlated with the type of branching in the polyethylene grades and to their processing behavior. The thermal degradation kinetics was further determined based on the Kissinger and Coats-Redfern methods. In terms of flammability, the addition of a triazine derivative and ammonium polyphosphate at a loading of 35 wt. %. was found to be the most efficient, leading to UL 94 V0 ranking in the case of the LDPE grade produced in an autoclave reactor.

The "challenging" fractures of the odontoid process: a review of the classification schemes.

Fractures of the odontoid process seem to have an unclear and not well-understood behavior. This is well demonstrated in the literature as there is a disagreement in many fields, including the patterns of fractures, the percentage of pseudarthrosis or the appropriate treatment that is required. This situation makes the fracture itself a "challenging" one. Indeed, despite the existence of extensive literature, there are still many unresolved problems concerning these fractures. We recognize six main classification schemes of the odontoid process fractures which clearly demonstrate the presence of differences but, also, the disadvantages that these classifications are related to. The most important factors that render these fractures "enigmatic" are the anatomy of the odontoid, the diversity of fractures encountered, the radiological evaluation, the stability and the inability to incorporate the whole spectrum of fractures in one classification. The progress made the last decades in the field of the radiology and their follow-up permitted to better analyze these lesions and to extract useful conclusions.

Donor's site evaluation after restoration with autografts or synthetic plugs in rabbits.

AIM: To investigate donor site's area histological and immunohistochemical knee cartilage appearances after resurfacing iatrogenic defects with biosynthetic plugs orautografts. METHODS: Thirty New Zealand White rabbits were used in this study. A full-thickness cylindrical defect of 4.5 mm (diameter) × 7 mm (depth) was created with a hand drill in the femoral groove of every animal. In Group A (n = 10) the defect of the donor site was repaired with a biosynthetic osteochondral plug, in Group B (n = 10) with an osteochondral autograft, while in Group C (control group of 10) rabbits were left untreated. RESULTS: Twenty-four weeks postoperatively, smooth articular cartilage was found macroscopically in some trocleas' surfaces; in all others, an articular surface with discontinuities was observed. Twenty-eight out of 30 animals were found with predominantly viable chondrocytes leaving the remaining two -which were found only in the control group- with partially viable chondrocytes. However, histology revealed many statistical differences between the groups as far as the International Cartilage Repair Society (ICRS) categories are concerned. Immunofluoresence also revealed the presence of collagen II in all specimens of Group B, whereas in Group A collagen II was found in less specimens. In Group C collagen IIwas not found. CONCLUSION: The matrix, cell distribution, subchondral bone and cartilage mineralization ICRS categories showed statistically differences between the three groups. Group A was second, while group B received the best scores; the control group got the worst ICRS scores in these categories. So, the donor site area, when repairing osteochondral lesions with autografting systems, is better amended with osteochondral autograft rather than bone graft substitute implant.

Association of MMP-1 -1607 1G/2G (rs1799750) polymorphism with primary knee osteoarthritis in the Greek population.

Osteoarthritis is the most common form of arthritis with still unknown pathogenic etiology and considerable contribution of genetic factors. One of the mechanisms of cartilage degradation in osteoarthritis is enzymatic proteolysis of the extracellular matrix by metalloproteinases. MMP-1, produced by chondrocytes and synovial cells, is a major proteinase of the MMPs family. The present study aims at evaluating the association of MMP1 gene -1607 1G/2G (rs1799750) polymorphism with primary knee osteoarthritis in the Greek population. One hundred fifty five patients with primary symptomatic knee osteoarthritis participated in the study along with 139 controls. Genotypes were determined using PCR-RLFP technique. Allelic and genotypic frequencies were compared between both study groups. There was no significant association between MMP1 -1607 1G/2G polymorphism and knee osteoarthritis, in crude analysis; however, after multiple logistic regression analysis, 1G/2G was associated with reduced odds of knee osteoarthritis by 75% in males, compared to genotypes 1G/1G + 2G/2G, adjusting for age and BMI (adjusted OR: 0.25, 95% CI: 0.069, 0.910, p = 0.035). The present study shows that MMP1 -1607 1G/2G (rs1799750) polymorphism might be a risk factor for knee osteoarthritis susceptibility in the Greek population. Further investigations are needed to confirm this association in the pathogenesis of osteoarthritis.

Confronting hip resurfacing and big femoral head replacement gait analysis.

