Influence of obesity on load-transfer mechanism, contact mechanics, and longevity of cemented acetabular cup.

Objective: This investigation aimed to assess the impact of obesity on the load-transfer mechanism, longevity, and contact mechanics of cemented acetabular cups. Methods: Three obesity scenarios were considered: obese case-I (100-110 kg), obese case-II (120-130 kg), and obese case-III (140-150 kg). Utilising six finite element models, the effects of different bodyweights on load transfer, contact mechanics, and cup longevity during normal walking conditions were assessed. Muscle forces and hip joint reaction forces were adjusted and linearly calibrated based on obesity cases. Results: Elevated stresses in cortical and cancellous bones, as well as the cement mantle, were observed in obese cases, suggesting a heightened risk of loosening and failure of the cemented fixation of the acetabular cup. Additionally, increased contact pressure and micromotion between articulating surfaces were noted in obese individuals, with a gradual escalation from obese case-I to obese case-III. Conclusions: These findings highlight the significant negative impact of obesity on the performance of cemented acetabular cups, emphasizing the importance of considering bodyweight variations in the design and assessment of orthopaedic implants for optimal functionality and durability.

Finite element analysis of vertebroplasty in the osteoporotic T11-L1 vertebral body: Effects of bone cement formulation.

Vertebral compression fractures are one of the most severe clinical consequences of osteoporosis and the most common fragility fracture afflicting 570 and 1070 out of 100,000 men and women worldwide, respectively. Vertebroplasty (VP), a minimally invasive surgical procedure that involves the percutaneous injection of bone cement, is one of the most efficacious methods to stabilise osteoporotic vertebral compression fractures. However, postoperative fracture has been observed in up to 30% of patients following VP. Therefore, this study aims to investigate the effect of different injectable bone cement formulations on the stress distribution within the vertebrae and intervertebral discs due to VP and consequently recommend the optimal cement formulation. To achieve this, a 3D finite element (FE) model of the T11-L1 vertebral body was developed from computed tomography scan data of the spine. Osteoporotic bone was modeled by reducing the Young's modulus by 20% in the cortical bone and 74% in cancellous bone. The FE model was subjected to different physiological movements, such as extension, flexion, bending, and compression. The osteoporotic model caused a reduction in the average von Mises stress compared with the normal model in the T12 cancellous bone and an increment in the average von Mises stress value at the T12 cortical bone. The effects of VP using different formulations of a novel injectable bone cement were modeled by replacing a region of T12 cancellous bone with the materials. Due to the injection of the bone cement at the T12 vertebra, the average von Mises stresses on cancellous bone increased and slightly decreased on the cortical bone under all loading conditions. The novel class of bone cements investigated herein demonstrated an effective restoration of stress distribution to physiological levels within treated vertebrae, which could offer a potential superior alternative for VP surgery as their anti-osteoclastogenic properties could further enhance the appeal of their fracture treatment and may contribute to improved patient recovery and long-term well-being.

Amyloid Targeting Red Emitting AIE Dots for Diagnostic and Therapeutic Application against Alzheimer's Disease.

The emergence of neurodegenerative diseases is connected to several pathogenic factors, including metal ions, amyloidogenic proteins, and reactive oxygen species. Recent studies suggest that cytotoxicity is caused by the small, dynamic, and metastable nature of early stage oligomeric species. This work introduces a small molecule-based red-emitting probe with smart features such as increased reactivities against multiple targets, metal-free amyloid-ß (Aß), and metal-bound amyloid-ß (Aß), and most importantly, early stage oligomeric species which are associated with the most common and widespread type of dementia, Alzheimer's disease (AD). Theoretical analyses like molecular dynamics simulation and molecular docking were performed to confirm the reactivity of the molecule toward Aß and found some excellent interactions between the molecule and the peptide. The in vitro and cellular studies demonstrated that this highly biocompatible molecule effectively reduces the structural damage to mitochondria while shielding cells from apoptosis, scavenges ROS (reactive oxygen species), and attenuates multifaceted amyloid toxicity.

Self-Assembly Driven Formation of Functional Ultralong "Artificial Fibers" to Mitigate the Neuronal Damage Associated with Alzheimer's Disease.

