Experimental study on the thermo-mechanical effects of underfill and low-CTE substrate in a flip-chip device

Moiré interferometry was used to analyze the thermal deformation of four flip-chip devices mounted on FR-4 substrate and a new multi-layer substrate, with and without underfill. Thermal loading was applied by cooling the devices from 100 °C to room temperature (25 °C). The effects of underfill and the low-CTE (coefficient of thermal expansion) substrate on thermal deformation were investigated. The experimental results showed that the underfill curved in a manner similar to the silicon chip. For the flip-chip devices mounted on the multi-layer substrate, the CTE mismatch between the silicon chip and substrate was reduced, and bending deformation decreased. Of the four flip-chip devices studied, the underfilled flip-chip device mounted on the multi-layer substrate had the least deformed solder balls.     

Anatomic variability of rejection in intestinal allografts after pediatric intestinal transplantation

The internal mammary artery is routinely used for coronary artery bypass grafting because of its optimal long-term patency profile. This vessel can be imaged by angiography, but only the proximal tract at the origin from the succlavian artery can be imaged by conventional echography. The aim of our study was to visualize the intrathoracic course of the native and grafted internal mammary arteries by a new ultrasound equipment which allows high-resolution transthoracic color Doppler imaging of the chest wall vessels and coronary arteries. We studied 35 patients, 16 non operated and 19 operated of coronary surgery with the internal mammary artery grafted to the left anterior descending coronary artery. We used a multifrequency 3.5-7 MHz transducer with a small insonating surface, placed at the second-fifth intercostal space at the left and right sternal border, to image the native mammary arteries. The grafted mammary artery was detected at the fourth-fifth left intercostal space 2-4 cm lateral to the sternal border. The native left internal mammary artery was visualized in all 16 non operated patients, and the right internal mammary artery in 14/16 (87%). The native left internal mammary artery peak flow velocity was 41-160 cm/s (mean 81 +/- 34 cm/s), and the mean flow velocity was 28-89 cm/s (mean 45 +/- 17 cm/s). The right internal mammary artery peak flow velocity was 35-153 cm/s (mean 82 +/- 36 cm/s), and mean flow velocity was 21-82 cm/s (mean 46 +/- 22 cm/s). The grafted left internal mammary artery was visualized in 16/19 patients (84%), evaluated at 6 days to 36 months after surgery. Peak diastolic flow velocity ranged from 24 to 80 cm/s (mean 48 +/- 17 cm/s), and mean diastolic flow velocity ranged from 13 to 57 cm/s (mean 33 +/- 11 cm/s). The left anterior descending peak flow velocity distal to the anastomosis was 22-62 cm/s (mean 37 +/- 15 cm/s) and mean flow velocity was 18-53 cm/s (mean 29 +/- 12 cm/s). We conclude that transthoracic color Doppler echocardiography allows to image the native and grafted mammary arteries, with potential clinical applications in the management of patients with coronary artery disease.     

Detection of Helicobacter pylori gene by means of immunomagnetic separation-based polymerase chain reaction in feces

BACKGROUND: Detection of Helicobacter pylori is usually performed by culture, polymerase chain reaction (PCR), histology, or urease test on gastric biopsy samples. Although methods based on feces are non-invasive, their sensitivity has been relatively low. In this study, to improve its sensitivity, immunomagnetic separation (IMS) was used as a pre-PCR step for direct detection of H. pylori in feces. METHODS: Fresh fecal samples were taken from 72 patients attending for endoscopy. Of these, 57 patients had a positive H. pylori status according to the results of culture, histology, and PCR on gastric biopsy samples. Anti-H. pylori antibody-sensitized immunomagnetic beads were used to concentrate the bacteria. PCR was then performed to detect the H. pylori urease A-encoding gene. RESULTS: Of the 57 H. pylori-positive patients, 35 (61.4%) had positive fecal samples by IMS-based PCR method. None of the 15 H. pylori-negative patients had positive fecal samples. The sensitivity of this method was 61.4%, and the specificity 100.0%. CONCLUSIONS: This study confirms that non-invasive diagnosis of H. pylori infection could be made from feces by using IMS-based PCR.     

Effect of Several Electrolyzed Waters on the Skin Permeation of Lidocaine,Benzoic Acid,and Isosorbide Mononitrate

The effects of several electrolyzed waters were evaluated on the permeation of model base, acid and non-ionized compounds, lidocaine (LC), benzoic acid (BA), and isosorbide mononitrate (ISMN), respectively, through excised hairless rat skin. Strong alkaline-electrolyzed reducing water (ERW) enhanced and suppressed the skin permeation of LC and BA, respectively, and it also increased the skin permeation of ISMN, a non-ionized compound. On the contrary, strong acidic electrolyzed oxidizing water (EOW) enhanced BA permeation, whereas suppressing LC permeation. Only a marginal effect was observed on the skin permeation of ISMN by EOW. These marked enhancing effects of ERW on the skin permeation of LC and ISMN were explained by pH partition hypothesis as well as a decrease in skin impedance. The present results strongly support that electrolyzed waters, ERW and EOW, can be used as a new vehicle in topical pharmaceuticals or cosmetics to modify the skin permeation of drugs without severe skin damage.     

Intestinal transplantation in children under FK 506 immunosuppression

Intestinal transplantation, solitary (n = 3) or in combination with the liver (n = 7), was performed in 10 pediatric patients with intestinal failure. The liver was only replaced if there was liver failure and portal hypertension. Immunosuppression was based on FK 506. Two patients died, one of graft-versus-host disease and one of lymphoproliferative disease. One patient as still in the intensive care unit 1 month posttransplantation due to perioperative complications. The function of the intestinal grafts in the remaining patients is normal. All nutrition and medications including immunosuppression are being administered enterally. This series indicates that small bowel transplantation, alone or in combination with the liver, is feasible in pediatric patients.     

Binding and catalytic properties of Xenopus (6-4) photolyase

Xenopus (6-4) photolyase binds with high affinity to DNA bearing a (6-4) photoproduct and repairs it in a light-dependent reaction. To clarify its repair mechanism of (6-4) photolyase, we determined its binding and catalytic properties using synthetic DNA substrate which carries a photoproduct at a single location. The (6-4) photolyase binds to T[6-4]T in double-stranded DNA with high affinity (KD = 10(-9)) and to T[6-4]T in single-stranded DNA and T[Dewar]T in double- and single-stranded DNA although with slightly lower affinity (KD = approximately 2 x 10(-8)). Majority of the T[6-4]T-(6-4) photolyase complex dissociates very slowly (koff = 2.9 x 10(-5) s-1). Its absolute action spectrum without a second chromophore in the 350-600 nm region closely matches the absorption spectrum of the enzyme. The quantum yield (phi) of repair is approximately 0.11. The fully reduced form (E-FADH-) of (6-4) photolyase is catalytically active. Direct analysis of the photoreactivated product showed that (6-4) photolyase restores the original pyrimidines. These findings demonstrate that cis, syn-cyclobutane pyrimidine dimer photolyase and (6-4) photolyase are quite similar, but they are different with regard to the binding properties.