Biomedical Engineering

TRIGANO, A.J., ET AL.: Lead Explantation Late After Atrial Perforation. Tbis report describes the case of a patient in wbom atrial perforation witb penetration of tbe tboracic wall was diagnosed 2 years after tbe implantation of an Accufix lead. Despite tbis complication, atrial detection in the bipolar mode and ventricular pacing were normal. Digital fluoroscopy detected a fracture witb extrusion of a short segment of tbe retention wire. Tbe rupture of tbe retention wire might have been the result, but was not the cause of tbe perforation. (PACE 1996; 19:1268-1269 atrial perforation, Accufix^'^ atrial lead

A study of the performance of five commercial radiotherapy treatment planning systems (TPSs) for common treatment sites regarding their ability to model heterogeneities and scattered photons has been performed. The comparison was based on CT information for prostate, head and neck, breast and lung cancer cases. The TPSs were installed locally at different institutions and commissioned for clinical use based on local procedures. For the evaluation, beam qualities as identical as possible were used: low energy (6 MV) and high energy (15 or 18 MV) x-rays. All relevant anatomical structures were outlined and simple treatment plans were set up. Images, structures and plans were exported, anonymized and distributed to the participating institutions using the DICOM protocol. The plans were then re-calculated locally and exported back for evaluation. The TPSs cover dose calculation techniques from correction-based equivalent path length algorithms to modelbased algorithms. These were divided into two groups based on how changes in electron transport are accounted for ((a) not considered and (b) considered). Increasing the complexity from the relatively homogeneous pelvic region to the very inhomogeneous lung region resulted in less accurate dose distributions. Improvements in the calculated dose have been shown when models consider volume scatter and changes in electron transport, especially when the extension of the irradiated volume was limited and when low densities were present in or adjacent to the fields. A Monte Carlo calculated algorithm input data set and a benchmark set for a virtual linear accelerator have been produced which have facilitated the analysis and interpretation of the results. The more sophisticated

Second-harmonic generation (SHG) and two-photon excitation fluorescence (TPEF) are relatively new and promising tools for the detailed imaging of biological samples and processes at the microscopic level. By exploiting these nonlinear phenomena phototoxicity and photobleaching effects on the specimens are reduced dramatically. The main target of this work was the development of a compact inexpensive and reliable experimental apparatus for nonlinear microscopy measurements. Femtosecond laser pulses were utilized for excitation. We achieved high-resolution imaging and mapping of Caenorhabditis elegans (C. elegans) neurons and muscular structures of the pharynx, at the microscopic level by performing SHG and TPEF measurements. By detecting nonlinear phenomena such as SHG and TPEF it is feasible to extract valuable information concerning the structure and the function of nematode neurons.

Study Design. Prospective observational and analytic study. Objective. To investigate whether spontaneous intervertebral disc degeneration (IVDD) occurring in both chondrodystrophic (CD) and nonchondrodystrophic dogs (NCD) can be used as a valid translational model for human IVDD research. Summary of Background Data. Different animal models are used in IVDD research, but in most of these models IVDD is induced manually or chemically rather than occurring spontaneously. Methods. A total of 184 intervertebral discs (IVDs) from 19 dogs of different breeds were used. The extent of IVDD was evaluated by macroscopic grading, histopathology, glycosaminoglycan content, and matrix metalloproteinase 2 activity. Canine data were compared with human IVD data acquired in this study or from the literature. Results. Gross pathology of IVDD in both dog types (CD and NCD) and humans showed many similarities, but the cartilaginous endplates were signifi cantly thicker and the subchondral cortices signifi cantly thinner in humans than in dogs. Notochordal cells were still present in the IVDs of adult NCD but were not seen in the CD breeds or in humans. Signs of degeneration were seen in young dogs of CD breeds ( < 1 year of age), whereas this was only seen in older dogs of NCD breeds (5-7 years of age). The relative glycosaminoglycan content and metalloproteinase 2 activity in canine IVDD were similar to those in humans: metalloproteinase 2 activity increased and glycosaminoglycan content decreased with increasing severity of IVDD. Conclusion. IVDD is similar in humans and dogs. Both CD and NCD breeds may therefore serve as models of spontaneous IVDD for human research. However, as with all animal models, it is important to recognize interspecies differences and, indeed, the intraspecies differences between CD and NCD breeds (early vs. late onset of IVDD, respectively) to develop an optimal canine model of human IVDD.

