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PubMed2006

Lifting the mirror symmetry of metal surfaces: decoupling the electronic and physical manifestations of surface chirality.

Naturally occurring metal surfaces possess planes of mirror symmetry on the nanometer-length scale. This mirror symmetry can be lifted and chirality "physically" conveyed onto a surface by adsorbing a chiral molecule. Until now, it has not been known whether the conveying of chirality is limited to just the physical structure or whether it goes deeper and permeates the electronic structure of the underlying surface. By using optically active second harmonic generation (OA-SHG), it is demonstrated that the adsorption of some, but not all, chiral molecules can reversibly, and without significant structural rearrangement, measurably lift the mirror symmetry of the surface electronic structure of a metal. It is proposed that the ability of a chiral molecule to place a significant "chiral perturbation" on the electronic structure of a surface is correlated to its adsorption geometry. The microscopic origins of the observed optical activity are also discussed in terms of classical models of chirality. The results of the study challenge current models of how chiral adsorbates induce enantioselectivity in the chemical/physical behavior of heterogeneous systems, which are based on geometric/stereochemical arguments, by suggesting that chiral electronic perturbations could play a role.

Metals↗
PubMed2006

Lifting a wet glass from a table: a microscopic picture.

Why is it so hard to lift a wet glass from a table? Is it easier when there is whiskey between the glass and the table? Macroscopically, the picture is quite simple: two surfaces have to be disrupted that are connected indirectly through hydrogen bonds and/or van der Waals forces. In the beginning, a surface has to be created leading to surface tension, and after that a liquid bridge has to be broken. Here we study the phenomenon at the microscopic level using molecular dynamics simulations. The effective force between two quartz plates is measured at different distances and with different alcohol/water mixtures between them. This allows us to compute the total work necessary to "lift the glass from the table". Different aspects of the process, such as clustering and liquid ordering are discussed. We compare the structure of the liquid/glass interface to that of a liquid/vapor interface, for which we present simulation results, like surface tension, as well. On the basis of the simulations, we are able to provide a detailed description of the energetics during the separation process as a function of alcohol concentration. It is shown that there is a net entropy loss upon separating two plates with water or a 10% MeOH solution between them, whereas for higher alcohol concentrations, there is net entropy gain. These findings increase our understanding of the properties of colloid suspensions which is important for process technology.

Journal Article↗
PubMed2006

Initial clinical impressions of the U.C. Davis large animal lift and its use in recumbent equine patients.

The U.C. Davis Large Animal Lift (LAL) is a lightweight sling developed to help lift horses in clinical and rescue situations. Here we report on its first use in 16 recumbent horses with neurologic, muscular and musculoskeletal disorders. For each horse, history, sedation, ease and time of LAL application and hoisting, standing ability, LAL tolerance and outcome were recorded. The LAL was easily and safely applied in all horses in less than five minutes and the procedure was well tolerated with minimal to no sedation. While 10 horses were able to stand in the LAL after being hoisted, 6 horses were unable to stand and were eventually euthanized due to the inability to regain weight bearing function. The LAL has shown to be a useful devise to evaluate the standing ability of recumbent horses and can be used alone or in combination with the Anderson Sling Support Devise to allow standing support of horses with a variety of debilitating problems.

Animals↗
PubMed1999

[Face lift--indications, contraindications and operation].

The face lift procedure is often performed in aesthetic plastic surgery. It corrects the stigmata of age, i.e. the multiple facial wrinkles and the sagging of the atrophic soft tissues by undermining and retensioning the superficial and deeper facial and cervical structures. Since the public can not fully appreciate the extent and the inconveniences involved with this operation, emphasis must be laid on an exact preoperative information of the patient with regards to possible complications, the pros and cons of this procedure and the results to be expected. In this paper the face lift operation is explained in detail and the indications and contraindications given. The most frequent postoperative complications are outlined and the preventive measures and modalities of treatment discussed. From the medico-legal point of view it is important that such an operation is performed by a certified and well experienced plastic surgeon.

Blepharoplasty↗
PubMed2002

What are the driving forces for water lifting in the xylem conduit?

