Ultrafast oleophobic-hydrophilic switching surfaces for antifogging, self-cleaning, and oil-water separation.

Smooth copolymer-fluorosurfactant complex film surfaces are found to exhibit fast oleophobic-hydrophilic switching behavior. Equilibration of the high oil contact angle (hexadecane = 80°) and low water contact angle (<10°) values occurs within 10 s of droplet impact. These optically transparent surfaces display excellent antifogging and self-cleaning properties. The magnitude of oleophobic-hydrophilic switching can be further enhanced by the incorporation of surface roughness to an extent that it reaches a sufficiently high level (water contact angle <10° and hexadecane contact angle >110°), which, when combined with the inherent ultrafast switching speed, yields oil-water mixture separation efficiencies exceeding 98%.

Combining plasmachemical emulsion-templating with ATRP to create macroporous lipophilic surfaces.

Well-defined alkyl chain side group polymer brushes have been tethered onto high surface area macroporous pulsed plasmachemical emulsion-templated poly(vinylbenzyl chloride) initiator layers (typically 600-700 m2 g(-1)) using atom transfer radical polymerisation (ATRP). Immobilisation of phospholipids onto these bioactive surfaces is found to occur through interdigitation, and the efficacy of lipid binding is governed by the alkyl side group chain length of the polymer brushes.

Evaporation of picoliter droplets on surfaces with a range of wettabilities and thermal conductivities.

The evaporation of picoliter water and ethanol droplets generated by drop-on-demand inkjet printing was investigated on substrates with apparent contact angles between 10^{∘} and 135^{∘} and thermal conductivities between 0.25 and 149 Wm^{-1}K^{-1}. Drying times were calculated from a diffusion-limited model for droplets with both pinned and moving contact lines as a function of droplet diameter and apparent contact angle. Droplets with a moving contact line take longer to dry on hydrophilic substrates than pinned droplets. The difference in drying times between evaporative modes vanishes at large apparent contact angles. Hence similar drying times are obtained for both modes on hydrophobic substrates. The predicted drying times for glass and silicon substrates were in good quantitative agreement with experimental data, suggesting that thermal effects are negligible for substrates of these base materials. However, on a PTFE substrate which has a lower thermal conductivity more relevant to inkjet printing, evaporative cooling reduces the evaporation rate causing drying times to be underpredicted by isothermal models.

Superhydrophobic hierarchical honeycomb surfaces.

Two-dimensional hexagonally ordered honeycomb surfaces have been created by solvent casting polybutadiene films under controlled humidity. Subsequent CF(4) plasmachemical fluorination introduces cross-linking and surface texturing, leading to hierarchical surfaces with roughness on both the 10 µm (honeycomb) and micrometer (texturing) length scales. For microliter droplets, these display high water contact angle values (>170°) in combination with low contact angle hysteresis (i.e., superhydrophobicity) while displaying bouncing of picoliter water droplets. In the case of picoliter droplets, it is found that surfaces which exhibit similar static contact angles can give rise to different droplet impact dynamics, governed by the underlying surface topography. These studies are of relevance to technological processes such as rapid cooling, delayed freezing, crop spraying, and inkjet printing.

Impact of picoliter droplets on superhydrophobic surfaces with ultralow spreading ratios.

The impact of picoliter-sized water droplets on superhydrophobic CF(4) plasma fluorinated polybutadiene surfaces is investigated with high-speed imaging. Variation of the surface topography by plasmachemical modification enables the dynamics of wetting to be precisely controlled. Final spreading ratios as low as 0.63 can be achieved. A comparison of the maximum spreading ratio and droplet oscillation frequencies to models described in the literature shows that both are found to be much lower than theoretically predicted.

A substrate-independent lift-off approach for patterning functional surfaces.

A lift-off method for creating multifunctional patterned surfaces has been devised. It entails consecutive pulsed plasmachemical deposition of a reactive bottom layer and a protective top release layer. By way of example, a bottom/top layer combination comprising pulsed plasma deposited poly(glycidyl methacrylate)/poly(pentafluorostyrene) has been shown to display selective adhesive lift-off of the latter. Application of a prepatterned adhesive template yields well-defined arrays of reactive epoxide functionality surrounded by a passive fluoropolymer background or vice versa.

Technique of controlled reperfusion of the transplanted lung in humans.