A remote magnetic navigation system (MNS) is available and has been used with a 4-mm-tip magnetic catheter for radiofrequency (RF) ablation of some supraventricular and ventricular arrhythmias; however, it has not been evaluated for the ablation of cavotricuspid isthmus-dependent right atrial flutter (AFL). The present study evaluates the feasibility and efficiency of this system and the newly available 8-mm-tip magnetic catheter to perform RF ablation in patients with AFL. Twenty-six consecutive patients (23 men, mean age 64.6 +/- 9.6 years) underwent RF ablation using a remote MNS. RF ablation was performed with an 8-mm-tip magnetic catheter (70 degrees C, maximum power 70 W, 90 seconds). The endpoint of ablation was complete bidirectional isthmus block. To assess a possible learning curve, procedural data were compared between the first 14 (group 1) and the rest (group 2) of the patients. The initial rhythm during ablation was AFL in 20 (19 counterclockwise and 1 clockwise) and s...

The acute hemodynamic efficacy of an implantable counter-pulsation device (CPD) was evaluated. The CPD is a valveless single port, 32-ml stroke volume blood chamber designed to be connected to the human axillary artery using a simple surface surgical procedure. Blood is drawn into the pump during systole and ejected during diastole. The acute hemodynamic effects of the 32-ml CPD were compared to a standard clinical 40-ml intra-aortic balloon pump (IABP) in calves (80 kg, n = 10). The calves were treated by a single oral dose of Monensin to produce a model of diminished cardiac function (DCF). The CPD and IABP produced similar increases in cardiac output (6% CPD vs. 5% IABP, p > 0.5) and reduction in left ventricular external work (14% CPD vs. 13% IABP, p > 0.5) compared to DCF (p < 0.05). However, the ratio of diastolic coronary artery flow to left ventricular external work increase from DCF baseline (p < 0.05) was greater with the CPD compared to the IABP (15% vs. 4%, p < 0.05). The CPD also produced a greater reduction in left ventricular myocardial oxygen consumption from DCF baseline (p < 0.05) compared to the IABP (13% vs. 9%, p < 0.05) despite each device providing similar improvements in cardiac output. There was no early indication of hemolysis, thrombus formation, or vascular injury. The CPD provides hemodynamic efficacy equivalent to an IABP and may become a therapeutic option for patients who may benefit from prolonged counterpulsation.

For musculoskeletal tissues that transmit loads during movement, the interfaces between tissues are essential to minimizing injury. Therefore, the reproduction of functional interfaces within engineered musculoskeletal tissues is critical to the successful transfer of the technology to the clinic. The goal of this work was to rapidly engineer ligament equivalents in vitro that contained both the soft tissue sinew and a hard tissue bone mimetic. This goal was achieved using cast brushite (CaHPO 4 Á2H 2 O) anchors to mimic bone and a fibrin gel embedded with fibroblasts to create the sinew. The constructs formed within 7 days. Fourteen days after seeding, the interface between the brushite and sinew could withstand a stress of 9.51 AE 1.7 kPa before failure and the sinew reached a Young's modulus value of 0.16 AE 0.03 MPa. Treatment with ascorbic acid and proline increased the collagen content of the sinew (from 1.34% AE 0.2% to 8.34% AE 0.37%), strength of the interface (29.24 AE 6 kPa), and modulus of the sinew (2.69 AE 0.25 MPa). Adding transforming growth factor-b resulted in a further increase in collagen (11.25% AE 0.39%), interface strength (42 AE 8 kPa), and sinew modulus (5.46 AE 0.68 MPa). Both scanning electron and Raman microscopy suggested that the interface between the brushite and sinew mimics the in vivo tidemark at the enthesis. This work describes a major step toward the development of tissue-engineered ligaments for the repair of ligament ruptures in humans.

