The Influence of Nano CaCO3 on Nucleation and Interface of PP Nano Composite: Matrix Processability and Impact Resistance.

Polypropylene (PP) is a commodity material that has been increasingly used in different industries in the past two decades due to its versatile properties when enhanced with additives. Homo polypropylene, in general, has weak mechanical properties and limited chemical resistance; thus, using a different type of fillers to adjust such properties to fit the required applications opened a large market for this commodity. Understanding the interface constituent between the polymer matrix and the added filler and the nucleation behavior is a key to fine control of the enhancement of PP properties. In this study, PP was incorporated with nano calcium carbonate (CaCO3) at 2 and 5 wt% in the presence of maleic anhydride (MAH) to overcome the weak interface due to low polymer polarity. The mix was compounded in a twin screws extruder at a temperature range of 180-200 °C ; then, the prepared samples were left to dry for 24 h at 25 °C. Nuclear Magnetic Resonance (NMR) was used to study the interface adhesion of the nanofiller and the curved revealed that at 2% of nano CaCO3 PP structure remained the same and the nano experienced good adhesion to the polymer matrix. The mechanical impact resistance results showed a real enhancement to the polymer matrix of the nanocomposite by 37%. Moreover, DSC results showed a faster crystallinity rate due to the nanofiller acting as a nucleating agent and rheology tests indicated that low content of nano additive (2%) has better processability behavior, with suitable viscosity complex values at high frequencies.

Change in the Apparent Order at Different Temperatures and Catalyst Volumes: Hydrodesulfurization of KEC-AR.

This paper tackles the effect of reaction temperature on the apparent order of the hydrodesulfurization (HDS) reactions of an atmospheric residue (KEC-AR) derived from Kuwait Export Crude (KEC). Testing was carried out using a pilot plant consisting of five identical fixed-bed reactors arranged in series. A moderate-HDS-activity catalyst was used under a 120 bar (total) operating pressure, a feed flow rate of 120 mL per hour (mL/h), and a hydrogen-to-feed ratio of 1000 mL/mL. The liquid hourly space velocity (LHSV) varied by 4.0, 2.0, 1.0, 0.5, and 0.25 relative to the catalyst accumulative volumes in the five reactors. Testing was conducted between 360 and 420 °C with a temperature increase of 10 °C each time. Product samples were collected between the reactors using customized inter-reactor sampling systems that operate under the pilot plant's total pressure. The results showed that the HDS apparent order decreases with an increase in reaction temperature. The order dropped from 4.9 at 360 °C to 1.62 at 420 °C. Using the least-squares method (LSM), we demonstrated that the apparent overall orders are aggregates of several first-order reactions occurring consecutively at different rates and dependent on sulfur total disappearance. On the other hand, we showed that the apparent overall orders are aggregates of several reactions of different orders occurring simultaneously and independently of sulfur total disappearance. The first-order reactions' activation energy was found to be 22.1 kcal/mol and in total agreement with that reported in the literature for the sulfur removal from KEC-AR.

Termination of Electrical Storm After Double Valve Replacement Using Sympathectomy.

Electrical storm is a fatal condition unless aborted. Various treatments are available, each with its own limitations. Here, we present a case in which all forms of therapy failed except sympathectomy, which terminated the storm successfully.

Ischemic mitral regurgitation in a patient with dextrocardia and situs inversus totalis.

Dextrocardia with situs inversus is a rare condition. Few previously published cases have addressed the observation of isolated coronary artery disease or isolated mitral valve disease in these patients. However, the occurrence of ischemic mitral regurgitation in such cases has never been previously reported. Here, we report such a case with emphasis on both surgical and echocardiographic features.

Right Atrial Mass Mimicking a Myxoma as a First Presentation of Antiphospholipid Syndrome.

Antiphospholipid syndrome is characterized by recurrent spontaneous abortion, recurrent arterial/venous thrombosis, and thrombocytopenia. The presentation of an atrial mass mimicking a myxoma in this syndrome is exceedingly rare, leading to misdiagnosing of the condition and further risking recurrence due to lack of anticoagulation. In this report, we present such a case that was mistakenly thought to be a myxoma.

Successful thrombolysis of a thrombosed prosthetic mitral valve using a synthetic tissue plasminogen activator: a case report.

INTRODUCTION: Prosthetic valve thrombosis is a rare but life-threatening condition that requires careful evaluation and prompt treatment. While surgical intervention remains the gold standard, thrombolytic therapy is now emerging as a potential substitute. Various thrombolytic treatments including streptokinase, urokinase and recombinant tissue plasminogen activators have been reported with variable success rates. However, the data on the use of tenecteplase (a synthetic tissue plasminogen activator) is limited. CASE PRESENTATION: A 44-year-old Middle Eastern man with a previously implanted prosthetic mitral valve presented with exertional dyspnea and orthopnea. Investigations revealed a thrombosed prosthetic mitral valve. Successful thrombolysis was achieved using tenecteplase which lead to the complete restoration of valve function with no risk to the patient. CONCLUSION: Prosthetic valve thrombosis is a rare but life threatening condition, the diagnosis of which requires a high index of suspicion. Tenecteplase can be used successfully in the management of such cases. It has proved to be useful with no extra risk to the patient.

Excision of a left atrial myxoma in the presence of a calcified ascending aorta: a surgical challenge.

Atrial myxomas are rare tumors that require surgical excision. However, in the presence of a severely calcified ascending aorta, such excision becomes rather challenging and difficult. Here we report a case of a left atrial myxoma in a 64-year-old woman with an extensively calcified aorta that was successfully excised using cardiopulmonary bypass beating-heart technique without the need for cardioplegic cardiac arrest and aortic cross-clamping. The use of this technique proved useful with no increased risk incurred to the patient.

Coronary artery bypass grafting in a patient with polycythaemia rubra vera - a rare indication with a spectrum of complication: a case report.

Coronary artery bypass surgery for coronary artery thrombosis in patients with polycythaemia rubra vera has been rarely described. The main issue with such patients is their risk of both bleeding and thrombosis and as such the ideal postoperative management of such cases is unknown. Hereby, we describe a case of a 62-year-old man with polycythaemia rubra vera who underwent coronary artery bypass surgery. Although his initial postoperative course was complicated, his long-term outcome was good.

Blood component transfusion in primary coronary artery bypass surgery in Kuwait.

OBJECTIVE: The aims of this study were to determine the rate of blood product transfusion, associated perioperative factors and cost of such blood product transfusion in primary coronary artery bypass surgery (CABG). SUBJECTS AND METHODS: The medical records of 159 consecutive primary CABG patients (142 male, 17 female) from January 1, 2003 to June 30, 2003 at Chest Diseases Hospital, Kuwait, were reviewed. Urgent and emergency cases were included. RESULTS: The mean age of the patients was 57.2 (range 36-77 years). Overall, 128 (80.5%) patients received blood product transfusion during primary CABG: 113 (70.5%) packed red blood cells (RBC), 54 (33.9%) fresh frozen plasma, and 13 (8%) platelets. Overall, 23 patients (12.6%) received more than two RBC transfusions intraoperatively. Significant factors for intraoperative RBC transfusion were: age >60 years, female gender, preoperative hemoglobin <12 g/dl, and 3 or more coronary bypass grafts constructed. One hundred and fifty-nine patients consumed 342 units of RBC at an average of 2.1 RBC units per patient. The cost per patient was 80 Kuwaiti dinar (KD; USD 240). CONCLUSION: The findings indicate a high rate of blood component transfusion in primary CABG patients in Kuwait that could expose the patients to the possible adverse effects, and such transfusions have high economic impact.