Nonisomorphic nucleation pathways arising from morphological transitions of liquid channels.

Motivated by unexpected morphologies of the emerging liquid phase (channels, bulges, droplets) at the edge of thin, melting alkane terraces, we propose a new heterogeneous nucleation pathway. The competition between bulk and interfacial energies and the boundary conditions determine the growth and shape of the liquid phase at the edge of the solid alkane terraces. Calculations and experiments reveal a "precritical" shape transition (channel-to-bulges) of the liquid before reaching its critical volume along a putative shape-conserving path. Bulk liquid emerges from the new shape, and, depending on the degree of supersaturation, the new pathway may have two, one, or zero energy barriers. The findings are broadly relevant for many heterogeneous nucleation processes because the novel pathway is induced by common, widespread surface topologies (scratches, steps, etc.).

Delayed coalescence of droplets with miscible liquids: Lubrication and phase field theories.

Mixing of droplets with a body of different liquids shows an interesting behavior for small contact angles at solid substrate. The droplets interact with each other, a liquid exchange appears between the approaching drops owing to surface tension gradients at the droplets interface. But the drops remain separated for some seconds (up to minutes), until the merging into a single drop occurs (Langmuir 24, 6395 (2008)). We investigate this phenomenon using lubrication approximation and phase field approach. For both methods, 2D quantitative computer simulations for delayed fusion of perfectly miscible thin liquid films/droplets with low contact angles are reported.

Spreading and two-dimensional mobility of long-chain alkanes at solid/gas interfaces.

Long-chain n alkanes on solid surfaces can form partially wetting liquid alkane droplets coexisting with solid multilayer terraces. We propose a diffusivelike alkane flow between terrace edge and droplet perimeter through a molecularly thin "precursorlike" film. Depending on the (uniform!) sample temperature, either droplet or terrace edge are not in thermodynamic equilibrium. This leads to a chemical potential gradient, which drives the reversible alkane flow. The gradient can be adjusted and calculated independently from the phenomenological diffusion coefficient.

Pulmonary surfactant protein C containing lipid films at the air-water interface as a model for the surface of lung alveoli.

The pulmonary surfactant lines as a complex monolayer of lipids and proteins the alveolar epithelial surface. The monolayer dynamically adapts the surface tension of this interface to the varying surface areas during inhalation and exhalation. Its presence in the alveoli is thus a prerequisite for a proper lung function. The lipid moiety represents about 90% of the surfactant and contains mainly dipalmitoylphosphatidylcholine (DPPC) and phosphatidylglycerol (PG). The surfactant proteins involved in the surface tension adaption are called SP-A, SP-B and SP-C. The aim of the present investigation is to analyse the properties of monolayer films made from pure SP-C and from mixtures of DPPC, DPPG and SP-C in order to mimic the surfactant monolayer with minimal compositional requirement. Pressure-area diagrams were taken. Ellipsometric measurements at the air-water interface of a Langmuir film balance allowed measurement of the changes in monolayer thickness upon compression. Isotherms of pure SP-C monolayers exhibit a plateau between 22 and 25 mN/m. A further plateau is reached at higher compression. Structures of the monolayer formed during compression are reversible during expansion. Together with ellipsometric data which show a stepwise increase in film thickness (coverage) during compression, we conclude that pure SP-C films rearrange reversibly into multilayers of homogenous thickness. Lipid monolayers collapse locally and irreversibly if films are compressed to approximately 0.4 nm2/molecule. In contrast, mixed DPPG/SP-C monolayers with less than 5 mol% protein collapse in a controlled and reversible way. The pressure-area diagrams exhibit a plateau at 20 mN/m, indicating partial demixing of SP-C and DPPG.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of a human monoclonal anti-HIV-1 antibody in CHO cells.

The cDNA coding for the light and heavy chains, respectively, of the human monoclonal antibody 3D6 (IgG1, kappa), which binds specifically to human immunodeficiency virus-1 (HIV-1) gp41, was inserted into three different mammalian expression vectors and transfected into Chinese hamster ovary (CHO) cells. Transcription was under the control of Rous sarcoma virus long terminal repeat (RSV LTR), human cytomegalovirus major immediate early (CMV IE) promoter, and mouse mammary tumor virus long terminal repeat (MMTV LTR), respectively. Antibody productivity was monitored in the supernatants of selected clones. The binding characteristics of the CHO-derived antibody to HIV-1 gp41 were found to be identical to that of the original antibody produced by hybridoma cells.

A developmental analysis of rule-following.

