Probing the reaction mechanism between a laser welded polyamide thin film and titanium with XPS and ToF-SIMS.

The biomedical industry uses more and more polymer/metal hybrid assemblies because of the ability to combine the advantages and lower the inconveniences of both materials. The key is to assemble them. Among the high variety of existing assembling techniques, laser welding appears as an excellent option. It is a quick process allowing a great design flexibility, high reproducibility without intermediate material needed to create the adhesion, which is advantageous for biomedical applications. The laser welding process creates strong adhesion between dissimilar materials, but the root cause for adhesion is still unclear. The analytical challenge is to gain an information at the molecular level from an interface that is deeply buried between the two materials. Such a study requires extremely surface sensitive analytical methods, such as ToF-SIMS or XPS in order to detect chemical bonds, but also a method to expose the interface to the X-ray or ion beam. In order to investigate the chemical bonding at the interface between polyamide-6.6 and titanium, mirror polished titanium surfaces were prepared, on which a thin polyamide-6.6 film was spin-coated. The samples were laser welded, and after dissolving the polymer thin film, XPS and ToF-SIMS measurement were performed. The ToF-SIMS data interpretation was assisted by a principal component analysis. This multivariate analysis is rather common for ToF-SIMS data but is more rarely used to solve adhesion problems. This allowed to show the nature of the chemical bond at the interface and to propose a reaction mechanism.

Prevalence and risk factors of albuminuria in Type 2 diabetes in Bahrain.

Microalbuminuria is the earliest sign of diabetic nephropathy, and is a marker of increased diabetic cardiovascular morbidity and mortality. We investigated the prevalence of albuminuria and associated risk factors among Type 2 diabetes (T2DM) patients, who were attending diabetes clinics at primary healthcare facilities in Bahrain. This was a cross-sectional study on 712 adult T2DM Bahraini patients screened for albuminuria using albumin:creatinine ratio test (ACR), in 9 selected primary healthcare centers in Bahrain in the period February-March 2006. Of the 702 participants, 196 (27.9%) were albuminuric. The prevalence of microalbuminuria (ACR>3.4 mg albumin/mmol creatinine) and macroalbuminuria (protein:creatinine ratio >22 mg protein/ mmol creatinine) were 22.0% (no.=155) and 5.8% (no.=41), respectively. Univariate analysis demonstrated significant associations between albuminuria and older age (>65 yr), longer duration of diabetes, high glycated hemoglobin (HbA1c), elevated triglycerides, total- and LDL-cholesterol, systolic (>160 mmHg) and diastolic (>90 mmHg) blood pressure (BP), and retinopathy. Multivariate regression analysis showed that high HbA1c, higher systolic BP, and long duration of diabetes, were significant predictors of albuminuria, while older age, male gender, and higher triglycerides were borderline predictors. Albuminuria in Bahraini T2DM patients was related to poor glycemic control, higher systolic BP, and longer duration of diabetes. Effective preventive and control strategies of those factors should be urgently implemented.

Fibrous pseudotumor of the epididymis and tunica vaginalis.

We present a case of fibrous pseudotumor of the epididymis and tunica vaginalis which is one of the rarest paratesticular tumors. Fibrous pseudotumor presents as a solid scrotal mass with normal serum markers. Pathological examination is the only reliable way to make the diagnosis with these tumors exhibiting characteristic macroscopic and microscopic features. It is important to recognize this entity since local excision is the treatment of choice and orchiectomy is unnecessary.