ITI dental implants are available with two bone-anchoring surfaces, a titanium plasma-sprayed (TPS) surface, and a recently introduced sandblasted and acid-etched (SLA) surface. Cell culture and animal tests demonstrate that the SLA surface stimulates bone cell differentiation and protein production, has large amounts of bone-to-implant contact, and results in large removal torque values in functional testing of the bone contact. As a result of these studies, a prospective human clinical trial was initiated to determine whether the 4.1 mm diameter SLA ITI solid screw implants could be predictably and safely restored as early as six weeks after implant placement surgery.

Indices of heart rate variability (HRV) based on fractal signal models have recently been shown to possess value as predictors of mortality in specific patient populations. To develop more powerful clinical indices of HRV based on a fractal signal model, the study investigated two HRV indices based on a monofractal signal model called fractional Brownian motion and an index based on a multifractal signal model called multifractional Brownian motion. The performance of the indices was compared with an HRV index in common clinical use. To compare the indices, 18 normal subjects were subjected to postural changes, and the indices were compared on their ability to respond to the resulting autonomic events in HRV recordings. The magnitude of the response to postural change (normalised by the measurement

Ankle Foot Orthoses (AFOs) to promote walking ability are a common treatment in patients with neurological or muscular diseases. However, guidelines on the prescription of AFOs are currently based on a low level of evidence regarding their efficacy. Recent studies aiming to demonstrate the efficacy of wearing an AFO in respect to walking ability are not always conclusive. In this paper it is argued to recognize two levels of evidence related to the ICF levels. Activity level evidence expresses the gain in walking ability for the patient, while mechanical evidence expresses the correct functioning of the AFO. Used in combination for the purpose of evaluating the efficacy of orthotic treatment, a conjunct improvement at both levels reinforces the treatment algorithm that is used. Conversely, conflicting outcomes will challenge current treatment algorithms and the supposed working mechanism of the AFO. A treatment algorithm must use relevant information as an input, derived from measur...

The main objective of this work is the evaluation, by means of the finite element method (FEM) of the mechanical stability and long-term microstructural modifications in bone induced to three different kinds of fractures of the distal femur by three types of implants: the Condyle Plate, the less invasive stabilization system plate (LISS) and the distal femur nail (DFN). The displacement and the stress distributions both in bone and implants and the internal bone remodelling process after fracture and fixation are obtained and analysed by computational simulation. The main conclusions of this work are that distal femoral fractures can be treated correctly with the Condyle Plate, the LISS plate and the DFN. The stresses both in LISS and DFN implant are high especially around the screws. When respect to remodelling, the LISS produces an important resorption in the fractured region, while the other two implants do not strongly modify bone tissue microstructure.

Introduction: The purpose of this study was to investigate the condyle-fossa relationship, the position of the condyles in their respective mandibular fossae, and the dimensional and positional symmetries between the right and left condyles in a sample with normal occlusion. Methods: Thirty subjects from 15 to 32 years of age with normal occlusion had computed tomography scans of their temporomandibular joints. The images obtained from the axial slices were evaluated for possible asymmetries in size and position between the condylar processes. The images obtained from the sagittal slices were used to assess the depth of the mandibular fossa, the condyle-fossa relationship, and the centralization of the condyles in their respective mandibular fossae. Paired Student t tests were applied, and Pearson product moment correlations were determined after measurements on both sides were obtained. Results: The largest mediolateral diameter of the mandibular condylar processes (P 5 0.022) and the posterior joint spaces (P 5 0.048) showed statistically significant differences between the right and left sides. Statistically significant (P \0.05) anterior positioning of the condyles (noncentralized position) was observed. Conclusions: No singular characteristic in the temporomandibular joints of the normal occlusion group was verified. The largest mediolateral diameter of the mandibular condylar processes and the posterior joint spaces showed statistically significant differences between the right and left sides. Evaluation of the position of the condyles in their respective mandibular fossae showed noncentralized positioning for the right and left sides. (Am J Orthod Dentofacial Orthop 2011;140:18-24)

The aim of this study was to evaluate the results associated with left atrial appendage closure (LAAC) with the AMPLATZER Cardiac Plug (ACP) (St. Jude Medical, Minneapolis, Minnesota) in patients with nonvalvular atrial fibrillation and absolute contraindications to anticoagulation therapy.

