Biological Materials Research Articles

Polyurethane-based three-dimensional printing for biological mesh carriers

Repair and reconstruction of the myopectineal orifice area using meshes is the mainstay of surgical treatment of inguinal hernias. However, the limitations of existing meshes are becoming increasingly evident in clinical applications; thus, the idea of using three-dimensionally (3D)-printed biological meshes was put forward. According to the current level of the 3D printing technology and the inherent characteristics of biological materials, the direct use of the 3D printing technology for making biological materials into finished products suitable for clinical applications is not yet supported, but synthetic materials can be first printed into 3D form carriers, compounded with biological materials, and finally made into finished products. The purpose of this study was to develop a technical protocol for making 3D-printed biomesh carriers using polyurethane as a raw material. In our study: raw material, polyurethane; weight, 20–30 g/m2; weaving method, hexagonal mesh; elastic tension aspect ratio, 2:1; diameters of pores, 0.1–1 mm; surface area, 8 × 12 cm2; the optimal printing layer height, temperature and velocity were 0.1 mm, 210–220 °C and 60 mm/s. Its clinical significance lies in: (1) applied to preoperative planning and design a detailed surgical plan; (2) applied to special types of surgery including patients in puberty, recurrent and compound inguinal hernias; (3) significantly improve the efficiency of doctor-patient communication; (4) it can shorten the operation and recovery period by about 1/3 and can save about 1/4 of the cost for patients; (5) the learning curve is significantly shortened, which is conducive to the cultivation of reserve talents.

A Comprehensive Examination of UV-VIS Spectrophotometric Methods in Pharmaceutical Analysis Between 2015-2023.

Quality control is a system of validated procedures in which many samples, including active pharmaceutical ingredients and final products, are analyzed using standard or validated analytical methods. Analytical methods used in analyzing active pharmaceutical ingredients or final products in the pharmaceutical industry can be methods registered in pharmacopeias and developed by the company itself. For this reason, published papers related to pharmaceutical analysis attract analysts and researchers' attention. In this study, pharmaceutical analysis and bioanalysis studies carried out between 2015 and 2023 were examined using Google Scholar, and the recent trends were determined for pharmaceutical analysis. Among the published papers performing conventional analytical techniques for pharmaceutical analysis, those applying UV-VIS spectrophotometry method were selected to predict a future perspective in this study. In addition to the data obtained, the current situation of the pharmaceutical industry was considered to correlate with the obtained data for pharmaceutical analysis. The results were presented with comparative tables and summarizing graphs. Interpreting the results allowed us to determine the trends that pharmaceutical analysis studies will lead in the future. This study can be helpful for researchers working on pharmaceutical analysis in both the industry and academia to predict future trends in pharmaceutical analysis. As a result of the literature research covering the dates 2015-2023, 56% of UV-VIS Spectrophotometric methods are used on pharmaceutical dosage forms, 27% are bulk, 16% are pure, 2% are biological materials, and 0.4% are herbal. Made from materials. Of these studies, 28% were conducted in the 200-240 nm range, 27% were conducted in the 240-300 nm range, and only 44% were conducted at >300 nm. Interpreting the results allowed us to determine the trends that pharmaceutical analysis studies will lead in the future. This study can be helpful for researchers working on pharmaceutical analysis in both the industry and academy side to predict future trends for pharmaceutical analysis.

Impacts of ICT as Tools in Teaching Biology in Senior Secondary Schools

Information and Communication Technology (ICT) has been pivotal in training across the world. Due to the abstractness of Biology in schools, it is essential to develop an effective strategy of ICT tools to improve student’s learning process. Similarly, biology helps people understand how organisms adapt to their environment and the importance of biodiversity in sustaining our planet's delicate balance. Therefore, this study investigates the impacts of ICT as instructional material in teaching and learning biology and its gender dimension in senior secondary school at Ado-Odo Ota local government area of Ogun State, Nigeria. The sample size for this research was 240 which consisted of 180 Biology students and 60 Biology teachers. The research questions were investigated with descriptive statistics; Frequency and percentage with the Statistical Package for Social Science (SPSS). The results show a sizable correlation between information communication and technology and the performance of students offering biology in senior secondary school at Ado Odo Ota local government area of Ogun State. It also showed a notable difference in the performance of male students taught with information and communication technology-related facilities and female students taught with ICT-related facilities in Ado-Odo Ota local government area of Ogun State. It was concluded that ICT tools in Biology class can make students more interested in learning Biology. Therefore, Biology concepts should be incorporated into ICT tools to make learning Biology worthwhile, seamless, and entertaining.