Fibrillation of amyloid beta (Aß) is the key event in the amyloid neurotoxicity process that induces a chain of toxic events including oxidative stress, caspase activation, poly(ADP-ribose) polymerase cleavage, and mitochondrial dysfunction resulting in neuronal loss and memory decline manifesting as clinical dementia in humans. Herein, we report the development of a novel, biologically active supramolecular probe, INHQ, and achieve functional nanoarchitectures via a self-assembly process such that ultralong fibers are achieved spontaneously. With specifically decorated functional groups on INHQ such as imidazole, hydroxyquinoline, hydrophobic chain, and hydroxyquinoline molecules, these ultralong fibers coassembled efficiently with toxic Aß oligomers and mitigated the amyloid-induced neurotoxicity by blocking the aforementioned biochemical events leading to neuronal damage in mice. These functional ultralong "Artificial Fibers" morphologically resemble the amyloid fibers and provide a higher surface area of interaction that improves its clearance ability against the Aß aggregates. The efficacy of this novel INHQ molecule was ascertained by its high ability to interact with Aß. Moreover, this injectable, ultralong INHQ functional "artificial fiber" translocates through the blood-brain barrier and successfully attenuates the amyloid-triggered neuronal damage and pyknosis in the cerebral cortex of wild-type mouse. Utilizing various spectroscopic techniques, morphology analysis, and in vitro, in silico, and in vivo studies, these ultralong INHQ fibers are proven to hold great promise for treating neurological disorders at all stages with a potential to replace the existing medications, reduce complications in the brain, and eradicate the amyloid-triggered neurotoxicity implicated in numerous disorders in human through a rare synergistic mechanism.

Effect of Uniaxial Compression Frequency on Osteogenic Cell Responses in Dynamic 3D Cultures.

The application of mechanical stimulation on bone tissue engineering constructs aims to mimic the native dynamic nature of bone. Although many attempts have been made to evaluate the effect of applied mechanical stimuli on osteogenic differentiation, the conditions that govern this process have not yet been fully explored. In this study, pre-osteoblastic cells were seeded on PLLA/PCL/PHBV (90/5/5 wt.%) polymeric blend scaffolds. The constructs were subjected every day to cyclic uniaxial compression for 40 min at a displacement of 400 µm, using three frequency values, 0.5, 1, and 1.5 Hz, for up to 21 days, and their osteogenic response was compared to that of static cultures. Finite element simulation was performed to validate the scaffold design and the loading direction, and to assure that cells inside the scaffolds would be subjected to significant levels of strain during stimulation. None of the applied loading conditions negatively affected the cell viability. The alkaline phosphatase activity data indicated significantly higher values at all dynamic conditions compared to the static ones at day 7, with the highest response being observed at 0.5 Hz. Collagen and calcium production were significantly increased compared to static controls. These results indicate that all of the examined frequencies substantially promoted the osteogenic capacity.

A finite element model of contusion spinal cord injury in rodents.

Traumatic spinal cord injuries result from high impact forces acting on the spine and are proceeded by an extensive secondary inflammatory response resulting in motor, sensory, and autonomic dysfunction. Experimental in vivo traumatic spinal cord injuries in rodents using a contusion model have been extremely useful in elucidating the underlying pathophysiology of these injuries. However, the relationship between the pathophysiology and the biomechanical factors is still not well understood. Therefore, the aim of this research is to provide a comprehensive analysis of the biomechanics of traumatic spinal cord injury in a rat contusion model. This is achieved through the development and validation of a finite element model of the thoracic rat spinal cord and subsequently simulating controlled cortical impact-induced traumatic spinal cord injury. The effects of impactor velocity, depth, and geometry on the resulting stresses and strains within the spinal cord are investigated. Our results show that increasing impactor depth results in larger stresses and strains within the spinal cord tissue as expected. Further, for the first time ever our results show that impactor geometry (spherical versus cylindrical) plays an important role in the distribution and magnitude of stresses and strains within the cord. Therefore, finite element modelling can be a powerful tool used to predict stresses and strains that occur in spinal cord tissue during trauma.

