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Purpose: Mitral valve surgery in children involves correcting congenital and acquired pathologies, with a reported mortality rate of 0.9%. Low cardiac output syndrome (LCOS) is a serious complication with the incidence of 20-25%. The aim of the study was to estimate possible prognostic factors of LCOS in children undergoing mitral valve procedure., Material and Method: This single-center retrospective analysis enrolled children aged <18 years who underwent mitral valve surgery during 24 year period. Preoperative clinical and laboratory parameters, and operative factors were analyzed., Results: Thirty consecutive pediatric patients (11 (37%) males and 19 (63%) females) in median (Q 1 - Q 3 ) age of 57 (25-115) months, who underwent mitral valve replacement, were included. The 30-day mortality was 7% (2 patients) and was related to postoperative multiorgan failure. LCOS occurred in 8 (27%) children. The receiver operator curve (ROC) analysis established parameters that have predictive value for LCOS occurrence: cardiopulmonary bypass (CPB) time, with 89 ​min as optimal cut-off point (AUC ​= ​0.744, p ​= ​0.011) yielding sensitivity of 100% and specificity of 42.9%; left ventricular ejection fraction (LVEF) ​< ​60 % (AUC ​= ​0.824, okp ​= ​0.001) with sensitivity of 62.5% and specificity of 93.75%; and red blood cell distribution width (RDW) above 14.5 % (AUC ​= ​0.840, p ​< ​0.001; sensitivity of 87.5% and specificity of 75%)., Conclusions: In mitral valve replacement in pediatric patients, CPBtime above 89 ​min, preoperative LVEF below 60% and preoperative RDW above 14.5% can be regarded as the potential predictors of LCOS., Competing Interests: Declaration of competing interest The authors declare no conflict of interests., (Copyright © 2024. Published by Elsevier B.V.)

Handoff mechanisms are very important in fifth-generation (5G) mobile networks because of the cellular architecture employed to maximize spectrum utilization. Together with call admission control (CAC) mechanisms, they enable better optimization of bandwidth use. The primary objective of the research presented in this article is to analyze traffic levels, aiming to optimize traffic management and handling. This article considers the two most popular CAC mechanisms: the resource reservation mechanism and the threshold mechanism. It presents an analytical approach to occupancy distribution and blocking probability calculation in 5G mobile networks, incorporating connection handoff and CAC mechanisms for managing multiple traffic streams generated by multi-service sources. Due to the fact that the developed analytical model is an approximate model, its accuracy was also examined. For this purpose, the results of analytical calculations of the blocking probability in a group of 5G cells are compared with the simulation data. This paper is an extended version of our paper published in 17th ConTEL 2023.

The use of 2,5-diformylpyrrole in self-assembly reactions with diamines and Zn(II)/Cd(II) salts allowed the preparation of [2]catenane, trefoil knot, and Borromean rings. The intrinsically dynamic nature of the diiminopyrrole motif rendered all of the formed assemblies intramolecularly flexible. The presence of diiminopyrrole revealed new coordination motifs and influenced the host-guest chemistry of the systems, as illustrated by hexafluorophosphate encapsulation by Borromean rings., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Causal analysis plays a significant role in physics, chemistry, and biology. Dynamics of complex (bio)molecular and nanosystems, from the microscopic to the macroscopic scale, are characterized by time-dependent vectors such as positions, forces, momenta, angular momenta, or torques. Identification and analysis of causal relationships between these time-dependent signals is an important problem in the multidimensional time-series analysis and is of great practical importance in describing the properties of such dynamical systems, and to understanding their functionality. For linear stochastic systems characterized by multidimensional scalar signals, Granger proposed a simple procedure to detect causal relationships, called Granger causality. In this study we extended this formalism to vector signals representing physical vector quantities. For this purpose, we used quaternion algebra, where vector signals are treated as time-dependent quaternions. The developed analytical model is based on the autoregressive formalism. This formalism (Q-MVAR) and its numerical implementation were validated using two simple dynamic models: a rigid body model represented by a benzenelike molecular fragment, interacting with a short-range harmonic potential with a wall, as well as a system of three model atomic balls moving inside a soft spherical surface and interacting with long range electrostatic forces. Although the motivation to these studies was the analysis of classical motions in complex (bio)molecular systems, described with a mechanical model and based on molecular dynamics (MD) simulations, in particular coarse-grained ones, it should be noted that the developed extended formalism can be applied to any system composed of many rigid elements that interact with arbitrary potentials and are characterized by complex internal motions. A description of the detailed procedure for calculating causality measures is provided in the Appendices of the Supplemental Material. This formalism and the prototype of its numerical implementation can be further developed and applied in many different fields of physical, natural, and engineering sciences.

