Avoidance of stomas and delayed anastomosis for bowel necrosis: the ''clip and drop-back'' technique

Necrotizing enterocolitis (NEC) and midgut volvulus (MGV) often are associated with extensive bowel necrosis. These cases may require extensive enterectomy and the formation of high or multiple stomas, and frequently are complicated by short bowel syndrome, excessive fluid losses, fistulas, stenosis, and skin breakdown. This report describes a "clip and drop-back" technique, followed by delayed anastomosis performed 48 to 72 hours later. The technique was successful in five severely ill infants (3 NEC, 2 MGV) with extensive necrosis, bowel perforation(s), and peritonitis, who required either a high stoma near the ligament of Treitz or multiple resections and enterostomies. This method removes obvious necrotic perforated bowel, controls contamination, avoids stomas (and their inherent complications in this age group), and preserves bowel length. All five babies survived. The technique is a useful addition to the pediatric surgeon's operative armamentarium in selective cases.     

Functional correction of renal defects in a mouse model for ARPKD through expression of the cloned wild-type Tg737 cDNA

Autosomal recessive polycystic kidney disease (ARPKD) is characterized by the formation of large collecting tubule and ductular cysts that often result in renal insufficiency within the first decade of life. Understanding the process leading to cyst formation will require the identification and characterization of genes involved in the etiology of this disease. In this regard, we previously described the generation of a mouse model (TgN737Rpw) for ARPKD and the cloning of a candidate gene. Here we show direct involvement of the Tg737 gene in collecting duct cyst formation by expressing the wild-type Tg737 cDNA as a transgene in TgN737Rpw mutants. In contrast to TgN737Rpw mutants, the "rescued" animals survive longer, have normal renal function and normal localization of the EGFr to the basolateral surfaces of collecting duct epithelium.     

Nonsystematic Search and No-Good Learning

Nonsystematic search algorithms seem, in general, to be well suited to large-scale problems with many solutions. However, they tend to perform badly for problems with few solutions, and they cannot be used for insoluble problems, since they are incomplete.Here we present a new algorithm, learn-SAT, that, although based on nonsystematic search, is complete. Completeness is realized through a process of no-good learning, learning-by-merging. This requires exponential space in the worst case. We show, nevertheless, that learn-SAT performs very well on certain SAT problems that are tightly constrained or insoluble. Indeed, its performance generally approximates the best SAT algorithms and does much better at lower clause densities. Learn-SAT also maintains much of the efficient performance of nonsystematic search for large-scale problems with many solutions, at least relative to backtrack search algorithms.These results indicate that the burden on memory, imposed by no-good learning, is not generally a problem for learn-SAT. This is perhaps surprising in view of previous work. What is even more surprising is the scalability of learn-SAT. For some types of problem it scales very much better than the nearest competitive algorithm. There are other types, however, for which this is not the case.The performance profile of learn-SAT emerges from an experimental methodology related to the one outlined by Mammen and Hogg in 1997.     

Models of human reaction to vehicle environments

Models for predicting human comfort responses to environmental variables are presented for diverse vehicles. Air mode studies reveal that comfort is a function of vertical and transverse accelerations, noise levels and seat factors, as well as manoeuvre conditions. Comfort models for ground-based vehicles involve roll rates and noise levels.     

Application of ion-etching of grooves into quartz for surface acoustic wave devices

The application of r.f.-sputter etching techniques to the fabrication of grooves in the surface of quartz is reported. This process has been used for the construction of devices which employ the interaction of surface acoustic waves with arrays of well-defined parallel grooves. Devices have been produced with grooves up to 2.5 m deep, which have substantially rectangular profiles and controllable mark-to-space ratios. The groove geometries have been characterized using Talysurf, optical microscopy, SEM and TEM techniques.     

Frequency multiplexed superconducting quantum interference device readout of large bolometer arrays for cosmic microwave background measurements

A technological milestone for experiments employing transition edge sensor bolometers operating at sub-Kelvin temperature is the deployment of detector arrays with 100s-1000s of bolometers. One key technology for such arrays is readout multiplexing: the ability to read out many sensors simultaneously on the same set of wires. This paper describes a frequency-domain multiplexed readout system which has been developed for and deployed on the APEX-SZ and South Pole Telescope millimeter wavelength receivers. In this system, the detector array is divided into modules of seven detectors, and each bolometer within the module is biased with a unique ～MHz sinusoidal carrier such that the individual bolometer signals are well separated in frequency space. The currents from all bolometers in a module are summed together and pre-amplified with superconducting quantum interference devices operating at 4 K. Room temperature electronics demodulate the carriers to recover the bolometer signals, which are digitized separately and stored to disk. This readout system contributes little noise relative to the detectors themselves, is remarkably insensitive to unwanted microphonic excitations, and provides a technology pathway to multiplexing larger numbers of sensors.     

Characterization of the thermodynamic cycle of a MEMS-based external combustion resonant engine

The thermodynamic cycle of a resonant, MEMS-based, micro heat engine is characterized. The micro heat engine is an external combustion engine made of a cavity encapsulated between two membranes. The cavity is filled with saturated liquid–vapor mixture working fluid. Heat is added to and rejected from the engine at a frequency corresponding to the resonant frequency of the engine. Both pressure–volume and temperature-entropy diagrams are used to investigate the thermodynamic cycle of the resonant micro heat engine. The results show that the working cycle is nearly rectangular in shape and consists of two constant temperature processes and two constant volume processes. We hypothesize that major sources of irreversibility in the engine are heat transfer over finite temperature differences during heat addition and rejection, heat transfer into and out of engine thermal mass, viscous losses due to liquid working fluid motion, and heat escape from the engine to the surroundings. The maximum pressure and volume changes measured inside the engine cavity are 45?Pa and 0.55?mm³, respectively. The results show that for a heat addition of 1?mJ, the engine operates over a very small temperature difference. The small operating temperature difference is mostly attributable to the large thermal storage of the engine structure, the membranes and the wicks. The measured second law efficiency of the micro heat engine is 16?%.     

The influences of thermal stratification and flow interaction on the enhanced natural convective heat transfer at low temperatures

This paper applies the modified heat transfer correlation: Nu/Nu_iso = f(S) to horizontal cylinders immersed in the thermally stratified vapour over boiling liquid nitrogen. Correlation of the heat transfer data confirms that the thermal stratification parameter, S is the appropriate parameter to account for the observed heat transfer enhancement.When the data are compared with the theory for natural convection in an extensive environment with a linear thermal stratification, it is found that heat transfer in the cryogenic vapour columns is significantly enhanced. This enhancement appears to arise from a secondary flow circulation inducecd by the interaction of the flow field around the heated cylinder with the primary flow of the cold vapour column. The influence of this flow interaction upon the heat transfer has been studied by varying the cylinder and vapour column diameters. The data have been analysed and correlated with the empirical relation:

$\text{Nu}\text{Nu}{}_{\mathrm{iso}}\text{=0.80}{}^{0.5}\text{(}\text{D}\text{W}\text{)}{}^{-0.4}$

All the results on enhanced convective heat transfer obtained at Southampton are reported and the conditions under which heat transfer enhancement takes place are discussed.     

A 3D moving grid algorithm for process simulation

A moving grid algorithm is presented for simulation of 3D oxidation processes. The algorithm combines local displacement of mesh points according to material velocity and local mesh cleanup. Several examples are shown that demonstrate the capabolity to simulate both the growth of thin layers of oxide during polysilicon gate reoxidation, as well at stress dependent growth of 3D locos oxides.