Improved hip kinematics and bone preservation have been reported after resurfacing total hip replacement (THRS). On the other hand, hip kinematics with standard total hip replacement (THR) is optimized with large diameter femoral heads (BFH-THR). The purpose of this study is to evaluate the functional outcomes of THRS and BFH-THR and correlate these results to bone preservation or the large femoral heads. Thirty-one patients were included in the study. Gait speed, postural balance, proprioception and overall performance. Our results demonstrated a non-statistically significant improvement in gait, postural balance and proprioception in the THRS confronting to BFH-THR group. THRS provide identical outcomes to traditional BFH-THR. The THRS choice as bone preserving procedure in younger patients is still to be evaluated.

Association of NADPH oxidase p22phox gene C242T, A640G and -930A/G polymorphisms with primary knee osteoarthritis in the Greek population.

Osteoarthritis (OA) is the most common form of arthritis with still unknown pathogenic etiology and considerable contribution of genetic factors. Recently, a new emerging role of oxidative stress in the pathology of OA has been reported, lacking however elucidation of the underlying mechanism. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase being a complex enzyme produced by chondrocytes, presents the major source of reactive oxygen species and main contributor of increased oxidative stress. The present study aims to evaluate the association of NADPH oxidase p22phox gene C242T, A640G and -A930G polymorphisms with primary knee OA in the Greek population. One hundred fifty five patients with primary symptomatic knee OA participated in the study along with 139 matched controls. Genotypes were determined using polymerase chain reaction and restriction fragment length polymorphism technique. Allelic and genotypic frequencies were compared between both study groups. NADPH p22phox -A930G polymorphism was significantly associated with knee OA in the crude analysis (P = 0.018). No significant difference was detected for C242T and A640G polymorphisms (P > 0.05). The association between -A930G polymorphism and knee OA disappeared when the results were adjusted for obesity (P = 0.078, odds ratio 0.54, 95 % CI 0.272-1.071). The interaction between all three polymorphisms was not significant. The present study shows that NADPH oxidase p22phox gene C242T, A640G and -A930G polymorphisms are not risk factors for knee OA susceptibility in the Greek population. Further studies are needed to give a global view of the importance of this polymorphism in the pathogenesis of OA.

Analysis of the corrective forces exerted by a dynamic derotation brace (DDB).

BACKGROUND: Discrepancies exist in the current literature for bracing of spinal curvature conditions. This can be explained by the diversity of brace types, the different curve patterns and the various measurement methods and instruments. OBJECTIVES: The aim of this study was the analysis of the corrective forces exerted by a dynamic derotation brace (DDB), at the skin-brace interface, altering the strap tension and body posture. STUDY DESIGN: We analysed the direct forces exerted by a DDB's main pad, on 44 (38 girls, 6 boys) idiopathic scoliotic patients. Twenty-seven patients had a single right thoracic and 17 a single left or right thoracolumbar curve. METHODS: We used the F-Socket 9801 pressure sensor and the MatScan Research BETA STAM 6.30 software, while patients adopted nine different postures. The patients were divided into three different groups: those who wore the brace for the first time, those who were changing their brace for a new one, and those who were having adjustments made to their existing brace. RESULTS: These patients who were having adjustments made to their existing brace caused the highest mean exerted force. Changes in strap tension and body posture resulted in statistically significant alterations of the interface pressure and the forces exerted on the patient's body. CONCLUSIONS: Tightening the brace's straps always produces a significant force increase, independent of the body posture and the curve type. Also there are some body postures which significantly modify the exerted force. The body posture of maximum inspiration for thoracolumbar curves and, additionally, prone and lying left for thoracic curves.

Serum kinetics of soluble triggering receptor expressed on myeloid cells-1 differs in relation to the type of arthroplasty.

CONTEXT: Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) participates in the inflammatory process. PURPOSE: To describe changes of sTREM-1 in the serum after hemiarthroplasty (HA) and total hip arthroplasty (THA). METHODS: Serial blood samples were drawn from 122 patients with hip fracture. Interleukin-6 (IL-6), sTREM-1, and C-reactive protein (CRP) were measured. RESULTS: IL-6 and CRP were similarly increased after both HA and THA. sTREM-1 was increased early in HA and late after THA. The only parameter that was higher among patients who developed systemic inflammatory response syndrome was IL-6. CONCLUSIONS: Kinetics of sTREM-1 differs among patients undergoing HA of the hip and those undergoing THA.