Constantly advancing computer simulations of biomolecules provide huge amounts of data that are difficult to interpret. In particular, obtaining insights into functional aspects of macromolecular dynamics, often related to cascades of transient events, calls for methodologies that depart from the well-grounded framework of equilibrium statistical physics. One of the approaches toward the analysis of complex temporal data which has found applications in the fields of neuroscience and econometrics is Granger causality analysis. It allows determining which components of multidimensional time series are most influential for the evolution of the entire system, thus providing insights into causal relations within the dynamic structure of interest. In this work, we apply Granger analysis to a long molecular dynamics trajectory depicting repetitive folding and unfolding of a mini β-hairpin protein, CLN025. We find objective, quantitative evidence indicating that rearrangements within the hairpin turn region are determinant for protein folding and unfolding. On the contrary, interactions between hairpin arms score low on the causality scale. Taken together, these findings clearly favor the concept of zipperlike folding, which is one of two postulated β-hairpin folding mechanisms. More importantly, the results demonstrate the possibility of a conclusive application of Granger causality analysis to a biomolecular system.

Protein structure networks (PSNs) have long been used to provide a coarse yet meaningful representation of protein structure, dynamics, and internal communication pathways. An important question is what criteria should be applied to construct the network so that to include relevant interresidue contacts while avoiding unnecessary connections. To address this issue, we systematically considered varying residue distance cutoff length and the probability threshold for contact formation to construct PSNs based on atomistic molecular dynamics in order to assess the amount of mutual information within the resulting representations. We found that the minimum in mutual information is universally achieved at the cutoff length of 5 Å, irrespective of the applied contact formation probability threshold in all considered, distinct proteins. Assuming that the optimal PSNs should be characterized by the least amount of redundancy, which corresponds to the minimum in mutual information, this finding suggests an objective criterion for cutoff distance and supports the existing preference towards its customary selection around 5 Å length, typically based to date on heuristic criteria., (© 2021 Wiley Periodicals LLC.)

Introduction: Triple-negative breast cancer (TNBC) is associated with lack of expression of estrogen and progesterone receptors and HER2 and is the subgroup of breast cancers with the worst prognosis. Osteopontin is a phosphorylated glycoprotein whose overexpression may occur in pathological states such as cancers. The main purpose of our study was to evaluate the immunohistochemical expression of osteopontin in connection with the analysis of recognized clinical and pathological prognostic factors in primary sites of TNBC with and without lymph node metastases., Material and Methods: The immunohistochemical evaluation of osteopontin expression in 35 women with TNBC, chosen from a group of 726 patients, was performed. The material came from the excisional biopsies of primary breast cancers and total mastectomies., Results: All patients showed expression of osteopontin, in most cases the expression of osteopontin rated at [+] (57.1%) and [++] (42.9%). Our study analyzed the relationship between the expression of osteopontin and traditional prognostic markers, such as the tumor grade, size, and lymph node involvement. We found a strong relationship only between the expression of osteopontin and the presence of lymph node metastases ( p ≤ 0.0001). 93% of patients for whom the expression of osteopontin was determined at [++] had metastasis to lymph nodes and, for comparison, only 15% of women for whom the expression of osteopontin was rated at [+] showed the presence of metastases in the lymphatic nodes., Conclusions: There is a correlation between osteopontin expression and the presence of lymph node metastases in TNBC, suggesting that osteopontin plays an important role in the invasiveness of TNBC., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2020 Termedia & Banach.)

