•High-performance p-type mc-Si material is characterized by 13 research groups.•Highest (lowest) lifetime regions limited by interstitial iron (Cu precipitates).•Dislocations reduce cell efficiency ...by only 0.25% absolute.•Ingot metrology predicts PERC efficiency best using lifetime and dislocation density.•Cell efficiency limited to 22.5% if Fe and Cu density above 1010 cm−3 and 1013 cm−3.
Recent progress in the electronic quality of high-performance (HP) multicrystalline silicon material is reported with measurements and modeling performed at various institutions and research groups. It is shown that recent progress has been made in the fabrication at Trina Solar mainly by improving the high excess carrier lifetimes τ due to a considerable reduction of mid-gap states. However, the high lifetimes in the wafers are still reduced by interstitial iron by a factor of about 10 at maximum power point (mpp) conditions compared to mono-crystalline Cz wafers of equivalent resistivity. The low lifetime areas of the wafers seem to be limited by precipitates, most likely Cu. Through simulations, it appears that dislocations reduce cell efficiency by about 0.25% absolute. The best predictors for PERC cell efficiency from ingot metrology are a combination of mean lifetime and dislocation density because dislocations cannot be improved considerably by gettering during cell processing, while lifetime-limiting impurities are gettered well. In future, the material may limit cell efficiency above about 22.5% if the concentrations of Fe and Cu remain above 1010 and 1013 cm−3, respectively, and if dislocations are not reduced further.
The role of purinergic signaling in human ENS is not well understood. We sought to further characterize the neuropharmacology of purinergic receptors in human ENS and test the hypothesis that ...endogenous purines are critical regulators of neurotransmission.
LSCM-Fluo-4/(Ca2+)-imaging of postsynaptic Ca2+ transients (PSCaTs) was used as a reporter of synaptic transmission evoked by fiber tract electrical stimulation in human SMP surgical preparations. Pharmacological analysis of purinergic signaling was done in 1,556 neurons (identified by HuC/D-immunoreactivity) in 235 ganglia from 107 patients; P2XR-immunoreactivity was evaluated in 19 patients. Real-time MSORT (Di-8-ANEPPS) imaging tested effects of adenosine on fast excitatory synaptic potentials (fEPSPs).
Synaptic transmission is sensitive to pharmacological manipulations that alter accumulation of extracellular purines: Apyrase blocks PSCaTs in a majority of neurons. An ecto-NTPDase-inhibitor 6-N,N-diethyl-D-β,γ-dibromomethyleneATP or adenosine deaminase augments PSCaTs. Blockade of reuptake/deamination of eADO inhibits PSCaTs. Adenosine inhibits fEPSPs and PSCaTs (IC50 = 25 µM), sensitive to MRS1220-antagonism (A3AR). A P2Y agonist ADPβS inhibits PSCaTs (IC50 = 111 nM) in neurons without stimulatory ADPbS responses (EC50 = 960 nM). ATP or a P2X1,2,2/3 (α,β-MeATP) agonist evokes fast, slow, biphasic Ca2+ transients or Ca2+ oscillations (ATP,EC50 = 400 mM). PSCaTs are sensitive to P2X1 antagonist NF279. Low (20 nM) or high (5 µM) concentrations of P2X antagonist TNP-ATP block PSCaTs in different neurons; proportions of neurons with P2XR-immunoreactivity follow the order P2X2 > P2X1 >> P2X3; P2X1 + P2X2 and P2X3 + P2X2 are co-localized. RT-PCR identified mRNA-transcripts for P2X1–7, P2Y1,2,12–14R.
Purines are critical regulators of neurotransmission in human ENS. Purinergic signaling involves P2X1, P2X2, P2X3 channels, P2X1 + P2X2 co-localization and inhibitory P2Y or A3 receptors. These are potential novel therapeutic targets for neurogastroenterology.
•Purinergic receptors are potential therapeutic targets for IBD and IBS.•Optical recording techniques made it possible to study human ENS neuropharmacology.•A comprehensive analysis was done in 1,556 submucous neurons from 107 human surgical specimens.•Novel neuronal targets identified are P2X1, P2X1 and P2X2 co-localization, P2X3, P2X2/3, P2Y and A3.•Purines are critical regulators of neurotransmission at several synapses in human enteric nervous system.
Essential fatty acid (EFA) deficiency has been shown to protect against the glomerulonephritis in a murine model of systemic lupus erythematosus. Since macrophages are an important cellular ...constituent of the inflammatory lesion, the effects of EFA deficiency on the eicosanoid metabolism and function of these cells were determined. EFA-deficient macrophages exhibited a depletion of phospholipid arachidonate and an accumulation of 20:3(n-9); phosphatidylinositol was the phospholipid most affected. When these macrophages were stimulated with unopsonized zymosan, they produced markedly less leukotriene C4 and B4 than control macrophages. EFA-deficient macrophages also synthesized leukotriene C3 from endogenous 20:3(n-9). No leukotriene B3 was detected. In contrast to the effects on leukotriene production, prostaglandin and thromboxane production were only minimally affected by EFA deficiency. When challenged with zymosan, EFA-deficient macrophages released less arachidonate relative to control macrophages and released half again as much 20:3(n-9) as arachidonate. Release of arachidonate from phosphatidylcholine in the EFA-deficient cells was highly selective for arachidonate; however, release of arachidonate from phosphatidylinositol was depressed relative to control and was not selective. Incubation of macrophages with exogenous arachidonate and 20:3(n-9) established that 20:3(n-9) decreased leukotriene C4 and B4 synthesis from arachidonate but did not affect prostaglandin production. To determine the functional effects of the deficiency state, receptor-mediated pinocytosis and phagocytosis were also examined in EFA-deficient cells. EFA-deficient macrophages exhibited a marked reduction in receptor-mediated pinocytosis. Phagocytosis, however, was unaffected by the deficiency state. These effects on macrophage eicosanoid metabolism and function may comprise a significant component of the anti-inflammatory effect of EFA deficiency.