A computational analysis of a novel therapeutic approach combining an advanced medicinal therapeutic device and a fracture fixation assembly for the treatment of osteoporotic fractures: Effects of physiological loading, interface conditions, and fracture fixation materials.

The occurrence of periprosthetic femoral fractures (PFF) has increased in people with osteoporosis due to decreased bone density, poor bone quality, and stress shielding from prosthetic implants. PFF treatment in the elderly is a genuine concern for orthopaedic surgeons as no effective solution currently exists. Therefore, the goal of this study was to determine whether the design of a novel advanced medicinal therapeutic device (AMTD) manufactured from a polymeric blend in combination with a fracture fixation plate in the femur is capable of withstanding physiological loads without failure during the bone regenerative process. This was achieved by developing a finite element (FE) model of the AMTD together with a fracture fixation assembly, and a femur with an implanted femoral stem. The response of both normal and osteoporotic bone was investigated by implementing their respective material properties in the model. Physiological loading simulating the peak load during standing, walking, and stair climbing was investigated. The results showed that the fixation assembly was the prime load bearing component for this configuration of devices. Within the fixation assembly, the bone screws were found to have the highest stresses in the fixation assembly for all the loading conditions. Whereas the stresses within the AMTD were significantly below the maximum yield strength of the device's polymeric blend material. Furthermore, this study also investigated the performance of different fixation assembly materials and found Ti-6Al-4V to be the optimal material choice from those included in this study.

Ethno-pharmacological and industrial attributes on the underutilized Arenga species in India.

The genus Arenga belongs to the Arecaceae family, which has a significant economic value. Several species of this genus have a decent potential of becoming an industrial crop. In India, four species of the genus, namely Arenga pinnata, A. obtusifolia, A. micranta, and A. wightii have been reported. These species have not been cultivated on a commercial scale in most of the growing regions. People use this plant directly from the forest or those produced in their backyard, even though productivity is minimal. To date, several studies from throughout the world have reported numerous beneficial roles of such species. Proper use of such plants or their products has immense significance in the food, fiber, and pharmaceutical industry. These plants are also recognized as ecologically significant plants. In this article, we have presented an up-to-date review on the species of Arenga reported from India along with their potential utility as industrial crops. This review is motivated by the desire to produce many eco-friendly resources from A. pinnata and other species of Arenga, which can contribute to an increase in the standard of living and economy of many nations, including India. PRACTICAL APPLICATIONS: Arenga has a lot of potential as medicinal as well as industrial raw materials. Despite this, these plants are somehow underutilized and have not gained much attention in international trade. In this communication, we have presented some aspects of these plants by reviewing many research articles and conference proceedings. The utilization of these plants as traditional medicine serves an important part in basic health care for many people in developing nations. Gradual study and clinical trial of different formulations of these plants can explore novel drugs for some critical disorders. We also highlighted the industrial uses of these species. Biofuel and fiber obtained from A. pinnata have been appreciated by the researchers. This article points out some attributes of these plants that required further improvement. Botanists and phytochemists will appreciate the description of the medicinal properties of these plants and the biological data provided in the article.

Understanding the Re-entrant Phase Transition in a Non-magnetic Scheelite.

The stereochemical activity of lone pair electrons plays a central role in determining the structural and electronic properties of both chemically simple materials such as H2O, as well as more complex condensed phases such as photocatalysts or thermoelectrics. TlReO4 is a rare example of a non-magnetic material exhibiting a re-entrant phase transition and emphanitic behavior in the long-range structure. Here, we describe the role of the Tl+ 6s2 lone pair electrons in these unusual phase transitions and illustrate its tunability by chemical doping, which has broad implications for functional materials containing lone pair bearing cations. First-principles density functional calculations clearly show the contribution of the Tl+ 6s2 in the valence band region. Local structure analysis, via neutron total scattering, revealed that changes in the long-range structure of TlReO4 occur due to changes in the correlation length of the Tl+ lone pairs. This has a significant effect on the anion interactions, with long-range ordered lone pairs creating a more densely packed structure. This resulted in a trade-off between anionic repulsions and lone pair correlations that lead to symmetry lowering upon heating in the long-range structure, whereby lattice expansion was necessary for the Tl+ lone pairs to become highly correlated. Similarly, introducing lattice expansion through chemical pressure allowed long-range lone pair correlations to occur over a wider temperature range, demonstrating a method for tuning the energy landscape of lone pair containing functional materials.