Objectives: To perform the preliminary tests of coarctation of aorta repair trainer, evaluate the surgical properties of the simulation and to assess and enhance residents' skills., Methods: Single patient's angio-CT anatomy data were converted into magnified 3D-printed model of aortic coarctation with hypoplastic aortic arch, serving for creation of a mould used during wax copies casting. Wax cores were painted with six layers of elastic silicone and melted, yielding phantoms that were consecutively fixed in a mounting with and without a thoracic wall. Simulation included: proximal and distal aortic arch clamping, incision of its lesser curvature, extended end-to-end anastomosis with 7-0 suture. A head-mounted camera video recording enabled anastomosis time and mean one suture bite time evaluation. Leakage assessment was done by a water test., Results: Two residents performed nine simulations each. Last four runs were performed with thoracic wall attached. All phantoms performed well, enabling tissue-like handling and cutting, excellent suture retention, and satisfactory elasticity. Median anastomosis times were 22'33″ and 24'47″ for phantoms without and with thoracic wall (p = not significant (NS)). Median times needed to pass suture through one side of anastomosis and regrasp needle were, respectively, 9″ and 13″ (p < 0.001). Median total number of leakages per phantom equalled 2 for both difficulty levels. There were no significant inter-resident differences in all assessed parameters., Conclusions: This medium-fidelity aortic coarctation repair trainer showed its feasibility in replication of major critical steps of the real operation. Objective surgical efficiency parameters could be obtained from each simulation and compared between trainees and at different adjustable difficulty levels.

The acceptance of many foods is related to traditional cooking practices, which create taste and texture and are important to digestibility, preservation, and the reduction of foodborne illnesses. A wide range of compounds are formed during the cooking of foods, a number of these have been shown to lead to adverse effects in classical toxicological models and are known as food processing contaminants (FPC). It is essential that the presence and effects of such compounds alone and in combination within the diet are understood such that proportionate risk management measures can be developed, while taking a holistic view across the whole value chain. Furan and alkylfurans (principally 2- and 3-methylfuran) are highly volatile FPC, which are formed in a wide range of foods at low amounts. The focus of research to-date has been on those foods, which have been identified to be most consequential in terms of being sources of exposure, namely jarred and canned foods for infants and young children (meals and drinks) and coffee (roast and ground, soluble). This report presents (i) new industry data on the occurrence of furan and methylfurans in selected food categories following previous coffee studies, (ii) the most salient parameters that impact furan formation, and (iii) aspects of importance for the risk assessment., (© 2019 Institute of Food Technologists®.)

Injuries to the extremities often require resection of necrotic hard tissue. For large-bone defects, autogenous bone grafting is ideal but, similar to all grafting procedures, is subject to limitations. Synthetic biomaterial-driven engineered healing offers an alternative approach. This work focuses on three-dimensional (3D) printing technology of solid-free form fabrication, more specifically robocasting/direct write. The research hypothesizes that a bioactive calcium-phosphate scaffold may successfully regenerate extensive bony defects in vivo and that newly regenerated bone will demonstrate mechanical properties similar to native bone as healing time elapses. Robocasting technology was used in designing and printing customizable scaffolds, composed of 100% beta tri-calcium phosphate (β-TCP), which were used to repair critical sized long-bone defects. Following full thickness segmental defects (~11 mm × full thickness) in the radial diaphysis in New Zealand white rabbits, a custom 3D-printed, 100% β-TCP, scaffold was implanted or left empty (negative control) and allowed to heal over 8, 12, and 24 weeks. Scaffolds and bone, en bloc, were subjected to micro-CT and histological analysis for quantification of bone, scaffold and soft tissue expressed as a function of volume percentage. Additionally, biomechanical testing at two different regions, (a) bone in the scaffold and (b) in native radial bone (control), was conducted to assess the newly regenerated bone for reduced elastic modulus (E r ) and hardness (H) using nanoindentation. Histological analysis showed no signs of any adverse immune response while revealing progressive remodelling of bone within the scaffold along with gradual decrease in 3D-scaffold volume over time. Micro-CT images indicated directional bone ingrowth, with an increase in bone formation over time. Reduced elastic modulus (E r ) data for the newly regenerated bone presented statistically homogenous values analogous to native bone at the three time points, whereas hardness (H) values were equivalent to the native radial bone only at 24 weeks. The negative control samples showed limited healing at 8 weeks. Custom engineered β-TCP scaffolds are biocompatible, resorbable, and can directionally regenerate and remodel bone in a segmental long-bone defect in a rabbit model. Custom designs and fabrication of β-TCP scaffolds for use in other bone defect models warrant further investigation., (© 2018 John Wiley & Sons, Ltd.)