Widefield Super-Resolution Infrared Spectroscopy and Imaging of Autofluorescent Biological Materials and Photosynthetic Microorganisms Using Fluorescence Detected Photothermal Infrared (FL-PTIR).

We have demonstrated high-speed, super-resolution infrared (IR) spectroscopy and chemical imaging of autofluorescent biomaterials and organisms using camera-based widefield photothermal detection that takes advantage of temperature-dependent modulations of autofluorescent emission. A variety of biological materials and photosynthetic organisms exhibit strong autofluorescence emission under ultraviolet excitation and the autofluorescent emission has a very strong temperature dependence, of order 1%/K. Illuminating a sample with pulses of IR light from a wavelength-tunable laser source causes periodic localized sample temperature increases that result in a corresponding transient decrease in autofluorescent emission. A low-cost light-emitting diode-based fluorescence excitation source was used in combination with a conventional fluorescence microscopy camera to detect localized variations in autofluorescent emission over a wide area as an indicator of localized IR absorption. IR absorption image stacks were acquired over a range of IR wavelengths, including the fingerprint spectral range, enabling extraction of localized IR absorption spectra. We have applied widefield fluorescence detected photothermal IR (FL-PTIR) to an analysis of autofluorescent biological materials including collagen, leaf tissue, and photosynthetic organisms including diatoms and green microalgae cells. We have also demonstrated the FL-PTIR on live microalgae in water, demonstrating the potential for label-free dynamic chemical imaging of autofluorescent cells.

Precise measurement of Fe isotopes in marine and biological samples by pseudo-high-resolution multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS).

This paper introduces an enhanced technique for analyzing iron isotopes in complex marine and biological samples. A dedicated iron purification method for biological marine matrices, utilizing three ion exchange columns, is validated. The MC-ICPMS in pseudo-high-resolution mode determines precise iron isotopic ratios, with sensitivity improved through the DSN-100 desolvating nebulizer system and Apex-IR. Only 2µg of iron on DSN versus 1µg on Apex is needed for six replicates (30-60 times improvement) while 10 to 20µg is required for a single measurement on awet system considering the resolution power (Rp) is maintained at 11,000-13,000. The Ni-doping method with a Fe/Ni ratio of 1 yields more accurate isotopic ratios than standard-sample bracketing alone. Measurement reproducibility of triplicate samples from marine biological experiments on MC-ICPMS is ± 0.03‰ (2SD) for δ56Fe and ± 0.07‰ for δ57Fe (2SD). This study introduces a novel iron purification process specifically designed for marine and biological samples, enhancing sensitivity and enabling more reliable measurements with smaller sample sizes and reduced uncertainties. It proposes iron isotopic compositions for biological reference materials, offering a valuable reference dataset in diverse scientific disciplines.

Application of Platelet-rich Fibrin as a Method of Treatment for Medication-related Osteonecrosis of the Jaws in Bulgaria

Lately, medication-related osteonecrosis of the jaw (MRONJ) has emerged as a common disease due to the increasing use of antiresorptive drugs (intravenous bisphosphonates) for the treatment of oncological and osteoporotic diseases, which at an advanced stage significantly affects the quality of life of patients. Therefore, new therapies that accelerate the recovery of musculoskeletal tissue have become preferred in the treatment of such diseases in recent years. An innovative approach, which supports the healing processes is the application of autologous platelet concentrates known as platelet-rich plasma (PRP) and platelet-rich fibrin (PRF). Platelets are unique blood elements responsible for hemostasis. Activated platelets secrete a large amount of growth factors that initiate regeneration in soft tissues and bones. PRP is plasma with many more platelets than are usually found in the blood. The concentration of platelets and therefore the concentration of growth factors may be 5–10 times higher (or richer) than usual. PRF is a biological material, which has the ability to release growth factors over time. Growth factors stimulate stem cells, which improve collagen and elastin in the skin. Platelets in PRF are thought to survive better than those in PRP and thus contribute to faster recovery and formation of new tissue. Fibrin is a biological scaffold that forms when an injury occurs anywhere in the body. Platelets normally circulate in the blood and bind to the fibrin scaffold. Thus connected, they are activated and release growth factors, which are small “granules”. These growth factors begin the process of wound healing by creating new skin cells, collagen and blood vessels. The present study is related to the treatment of MRONJ with PRF. It is aimed at researching the attitudes of oral and maxillofacial surgeons in Bulgaria regarding the application of innovative medical technology such as PRF in the treatment of MRONJ. An author's questionnaire was developed with the help of which the survey was carried out. The analysis of the data shows that the interest in PRF in Bulgaria is great, but unfortunately it is rarely applied. However, respondents believe that this is a promising and innovative method in various aspects of surgery.