BACKGROUND: Reperfusion injury remains a significant and sometimes fatal problem in clinical lung transplantation. Controlled reperfusion of the transplanted lung using white cell-filtered, nutrient-enriched blood has been shown recently to significantly ameliorate reperfusion damage in a porcine model. We modified this experimental technique and applied it to human lung transplantation. METHODS: Approximately 1,500 mL of arterial blood was slowly collected in a cardiotomy reservoir during the lung implant, and mixed to make a 4:1 solution of blood:modified Buckberg perfusate. This solution was passed through a leukocyte filter and into the transplant pulmonary artery for 10 minutes, at a controlled rate (200 mL/min) and pressure (less than 20 mm Hg), immediately before removal of the vascular clamp. RESULTS: Five patients underwent lung transplantation (1 bilateral, 4 single lung) using this technique. All patients were ventilated on a 40% fraction of inspired oxygen within a few hours and extubated on or before the first postoperative day. CONCLUSIONS: Controlled reperfusion of the transplanted lung with white cell-filtered, nutrient-enriched blood has given excellent functional results in our small initial clinical series.

Definition of distinct compartments in polarized Madin-Darby canine kidney (MDCK) cells for membrane-volume sorting, polarized sorting and apical recycling.

Previous studies of fibroblasts have demonstrated that recycling of endocytic receptors occurs through a default mechanism of membrane-volume sorting. Epithelial cells require an additional level of polar membrane sorting, but there are conflicting models of polar sorting, some suggesting that it occurs in early endosomes, others suggesting it occurs in a specialized apical recycling endosome (ARE). The relationship between endocytic sorting to the lysosomal, recycling and transcytotic pathways in polarized cells was addressed by characterizing the endocytic itineraries of LDL, transferrin (Tf) and IgA, respectively, in polarized Madin-Darby canine kidney (MDCK) cells. Quantitative analyses of 3-dimensional images of living and fixed polarized cells demonstrate that endocytic sorting occurs sequentially. Initially internalized into lateral sorting endosomes, Tf and IgA are jointly sorted from LDL into apical and medical recycling endosomes, in a manner consistent with default sorting of membrane from volume. While Tf is recycled to the basolateral membrane from recycling endosomes, IgA is sorted to the ARE prior to apical delivery. Quantifications of the efficiency of sorting of IgA from Tf between the recycling endosomes and the ARE match biochemical measurements of transepithelial protein transport, indicating that all polar sorting occurs in this step. Unlike fibroblasts, rab11 is not associated with Tf recycling compartments in either polarized or glass-grown MDCK cells, rather it is associated with the compartments to which IgA is directed after sorting from Tf. These results complicate a suggested homology between the ARE and the fibroblast perinuclear recycling compartment and provide a framework that justifies previous conflicting models of polarized sorting.

Apical and basolateral endocytic pathways of MDCK cells meet in acidic common endosomes distinct from a nearly-neutral apical recycling endosome.

Quantitative confocal microscopic analyses of living, polarized MDCK cells demonstrate different pH profiles for apical and basolateral endocytic pathways, despite a rapid and extensive intersection between the two. Three-dimensional characterizations of ligand trafficking demonstrate that the apical and basolateral endocytic pathways share early, acidic compartments distributed throughout the medial regions of the cell. Polar sorting for both pathways occurs in these common endosomes as IgA is sorted from transferrin to alkaline transcytotic vesicles. While transferrin is directly recycled from the common endosomes, IgA is transported to a downstream apical compartment that is nearly neutral in pH. By several criteria this compartment appears to be equivalent to the previously described apical recycling endosome. The functional significance of the abrupt increase in lumenal pH that accompanies IgA sorting is not clear, as disrupting endosome acidification has no effect on polar sorting. These studies provide the first detailed characterizations of endosome acidification in intact polarized cells and clarify the relationship between the apical and basolateral endocytic itineraries of polarized MDCK cells. The extensive mixing of apical and basolateral pathways underscores the importance of endocytic sorting in maintaining the polarity of the plasma membrane of MDCK cells.

Molecular interactions between human B-cell progenitors and the bone marrow microenvironment.