We have investigated the haematocrit dependence of the electrical parameters (relative permittivity and conductivity) of blood. The measuring set-up, composed of an impedancemeter (HP 4291A), an open-ended coaxial line and a temperature controlling set, was designed for dielectric measurements in the 1 MHz to 1 GHz frequency range. Measurements were performed on ex vivo animal (cow and sheep) blood at 37 • C. The two dielectric parameters appeared to be strongly dependent on the haematocrit. The permittivity versus frequency decreases then increases when the haematocrit decreases. The conductivity increases in the whole frequency range when the haematocrit decreases. Due to the lack of comparative data on the frequency range explored, we compare the dielectric profiles with those deduced from the Maxwell-Fricke theoretical model.

The anatomy and physiology of nerve tissue and the peripheral nerve are reviewed. The importance of the anatomical and physiological understanding of nerve tissue in the surgical repair of nerve injuries is discussed. This includes an outline of the light and electron microscopic histology of nerve and a short review of axoplasmic flow. In addition, the nerve coverings, endoneurium, perineurium, and epineurium, are described. The relationship of these coverings to the surgical therapy of nerve injuries is outlined. By maintaining, where possible, nerve fascicle continuity and by restoring, where practical, the normal physiology of distorted but not disrupted fascicles, with the use of careful internal neurolysis, optimal clinical return of function should be achieved.

During the resorbable-polymer-boom of the 1970s and 1980s, polycaprolactone (PCL) was used in the biomaterials field and a number of drug-delivery devices. Its popularity was soon superseded by faster resorbable polymers which had fewer perceived disadvantages associated with long term degradation (up to 3-4 years) and intracellular resorption pathways; consequently, PCL was almost forgotten for most of two decades.

Purpose: Normal tissue complication probability ͑NTCP͒ of the rectum, bladder, urethra, and femoral heads following several techniques for radiation treatment of prostate cancer were evaluated applying the relative seriality and Lyman models. Methods: Model parameters from literature were used in this evaluation. The treatment techniques included external ͑standard fractionated, hypofractionated, and dose-escalated͒ three-dimensional conformal radiotherapy ͑3D-CRT͒, low-dose-rate ͑LDR͒ brachytherapy ͑I-125 seeds͒, and highdose-rate ͑HDR͒ brachytherapy ͑Ir-192 source͒. Dose-volume histograms ͑DVHs͒ of the rectum, bladder, and urethra retrieved from corresponding treatment planning systems were converted to biological effective dose-based and equivalent dose-based DVHs, respectively, in order to account for differences in radiation treatment modality and fractionation schedule. Results: Results indicated that with hypofractionated 3D-CRT ͑20 fractions of 2.75 Gy/fraction delivered five times/week to total dose of 55 Gy͒, NTCP of the rectum, bladder, and urethra were less than those for standard fractionated 3D-CRT using a four-field technique ͑32 fractions of 2 Gy/fraction delivered five times/week to total dose of 64 Gy͒ and dose-escalated 3D-CRT. Rectal and bladder NTCPs ͑5.2% and 6.6%, respectively͒ following the dose-escalated four-field 3D-CRT ͑2 Gy/fraction to total dose of 74 Gy͒ were the highest among analyzed treatment techniques. The average NTCP for the rectum and urethra were 0.6% and 24.7% for LDR-BT and 0.5% and 11.2% for HDR-BT. Conclusions: Although brachytherapy techniques resulted in delivering larger equivalent doses to normal tissues, the corresponding NTCPs were lower than those of external beam techniques other than the urethra because of much smaller volumes irradiated to higher doses. Among analyzed normal tissues, the femoral heads were found to have the lowest probability of complications as most of their volume was irradiated to lower equivalent doses compared to other tissues.