Computational Analysis of a Four-Flap Valveless Micropump (FFVM) for Low Reynolds Number Applications in Microfluidic Systems

Abstract Microfluidic systems are crucial in various fields including biological fluid handling and microelectronic cooling. Micropumps play a vital role in microfluidics. Valveless micropumps are the preferred choice in microfluidics because of their ability to minimize the risk of clogging and gently handle biological materials. In this comprehensive Four-Flap Valveless Micropump (FFVM) simulation, the fluid flow and associated deformation in the valveless micropump are analyzed. The oscillatory fluid motion generated by a straightforward reciprocating pumping mechanism is transformed into a unidirectional net flow by the micropump. This pump eliminates the need for intricate actuation mechanisms found in valve-based pumps while offering precise direction control. The input is given in terms of the Reynolds number or inflow velocity. In this study, the Reynolds numbers were changed from 16 to 50, which resulted in a positive correlation with the net flow rates, yielding a maximum net flow rate of 20.81 µl /min at a Reynolds number of 50. The influence of the average flow velocity is evident, with a peak net flow rate of 29.16 µl/min at 50 cm/sec. The FFVM showcases adaptability by delivering fluid within microfluidic pathways, holding promising applications in precision drug delivery systems

Odor Biosensors Based on Cell Expressing Olfactory Receptor: Recent Advances

AbstractInspired by the powerful biological olfaction, scientists extracted numerous materials such as olfactory sensory neuron, olfactory receptor (OR) protein, and odorant binding protein from animal olfactory systems, then combined them with transducers to form multiple odor biosensors. These biosensors, despite well inheriting the sensing ability of creatures, have several drawbacks, such as complex preparation process, unstable sensing material characteristics, and high cost. Unlike the biological materials listed above, cell expressing heterologous OR maintains a stable sensing performance after passaging for multiple generations, also its experimental operation is simple, and cost is low. Therefore, odor biosensors based on cell expressing OR have been well developed in recent years. In this review, we first listed several odor biosensors based on cell expressing OR, mainly focusing on fluorescent and electrophysiological measurement methods. Furthermore, we illustrated the techniques to improve the biosensor performance, e. g., wider detection range, longer lifetime, more OR types, and higher quantification efficiency. In addition, we explained the possible prospects such as big sensor array and predicting odor response.

Acidentes de trabalho com exposição a material biológico entre profissionais de enfermagem no Paraná

The objective was to analyze the epidemiological profile of notifications of work accidents with exposure to biological material among nursing professionals in Parana, through the historical series determined for the years 2013 to 2022. Descriptive observational epidemiological study of the survey type, based on descriptive epidemiology, based on data from the System Information on Notifiable Diseases and the National Registry of Health Establishments. 48,405 cases were identified, with a prevalence of 98.54/1,000. More occurrences among female nursing technicians aged between 31 and 40 years old, from the Metropolitan Health Regional Facilities, in year 2019, stand out. Among nurses, the age range was between 18 and 30 years old, with discharge progressing without serological conversion and negative sources of disease. The high number of abandoned treatments and underreporting stands out. Investing in professional training, continuing education, quality protective equipment and implementing protocols for prophylactic treatment are essential to prevent the disease.

A Standardized Nomenclature Design for Systematic Referencing and Identification of Animal Cellular Material

The documentation, preservation and rescue of biological diversity increasingly uses living biological samples. Persistent associations between species, biosamples, such as tissues and cell lines, and the accompanying data are indispensable for using, exchanging and benefiting from these valuable materials. Explicit authentication of such biosamples by assigning unique and robust identifiers is therefore required to allow for unambiguous referencing, avoid identification conflicts and maintain reproducibility in research. A predefined nomenclature based on uniform rules would facilitate this process. However, such a nomenclature is currently lacking for animal biological material. We here present a first, standardized, human-readable nomenclature design, which is sufficient to generate unique and stable identifying names for animal cellular material with a focus on wildlife species. A species-specific human- and machine-readable syntax is included in the proposed standard naming scheme, allowing for the traceability of donated material and cultured cells, as well as data FAIRification. Only when it is consistently applied in the public domain, as publications and inter-institutional samples and data are exchanged, distributed and stored centrally, can the risks of misidentification and loss of traceability be mitigated. This innovative globally applicable identification system provides a standard for a sustainable structure for the long-term storage of animal bio-samples in cryobanks and hence facilitates current as well as future species conservation and biomedical research.

Toward Multiscale, Multimaterial 3D Printing.