Introduction: Cardioplegia is one of the most important modalities of myocardial protection during heart surgery., Aim: To assess the impact of blood cardioplegia on postoperative variables, in comparison with two types of crystalloid cardioplegic solutions during pediatric heart surgery., Material and Methods: One thousand one hundred and twenty-nine patients underwent surgical correction of congenital heart disease with cardioplegia administration between 2006 and 2012. Nonlinear regression models of postoperative low cardiac output syndrome (LCOS) incidence, catecholamine index and total complication count were developed using a genetic algorithm. The Akaike information criterion was applied for selection of the best model. The following explanatory variables were evaluated: cardioplegia type (ST - Saint Thomas, n = 440; FR - Fresenius, n = 432; BL - Calafiore, n = 257), congenital heart diseases (CHD) type, age, sex, genetic disorder presence, body surface area (BSA), cardiopulmonary bypass (CBP) time, aortic cross-clamp time, operation urgency, redo surgery, surgeon., Results: Low cardiac output syndrome presence and higher than average catecholamine indexes were negatively influenced by use of crystalloid cardioplegia (ST or FR), presence of specific CHDs, redo surgery and prolonged CBP time. Increased complication count was related to: crystalloid cardioplegia, presence of specific CHDs, redo surgery, urgency of operation, operation time and CBP time. Higher BSA had a protective effect against higher catecholamine index and increased complication count. Older age was protective against LCOS., Conclusions: Cardioplegic solutions type influences postoperative variables in children after heart surgery by the negative impact of crystalloid cardioplegia. Blood cardioplegia presents potential advantages for patients - its application may reduce the incidence of low cardiac output syndrome and related complications.

Total joint arthroplasty of the hip and knee are successful orthopedic procedures that reduce pain and improve mobility in patients. As the implanted materials used in these procedures have improved, the lifetime of the implants has now reached more than 20 years. Younger patients are undergoing total joint arthroplasty at increasing rates, which has increased the need for improvements in materials for extended implant longevity. In this review, we aim to provide historical perspective on the evolution of ultra-high-molecular-weight polyethylene in total joint arthroplasty. We review this material with respect to its structure, mechanical properties, wear rates, sterilization effects, crosslinking, and other new polymer innovations. Ultra-high-molecular-weight polyethylene (UHMWPE) has been a cornerstone for total joint arthroplasty and with continued design improvements will continue to be vital to this successful orthopedic operation.

The fungi of the genus Fusarium cause Fusarium head blight (FHB), a devastating disease that reduces grain yield and quality. They also produce mycotoxins which may pose a serious threat to human and animal health. This study investigated the effects of NPK fertilisation, foliar application of Cu, Zn, and Mn, applied separately and in combination, and of the Nano-Gro® organic growth stimulator on the occurrence of FHB in cultivar Dańkowskie Diament rye based on the mycological analysis of kernels and on the concentrations of Fusarium mycotoxins in grain. The severity of FHB caused by seven species of the genus Fusarium was influenced by weather conditions in the analysed growing seasons. The applied fertilisation and the Nano-Gro® organic growth stimulator exerted varied effects on FHB development and the biosynthesis of Fusarium mycotoxins (deoxynivalenol, nivalenol, zearalenone and fumonisins) in grain. The greatest reduction in deoxynivalenol and nivalenol concentrations was noted in 2013, and the levels of moniliformin were lower in treated samples than in absolute control (untreated) samples in both years of the study. The severity of FHB positively correlated with the concentrations of zearalenone, deoxynivalenol, nivalenol, and moniliformin in the grain samples. Greater accumulation of ergosterol was noted in the rye grain harvested in 2013 than in 2012, and fertiliser treatment led to higher ergosterol concentrations than did control treatment.