Apoptosis of normal and leukemic immature B-cells in vitro is suppressed when either cell type is grown in direct contact with a feeder layer of bone marrow-derived stromal cells, including fibroblasts, macrophages, endothelial cells, and adipocytes. In this study, our objective was to identify a stromal cell type which is essential for lymphoblast survival and to characterize the molecules involved in lymphoblast adhesion to these cells. In experiments with B-lineage acute lymphoblastic leukemia (ALL) cells (n = 28) and purified CD19(+) cells from normal bone marrow (n = 6) we found that homogeneous populations of bone marrow fibroblasts could sustain survival of normal and leukemic immature B-cells as efficiently as composite bone marrow stromal layers. Electron microscopic studies showed that leukemic lymphoblasts associate with fibroblasts and with the extracellular matrix (ECM) primarily via their specialized cell surface structures. Immunogold labelingsoliduselectron microscopy analysis revealed that the areas of contact between lymphoblasts and fibroblasts contained beta1 integrins (VLA-4 and VLA-5), fibronectin, vascular cell adhesion molecule (VCAM-1), and a cartilage-link protein, CD44. Double immunogold labeling studies disclosed a direct in situ relationship between fibronectin and VLA-4, VLA-5, and CD44. We hypothesize that these molecular interactions either bring lymphoblasts into close physical proximity with other fibroblast-bound or ECM-bound survival factors or provide survival signals themselves.

Xanthogranulomatous pyelonephritis: report of nonsurgical management of a case and review of the literature.

A case of focal xanthogranulomatous pyelonephritis (XPN) in a child, successfully cured with antibiotics only, is presented, and this report is followed by a review of the literature on XPN in both children and adults. XPN is a rare inflammatory disease of the kidney. Factors strongly implicated in the development of XPN are genitourinary obstruction and urinary tract infection, although other contributing factors have been suggested. The clinical presentation of the disease is remarkably nonspecific and variable; it therefore is frequently misdiagnosed as other, more common diseases that cause focal or diffuse renal masses, including renal neoplasms, abscesses, and tuberculosis. Diagnosis requires acquisition of renal tissue for special pathological staining. The long-standing mainstay of therapy for XPN has been nephrectomy or partial nephrectomy. However, this report and other recent reports of the successful medical management of focal XPN suggest that a trial of antibiotics prior to surgery is warranted in cases of focal XPN.

A23187 releases bound rather than free calcium from calcium-loaded liposomes.

We have investigated sonication-, osmotic shock-, and A23187-induced calcium and horseradish peroxidase release from phosphatidylcholine liposomes. We report that sonication and osmotic shock both cause release of liposome-entrapped horseradish peroxidase activity, thus, completely releasing the entrapped volume into and mixing it with the external medium. However, we find that neither sonication nor osmotic shock releases significant amounts of calcium from liposomes pre-loaded with calcium, while A23187 causes release of significant amounts of calcium from similarly prepared liposomes. We also find that A23187 can release calcium from liposomes after release of entrapment volume by sonication or osmotic shock. Alteration of the net charge of liposomes by substitution of phosphatidylcholine with phosphatidylserine or stearylamine dramatically changes the amount of calcium associated with calcium-loaded liposomes; sonication or addition of A23187 to liposomes containing significant amounts of PS does not appear to release calcium bound to these vesicles. These results suggest that a large fraction (> 99%) of the calcium associated with liposomes is bound to the membranes of the liposomes and that the calcium released by A23187 is due to release of bound rather than entrapped calcium.

The popliteal artery as inflow for distal bypass grafting.