Biomechanical performance of the cemented acetabular cup with combined effects of bone quality, implant material combinations and bodyweight.

GRAPHICAL ABSTRACT: [Formula: see text].

Biomechanical analysis of three popular tibial designs for TAR with different implant-bone interfacial conditions and bone qualities: A finite element study.

BACKGROUND: The long-term success of total ankle replacement (TAR) depends on both bone ingrowth and remodelling. The extreme values of implant-bone micromotion hinder bone ingrowth. Whereas, bone resorption due to bone remodelling is triggered by stress shielding. This study aims to investigate the biomechanical performance of three popular tibial designs (STAR, Salto and Mobility) for TAR with different implant-bone interfacial conditions and bone qualities. METHODS: In this study, CT data were used for the geometric modelling of bone. The cancellous bone was considered to be heterogeneous with location-based properties. Total 48 Finite Element (FE) models were prepared i.e., 45 implanted and 3 intact. For the three designs, three bone qualities were considered. For each bone quality, five implant-bone interface coefficients of friction were considered (0.1 to 0.5). The proximal part of the tibia was fully constrained and dorsiflexion loading condition was applied. RESULTS: There was a reduction in micromotion as the coefficient of friction increased and increase in micromotion as the bone quality reduced. The effect of implant-bone coefficient of friction was trivial on tibial stress (von Mises stress) however, bone quality and implant design was considerable. Stress shielding was seen in all the models and it increased when the bone quality degraded. CONCLUSIONS: This study establishes the effect of the implant-bone interfacial condition, bone quality and implant design on implant-bone micromotion and bone stress. For long-term fixation of the tibial component, due attention should be given while selecting the tibial component design for TAR, especially for STAR and Mobility design.

Colorimetric and fluorimetric detection of fluoride ion using thiazole derived receptor.

Thiazole based receptor 3, was designed and synthesized by condensation reactionof5-chlorosalicylaldehyde with 4-(4-phenylthiazol-2-yl)semicarbazide for colorimetric and fluorimetric detection of fluoride ion. Receptor 3 was characterized by 1H NMR, 13C NMR, and HRMS, and shows absorption in 280-400 nm region with emission at 442 nm in tetrahydrofuran (THF). Addition of fluoride ion to the THF solution of receptor 3 results in color change from colorless to yellow with significant change in UV-Visible absorption. The receptor-anion interaction occurs via hydrogen bonding followed by deprotonation which results in large bathochromic shift in absorption spectra and naked-eye color change. The colorimetric changes show selective response for fluoride ions over other anions. Fluorescence studies exhibit remarkable enhancement in emission intensity upon addition of fluoride ion with a limit of detection (LOD) of 8.6 nM. The 1H NMR titration studies exhibit deprotonation of the -OH proton of the salicylaldimine moiety resulting significant colorimetric and fluorimetric changes.

Electronic structure, phonons and optical properties of baryte type scintillators TlXO4(X=Cl, Br).

This article thoroughly addresses the structural, mechanical, vibrational, electronic band structure and the optical properties of the unexplored thallous perchlorate and perbromate fromab initiocalculations. The zone centered vibrational phonon frequencies shows, there is a blue shift in the mid and high frequency range from Cl → Br due to change in mass and force constant with respect to oxygen atom. From the band structure it is clear that the top of the valence band is due to thalliumsstates, whereas the bottom of the conduction band is due to halogensand oxygenpstates, showing similar magnitude of dispersion and exhibits a charge transfer character. These characteristics and the band gap obtained are consistent with that of a favourable scintillators. Our findings deliver directions for the design of efficient TlXO4based scintillators with high performance which are desirable for distinct applications such as medical imaging, high energy physics experiments, nuclear security.

Wearable Sensing Devices for Point of Care Diagnostics.