After Renner had shown convincingly in 1925 that the transpirational water loss generates tensions larger than 0.1 MPa (i.e. negative pressures) in the xylem of cut leafy twigs the Cohesion Theory proposed by Böhm, Askenasy, Dixon and Joly at the end of the 19th century was immediately accepted by plant physiologists. Introduction of the pressure chamber technique by Scholander et al. in 1965 enforced the general belief that tension is the only driving force for water lifting although substantial criticism regarding the technique and/or the Cohesion Theory was published by several authors. As typical for scientific disciplines, the advent of minimal- and non-invasive techniques in the last decade as well as the development of a new, reliable method for xylem sap sampling have challenged this view. Today, xylem pressure gradients, potentials, ion concentrations and volume flows as well as cell turgor pressure gradients can be monitored online in intact transpiring higher plants, and within a given physiological context by using the pressure probe technique and high-resolution NMR imaging techniques, respectively. Application of the pressure probe technique to transpiring plants has shown that negative absolute pressures (down to - 0.6 MPa) and pressure gradients can exist temporarily in the xylem conduit, but that the magnitude and (occasionally) direction of gradients contrasts frequently the belief that tension is the only driving force. This seems to be particularly the case for plants faced with problems of height, drought, freezing and salinity as well as with cavitation of the tensile water. Reviewing the current data base shows that other forces come into operation when exclusively tension fails to lift water against gravity due to environmental conditions. Possible candidates are longitudinal cellular and xylem osmotic pressure gradients, axial potential gradients in the vessels as well as gel- and gas bubble-supported interfacial gradients. The multiforce theory overcomes the problem of the Cohesion Theory that life on earth depends on water being in a highly metastable state.

Journal Article↗
PubMed1987

Kinematic form and scaling: further investigations on the visual perception of lifted weight.

Observers are able to judge accurately the weight lifted by another person when only the motions of reflective patches attached to the lifter's major limb joints and head can be seen (Runeson & Frykholm, 1981). What properties of these complex kinematic patterns allow judgments of weight to be made? The pattern of variation in velocity of the lifted object over position is explored as a source of information for weight: It is found to provide limited information. How are variations in kinematic patterns scaled to allow judgments of weight, a kinetic quantity? The possibility of a source of information for scaling in the kinematics is investigated. Judgments based only on patch-light displays are accurate to a degree that is improved by an extrinsic scaling basis. Finally, the sensitivity to scaling of alternative metrics used in judging is explored. Intrinsic metrics are discovered to be less sensitive to the absence of an extrinsic basis for scaling.

Concept Formation↗
PubMed2000

Assessment of maxillary sinus volume for the sinus lift operation by three-dimensional magnetic resonance imaging.

OBJECTIVES: To calculate sinus and bone graft volumes and vertical bone heights from sequential magnetic resonance imaging (MRI) examinations in patients undergoing a sinus lift operation. METHODS: MRI scans were obtained pre-operatively and at 10 days and 10 weeks post-operatively, using a 0.95 tesla MRI scanner and a three-dimensional (3D) magnetisation prepared, rapid acquisition gradient-echo (MP-RAGE) sequence. RESULTS: Estimates of the bone graft volumes required for a desired vertical bone height were made from the pre-operative MRI scan. Measurements of the graft volumes and bone heights actually achieved were made from the post-operative scans. The MRI appearance of the graft changed between the 10 day and 10 week scans. CONCLUSIONS: We have proposed a technique which has the potential to give the surgeon an estimate of the optimum volume of graft for the sinus lift operation from the pre-operative MRI scan alone and demonstrated its application in a single patient. Changes in the sequential MRI appearance of the graft are consistent with replacement of fluid by a matrix of trabecular bone.

Adolescent↗
PubMed1990

A child with signs of developmental apraxia of speech with whom a palatal lift prosthesis was used to manage palatal dysfunction.

A client is described who exhibited a large number of characteristics consistent with developmental apraxia of speech (DAS). The exhibited symptoms included excessive nasal resonance and nasal emission of air due to velopharyngeal port dysfunction, for which successful management was achieved by use of a palatal lift prosthesis. The results of the client's use of the lift, in conjunction with her speech and language remedial programming, is presented.

Apraxias↗
PubMed2003

A percutaneous approach to eyebrow lift: the Salvadorean option.

BACKGROUND: Surgical eyebrow lift can result in a number of complications. A nonsurgical simple method of lifting the brow is presented. OBJECTIVE: To raise the eyebrows using a simple, quick, and noninvasive approach. METHODS: Twenty-nine patients, 27 women and 2 men, whose ages varied from 24 to 56 years (mean of 32 years) were included in the study. Preoperative and postoperative photographs were taken. In two patients, brow suspension was performed at the time of blepharoplasty. Informed consent was signed by all of the patients. For measuring the degree of satisfaction of the patients, we gave to them a sheet grading it from one to three (with one being the least satisfactory). Local anesthesia (1% lidocaine, 1:400,000 epinephrine), a conveniently sized Keith needle, and prolene 3/0 sutures were used. RESULTS: Satisfying results were obtained in all cases. The only problem encountered in two patients was temporary edema, and it settled in a few days. CONCLUSION: This is a very simple, quick, and noncomplicated method of raising the eyebrows. It can be repeated, revised easily, or combined with other modalities, such as peels, topical tretinoin, oral isotretinoin, fat injection, Goretex, and Botox as part of a facial rejuvenation program.