Limited oral access presents a unique challenge to prosthodontic treatment. An edentulous patient who developed microstomia after a maxillary lip resection is presented. The clinical procedure and the rationale for the treatment approach using implanted-supported overdentures are discussed. (J Prosthet Dent 2006;96:1-6.)

The purpose of this 2-part opinion article was to project the developments expected to occur in the next few years in orthodontic materials research and applications. Part 1 reviewed developments in bonding to enamel. Part 2 looks at other orthodontic materials applications and explores emerging research strategies for probing the biological properties of materials. In the field of metallic brackets, expansion of the use of titanium alloys with improved hardness and nickel-free steels with better corrosion resistance and increased hardness is expected. Manufacturing techniques might be modified to include laser-welding methods and metal injection molding. Esthetic bracket research will involve the synthesis of high-crystallinity biomedical polymers with increased hardness and stiffness, decreased water sorption, and improved resistance to degradation. New plastic brackets might incorportate ceramic wings. Fiber-reinforced composite archwires, currently experimental, could soon be commercially available, and long-term applications of shape-memory plastics might become viable. Advancements in elastomeric materials will result in polymers with reduced relaxation, broader use of fluoride-releasing elastomers with decreased relaxation, and large-scale film coating of elastomers to decrease reactivity, water sorption, and degradation. Finally, biocompatibility assessments will incorporate testing of potential endocrinological action. New polymer formulations might be tested in adhesive and plastic bracket manufacturing, based on benzoic ring-free monomers to avoid the adverse effects of the estrogenic molecule bisphenol-A. (Am J Orthod Dentofacial Orthop 2007;131:253-62) T he second part of this article includes a review of the current status of brackets, elastomerics, and archwires along with a projection of future developments in materials technology and clinical applications. It also gives a brief description of the novel assessment of the biological properties of polymers, which have already been implemented in associated biomedical disciplines.

Measuring blood hematocrit noninvasively is reviewed in this paper. Although there is an inclination to
measure the hematocrit by determining the bioelectrical impedance of the blood, in vitro experimental
methods still remain practically inapplicable. The blood sample size is determined when blood samples
are examined. Determining the impedance and volume of blood is the biggest challenge in measuring
the hematocrit noninvasively without drawing a blood sample. Calculating the blood impedance in vivo
requires developing an impedance measurement using a multi-frequency method and also calculating
the change in pressure simultaneously during the heart’s pulsatile cycle.

Combinatorial strategy has been used in therapeutic angiogenesis in animal models of peripheral arterial disease (PAD) and coronary artery disease for decades. Previous studies have shown that basic fibroblast growth factor (FGF-2) and platelet-derived growth factor BB (PDGF-BB) proteins together establish functional and stable vascular networks on mouse corneal and also in animal model of hindlimb ischemia. However, the short half life of protein by single injection is not sufficient to achieve effective dosage, repeated and prolonged injection causes systemic toxicity. Here we study the synergistic effects of FGF-2 and PDGF-BB by intramuscular injection of naked plasmid DNA on therapeutic angiogenesis in rabbit model of hindlimb ischemia. We found that transient delivery of FGF-2 and PDGF-BB naked DNA together resulted in greater increases in capillary growth, collateral formation and popliteal blood flow compared with control and single gene delivery. Our data provided novel evidence of beneficial effects of DNA-based FGF-2 and PDFG-BB on muscle repair after ischemic injury. These findings reveal an alternative therapeutic approach in the treatment of ischemic diseases and even in muscular disorders.