Biological materials and organisms possess the fundamental ability to self-organize, through which different components are assembled from the molecular level up to hierarchical structures with superior mechanical properties and multifunctionalities. These complex composites inspire material scientists to design new engineered materials by integrating multiple ingredients and structures over a wide range. Additive manufacturing, also known as 3D printing, has advantages with respect to fabricating multiscale, and multi-material structures. The need for multifunctional materials is driving 3D printing techniques toward arbitrary 3D architectures with the next level of complexity. In this paper, we aim to highlight key features of those 3D printing techniques that can produce either multiscale or multimaterial structures, including innovations in printing methods, materials processing approaches, and hardware improvements. Several issues and challenges related to current methods are discussed. Ultimately, we also provide our perspective on how to realize the combination of multiscale and multimaterial capabilities in 3D printing processes and future directions based on emerging research. This article is protected by copyright. All rights reserved.

Brittle and ductile yielding in soft materials

Many soft materials yield under mechanical loading, but how this transition from solid-like behavior to liquid-like behavior occurs can vary significantly. Understanding the physics of yielding is of great interest for the behavior of biological, environmental, and industrial materials, including those used as inks in additive manufacturing and muds and soils. For some materials, the yielding transition is gradual, while others yield abruptly. We refer to these behaviors as being ductile and brittle. The key rheological signatures of brittle yielding include a stress overshoot in steady-shear-startup tests and a steep increase in the loss modulus during oscillatory amplitude sweeps. In this work, we show how this spectrum of yielding behaviors may be accounted for in a continuum model for yield stress materials by introducing a parameter we call the brittility factor. Physically, an increased brittility decreases the contribution of recoverable deformation to plastic deformation, which impacts the rate at which yielding occurs. The model predictions are successfully compared to results of different rheological protocols from a number of real yield stress fluids with different microstructures, indicating the general applicability of the phenomenon of brittility. Our study shows that the brittility of soft materials plays a critical role in determining the rate of the yielding transition and provides a simple tool for understanding its effects under various loading conditions.

Biologicals and Biomaterials for Corneal Regeneration and Vision Restoration in Limbal Stem Cell Deficiency.

The mammalian cornea is decorated with stem cells bestowed with the life-long task of renewing the epithelium, provided they remain healthy, functional and in sufficient numbers. If not, a debilitating disease known as limbal stem cell deficiency (LSCD) can develop causing blindness. Decades after the first stem cell (SC) therapy was devised to treat this condition, patients continue to suffer unacceptable failures. During this time, improvements to therapeutics have included identifying better markers to isolate robust SC populations and nurturing them on crudely modified biological or biomaterial scaffolds including human amniotic membrane, fibrin and contact lenses, prior to their delivery. Researchers are now gathering information about the biomolecular and biomechanical properties of the corneal SC niche to decipher what biological and/or synthetic materials can be incorporated into these carriers. Advances in biomedical engineering including electrospinning and 3D bioprinting with surface functionalization and micropatterning, and self-assembly models, have generated a wealth of biocompatible, biodegradable, integrating scaffolds to choose from, some of which are being tested for their SC delivery capacity in the hope of improving clinical outcomes for patients with LSCD. This article is protected by copyright. All rights reserved.

Succession changes of microbial community for inferring the time since deposition of saliva.

Saliva is a common biological examination material at crime scenes and has high application value in forensic case investigations. It can reflect the suspect's time of crime at the scene and provide evidence of the suspect's criminal facts. Even though many researchers have proposed their experimental protocols for estimating the time since deposition (TsD) of saliva, there is still a relative lack of research on the use of microorganisms to estimate TsD. In the current study, the succession change of microbial community in saliva with different TsD values was explored to discern the microbial markers related to TsD of saliva. We gathered saliva samples from six unrelated healthy Han individuals living in Guizhou, China and exposed these samples to indoor conditions at six time points (0, 1, 3, 7, 15, and 28 days). Temporal changes of microbial compositions in these samples were investigated by 16S rRNA sequencing (V3-V4 regions). By assessing temporal variation patterns of microbial abundance at the genus level, four bacteria (Brucella, Prevotella, Pseudomonas, and Fusobacterium) were observed to show good time dependence in these samples. In addition, the hierarchical clustering and principal co-ordinates analysis results revealed that these saliva samples could be classified into t-short (≤7 days) and t-long (>7 days) groups. In the end, the random forest model was developed to predict the TsD of these samples. For the model, the root mean square error, R2, and mean absolute error between predicted and actual TsD values were 1.5213, 0.9851, and 1.1969, respectively. To sum up, we identified TsD-related microbial markers in saliva samples, which could be viewed as valuable markers for inferring the TsD of saliva.

Electrospun Nanofiber Scaffold for Skin Tissue Engineering: A Review.