Adult↗
PubMed1999

[Endoscopic forehead, face and neck lifting].

Endoscopic procedures are a more recent addition to the techniques of aesthetic plastic surgery of the head and neck region. This "buttonhole surgery" appeals particularly to patients and plastic surgeons alike because of tiny scars and reduced morbidity. The technique of video-assisted surgery with monitor control must be learned and practiced in teaching courses with hands-on experience in the laboratory. The indication for endoscopic forehead lifting is already well established. There is only a relative indication for endoscopic neck lifting. In the midface, the endoscope may more safely facilitate subperiosteal composite dissection. The results and the nature and rate of complications is comparable to conventional facelifting techniques. In the forehead, the endoscope renders the large bi-coronal scalping incision unnecessary. Good candidates are younger individuals with elastic skin and without major skin surplus. Long-term results are not yet available.

Endoscopes↗
PubMed2001

SOOF lift and lateral retinacular canthoplasty.

Eyelid rejuvenation surgery may be slowly shifting from pure fat removal techniques to those that preserve and reposition the periorbital fat. The traditional subciliary incision blepharoplasty was fraught with minor and major complications, and while the transconjunctival blepharoplasty afforded lower morbidity, its inability to address all aspects of periorbital rejuvenation eventually limited its popularity. Coincidentally, a search by aesthetic surgeons was on for better techniques to lift the midface, soften the nasolabial fold, and efface the tear trough deformity. In an effort to avoid the lid malposition complications that often accompany transblepharoplasty cheek lifting, innovative canthoplasty and canthopexy techniques were developed, which paved the way for a safe return to subciliary blepharoplasty surgery. Effacement of the tear trough deformity, now considered to be a major determinant in successful periorbital rejuvenation, could be achieved through fat repositioning and without the use of alloplastic implants or free fat grafts, thus improving reliability while minimizing complications. By preserving periorbital fat the hollowed out orbit, often seen after traditional blepharoplasty, could be avoided. The technique described in this article is a composite of several previously published approaches, is simple for the experienced blepharoplasty surgeon to master, and has been used with safety and reliability over the past 18 months in the senior author's practice.

Adipose Tissue↗
PubMed2003

The extended centrolateral endoscopic midface lift.

Most of the advances in face lift techniques in the past decade have been directed at altering the aging changes of the midface. Our technique for endoscopic midface lifting releases the entire central and lateral midface, which allows for a complete resuspension and rejuvenation. This technique utilizes a subperiosteal release of the midface from the infraorbital rim to the inferior aspect of the maxilla and laterally over the entire zygomatic arch to the gonial angle beneath the masseteric aponeurosis. Suspension is achieved superolaterally to the deep temporal fascia and repositions the malar fat pad, SOOF, and soft tissues overlying the angle of the mandible. Over 400 procedures have been performed. We found the degree of improvement in the following order, from greatest to least: (1) correction of midface ptosis and infraorbital hollowing, (2) improvement of the depth of the nasolabial fold, and (3) improvement of the degree of jowling. This technique is one of low morbidity and few complications.

Aging↗
PubMed2005

Subperiosteal deep plane rhytidectomy: the composite midface lift.

Techniques for facial rejuvenation have long involved specific remedies for each facial segment affected by the aging process. Traditional facial rejuvenation techniques have addressed the anterior neck and platysma complex as well as the acquired jaw deformity. These techniques often left the nasolabial complex and the "infraorbital hollow" un-addressed. Modern techniques, including the composite rhytidectomy, the subperiosteal midface lift, and the deep-plane and the triplane rhytidectomy, have contributed to redefining the challenge of correcting the problem of the orbicularis-malar soft tissue complex descent and as such focus on a particular segment of the facial rejuvenation. This evolution of the facelift demonstrates that one size does not fit all and that surgeons should consider their rejuvenations to be not a generic facelift but a midface, lower face, and neck lift. This concept has evolved into our appreciation of distinct surgical zones. This is especially important in males, and adjunctive techniques such as the ones we describe may add benefit and enhance the final result in male patients. As discussed, the male anatomy, because of its increased surface area and weight, is more difficult to gain leverage with in rejuvenation procedures. The author describes his preferred technique for facial rejuvenation in males, the subperiosteal deep plane rhytidectomy (SPDPR), which combines a deep plane rhytidectomy with a subperiosteal dissection. Although combining subperiosteal "release" of midfacial anatomy has been reviewed by other authors, the combination of subperiosteal release and deep-plane rhytidectomy has not been previously reported or advocated. The operative technique, complications, and results of this combined technique are reviewed. The procedure as described is used as an isolated procedure for midfacial descent as well as an incorporated technique when completing a "full" rhytidectomy.