In this study, an equivalent circuit model (ECM) to simulate the Neuromuscular Electrical Stimulation (NMES) has been developed. The ECM includes all regions from the transcutaneous electrodes to the neuron cell membrane to simulate the nerve stimulation with biphasic rectangular waveform. The model was developed as a series of 'tissue subsystems', hence these can be treated independently. The frequency and current density dependency of the electrodeelectrolyte and gel-skin interfaces and the frequency dependency of the tissues were considered. The ECM was used to simulate in PSpice 6 strength-duration curves obtained by experimental transcutaneous stimulation of the extensor muscles in the forearm of one subject using two fully gelled electrodes of size 45x80 mm². To monitor muscle contraction, a three axial accelerometer was placed on the proximal phalange of the middle finger. The mean voltage response in the stimulation experiments was compared with ECM simulations. The energy dissipation in the human tissue layers was investigated using the ECM. The correlation coefficient was used to evaluate quantitatively the agreement between simulations and experiments.

Signalling interactions between the polarizing region, which produces SHH, and the apical ectodermal ridge, which produces FGFs, are essential for outgrowth and patterning of vertebrate limbs. However, mechanisms that mediate translation of early positional information of cells into ...

The approach to supraventricular tachycardia (SVT) diagnosis can be complex because it involves synthesizing baseline electrophysiologic features, features of the SVT, and the response(s) to pacing maneuvers. In this two-part review, we will mainly explore the latter while recognizing that neither of the former can be ignored, for they provide the context in which diagnostic pacing maneuvers must be correctly chosen and interpreted. Part 1 involved a detailed consideration of ventricular overdrive pacing, since this pacing maneuver provides the diagnosis in the majority of cases. In Part 2, other diagnostic pacing maneuvers that might be helpful when ventricular overdrive pacing is not diagnostic or appropriate, including attempts to reset SVT with single atrial or ventricular beats, para-Hisian pacing, apex versus base pacing, and atrial overdrive pacing, are discussed, as are some specific diagnostic SVT challenges encountered in the electrophysiology lab. There is considerable literature on this topic, and this review is by no means meant to be all-encompassing. Rather, we hope to clearly explain and illustrate the physiology, strengths, and weaknesses of what we consider to be the most important and commonly employed diagnostic pacing maneuvers, that is, those that trainees in cardiac electrophysiology should be well familiar with at a minimum. (PACE 2012; 35:757-769)

Evidence-based medicine (EBM) is the combination of the best available research evidence with clinical experience and patient needs. The concept of EBM as a part of clinical decision making has become increasingly popular over the last decade. In the hierarchy of studies meta-analysis and systematic reviews occupy the highest levels. A systematic review of a clinical question can be performed by following a relatively standard form. These techniques as described here can be performed without formal training. Systematic reviews conducted in this fashion can be used as a higher form of current concepts or as review articles and replace the traditional expert opinion narrative review.

This paper describes the highlights of presentations and discussions during the Third International BCI Meeting in a workshop that evaluated potential brain-computer interface (BCI) signals and currently available recording methods. It defined the main potential user populations and their needs, addressed the relative advantages and disadvantages of noninvasive and implanted (i.e., invasive) methodologies, considered ethical issues, and focused on the challenges involved in translating BCI systems from the laboratory to widespread clinical use. The workshop stressed the critical importance of developing useful applications that establish the practical value of BCI technology.

The paper examines electrophysiological activity produced by exposing the brains of laboratory animals to rectangular pulses of microwave energy. These results suggest that a microwave auditory phenomenon is evoked by a mechanism similar to conventional sound reception, and that the primary interaction site is peripheral to the cochlea. It is shown that the peak pressure due to thermal expansion is greater than the radiation pressure or electrostriction, and that the induced sound frequency is only a function of the size and acoustic property of the brain. Several suggestions were made for future research in microwave auditory effect and its health implications. ~~~~~~~ TITLE: Sensation and perception of microwave energy Authors: Michaelson, S. M. (Rochester Univ.)