The growth of smart wearable sensing systems has gained immense importance in the present mode of data acquisition and signaling in pharmaceutical, healthcare, and wellness industries. Presently, application of smart wearables is gaining prominence in several fitness activities, therapeutics, and diagnostic areas. Smart wearable biosensors offer real-time monitoring of physiological metrics and biomarkers that are specific to certain diseases in ambulant condition. This review offers a broad overview of the state-of-the-art progress on smart wearable biosensors focusing on applications in point of care diagnostics. A careful comparison of presently available commercial devices, implementation in clinical trials, and validation also have been highlighted in the present review. This work concludes with challenges and future prospects for scientists and engineers working in the nascent interdisciplinary field.

Comparative DFT study of vibrational, electronic, and optical properties of energetic alkali metal salts based on nitrogen-rich 5-aminotetrazole.

This article presents a thorough density functional theory based comparative study on nitrogen-rich 5-aminotetrazole alkali metal salts M 5-At (M = Li, K, Rb, Cs). The calculated structural parameters using plane-wave pseudopotential method are consistent with the experimental results. The computed vibrational frequencies at ambient pressure show that vibrational modes in high energy region are due the NH bond of NH2 group. Pressure variation IR spectra of these materials show clear frequency shifts where Li 5-At shows an overall red shift below 900 cm-1 contrary to the blue shift seen in other materials in this range. The born effective charge values reveal the presence of strong covalency between N, H, and C atoms whereas an increased ionic nature is seen as the atomic number of metal atoms increases. Furthermore, we used full potential linear augmented plane wave (FP-LAPW) method for calculating electronic structure and optical properties with TB-mBJ potential which provides an enhanced band gap for all materials compared to standard GGA functional. Electronic structure calculation reveals that all the compounds are indirect band gap insulators with the exception of Li 5-At. The computed partial density of states show mixed ionic-covalent nature in metal-N/C bonds and covalent nature in NC bonds. In addition, we are also presenting the optical properties such as real and imaginary dielectric constant, absorption, refraction, reflection, loss spectrum as functions of photon energy. From the optical properties we can conclude that all the studied compounds are optically anisotropic in nature and are good absorbers in the ultraviolet (UV) region.

Influence of cancellous bone material and dead zone on stress-strain, bone stimulus and bone remodelling around the tibia for total ankle replacement.

Extreme bone resorption due to bone remodelling is one of the reasons for ankle component loosening. Finite element (FE) analysis has been effectively used nowadays for pre-clinical analysis of orthopaedic implants. For FE modelling, the selection of bone material and dead zone play a vital role to understand the bone remodelling. This study deals with the effects of different cancellous elastic modulus-density relationships and dead zone on bone remodelling around the tibia owing to total ankle replacement (TAR), using finite element analysis with physiological loading conditions. This study also investigated the bone stimulus distribution in the tibia to identify the initial indication of bone density changes due to bone remodelling. Additionally, the Hoffman failure criterion was used to investigate the chances of implant-bone interface failure due to different cancellous bone material modelling and bone remodelling. The present bone remodelling study consists of three different dead or lazy zones (±0.75, ±0.60 and ±0.35) to examine the influence of the dead zone on bone remodelling. Differences in stress/strain distribution were observed in the tibia bone due to different cancellous bone material modelling. Despite little variations, bone density changes due to bone remodelling were found to be almost similar for two FE models having different cancellous bone material. Similar to these results, the effect of different dead zone on bone density changes due to bone remodelling was found to be minimal. Bone stimulus distribution in the cancellous bone was found to be almost similar for FE models having different cancellous bone material modelling and different dead zones. To understand the stress/strain and interface related failure of the tibial component, cancellous bone material modelling plays a crucial role. However, cancellous bone material modelling and dead zone have minimal influence on bone remodelling around the tibia cancellous bone due to TAR.

Amyloid Targeting "Artificial Chaperone" Impairs Oligomer Mediated Neuronal Damage and Mitochondrial Dysfunction Associated with Alzheimer's Disease.

