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Limitations Inherent (limitation + inherent)
Selected AbstractsThe Art of Repair in Surgical Hair Restoration Part I: Basic Repair StrategiesDERMATOLOGIC SURGERY, Issue 9 2002Robert M. Bernstein MD background. An increasingly important part of many hair restoration practices is the correction of hair transplants that were performed using older, outdated methods, or the correction of hair transplants that have left disfiguring results. The skill and judgment involved in these repair procedures often exceed those needed to operate on patients who have had no prior surgery. The use of small grafts alone does not protect the patient from poor work. Errors in surgical and aesthetic judgment, performing procedures on noncandidate patients, and the failure to communicate successfully with patients about realistic expectations remain major problems. objective. This two-part series presents new insights into repair strategies and expands upon several techniques previously described in the hair restoration literature. The focus is on creative aesthetic solutions to solve the supply/demand limitations inherent in most repairs. This article is written to serve as a guide for surgeons who perform repairs in their daily practices. methods. The repairs are performed by excision with reimplantation and/or by camouflage. Follicular unit transplantation is used for the restorative aspects of the procedure. results. Using punch or linear excision techniques allows the surgeon to relocate poorly planted grafts to areas that are more appropriate. In special situations, removal of grafts without reimplantation can be accomplished using lasers or electrolysis. The key elements of camouflage include creating a deep zone of follicular units, angling grafts in their natural direction, and using forward and side weighting of grafts to increase the appearance of fullness. The available donor supply is limited by hair density, scalp laxity, and scar placement. conclusion. Presented with significant cosmetic problems and severely limited donor reserves, the surgeon performing restorative hair transplantation work faces distinct challenges. Meticulous surgical techniques and optimal utilization of a limited hair supply will enable the surgeon to achieve the best possible cosmetic results for patients requiring repairs. [source] An Approach to Interdisciplinary Training in Postgraduate EducationEUROPEAN JOURNAL OF DENTAL EDUCATION, Issue 2 2006P Brodin Aims, A primary goal for clinical graduate training is to provide the student with the expertise required for specialist treatment in the actual discipline. At the same time there is an increasing need for a broader perspective on specialist care and the students should be aware of the limitations inherent in own specialty. In order to plan treatment in the best interest of the patient, and to be prepared to take part in treatments involving other specialties, the students should be exposed to interdisciplinary cooperation throughout the training. An approach to joint academic and clinical training with the purpose of providing graduate students with a broader perspective on specialist care is described and discussed. Material and methods, During their first year graduate students in the 7 different disciplines complete a joint Core Curriculum consisting of 8 different courses to stimulate a scientific approach to their profession and understanding of basic biologic mechanisms. To create a learning environment focusing on the development of interdisciplinary competence, a joint clinic has been established. Teams of students from different disciplines have been organized in order to establish ,partnership' for the treatment of patients with complex problems. The students also take part in the sessions held by a faculty Team of experts for assessment and treatment planning of referred patients with complex problems. Furthermore, faculty members conduct courses and seminars for students from other disciplines and students also participate in selected parts of the regular program in other disciplines. Results, Formal evaluation has so far been conducted for the Core Curriculum. Most students respond that they are satisfied with the courses, and the curriculum has also been adjusted based on the comments. The students report that treatment of patients in need of interdisciplinary treatment has been facilitated by having ,partners' in other disciplines. Participation in the Team of expert's sessions has been appreciated, and the attendance at interdisciplinary courses and seminars has been good. Conclusions, Based on the experience over the last 5 years, the interdisciplinary aspects of graduate training should be expanded to stimulate a holistic approach also to specialist treatment. [source] n-Type Doping of Organic Thin Films Using Cationic Dyes,ADVANCED FUNCTIONAL MATERIALS, Issue 3 2004A. Werner Abstract We present an approach to stable n-type doping of organic matrices using organic dopants. In order to circumvent stability limitations inherent to strong organic donors, we produce the donor from a stable precursor compound in situ. As an example, the cationic dye pyronin B chloride is studied as a dopant in a 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTCDA) matrix. Conductivities of up to 1.9,×,10,4,S,cm,1 are obtained for doped NTCDA, two orders of magnitude higher than the conductivity of NTCDA doped with bis(ethylenedithio)-tetrathiafulvalene as