Passive optical network (PON) is one of the most successful broadband access architectures being deployed worldwide. PONs provide high capacity, increased reach, and low-power consumption at a very reasonable cost, on par with the cost of DSL deployments today. This paper provides an overview of present and emerging PON technologies, and discusses PON's important role in the evolution of optical access from the architectural perspective. While describing the evolution of optical access architecture, we present two important integration options: optical+wireless access integration and metro+access integration. Potential PON capacity upgrades are discussed with special emphasis on achieving a seamless upgrade. We evaluate different PON evolution strategies in the context of next-generation PON, where gradual, demand-based migration demonstrates a number of significant benefits.

Intentional replantation has been practised for many years as a treatment modality for pulpless teeth. Although the success ratio for intentional replantation is far below that for routine or surgical endodontics, this procedure should be considered an alternative to tooth extraction. A case of mandibular second molars treated with intentional replantation and retrograde fillings is reported in this article. At the eight-year recall visit, radiographs showed no evidence of pathological changes.

Novel microfluidic tools allow new ways to manufacture and test drug delivery systems. Organ-on-a-chip systems - microscale recapitulations of complex organ functions - promise to improve the drug development pipeline. This review highlights the importance of integrating microfluidic networks with 3D tissue engineered models to create organ-on-a-chip platforms, able to meet the demand of creating robust preclinical screening models. Specific examples are cited to demonstrate the use of these systems for studying the performance of drug delivery vectors and thereby reduce the discrepancies between their performance at preclinical and clinical trials. We also highlight the future directions that need to be pursued by the research community for these proof-of-concept studies to achieve the goal of accelerating clinical translation of drug delivery nanoparticles.

Novel microfluidic tools allow new ways to manufacture and test drug delivery systems. Organ-on-a-chip systems - microscale recapitulations of complex organ functions - promise to improve the drug development pipeline. This review highlights the importance of integrating microfluidic networks with 3D tissue engineered models to create organ-on-a-chip platforms, able to meet the demand of creating robust preclinical screening models. Specific examples are cited to demonstrate the use of these systems for studying the performance of drug delivery vectors and thereby reduce the discrepancies between their performance at preclinical and clinical trials. We also highlight the future directions that need to be pursued by the research community for these proof-of-concept studies to achieve the goal of accelerating clinical translation of drug delivery nanoparticles.

Background: Over fifty percent of stroke patients experience chronic arm hand performance problems, compromising independence in daily life activities and quality of life. Task-oriented training may improve arm hand performance after stroke, whereby augmented therapy may lead to a better treatment outcome. Technology-supported training holds opportunities for increasing training intensity. However, the effects of robot-supported task-oriented training with real life objects in stroke patients are not known to date. The aim of the present study was to investigate the effectiveness and added value of the Haptic Master robot combined with task-oriented arm hand training in chronic stroke patients.

Materials for solid photoacoustic breast phantoms, based on poly(vinyl alcohol) hydrogels, are presented. Phantoms intended for use in photoacoustics must possess both optical and acoustic properties of tissue. To realize the optical properties of tissue, one approach was to optimize the number of freezing and thawing cycles of aqueous poly(vinyl alcohol) solutions, a procedure which increases the turbidity of the gel while rigidifying it. The second approach concentrated on forming a clear matrix of the rigid poly(vinyl alcohol) gel without any scattering, so that appropriate amounts of optical scatterers could be added at the time of formation, to tune the optical properties as per requirement. The relevant optical and acoustic properties of such samples were measured to be close to the average properties of human breast tissue. Tumour simulating gel samples of suitable absorption coefficient were created by adding appropriate quantities of dye at the time of formation; the samples were then cut into spheres. A breast phantom embedded with such 'tumours' was developed for studying the applicability of photoacoustics in mammography.