A 67-year-old man presented to orthopaedic care with a painful knee. Workup was consistent with septic arthritis of a native knee, and the patient underwent operative treatment. Cultures from the operating room were speciated to Staphylococcus lugdunensis. To the investigators' knowledge, this is the first reported S. lugdunensis infection in a peripheral joint in the absence of an orthopaedic prosthesis. Although traditionally associated with infectious endocarditis, S. lugdunensis has been identified as a causative agent in many organ systems, including orthopaedic infections. This case report emphasizes the importance of familiarity with this emerging pathogen in the treatment of a septic joint.

Introduction: Animal pericardial patches are widely used in adult and pediatric cardiac surgery. A search is ongoing for a new material with optimal surgical properties that will reduce intraoperative bleeding and the occurrence of restenosis, calcification, and pseudoaneurysms in long-term observation. One product of interest is the CardioCel bovine pericardial patch., Aim: Evaluation of the short-term results of CardioCel bovine pericardial patch implantation during pediatric cardiac surgery., Material and Methods: The study included 8 patients who underwent surgical correction of congenital cardiac defects between January 2015 and February 2016. Pericardial patches were used to repair supravalvular aortic stenosis and reconstruct the aortic arch and pulmonary arteries. The age of the patients ranged from 10 days to 14 years., Results: There were no hospital deaths. The new material exhibited satisfactory durability and elasticity during surgery, facilitating optimal adaptation of the patch to the patient's tissues. No significant bleeding was reported from the suture site. The median duration of follow-up was 58 days. During the follow-up, there were no symptoms of pseudoaneurysm formation, patch thickening, or calcification in the areas where the pericardial patches were implanted. No clinical or laboratory symptoms of infection were observed in locations where the new material was applied., Conclusions: Satisfactory surgical properties of the patch were observed intraoperatively. Positive results using the new pericardial patch were obtained in short-term follow-up.

The human vocal folds are complex structures made up of distinct layers that vary in cellular and extracellular composition. The mechanical properties of vocal fold tissue are fundamental to the study of both the acoustics and biomechanics of voice production. To date, quantitative methods have been applied to characterize the vocal fold tissue in both normal and pathologic conditions. This review describes, summarizes, and discusses the most commonly employed methods for vocal fold biomechanical testing. Force-elongation, torsional parallel plate rheometry, simple-shear parallel plate rheometry, linear skin rheometry, and indentation are the most frequently employed biomechanical tests for vocal fold tissues and each provide material properties data that can be used to compare native tissue to diseased or treated tissue. Force-elongation testing is clinically useful, as it allows for functional unit testing, while rheometry provides physiologically relevant shear data, and nanoindentation permits micrometer scale testing across different areas of the vocal fold as well as whole organ testing. Thoughtful selection of the testing technique during experimental design to evaluate a hypothesis is critical to optimize biomechanical testing of vocal fold tissues., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Predicting FRET pathways in proteins using computer simulation techniques is very important for reliable interpretation of experimental data. A novel and relatively simple methodology has been developed and applied to purine nucleoside phosphorylase (PNP) complexed with a fluorescent ligand - formycin A (FA). FRET occurs between an excited Tyr residue (D*) and FA (A). This study aims to interpret experimental data that, among others, suggests the absence of FRET for the PNPF159A mutant in complex with FA, based on novel theoretical methodology. MD simulations for the protein molecule containing D*, and complexed with A, are carried out. Interactions of D* with its molecular environment are accounted by including changes of the ESP charges in S1, compared to S0, and computed at the SCF-CI level. FRET probability W F depends on the inverse six-power of the D*-A distance, R da . The orientational factor 0 < k(2) < 4 between D* and A is computed and included in the analysis. Finally W F is time-averaged over the MD trajectories resulting in its mean value. The red-shift of the tyrosinate anion emission and thus lack of spectral overlap integral and thermal energy dissipation are the reasons for the FRET absence in the studied mutants at pH 7 and above. The presence of the tyrosinate anion results in a competitive energy dissipation channel and red-shifted emission, thus in consequence in the absence of FRET. These studies also indicate an important role of the phenyl ring of Phe159 for FRET in the wild-type PNP, which does not exist in the Ala159 mutant, and for the effective association of PNP with FA. In a more general context, our observations point out very interesting and biologically important properties of the tyrosine residue in its excited state, which may undergo spontaneous deprotonation in the biomolecular systems, resulting further in unexpected physical and/or biological phenomena. Until now, this observation has not been widely discussed in the literature.