investigated previously, and four orders of magnitude higher than nominally undoped NTCDA films. Field-effect measurements are used to prove n-type conduction and to study the doping effect further. The findings are interpreted using a model of transport in disordered solids using a recently published model. Combined FTIR, UV-vis, and mass spectroscopy investigations suggest the formation of leuco pyronin B during sublimation of pyronin B chloride. [source] The Science of Communicating the Art of Esthetic Dentistry.JOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 3 2000Part I: Patient-Dentist-Patient Communication ABSTRACT Many contemporary restorative procedures are primarily esthetically driven, and patients have high expectations. It is imperative for the restorative dentist to understand patients' desires and expectations prior to initiating irreversible therapy. It is equally important for patients to understand the anatomic and technical limitations inherent with restorative therapy. CLINICAL SIGNIFICANCE This article describes several relatively straightforward techniques that can assist in dentist-patient-dentist communication and allow the patient to visualize a reasonable facsimile of the definitive result prior to initiation of irreversible therapy. By using these techniques where indicated, the frustrating cycle of rejection and failure may be avoided. [source] Improving the coordination efficiency of limited-communication multi,autonomus underwater vehicle operations using a multiagent architectureJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 4 2010Christopher C. Sotzing This research addresses the problem of coordinating multiple autonomous underwater vehicle (AUV) operations. An intelligent mission executive has been created that uses multiagent technology to control and coordinate multiple AUVs in communication-deficient environments. By incorporating real-time vehicle prediction, blackboard-based hierarchical mission plans, mission optimization, and a distributed multiagent,based paradigm in conjunction with a simple broadcast communication system, this research aims to handle the limitations inherent in underwater operations, namely poor communication, and intelligently control multiple vehicles. In this research, efficiency is evaluated and then compared to the current state of the art in multiple AUV control. The research is then validated in real AUV coordination trials. Results will show that compared to the state of the art, the control system developed and implemented in this research coordinates multiple vehicles more efficiently and is able to function in a range of poor communication environments. These findings are supported by in-water validation trials with heterogeneous AUVs. © 2010 Wiley Periodicals, Inc. [source] Management of anticoagulation following central nervous system hemorrhage in patients with high thromboembolic riskJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 7 2010G. W. J. HAWRYLUK Summary.,Background:,Patients who present with central nervous system (CNS) hemorrhage while on anticoagulation (AC) for thromboembolic (TE) risk factors are a challenge to manage. Objective: We sought to inform decisions surrounding the timing and intensity of AC resumption by performing a systematic review. Methods:,Three reviewers screened publications from Medline and EMBASE and extracted data. Hemorrhagic and TE adverse events that occurred subsequent to the index hemorrhage were recorded, as was their timing relative to presentation and covariates that might influence their occurrence. Results:,Data were extracted from 63 publications detailing 492 patients; 7.7% of patients experienced hemorrhagic complications and 6.1% experienced TE complications. Hemorrhagic complications were more common within 72 h of presentation while TE complications were more common thereafter. Patients restarted on AC after 72 h were significantly more likely to have a TE complication (P = 0.006) and those restarted before 72 h were more likely to hemorrhage (P = 0.0727). Factors associated with re-hemorrhage included younger age, traumatic cause, subdural hematomas and failure to reverse AC. TE complications were more common in younger patients and those with spinal hemorrhage, multiple hemorrhages, and non-traumatic causes of the index hemorrhage. Re-initiation of AC at a lower intensity also significantly increased the risk of TE complications. Interpretation:,Our results suggest that it may be prudent to re-initiate AC earlier than previously thought, with the timing and intensity modified based on predictors of TE and hemorrhagic complications. These findings must be explored in a prospective study because of limitations inherent to the analyzed studies. [source] Review article: dual delayed release formulation of dexlansoprazole MR, a novel approach to overcome the limitations of conventional single release proton pump inhibitor therapyALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 9 2009D. C. METZ Summary Background, Proton pump inhibitors (PPIs) provide the most effective pharmacotherapy for treating acid-related disorders. However, PPIs do not completely control acid over 24 h with once-daily dosing. Aims, To discuss limitations inherent in the pharmacokinetics (PK) and pharmacodynamics of conventional PPI formulations, which provide a single drug release. Also, to consider approaches to extending the duration of acid suppression focusing on dexlansoprazole MR, a PPI with a