The development of rule-governed behavior begins when a class of verbal forms called instructions, in conjunction with other variables, systematically occasion functional consequences for compliance (or noncompliance). These instructional forms then function as specific stimulus controls for compliance, with the other variables potentially taking on conjoint or conditional stimulus control of that compliance. Experience with numerous instructions occasioning functional consequences for compliance can establish generalized compliance to an indefinitely large stimulus class of instructions, a stimulus class that readily and naturally includes those forms that describe relationships between events and response to them that we also call rules. The important conjoint variables may well be the instruction giver (rule stater), any of their other systematic characteristics that have occasioned functional consequences for compliance in the past, and the topography of the response requested. Generalization of compliance across people, settings, and topography can occur; this generalization can extend to self-instruction, and can fail to extend to certain topographies ("Thou shalt not kill"), certain rule staters (nonpeers who say "Don't use drugs" when peers say it is fun), and certain settings ("Don't play with John in class"). Finally, children's experiences with describing behavior can lead to new self-instructions that fit the already established discriminative-stimulus class of rules and instructions for compliance, so that the novel self-instruction produces compliance. Compliance-oriented research has demonstrated how instruction givers can establish instructions as a discriminative-stimulus class for compliance, and how generalized compliance to new instructions and new instruction givers can be accomplished. Correspondence-training research has demonstrated that self-instructions can become discriminative for later performance of the described behaviors. Self-instruction research suggests that these forms of instructions also can control subsequent behavior, and that instructions and rules may be produced covertly as well as overtly. What has yet to be demonstrated is an ability to produce a novel self-instruction that controls subsequent behavior. The argument has been that the development of a behavior class, compliance to instructions, could provide a reasonable explanation for the acquisition of rule-governed behavior. Experiences within the natural environment, as well as research on compliance, correspondence, and self-instruction, suggest that a behavior class, compliance to instructions, could provide a reasonable model of the acquisition and ge

Recurrent dislocations and subluxations of the patella.

Seventy-four patients with patellar dislocations and subluxations were treated with a procedure described by Trillat. The Trillat method consists of stepwise correction of predisposing anatomic abnormalities including lateral retinacular release, patellar tubercle transfer, and advancement of the vastus medialis, if necessary. The follow-up period in 42 knees was from two to nine years with an average of 4.2 years. The results were excellent in six knees, good in 28 knees, fair in five knees, and poor in three knees. Thorough intraarticular examination is essential. If significant patellofemoral arthritis is present, a Maquet procedure should be performed.

Orthotic devices for the foot.

Orthotic devices have a multitude of applications. To properly prescribe them, one must have a clear understanding of the biomechanics of the lower limbs. These devices can support, correct, and prevent many pathologic conditions. The author has had experience with 235 patients, utilizing stance-phase, molded, thermoplastic orthotic devices. One hundred seventy-six patients responded to a questionnaire. Almost 80% of the patients experienced at least 50% improvement of their symptoms. With careful analysis, these devices not only can improve lower-segment malalignment syndromes in the athletic population but can also give relief to the patient with a painful foot and prevent serious ulcerations in the diabetic or rheumatoid patient.

Language training for generalization.

This paper presents a classroom-based language intervention program for preschool children with language delays or deficits. A major goal of the program is to ensure that children acquire missing skills through daily speech therapy and that they actively generalize these skills from therapy times to other classroom activities. This paper presents data collected with two children during daily speech therapy sessions and daily play activities. Instances in which the children generalized new language acquired in therapy to play activities will be discussed as well as instances in which the children failed to generalize new language. In addition, the influence of peer and teacher language usage on children's language production will be discussed. Finally, recommendations to enhance generalization of language skills within and across school settings will be presented.

Reconstruction for lateral instability of the ankle.

Lateral instability of the ankle in a young athlete is often very disabling. When conservative management of this instability fails, a surgical procedure described by Chrisman and Snook reconstructs both the anterior fibulotalar and fibulocalcaneal ligaments. In eleven patients who were followed for more than two years, this procedure gave predictably good results. Return to full sports activities can be expected for the young athlete.

Tuberculosis of the tongue.

A case of pulmonary tuberculosis of the tongue is reported, and tuberculosis of the upper airway in a VA Hospital is reviewed. A regimen of triple antituberculous drugs, isoniazid, ethambutol, and rifampin, was prescribed. Repeated radiographs of the chest showed considerable improvement of the pulmonary lesions. The lesion of the tongue was surgically excised as a diagnostic procedure and has not recurred.

Complications of deep puncture wounds of the foot.

Eleven cases of deep puncture wounds of the foot and their complications are reviewed. More than half of the patients had foreign materials introduced at the time of the injury which was not completely removed initially. The morbidity with these "simple puncture wounds" may be quite prolonged. The authors conclude that attention to details when the patient is first seen in the emergency room or the physician's office and aggressive treatment of these wounds will prevent serious sequelae in many instances.

Heterotopic bone formation after total hip arthroplasty.

Heterotopic bone formation is a common complication of total hip arthroplasty. A certain degree of heterotopic bone formation occurs in about one-half of the patients in degrees ranging from very mild to moderate involvement. The patients do not necessarily have any clinical disability; only 2 per cent of the patients developed severe heterotopic bone radiographically, and unsatisfactory functional results. There is no sex predilection for heterotopic bone formation except that the condition appears more severe in females. All ages are equally affected. The underlying disease process in the hip does not influence the occurrence of heterotopic bone. The incidence was significantly greater in patients who developed postoperative hematomas, prolonged wound drainage, or superficial infection. When surgical exposure is difficult and retraction of soft tissue aand soft tissue damage takes place, the incidence is much greater. Patients who have undergone previous surgical procedures about the hip present a greater risk in regards to development of disabling heterotopic bone formation. The etiology of heterotopic bone formation is not known. The following steps should be taken to avoid or greatly minimize the development of heterotopic bone: meticulous exposure with most careful retraction, copious irrigation with antibiotic solution, debridement of devitalized tissue prior to closure, instillation of drainage tubes, intraoperative and postoperative antibiotics, and carefully controlled postoperative anticoagulation.