The range of motion of 10 fresh cadaveric ankle specimens was measured for flexion, anterior-posterior drawer, inversion-eversion, and internal-external rotation under conditions that simulated ...normal weight-bearing. At a 70 kg load, range of motion significantly diminished in all directions (p < 0.005). Plantar flexion was diminished to a greater degree than dorsiflexion. For anterior-posterior drawer in the loaded state, ankle flexion did not play a significant role in determining stability. Factors such as ligamentous attachments may be more critical than mortise geometry in determining anterior-posterior translation. For torsion and version, stability was greatest in dorsiflexion. That ankle stability is related to articular congruity with increased load-bearing emphasizes the importance of anatomical restoration of the ankle mortise in the injury state.
Evolution of the laparoscopic gastric bypass McGrath, Virginia; Needleman, Bradley J; Melvin, W Scott
Journal of laparoendoscopic & advanced surgical techniques. Part A,
08/2003, Volume:
13, Issue:
4
Journal Article
Peer reviewed
Obesity is recognized as a health problem of epidemic proportions. Surgical intervention for the treatment of obesity is a well-studied and effective method. Various procedures have been utilized ...over the past decades. Roux-en-Y gastric bypass has emerged over the last 20 years and is currently the most commonly offered surgical treatment. Within the last decade, advances in laparoscopic technology and surgical experience have allowed the application of laparoscopic techniques to the surgical treatment of obesity. Many centers and individuals have developed excellent techniques through experience over time as well as improvements in instrumentation. Hand-assisted laparoscopy was reported as a technique, but has mostly fallen out of favor. Currently, laparoscopic application of adjustable gastric band and laparoscopic Roux-en-Y gastric bypass are widely used throughout the United States. Data have been generated to demonstrate the improvement in surgical outcomes associated with minimally invasive surgical techniques for the surgical treatment of obesity. Further advances will allow continued improvement in patient outcomes utilizing a variety of minimally invasive surgical approaches to the treatment of this difficult disease.
The purpose of this study was to determine the effect of syndesmotic screw fixation on ankle motion. Eight unpaired osteoligamentous cadaver ankles were tested. The study quantified ankle flexion, ...talar tilt, ankle drawer, and tibiotalar rotation for each specimen using an MTS biomechanical testing system. Each specimen was tested under a 15-kg and a 70-kg axial load. The testing was repeated after the placement of a syndesmotic screw, a 4.5-mm cortical screw, in accordance with AO technique. There was a statistically significant decrease (P less than .05) in tibiotalar external rotation. There was no statistical difference in ankle flexion. There was a significant decrease in the anterior and the posterior drawer tests with the foot in plantar flexion. These were the most significant results. Syndesmotic screw fixation is used for the internal fixation of certain unstable ankle fractures. Opinions differ as to whether the screw should be removed at 6 weeks (prior to weightbearing) or left in place indefinitely. It was concluded that the syndesmotic screw should be removed prior to the return to full activity. Leaving it in place will contribute to abnormal ankle motion; this may result in local discomfort and a possible fatigue fracture of the screw.
The aim of this study was to demonstrate the clinical utility of reconstructed 3-D intravascular ultrasound (IVUS) using a volume-based rendering technique. 3-D reconstruction of IVUS was performed ...in 15 patients with various vascular abnormalities. A stepping-motor was used to pull either a 12.5 or a 20 MHz US catheter through the lumen of a variety of vessels at a rate of 1.5 mm/sec. Images were downloaded to a LIFE Imaging system for 3-D reconstruction. A variety of abnormalities were demonstrated in 3-D IVUS, including arterial atheroma and plaque, aneurysm and pseudoaneurysm, aortic dissection and stenosis. Compared to 2-D IVUS, the vascular branches, accessory vessels, and their relationships were easily demonstrated on 3-D imaging by selecting an appropriate angle, plane and section of the 3-D volume. The dimensions and shapes of the vascular lumen were easily determined in the longitudinal view. 3-D IVUS proved useful for determining the distribution and type of plaque in vessels. Reconstructed 3-D IVUS allowed for global evaluation of the dissection entry site, extent of the flap, and the false lumen of a pseudoaneurysm. Intravascular 3-D US provides information complementary to that obtained with 2-D imaging. It provides information about spatial relationships of anatomic structures that cannot be evaluated using conventional imaging methods.
Human and animal laboratory studies have shown that stress delays healing of standardized punch biopsy wounds.
This 5-week prospective study of 17 women who underwent elective gastric bypass surgery ...addressed the association between postsurgical pain intensity and subsequent healing of a standard 2.0-mm punch biopsy wound.
Participants were assessed 1 week before surgery, within 3 hr before surgery, 1 to 3 days postsurgery, and at weekly intervals for 4 weeks following surgery.
Patient ratings of greater acute postsurgical pain, averaged over Days 1 and 2 postsurgery, and greater persistent postsurgical pain, averaged over 4 weekly postsurgery pain ratings, were significantly associated with subsequent delayed healing of the punch biopsy wound. Presence of depressive symptoms on the day of surgery, pre-existing persistent pain, and medical complications following initial discharge from the hospital were not related to wound healing. Depressive symptoms on the day of surgery and pre-existing persistent pain did predict persistent postsurgical pain intensity.
These findings extend the previous laboratory models of wound healing to a surgical population, providing the first evidence that pain plays an important role in postsurgery wound healing, a key variable in postsurgical recovery.
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