The human vocal fold is a complex structure made up of distinct layers that vary in cellular and extracellular matrix composition. Elucidating the mechanical properties of vocal fold tissues is critical for the study of both acoustics and biomechanics of voice production, and essential in the context of vocal fold injury and repair. Both quasistatic and dynamic behavior in the 10-300 Hz range was explored in this preliminary investigation. The resultant properties of the lamina propria were compared to that of the nearby thyroarytenoid muscle. Er, quantified via quasistatic testing of the lamina propria, was 609±138 MPa and 758±142 MPa in the muscle (p=0.001). E' of the lamina propria as determined by dynamic testing was 790±526 MPa compared to 1061±928 MPa in the muscle. Differences in E' did not achieve statistical significance via linear mixed effect modeling between the tissue types (p=0.95). In addition, frequency dependence was not significant (p=0.18)., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The present study aimed to characterize the mechanical response of beagle sartorius muscle fibers under strain rates that increase logarithmically (0.1mm/min, 1mm/min and 10mm/min), and provide an analysis of the fracture patterns of these tissues via scanning electron microscopy (SEM). Muscle tissue from dogs' sartorius was excised and test specimens were sectioned with a lancet into sections with nominal length, width, and thickness of 7, 2.5 and 0.6mm, respectively. Trimming of the tissue was done so that the loading would be parallel to the direction of the muscle fiber. Samples were immediately tested following excision and failures were observed under the SEM. No statistically significant difference was observed in strength between the 0.1mm/min (2.560±0.37MPa) and the 1mm/min (2.702±0.55MPa) groups. However, the 10mm/min group (1.545±0.50MPa) had a statistically significant lower strength than both the 1mm/min group and the 0.1mm/min group with p<0.01 in both cases. At the 0.1mm/min rate the primary fracture mechanism was that of a shear mode failure of the endomysium with a significant relative motion between fibers. At 1mm/min this continues to be the predominant failure mode. At the 10mm/min strain rate there is a significant change in the fracture pattern relative to other strain rates, where little to no evidence of endomysial shear failure nor of significant motion between fibers was detected., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Anterior cruciate ligament injury affects roughly 120,000 athletes in the United States every year. One of the most common techniques is the use of a bone-patellar tendon-bone graft. Graft harvest creates a sizeable defect in the remaining patellar tendon. Closure of this defect is based on surgeon preference. To date there has been no study on the effects of defect closure on the mechanical properties of remaining donor patellar tendon. The goal of this study was to investigate the effect of closure on both the strength and stiffness of the remaining patellar tendon. 7 pairs of fresh frozen cadaver patellar tendons were matched by tendon dimensions. Bone-patellar tendon-bone grafts were harvested from all of the specimens and then half of the paired tendons underwent defect closure. All of the donor tendons were then tested in a servohydraulic load frame to failure at a constant displacement rate at room temperature. This study found no differences in the load at failure, the engineering failure stress, stiffness or in the engineering modulus between the donor tendons that underwent defect closure versus those that did not., (© Georg Thieme Verlag KG Stuttgart · New York.)