Increased expression levels of apolipoprotein J/clusterin during primary osteoarthritis.

Osteoarthritis (OA) is a slowly progressive degenerative joint disease that is associated with joint space narrowing, osteophyte formation and subchondral sclerosis. Despite extensive effort actual breakthroughs in the field of genetic or biochemical biomarkers of OA are limited. As secretory apolipoprotein J/clusterin (sCLU) has been implicated in both inflammatory and apoptotic molecular processes which contribute to the OA phenotype, the sCLU concentration in human serum and synovial fluid during advanced primary knee and hip OA was analysed. Elevated sCLU protein levels were shown in these two biological fluids. sCLU mRNA expression was also studied in normal cartilage and in advanced primary knee and hip OA samples. A significant up-regulation of sCLU mRNA expression (~25-fold) was found in samples collected from the tibial bone that was osteotomized during total knee arthroplasty in patients with primary knee OA, as compared to healthy tissue samples collected from the femoral head of macroscopically normal cartilage during the surgical treatment of subcapital fractures. By studying sCLU mRNA expression levels in samples collected during total hip arthroplasty in patients with advanced primary hip OA, an additional up-regulation of the sCLU mRNA expression (~4-fold), as compared to advanced primary knee OA, was found. Taken together, these observations indicate that the sCLU protein or mRNA expression level may be of a significant diagnostic and/or prognostic value during OA progression.

The role of the immunogenetic background in the development and recurrence of acute idiopathic pericarditis.

OBJECTIVES: We assessed the role of the immunogenetic background in the development and recurrence of acute idiopathic pericarditis (AIP). METHODS: Fifty-five patients with a first episode of AIP were followed for 23.8 ± 6.3 months and recurrences were recorded. The control group consisted of 246 healthy individuals. In all subjects, genomic human leukocyte antigen (HLA) typing was performed. Moreover, circulating lymphocyte subpopulations were studied in 44 randomly selected patients and in 20 controls. RESULTS: An increased frequency of HLA-A*02, -Cw*07 and -DQB1*0202 alleles, and a decreased frequency of the -DQB1*0302 allele was detected in patients with AIP. The recurrence rate was 40% and time to recurrence was 202.8 ± 164.1 days. In patients with idiopathic recurrent pericarditis (RP), increased frequencies of HLA-A*02, -Cw*07 and -DQB1*0202 alleles were found. Notably, no patient with RP exhibited HLA-DRB1*04 and -DQB1*0302 alleles. Patients with RP exhibited lower CD4+/CD45RA+ naïve T cells (p = 0.03) than controls, and higher CD8+DR+ activated T cells (p = 0.01) than patients without recurrence and controls. CONCLUSIONS: HLA alleles may confer either susceptibility or resistance to AIP and RP. Circulating T-cell subpopulations may also predict RP. A combination of the above parameters might help to better define patients prone to recurrence.

Routine needle biopsy during vertebral augmentation procedures. Is it necessary?

Vertebral augmentation procedures are currently widely performed to treat vertebral compression fractures. The purpose of this study was to determine the frequency of underlying previously unrecognized etiology in a consecutive series of patients undergoing kyphoplasty to treat vertebral compression fractures. A prospective histological evaluation of vertebral body biopsy specimens from presumed osteoporotic vertebral compression fractures were performed in order to identify aforementioned causes. Over a 2-year period, vertebral body biopsies from 154 vertebral levels were performed in 75 patients undergoing kyphoplasty for vertebral compression fractures. All patients received a preoperative workup that included plain radiographs, MRI, whole body bone scan, and laboratory examinations. Bone specimens were obtained from affected vertebral bodies and submitted for histologic evaluation to identify the prevalence of an underlying cause. All specimens demonstrated fragmented bone with variable amounts of unmineralised bone, signs of bone-remodeling and/or fracture-healing. In 11 patients underlying pathology other than osteoporosis was identified (prostate cancer, 1; pancreatic cancer, 1; colon cancer, 1; breast cancer, 2; multiple myeloma, 3; leukemia, 1; and lung cancer, 2). In all but one patient the results of the biopsy confirmed the diagnosis suspected from the preoperative workup. For the last patient, namely the one with pancreatic cancer, the workup did not identify the origin of the primary tumor, although the patient was considered to have a compression fracture secondary to metastatic disease of unknown origin, the vertebral biopsy suggested the presence of adenocarcinoma which eventually was proven to be pancreatic cancer. In augmentation procedures for vertebral compression fractures, bone biopsy should be reserved for the patients where the preoperative evaluation raises the suspicion of a non-osteoporotic etiology.