OBJECTIVE: To examine the patency and limb salvage characteristics of the popliteal-distal artery saphenous-vein bypass in patients with minimal superficial femoral artery disease. DESIGN: A retrospective review. SETTING: A tertiary care university hospital in the Chicago, Ill, metropolitan area. PATIENTS: Fifty-two popliteal-distal artery saphenous-vein bypasses for occlusive disease were performed in 51 patients between 1980 and 1993. The mean age at operation was 62 years (range, 37 to 85 years); 34 patients (67%) were male, 45 (88%) were smokers, 44 (86%) had diabetes, and 34 (67%) had coronary disease. The primary indications for operation were gangrene (21 patients [41%]), ulcer (15 patients [29%]), and rest pain (16 patients [31%]). INTERVENTION: Bypass of diseased arterial segments was performed using popliteal-distal artery saphenous-vein bypass grafts. The proximal anastomoses were either to the above-knee popliteal artery (50%) or to the below-knee artery (50%), with outflow to tibial (79%) or pedal vessels (21%). MAIN OUTCOME MEASURES: Overall patient survival, limb salvage, and primary and secondary graft patency. RESULTS: Follow-up of graft patency ranged from 1 day to 11 years (mean follow-up, 2.7 years). The perioperative mortality was 2% and life-table survival was 94% at 1 year, 68% at 5 years, and 50% at 10 years. Primary patency was 90% at 1 month, 82% at 1 year, and 75% at 5 years. There were 14 primary graft failures, only two of which could be traced to progression of proximal disease; five failures occurred less than 30 days after operation. Six of these 14 patients contributed to secondary patency that was 96% at 1 month, 90% at 1 year, and 79% at 5 years. Limb salvage was 96% at 1 month, 90% at 1 year, and 87% at 5 years (seven major amputations were required). No significant differences in patency, limb salvage, or survival were observed on comparison of the level of the proximal or distal anastomosis, type of vein graft, or presence of comorbidities. CONCLUSIONS: We conclude that popliteal-distal artery bypass provides excellent patency and limb salvage for patients with severe ischemia. The use of a popliteal artery inflow source is preferable in patients with a paucity of venous segments since progression of proximal disease rarely leads to graft failure.

Highly localized tracks of human immunodeficiency virus type 1 Nef in the nucleus of cells of a human CD4+ T-cell line.

A human T-cell line constitutively expressing the nef gene from the human immunodeficiency virus type 1 SF2 isolate was used to examine the distribution of the Nef protein in the nucleus. High-resolution immunogold labeling/electron microscopic studies with polyclonal anti-Nef antibodies on nef+ and nef- cells revealed that a small fraction of Nef is in the nucleus and it is localized in specific curvilinear tracks that extend between the nuclear envelope and the nucleoplasm. An examination of the sequence of the SF2 nef gene revealed a putative nuclear targeting sequence that was previously found in several other eukaryotic nucleoplasmic proteins. The nuclear localization of Nef suggests a potential nuclear function for this protein. The presence of Nef in distinct nuclear tracks suggests that Nef is transported along a specific pathway that extends from the nuclear envelope into the nucleoplasm. A previous study [Meier, U. T. & Blobel, G. (1992) Cell 70, 127-138] has shown that the nucleolar protein of rat liver cells (Nopp140) shuttles from the nucleolus to the nuclear envelope on distinct tracks. The present study has suggested that the transport of a nucleoplasmic protein may also occur on distinct nuclear pathways.

Vaginal secretions increase the likelihood of intermale aggression in Syrian hamsters.

Although sexually receptive female hamsters prefer dominant males as mating partners, it is not clear what role the female might play facilitating aggressive interactions among males that would lead to the establishment of a status relationship. The ability of vaginal odors to stimulate male aggression was examined by paring randomly chosen males in a neutral arena with vaginal odors either present or absent. Males exhibited significantly more aggression when tested in the scented arena. Vaginal odors are efficient broadcast signals serving to space females, attract males, and to stimulate aggressive interactions among the males while inhibiting aggression towards the female.

Relation between choice of prostheses and late outcome in double-valve replacement.

The purpose of this study was to determine if the combination of a mechanical and bioprosthetic valve in the aortic and mitral positions influences late morbidity and mortality when compared with patients who had dual mechanical or dual bioprosthetic valves inserted. We reviewed the course of 89 hospital survivors of combined aortic and mitral valve replacement. The mean postoperative follow-up interval was 6.6 years, with a total follow-up of 583 years (98% complete). At 12 months after operation, mean functional class decreased from 3.1 to 1.7 (p < 0.05) and mean cardiac index increased from 2.1 to 2.5 L.min-1.m-2 (p < 0.05). Actuarial survival for the 89 patients (exclusive of < 30-day or in-hospital mortality, 14%) was 70%, 51%, and 33% at 5, 10, and 15 years. Freedom from reoperation was 93%, 78%, and 68%, and freedom from combined thromboembolism and anticoagulant-related hemorrhage was 82%, 60%, and 50%. These results show that there was no difference in overall survival in patients with dual mechanical valves, dual bioprosthetic valves, or a combination of both types at 15 years. There was, however, a lower reoperation rate in the group with dual mechanical valves as compared with the group with dual bioprosthetic valves (p < 0.05 at 10 years) or with a combination of valves (p < 0.05 at 15 years). The higher the number of mechanical valves the higher the combined risk of thromboembolism and anticoagulant-related hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)