Alzheimer's disease (AD) is an irreversible memory disorder associated with multiple neuropathological events including amyloid aggregation that triggers oxidative stress and mitochondrial dysfunction in humans. Herein, a new artificial chaperone, benzimidazole functionalized polyfluorene (PFBZ) is reported to efficiently sequester toxic amyloid beta (Aß) by binding at their 'amyloidogenic domain' (Aß16-21) with unprecedented selectivity and prevent amyloid-mediated neuronal damage in a wild-type (WT) mouse model. An accurate dose of PFBZ chaperone successfully attenuated an amyloid triggered internal hemorrhage and pyknosis in the cerebral cortex of WT mice. The structural advantage of the polymer results in an efficient Cu(II) chelation arresting a redox cycle to prevent reactive oxygen species (ROS) generation and protect mitochondria from ROS mediated damage. This was further evidenced by caspase activation and mitochondrial membrane potential (MMP) biomarkers and was complemented by brain histology and electron microscopy data which revealed that the PFBZ chaperone provided a protective coating over the amyloid surface and resists from interacting with cell membrane and prevents inducing toxicity. This conjugated polymer artificial chaperone-based nanodrug showed exceptional properties such as its multipotent and highly biocompatible nature, the first of its kind with specific amyloid (Aß16-21) targeting behavior, bioimaging, and BBB permeability with a potential to suppress amyloid triggered neurotoxicity implicated in numerous human disorders through a rare synergistic mechanism.

Assembling Homometallic Sb6 and Heterometallic Ti4Sb2 Oxo Clusters.

Isolation and structural characterization of novel organoantimony(V)-based oxo clusters are reported. (RSb)4(OH)4(t-BuPO3)6 and (RSb)2(O)(t-BuPO3H)6 independently in the presence of pyridine under solvothermal conditions afford the hexanuclear organoantimonate clusters [(RSb)6(µ3-O)2(µ2-O)6(t-BuPO3)4], where R = p-i-PrC6H4 (1), p-ClC6H4 (2). Further, reaction of organostibonate phosphonate with Ti(OiPr)4 in the presence of pyridine under solvothermal conditions afforded the mixed-metal titanium stibonate hexanuclear clusters [(RSb)2Ti4(µ3-O)2(µ2-O)2(t-BuPO3)4(µ-OCH3)4(OCH3)4], where R = p-i-PrC6H4 (3), p-ClC6H4 (4). Band gap measurements were performed on 1-4. They reveal a remarkable reduction in the band gap on moving from the heavier main-group-based oxo cages (1 and 2) to the titanium-incorporated oxo cages (3 and 4).

Experimental and finite element investigation of total ankle replacement: A review of literature and recommendations.

This paper briefly reviews the different methodology, technology, challenges, and outcomes of various studies related to TAR prosthesis based on numerical and experimental techniques. Very less in-vitro experimental studies on TAR have been found than finite element (FE) studies. Due to the invasive nature of the experimental approach, inadequacy and less clinical information, computational modelling has been widely used by the researchers. This paper critically examines the part related to FE modelling and experimental analysis. Some recommendation related to modelling of bones, cartilages, ligaments, muscles, and implant-bone interface condition were discussed for better understanding the results and better clinical significance.

Bone remodelling around the tibia due to total ankle replacement: effects of implant material and implant-bone interfacial conditions.

One of the major causes of implant loosening is due to excessive bone resorption surrounding the implant due to bone remodelling. The objective of the study is to investigate the effects of implant material and implant-bone interface conditions on bone remodelling around tibia bone due to total ankle replacement. Finite element models of intact and implanted ankles were developed using CT scan data sets. Bone remodelling algorithm was used in combination with FE analysis to predict the bone density changes around the ankle joint. Dorsiflexion, neutral, and plantar flexion positions were considered, along with muscle force and ligaments. Implant-bone interfacial conditions were assumed as debonded and bonded to represent non-osseointegration and fully osseointegration at the porous coated surface of the implant. To investigate the effect of implant material, three finite element models having different material combinations of the implant were developed. For model 1, tibial and talar components were made of Co-Cr-Mo, and meniscal bearing was made of UHMWPE. For model 2, tibial and talar components were made of ceramic and meniscal bearing was made of UHMWPE. For model 3, tibial and talar components were made of ceramic and meniscal bearing was made of CFR-PEEK. Changes in implant material showed no significant changes in bone density due to bone remodelling. Therefore, ceramic appears to be a viable alternative to metal and CFR-PEEK can be used in place of UHMWPE. This study also indicates that proper bonding between implant and bone is essential for long-term survival of the prosthetic components.