Characterization of effective moisture diffusivity based on pore structure of concrete.

Concrete durability is greatly influenced by the transport rate of aggressive chemicals. Moisture diffusion plays a key role in the long-term performance of cementitious materials, as it facilitates the entry of aggressive chemicals into concrete. The pore size distribution plays a critical role in determining moisture diffusivity. However, the characteristics of the concrete pore structure have not been included comprehensively in the material models so far. In this paper, a theoretical model was developed to obtain the pore size volume fractions for each diffusion mechanism including Molecular, Knudsen and Surface diffusions. An effective moisture diffusivity in concrete was then obtained using the weighted average based on the diffusion mechanisms and pore size volume fractions. The model's validity was demonstrated by comparing model predictions with available experimental data. The findings of this study provide valuable insights into the behavior of the concrete pore structure and its impact on moisture diffusivity.

Patellar osteoblastoma: A case report and literature review.

An osteoblastoma is a benign bone tumor characterized by osteoblast proliferation that is more commonly diagnosed in young men during adolescence and youth. The condition mainly occurs in the posterior regions of the spine and sacrum, but in rare cases, the patella as well. We present a case of patellar osteoblastoma successfully managed through intralesional curettage and grafting, highlighting the need for comprehensive imaging and pathological studies to ensure an accurate diagnosis. A 26-year-old male with a history of knee plica excision presented with persistent knee pain over 1 year. Radiographic and CT evaluations revealed an osteolytic lesion in the patella, further characterized by MRI. An incisional biopsy confirmed the diagnosis of osteoblastoma. Intralesional curettage and grafting were performed. Later, subsequent follow-up demonstrated complete pain relief, restoration of knee function, and optimal graft incorporation. As shown in this case, precise diagnosis and effective management are key to improving the quality of life of patients. Furthermore, it illustrates that intralesional curettage and grafting are effective treatments for patellar osteoblastomas. Given the rarity of this condition, further research and comprehensive case studies are imperative to establish standardized guidelines for improved healthcare and patient outcomes. In summary, while the clinical characteristics of patellar osteoblastoma resemble those of osteoblastomas in general, its unique presentation warrants specific attention. Individualized consideration of adjuvant measures, graft selection, and preventive fixation is vital to ensure optimal outcomes in patellar osteoblastoma management.

Surgical management of a retropharyngeal pseudomeningocele: Case report.

INTRODUCTION: Retropharyngeal pseudomeningocele is a very rare form of pseudomeningocele, that is known to be associated with cervical trauma. Identifying such pathology can be challenging leading to delayed management. CASE PRESENTATION: We report a case of post-traumatic retropharyngeal pseudomeningocele that was managed surgically in a 21-year-old gentleman with poly-trauma injuries due to a motor vehicle accident. After 10 weeks since the traumatic event, magnetic resonance imaging (MRI) and computerised tomography (CT) scan showed evidence of bilateral atlanto-occipital dislocation and a fluid collection of 8 × 4 × 2 cm in the retropharyngeal space. The patient was found to have dysphagia and muffled voice with difficult visualisation of the vocal cords upon examination. After a multidisciplinary team decision, the patient underwent cerebrospinal fluid (CSF) leak management, pseudomeningocele resection and dural defect repair with shunting conducted by the Neurosurgery and Otolaryngology. Postoperative assessments and patient's symptoms, at 9 months follow-up, were satisfactory and reassuring. DISCUSSION: It's believed that conservative management with bed rest, elevation of bed head and acetazolamide is the initial step in management. As an alternative measure, shunting of the CSF had led to resolution of the collection. However, surgical removal of the collection and direct dural defect repair have been suggested in the literature but needed to be properly studied. CONCLUSION: Early recognition of this condition is important to avoid management delay. With a multidisciplinary approach, surgical management can be safe and an acceptable option for retropharyngeal pseudomeningocele.

Quantitative SPET 99Tcm-DMSA uptake by the kidneys: age-related decline in healthy males.