novel Dual Delayed Release (DDR) formulation. Method, We reviewed the available literature regarding marketed and investigational PPIs. Results, Non-standard dosing of currently marketed PPIs has produced incremental advances in acid control. Multiple approaches are being evaluated to enhance acid suppression with PPIs. Dexlansoprazole MR is a DDR formulation of dexlansoprazole, an enantiomer of lansoprazole, with two distinct drug release periods to prolong the plasma dexlansoprazole concentration,time profile and extend duration of acid suppression. Clinical studies show that dexlansoprazole MR produces a dual-peak PK profile that maintains therapeutic plasma drug concentrations longer than lansoprazole, with a single-peak PK profile, and increases the percentage of time that intragastric pH >4. Conclusions, Novel drug delivery platforms, including the dexlansoprazole MR DDR formulation, may improve acid suppression and offer benefits over conventional single release PPI formulations. [source] REDUCTIONS IN OXYGEN CONSUMPTION DURING DIVES AND ESTIMATED SUBMERGENCE LIMITATIONS OF STELLER SEA LIONS (EUMETOPIAS JUBATUS)MARINE MAMMAL SCIENCE, Issue 2 2007Gordon D. Hastie Abstract Accurate estimates of diving metabolic rate are central to assessing the energy needs of marine mammals. To circumvent some of the limitations inherent with conducting energy studies in both the wild and captivity, we measured diving oxygen consumption of two trained Steller sea lions (Eumetopias jubatus) in the open ocean. The animals dived to predetermined depths (5,30 m) for controlled periods of time (50,200 s). Rates of oxygen consumption were measured using open-circuit respirometry before and after each dive. Mean resting rates of oxygen consumption prior to the dives were 1.34 (±0.18) and 1.95 (±0.19) liter/min for individual sea lions. Mean rates of oxygen consumption during the dives were 0.71 (±0.24) and 1.10 (±0.39) liter/min, respectively. Overall, rates of oxygen consumption during dives were significantly lower (45% and 41%) than the corresponding rates measured before dives. These results provide the first estimates of diving oxygen consumption rate for Steller sea lions and show that this species can exhibit a marked decrease in oxygen consumption relative to surface rates while submerged. This has important consequences in the evaluation of physiological limitations associated with diving such as dive duration and subsequent interpretations of diving behavior in the wild. [source] A flawed perspective: the limitations inherent within the study of Chinese nationalism1NATIONS AND NATIONALISM, Issue 1 2009ALLEN CARLSON ABSTRACT. Is nationalism in China on the rise? Is it making China more combative in the international arena? More fundamentally: Is a focus on nationalism the most effective intellectual framework for understanding how those living within the People's Republic of China (PRC) are defining their position in contemporary world politics? This article briefly answers each of these questions. It argues that, despite forwarding some compelling insights, previous work on Chinese nationalism has been undermined by a number of major flaws. It then finds that such shortcomings are in no small part a product of the narrowing gaze that a focus on nationalism alone imposes on the study of identity politics. The article then advocates that in place of the nationalism rubric, a turn to the broader question of national identity formation is merited. Utilising this perspective, it concludes by cautioning that incipient splits within contemporary Chinese national identity may portend a more tumultuous relationship between China and the rest of the world in the years to come. [source] Prospects for a waveguide Raman amplifier in porous silicon at 1.5 ,mPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2009Luigi Sirleto Abstract Recently, the possibility of light generation and/or amplification in silicon, based on Raman emission, has achieved significant results. However, limitations inherent to the physics of silicon have been pointed out, too. In order to overcome these limitations, a possible option is to consider low dimensional silicon. In this paper, an approach based on Raman scattering in porous silicon is investigated. First, we point out two significant advantages with respect to silicon: the broadening of the spontaneous Raman emission and the tuning of the Stokes shift. Then, we discuss about the prospect of Raman amplifier in porous silicon. Finally the design of a Raman amplifier in porous silicon waveguide is proposed. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Configurational-bias sampling technique for predicting side-chain conformations in proteinsPROTEIN SCIENCE, Issue 9 2006Tushar Jain Abstract Prediction of side-chain conformations is an important component of several biological modeling applications. In this work, we have developed and tested an advanced Monte Carlo sampling strategy for predicting side-chain conformations. Our method is based on a cooperative rearrangement of atoms that belong to a group of neighboring side-chains. This rearrangement is accomplished by deleting groups of atoms from the side-chains in a particular region, and regrowing them with the generation of trial positions that depends on both a rotamer library and a molecular mechanics potential function. This method allows us to incorporate flexibility about the rotamers in the library and explore phase space in a continuous fashion about