Adipose Tissue↗
PubMed2006

Endoscopic brow lifts uber alles.

Innumerable approaches to the ptotic brow and forehead have been described in the past. Over the last twenty-five years, we have used all these techniques in cosmetic and reconstructive patients. We have used the endoscopic brow lift technique since 1995. While no one technique is applicable to all patients, the endoscopic brow lift, with appropriate modifications for individual patients, can be used effectively for most patients with brow ptosis. We present the nuances of this technique and show several different fixation methods we have found useful.

Endoscopy↗
PubMed1987

A modified finger lift test reveals an asymmetry of motor overflow in adults.

A method of eliciting motor overflow in neurologically intact adults is reported. A weight was placed on either the middle or ring finger of the left or right hand, and the subject was instructed to lift that finger. Involuntary finger lifts of the contralateral hand were recorded. There were 32 right-handers per experiment. In Experiments I and II, the amount of weight placed on the subject's finger was in proportion to body weight, whereas in Experiment III, it was in proportion to each finger's strength. Across experiments, motor overflow was more prevalent when the left, rather than the right, hand was weighted. This shows that the asymmetry in motor overflow previously reported in children and brain-damaged adults also occurs in healthy adults, and that this movement asymmetry is not an artifact of the relative weakness of the left hand in right-handed individuals.

Body Weight↗
PubMed2001

Endoscopic forehead lift for ptosis of the brow caused by facial paralysis.

Twelve patients with ptosis of the brow caused by facial nerve paralysis were treated by endoscopic forehead lift. Four had an isolated paralysis of the temporal branch of the facial nerve and in eight the entire facial nerve was affected. In two of these patients the facial paralysis was bilateral, caused by Finnish hereditary amyloidosis. A standard subperiosteal endoforehead approach was used and the forehead was fixed by biodegradable pins (n = 8), anchor screws (n = 3), or a suture to the posterior scalp (n = 1). The procedure was a success in 10 patients, and failed in two after initially good results. The endoscopic brow lift is a good method of treating ptosis of the brow caused by paralysis of the temporal branch of the facial nerve.

Adult↗
PubMed2001

The effect of clay particles on the activity of suspended autotrophic nitrifying bacteria and on the performance of an air-lift reactor.

Clay minerals have some properties, namely a high surface area and the ability of ion exchange that may exert some effects on microbial systems. It is often difficult to know the way the clay is exerting its influence and whether its presence improves a given metabolic process. The present work concerns the study of the effect of the addition of powdered kaolin to autotrophic nitrification systems, and includes the study of the effects of the particles on the activity of a suspended nitrifying bacteria consortium and on the performance of an air-lift biofilm reactor used for tertiary nitrification. Concerning the suspended culture, kaolin particles produced stimulation on the specific endogenous and exogenous respiration rates of the bacteria, probably due to a nutritional effect supplied by the clay. This effect was more pronounced for the ammonia oxidation rates, although nitrite oxidation was also enhanced but to a lesser extent. In respect to the presence of kaolin particles in the air-lift reactor, the results obtained indicate that the clay particles become incorporated in the biofilm pellets, but do not change significantly their thickness or their shape. However, nitrate production decreased when the concentration of particles increased. The low adsorption of ammonia by the kaolin indicated that the clay particles embedded in the biofilm did not probably retain the ions. Although it was not proved, precipitation of salts may have occurred.

Adsorption↗
PubMed2006

Afferent contributions to digit force coupling and force level variation during performance of non-lift pinch.

Afferent contributions to the coordination of thumb and index finger forces during non-lift pinch were studied using an anesthetization case study design. Two subjects, one performing with and without digital anesthetization and one with intact sensation, produced dynamic pinch forces against a stable object, with and without visual feedback. Error corrections were less frequent post-anesthetization, and the cross correlation between digit forces was lower when sensation was removed. However, this decrease in cross correlation between digit forces seemed to reflect a loss in the magnitude of tightly coupled error corrections when sensation was removed, rather than more frequent deviations of force magnitude between the digit forces. Force-time output without visual feedback lacked these error corrections, and the correlation between digit forces remained high, irrespective of sensory status. Additionally, with vision occluded, the time rate of force change did not vary in a gradual manner as would be expected from a neural representation of a sinusoidal target, but was instead marked by sudden abrupt reversals of force rate of change, invariant of somatosensory status. The coupling of digit forces and rates of force change during non-lift pinch appear to be controlled primarily with feedforward mechanisms, where the lack of proprioceptive feedback does not seem to disrupt this coupling.

Adult↗