T he functional and esthetic restoration of severely damaged endodontically treated teeth is still a clinical challenge. 1 A typical protocol to restore these teeth is to use posts and cores and a full-coverage crown. However, with the development of adhesive dentistry, this goal is easily made feasible by an endocrown. 2 An endocrown is a one-piece, post-free ceramic restoration that assemble the crown and the pulpal cavity part in one component. 3 In comparison to the classical post-and-core approach, this modern alternative treatment modality offers several advantages, such as more preservation of tooth structure, less need for sufficient interocclusal space, reduced risk of root fracture, and possibility of retreatment in case of endodontic failure. Moreover, both the number of appointments and the cost decrease, as there is no need for the many technical steps for post cementation, core build up, and potential crown lengthening. 4,5 A systematic review done by Wittneben et al 6 revealed an overall survival rate of 91.6% after 5 years for computer-aided design/computer-assisted manufacture (CAD/CAM) single-tooth restorations, which is considered clinically similar to conventional restorations. However, the lowest rate was found in endocrowns (82.3%). This Purpose: To evaluate and compare the internal and marginal adaptations of chairside CAD/CAM (CEREC) endocrowns and crowns fabricated from lithium disilicate glass-ceramic (IPS e.max CAD), zirconia-reinforced lithium silicate glass-ceramic (VITA Suprinity), and hybrid ceramic (VITA Enamic). Materials and Methods: Dental models of the two first maxillary molars were selected. One was prepared for an endocrown, and the other for a standard all-ceramic crown. A total of 72 CAD/CAM restorations, including 36 endocrowns and 36 crowns made of IPS e.max CAD, VITA Suprinity, and VITA Enamic (n = 12 each), were fabricated. Discrepancies were measured in the buccal, mesial, lingual, and distal aspects of three sites (marginal, midaxial wall, and occlusal/floor) using the noncontact ATOS scanner. Statistical analysis was performed using MANOVA and between-subject effects tests (α = .05). Results: Mesial axial wall discrepancy was significantly lower in endocrowns compared to occlusal discrepancy in crowns, while distal axial wall discrepancy was significantly higher. Moreover, floor discrepancy was found to be significantly lower in endocrowns compared to occlusal discrepancy in crowns. However, type of material had no significant effect on any kind of discrepancy. Conclusion: The marginal and internal adaptation values were within a clinically acceptable range for both kinds of restoration and all three materials. However, restoration type (crown vs endocrown) was significantly different in the mesial and distal axial wall and occlusal/floor discrepancies, regardless of restoration material.

Objective. This investigation aims to determine (1) whether shockwave treatment helps fracture healing and (2) whether the effect of shockwave treatment on fracture healing is dose dependent. Design. Shockwave was applied over tibial osteotomy in an animal model to assess its effect on the healing of the fracture. Methodology. Bilateral tibial diaphyseal transverse osteotomy was conducted on 42 rabbits, dividing into experimental and control group, immobilized using an external skeletal fixator, with one leg tested with shockwave therapy and the contralateral leg acting as the control without therapy. Serial radiography and measurement of bone mineral density via dual-energy X-ray absorptiometry were performed to assess the fracture healing. The experimental animals had two or three sessions of shockwave therapy (5000 impulses, 0.32 mJ/mm 2 , Orthopedice) over the osteotomy sites on day 7, 21 and 35; while the control group did not receive any treatment. The animals were sacrificed on day 42 or 56. Then, bilateral tibias were harvested and sent for mechanical tests as well as the histological examination. The pertinent statistic methods were applied to analyze the results. Background. Shockwave therapy has become a useful alternative approach in treating various orthopedic conditions, but the mechanism which it works remains unclear. Thus far, shockwave therapy has been found effective in treating long bone pseudoarthrosis, but whether it can benefit fresh fracture healing continues to be debated. Results. Higher union rates occurred during the early but not the late stages in the experimental group, while mechanical strength was higher in the experimental group than in the control group. No significant dose-dependent response occurred between the second and third applications of shockwave treatment. No significant difference in mechanical strength occurred between the experimental groups at 4 weeks and the control group at 6 weeks, or between the experimental groups at 6 and 8 weeks. Furthermore, no significant correlation occurred between the absolute values of maximum torque and bone mineral density. Conclusion. Based on this investigation, shockwave treatment has a positive effect on early fracture healing while its long term effects require further investigation. Relevance Shockwave therapy can be a useful alternative adjunct modality in the treatment of fresh long bone fracture.