To evaluate if 99Tcm-dimercaptosuccinic acid (99Tcm-DMSA) uptake by the kidneys is related to age and creatinine clearance in males with normal renal function, quantitative single photon emission tomography (SPET) of DMSA uptake by the kidneys was performed in 18 volunteers aged 20-79 years. The quantitative uptake of DMSA in the right kidney was 13.9 +/- 2.9% and in the left kidney 14.2 +/- 3.0%. There was no statistically significant difference between left and right kidney uptake (t = 1.2, N.S.). Global kidney uptake (right + left) was 28.1 +/- 5.9%. There was a statistically significant age-related decline in global DMSA uptake. The estimated DMSA uptake (%) was given by -0.27 x age + 42 (r = -0.87, P < 0.001). A good correlation was found between creatinine clearance and global DMSA uptake (r = 0.87, y = 2.8x + 28.3, P < 0.001). The results suggest that normal values of DMSA uptake by the kidneys are age-dependent.

Reduced platelet aggregation after fluvastatin therapy is associated with altered platelet lipid composition and drug binding to the platelets.

AIMS: High plasma cholesterol concentration and increased platelet activity are two major risk factors for atherosclerosis. Lovastatin, the lipophilic drug was shown to inhibit platelet aggregation whereas pravastatin, the hydrophilic drug had no such effect. Analysis of the effect of fluvastatin which is both a lipophilic and hydrophilic drug, on platelet aggregation was the goal of the present study. METHODS: Fluvastatin 40 mg daily was administered to 25 patients with hypercholesterolaemia for up to 24 weeks. Normal subjects acted as controls. The influence of fluvastatin on plasma lipids and on platelet aggregation and fluidity was studied. The direct effect of fluvastatin on platelets was compared with that of other statins. RESULTS: Fluvastatin therapy (40 mg day (-1) for a period of 4 weeks) in hypercholesterolaemic patients resulted in a 23% and 29% reduction in plasma levels of total cholesterol and LDL-cholesterol respectively. Platelet cholesterol/phospholipids molar ratio was reduced by 26% and platelet aggregation was significantly (P<0.02) reduced by 10% after 4 weeks of fluvastatin treatment. On continuing fluvastatin therapy for additional 20 weeks, no further decrement in plasma LDL cholesterol levels or in platelet cholesterol/phospholipid ratio were noted. However, platelet aggregation was further significantly (P<0.01) reduced by up to 15%. Incubation of platelets with increasing concentrations of fluvastatin or lovastatin, demonstrated a dose-dependent reduction in platelet aggregation, whereas pravastatin showed no effect. This inhibitory effect of fluvastatin or lovastatin on platelet aggregation (up to 34% or 22% respectively at a concentration of 1 microg statin ml (-1) was found both in platelet rich plasma and in washed platelet suspensions. Fluvastatin and lovastatin (but not pravastatin), seem to share similar platelet binding sites, as non labelled fluvastatin or lovastatin were able to displace [3H]-labeled-fluvastatin from its binding sites on platelets. CONCLUSIONS: Fluvastatin therapy reduces platelet aggregation via a dual effect which involves its in vivo hypocholesterolaemic action on platelet cholesterol content, and also a direct effect of the drug binding to the platelets. The antiatherogenicity of fluvastatin may be related, in addition to its plasma cholesterol lowering ability, to its inhibitory effect on platelet activation.

Rhabdomyolysis complicating acute Epstein-Barr virus infection.

Infection with Epstein-Barr virus (EBV) is common and induces a broad spectrum of illness. In the majority of cases the disease manifests with typical signs of heterophile-positive infectious mononucleosis in which myalgia may be seen in up to 20% of cases. In this study, a case of rhabdomyolysis is reported occurring during the clinical course of an 18-year-old patient with infectious mononucleosis. This severe form of muscle involvement has been rarely associated with EBV infections. Five similar cases previously published in the English literature are also reviewed. The clinical implications of rhabdomyolysis and infectious mononucleosis are discussed.