Tumor necrosis factor-α antagonists (anti-TNFα) have become increasingly more common as a treatment for rheumatoid arthritis (RA). However, there has been an increased incidence of severe infections in patients taking anti-TNFα therapy. We present a case series of RA patients treated with anti-TNFα therapy that had previously underwent TJA and subsequently developed periprosthetic infections. All patients had a well-functioning implant for a period of 1 to 14 years prior to the development of infection. Each patient underwent two to five different joint replacements, and four patients developed infection in multiple sites. The infections proved difficult to eradicate with four patients requiring multiple procedures, and one patient ultimately requiring a hemipelvectomy. This study suggests that periprosthetic infections acquired by patients on anti-TNFα therapy are challenging to eradicate and treat; highlighting the need for the establishment of guidelines for perioperative and long-term management of anti-TNFα therapy, and infection monitoring in joint replacement patients.

Bone is a viscoelastic connective tissue composed primarily of mineral and type I collagen, which interacts with water, affecting its mechanical properties. Therefore, both the level of hydration and the loading rate are expected to influence the measured nanomechanical response of bone. In this study, we investigated the influence of three distinct hydration conditions, peak loads and loading/unloading rates on the elastic modulus and hardness of canine femoral cortical bone via nanoindentation. Sections from three canine femurs from multiple regions of the diaphysis were tested for a total of 670 indentations. All three hydration conditions (dry, moist and fully hydrated tissue) were tested at three different loading profiles (a triangular loading profile with peak loads of 600, 800 and 1000 μN at loading/unloading rate of 60, 80 and 100 μN/s, respectively; each test was 20s in duration). Significant differences were found for both the elastic modulus and hardness between the dry, moist and fully hydrated conditions (p≤0.02). For dry bone, elastic modulus and hardness values were not found to be significantly different between the different loading profiles (p>0.05). However, in both the moist and fully hydrated conditions, the elastic modulus and hardness were significantly different under all loading profiles (with the exception of the moist condition at the 600- and 800-μN peak load). Given these findings, it is critical to perform nanoindentation of bone under fully hydrated conditions to ensure physiologically relevant results. Furthermore, this work found that a 20-s triangular loading/unloading profile was sufficient to capture the viscoelastic behavior of bone in the 600- to 1000-μN peak load range. Lastly, specific peak load values and loading rates need to be selected based on the structural region for which the mechanical properties are to be measured., (© 2013.)

Background: The prevalence of dentin hypersensitivity is uncertain, yet appropriate diagnosis and treatment of dentin hypersensitivity require accurate knowledge regarding its prevalence. The authors conducted a study to estimate the prevalence of dentin hypersensitivity in general dental practices and to investigate associated risk factors., Methods: The authors conducted a cross-sectional survey of 787 adult patients from 37 general dental practices within Northwest Practice-based Research Collaborative in Evidence-based DENTistry (PRECEDENT). Dentin hypersensitivity was diagnosed by means of participants' responses to a question regarding pain in their teeth and gingivae, and practitioner-investigators conducted a clinical examination to rule out alternative causes of pain. Participants recorded their pain level on a visual analog scale and the Seattle Scales in response to a one-second air blast. The authors used generalized estimating equation log-linear models to estimate the prevalence and the prevalence ratios., Results: The prevalence of dentin hypersensitivity was 12.3 percent; patients with hypersensitivity had, on average, 3.5 hypersensitive teeth. The prevalence of dentin hypersensitivity was higher among 18- to 44-year olds than among participants 65 years or older; it also was higher in women than in men, in participants with gingival recession than in those without gingival recession and in participants who underwent at-home tooth whitening than in those who did not. Hypersensitivity was not associated with obvious occlusal trauma, noncarious cervical lesions or aggressive toothbrushing habits., Conclusions: One in eight participants from general practices had dentin hypersensitivity, which was a chronic condition causing intermittent, low-level pain. Patients with hypersensitivity were more likely to be younger, to be female and to have a high prevalence of gingival recession and at-home tooth whitening., Practical Implications: Given dentin hypersensitivity's prevalence, clinicians should diagnose it only after investigating all other possible sources of pain.