the primary rotamers. We have tested our algorithm on a set of 76 proteins using the all-atom AMBER99 force field and electrostatics that are governed by a distance-dependent dielectric function. When the tolerance for correct prediction of the dihedral angles is a <20° deviation from the native state, our prediction accuracies for ,1 are 83.3% and for ,1 and ,2 are 65.4%. The accuracies of our predictions are comparable to the best results in the literature that often used Hamiltonians that have been specifically optimized for side-chain packing. We believe that the continuous exploration of phase space enables our method to overcome limitations inherent with using discrete rotamers as trials. [source] Characterizing the Emerging Population of Prescription Opioid AbusersTHE AMERICAN JOURNAL ON ADDICTIONS, Issue 3 2006Stacey C. Sigmon PhD Despite an alarming recent increase in prescription opioid abuse, the characteristics of prescription opioid abusers remain largely unknown. In this study, the demographic and drug use characteristics of 75 methadone patients (36 prescription opioid and 39 heroin users) were compared using a retrospective chart review. Prescription opioid abusers exhibited a profile of characteristics that may predict favorable treatment response, including less severe opioid use and IV drug use, and greater social stability compared to primary heroin abusers. Despite the limitations inherent in this retrospective chart review, this study provides initial evidence that prescription opioid abusers may have a number of characteristics that predict favorable treatment response. This new information may inform and assist current efforts to develop efficacious treatments for prescription opioid abuse. [source] Thermodynamic Considerations in Solid Adsorption of Bound Solutes for Patient Support in Liver FailureARTIFICIAL ORGANS, Issue 7 2008John F. Patzer II Abstract:, New detoxification modes of treatment for liver failure that use solid adsorbents to remove toxins bound to albumin in the patient bloodstream are entering clinical evaluations, frequently in head-to-head competition. While generally effective in reducing toxin concentration beyond that obtainable by conventional dialysis procedures, the solid adsorbent processes are largely the result of heuristic development. Understanding the principles and limitations inherent in competitive toxin binding, albumin versus solid adsorbent, will enhance the design process and, possibly, improve detoxification performance. An equilibrium thermodynamic analysis is presented for both the molecular adsorbent recirculating system (MARS) and fractionated plasma separation, adsorption, and dialysis system (Prometheus), two advanced systems with distinctly different operating modes but with similar equilibrium limitations. The Prometheus analysis also applies to two newer approaches: sorbent suspension reactor and microsphere-based detoxification system. Primary results from the thermodynamic analysis are that: (i) the solute,albumin binding constant is of minor importance to equilibrium once it exceeds about 105 L/mol; (ii) the Prometheus approach requires larger solid adsorbent columns than calculated by adsorbent solute capacity alone; and (iii) the albumin-containing recycle stream in the MARS approach is a major reservoir of removed toxin. A survey of published results indicates that MARS is operating under mass transfer control dictated by solute,albumin equilibrium in the recycle stream, and Prometheus is approaching equilibrium limits under current clinical protocols. [source] A review of p53 expression and mutation in human benign, low malignant potential, and invasive epithelial ovarian tumorsCANCER, Issue 2 2003Leanne M. Kmet M.Sc. Abstract BACKGROUND In the current study, the authors present pooled data from studies that investigated p53 protein expression and/or mutation in human epithelial ovarian tumors. METHODS The English literature in the MEDLINE, PubMed, and Ingenta databases was searched to the end of the year 2000 to identify relevant studies. Data were pooled across eligible studies, and the prevalence of p53 expression and mutation among benign, low malignant potential (LMP), and invasive tumors was determined. Prevalence estimates by tumor histology, International Federation of Gynecology and Obstetrics (FIGO) stage, and grade also were calculated. RESULTS The pooled prevalence estimate for p53 overexpression among epithelial ovarian carcinomas was 51% (95% confidence intervals [95% CI], 50,53%) compared with 17% (95% CI, 15,20%) among LMP tumors and 7% (95% CI, 5,10%) among benign tumors. p53 mutation prevalence estimates were 45% (95% CI, 42,47%), 5% (95% CI, 2,9%), and 1% (95% CI, 0,5%), respectively, for invasive, LMP, and benign tumors. The prevalence of these p53 abnormalities was found to be associated positively with increasing tumor grade and stage. Differences based on histologic subtype also were found. CONCLUSIONS Although these pooled estimates might appear to offer support for various hypotheses regarding the role of p53 in ovarian carcinoma, the limitations inherent in these data hamper the interpretation of the significance of any of the findings. Future studies will require innovative methods to address the limitations of many previous investigations and more comprehensive investigation into defective tumor suppression mechanisms. Cancer 2003;97:389,404. © 2003 American Cancer Society. DOI 10.1002/cncr.11064 [source] | ||||||||||