Cement leakage in a symptomatic vertebral hemangioma: a case report and review of the literature.

We present the case of a 50-year-old male with consistent back pain, not resolving with conservative treatment. Plain radiograms demonstrated a lytic lesion at the level of the 8(th) thoracic vertebra. Thorough examination with computerized tomography and magnetic resonance imaging revealed a hemangioma extending to the posterior third of the vertebral body, compressing the spinal cord at the level of 8(th) thoracic vertebra. A percutaneous vertebroplasty was performed. The post-operative computerized tomography scan demonstrated cement leakage. After thorough cement removal combined with extensive decompression and posterior stabilization, the patient reported gradual improvement of his symptoms and was able to return successfully to his work a few months later.

Symptomatic intracranial abscess after treating lower cervical spine fracture with halo vest: a case report and review of literature.

We present the case of a nineteen year old male, who sustained a fracture of anterior-superior surface of C7, combined with anterior subluxation at the level of C6-C7 vertebrae. After x-ray and CT examination, he was treated conservatively by a Halo-vest. After mobilization, the patient was discharged from the hospital with instructions to visit the outpatient's clinic at regular bases.Despite of our instructions, he did not attend the regular follow-up and, three months later, he visited the emergencies complaining of pin loosening and serious headaches. He was admitted to the clinic in order to perform blood tests and new radiological control. During the first day, high fever (over 38,5 degrees C) was added to his symptoms. Blood exams were indicative of inflammation. Further investigation with CT-scan revealed the presence of a subdural abscess. After consulting the neurosurgeon, the patient was treated conservatively with antimicrobial drugs. Three weeks later he returned home without any symptoms. Since then, he is visiting regularly our clinic and no problems occurred during follow-up.

The effectiveness of two COX-2 inhibitors in the prophylaxis against heterotopic new bone formation: an experimental study in rabbits.

The purpose of this study was to present the effectiveness of 2 cyclooxygenase-2 inhibitors, meloxicam and parecoxib, in the prevention of heterotopic ossification. Eighteen white mature male rabbits were divided into 3 groups of 6 animals. One was the control group; 1 group was administered meloxicam subcutaneously, and 1 group was administered parecoxib subcutaneously. For the induction of heterotopic new bone, the Michelsson model was used. The extent of heterotopic new bone development was assessed according to Scott's classification. The meloxicam and parecoxib groups developed significantly less heterotopic bone when compared to the control group. There was no significant difference between the meloxicam and parecoxib group. We concluded that meloxicam and parecoxib are capable of preventing the development of heterotopic new bone in rabbits. The clinical relevance of this study is that meloxicam and parecoxib may be helpful in reducing heterotopic ossification in humans.

Bilateral blunt carotid artery trauma associated with a double lower thoracic spine fracture: a case report and review of the literature.

BACKGROUND: A 26 year old female suffering from a double fracture of the lower thoracic spine, as a result of a car accident, was referred to the Spine Unit of our Department. No neurological deficit was detected during clinical examination. Due to the fracture's instability, posterior stabilization was performed. CASE PRESENTATION: Postoperatively, the patient presented a decrease in Glasgow Coma Scale (GCS) combined with motor and sensory deficit from the right upper and lower extremities. Cerebral ischemia was diagnosed, secondary to distal emboli from the right and left internal carotid arteries bilaterally. CONCLUSION: Patients' neurological deficits eventually resolved after conservative treatment and anticoagulation therapy.

Results using the AO hook plate for dislocations of the acromioclavicular joint.

The AO Hook plate has been used for stabilization of acromioclavicular joint dislocations. We present our experience of this newly introduced device in a general hospital, since there are not many papers in the literature reporting on this. A total of 16 patients were treated with the AO Hook plate between November 2001 and November 2003 at Princess Alexandra Hospital in Harlow, UK. For functional assessment 6 months after removal of the plate, the constant score and the pain visual analogue score were used. The pain visual analogue score ranged from 0 to 6 (mean: 0.87) and the constant score ranged from 78 to 100 (mean: 96.4). In one instance, a patient developed instability after removal of the plate. The use of this device results in excellent functional outcome for the treatment of acromioclavicular joint dislocations.