Ultra high molecular weight polyethylene (UHMWPE) is a semicrystalline polymer that has been used for over four decades as a bearing surface in total joint replacements. The mechanical properties and wear properties of UHMWPE are of interest with respect to the in vivo performance of UHMWPE joint replacement components. The mechanical properties of the polymer are dependent on both its crystalline and amorphous phases. Altering either phase (i.e., changing overall crystallinity, crystalline morphology, or crosslinking the amorphous phase) can affect the mechanical behavior of the material. There is also evidence that the morphology of UHMWPE, and, hence, its mechanical properties evolve with loading. UHMWPE has also been shown to be susceptible to oxidative degradation following gamma radiation sterilization with subsequent loss of mechanical properties. Contemporary UHMWPE sterilization methods have been developed to reduce or eliminate oxidative degradation. Also, crosslinking of UHMWPE has been pursued to improve the wear resistance of UHMWPE joint components. The 1st generation of highly crosslinked UHMWPEs have resulted in clinically reduced wear; however, the mechanical properties of these materials, such as ductility and fracture toughness, are reduced when compared with the virgin material. Therefore, a 2nd generation of highly crosslinked UHMWPEs are being introduced to preserve the wear resistance of the 1st generation while also seeking to provide oxidative stability and improved mechanical properties.

This study examined the engineering and true axial stress-strain behavior of smooth cylindrical and shallow and deep notched cylindrical test specimens, under applied axial tensile loading using non-contacting methods, of both conventional and highly crosslinked ultra-high molecular weight polyethylenes (UHMWPEs). The smooth specimens experienced a uniaxial stress state, while the notched specimens experienced a triaxial stress state in the vicinity of the notch. Materials were all prepared from a single batch of medical grade GUR 1050 resin (Ticona, Bayport, TX). The two conventional UHMWPEs were as-received (virgin) and gamma radiation sterilized at 30 kGy in a nitrogen atmosphere (radiation sterilized). The two highly crosslinked UHMWPEs were each irradiated at 100 kGy and then post-processed with one of either of the two thermal treatments: annealing, which was done below the melt transition temperature (T(m)), at 110 degrees C for two hours (110 degrees C-annealed), and remelting, which was done above T(m), at 150 degrees C (150 degrees C-remelted). All of the materials showed notch strengthening; that is, a significant elevation of axial yield properties (both engineering and true) for the shallow and deep notched conditions. Axial ultimate properties (engineering and true) were significantly decreased for the notched conditions compared with the smooth condition. Hardening ratios (both true and engineering), which are defined in this work as the ratio of ultimate stress or strain to yield stress or strain, were also found to significantly decrease with notching. The extent of change was dependent on the UHMWPE material. The micromechanism of fracture differed between the smooth and notched conditions. This study suggests that notches inherent in the design of UHMWPE joint replacement components (posts, undercuts, grooves) will have different notch sensitivities depending on the UHMWPE formulation.

Background: Depressive illness is common. Depression in one family member is associated with an increased incidence of psychopathology in other family members. There are no data on the physical well being of the families of depressed individuals., Aim: To compare physical morbidity of family members of depressed patients with that of family members of comparison patients., Method: A comparative follow-up study from case notes. Two hundred and one subjects from 88 families with an index family member diagnosed with depression ('depression families') were compared with 200 subjects from 88 families with a matched index subject without depression ('comparison families'), using the Duke University Illness Severity Scores (ISS) to assess burden of illness experienced by both groups., Results: The cumulative incidence of depression over 11 months in depression families was 8.9% compared to 1.4% in the Family Practice Unit as a whole. Members of depression families had significantly greater ISS than members of comparison families (difference in means = 0.164; 95% confidence interval (CI) 0.113-0.215; P < 0.001). Excluding family members with depression (in addition to the index subject), ISS of members of depression families remained significantly greater than the comparison group (difference in means = 0.136; 95% CI 0.083-0.189; P < 0.001). Among depression families, mean ISS was significantly higher after presentation of depression in index subjects compared with before (difference in means = 0.155; 95% CI 0.115-0.194; P < 0.0001). No significant difference was seen between ISS of depression and comparison families before presentation of depression (difference in means = 0.008; 95% CI -0.004-0.058; P = 0.74)., Conclusion: Depression in patients is associated with increased physical morbidity in their families.