Skin tissue engineering (STE) is widely regarded as an effective approach for skin regeneration. Several synthetic biomaterials utilized for STE have demonstrated favorable fibrillar characteristics, facilitating the regeneration of skin tissue at the site of injury, yet they have exhibited a lack of in situ degradation. Various types of skin regenerative materials, such as hydrogels, nanofiber scaffolds, and 3D-printing composite scaffolds, have recently emerged for use in STE. Electrospun nanofiber scaffolds possess distinct advantages, such as their wide availability, similarity to natural structures, and notable tissue regenerative capabilities, which have garnered the attention of researchers. Hence, electrospun nanofiber scaffolds may serve as innovative biological materials possessing the necessary characteristics and potential for use in tissue engineering. Recent research has demonstrated the potential of electrospun nanofiber scaffolds to facilitate regeneration of skin tissues. Nevertheless, there is a need to enhance the rapid degradation and limited mechanical properties of electrospun nanofiber scaffolds in order to strengthen their effectiveness in soft tissue engineering applications in clinical settings. This Review centers on advanced research into electrospun nanofiber scaffolds, encompassing preparation methods, materials, fundamental research, and preclinical applications in the field of science, technology, and engineering. The existing challenges and prospects of electrospun nanofiber scaffolds in STE are also addressed.

MONITORING OF PESTICIDE RESIDUES IN GRAPEVINE LEAVES UNDER VARIANT FUNGAL DISEASE MANAGEMENT

Food contamination is the result of over-reliance on fungicides in crop production. The presence of pesticide residues in agricultural commodities needs to be strategically solved by applying gentle agrotechnical procedures. The research aimed to evaluate the effect of the treatment of grapevine with fungicides on the content and mobility of 4 active substances in the leaves of the variety Hibernal. The experiment included a control variant treated with fungicides and an untreated variant. We focused on monitoring the active substances of fungicides used in the first half of the vegetation: azoxystrobin, cyflufenamid, difenoconazole, myclobutanil, and another 25 active substances, in terms of multi-residue analysis methodologies. Grape leaves for analysis were collected on two dates: in the phenological phase of berry development BBCH 73 and 14 days after grape harvest – BBCH 91. Samples were prepared according to STN EN 15662. For qualitative analyzes of residues, we used the QuEChERS method in combination with liquid (LC-MS/MS) and gas (GC-MS/MS) chromatography with tandem mass spectrometry. In the untreated variant, the contents of residues from both leaves collection were in undetectable values. In the leaf samples of the treated variant collected in BBCH 73, we established higher values of residues than the MRL determines, namely for azoxystrobin 0.083 mg/kg (MRL – 0.01 mg/kg). Azoxystrobin is the active substance of the Quadris max fungicide, and we applied this preparation 41 days before the first collection of leaves. In the analyzes of leaf sampling from the treated variant after grape harvest in BBCH 91, we found a decrease in the content of all monitored residues below detectable values. We consider the gradual degradation of residues in biological materials to be a very favorable result from the point of view of their impact on consumer health and the environment. Through visual observations of the vegetation, we found out that even the untreated variant had a perfect state of health. Hibernal is a variety suitable for biological production systems, and we assume that even in vintages with high pressure of fungal diseases, it is possible to maintain the health of the grapevine with ecological products. Using the appropriate grape variety combined with the right agrotechnical interventions makes it possible to use safer ecological practices to produce healthy food, maintaining sustainability and a healthy natural environment. The research will continue in the early Table grape varieties, where the vegetation period is shorter, and space for breaking down the residues is more difficult.

The wildcat (Felis s. silvestris) in the Mediterranean forest: sighting through photo-trapping and non-invasive hair collection for genetic purposes.

The European wildcat (Felis silvestris silvestris) is a mesocarnivore species widely distributed in Europe, from Eastern Europe to Portugal and from Scotland to Italy. Recent biogeographical studies of wildcat populations have endeavoured to assess in detail the various issues that pose a threat to this species, including hybridization with domestic cats. The use of non-invasive sampling methods supported by photo-trapping and some attractants has made it possible to gather genetic material for the detection of native wildcats in locally threatened populations, some of which live in the Iberian Peninsula. Testimonies of naturalists, hunters and farm workers led our team to choose specific areas in two large territories of Mediterranean forests where the presence of wildcats has been historically attested: the Almonte River basin and the Sierra de San Pedro Mountains. Between 2014 and 2018, non-invasive hair sampling was performed using valerian (Valeriana officinalis) as an attractant and supported by photo-trapping to guarantee the collection of genuine biological material (hair samples). The hair samples were genetically assessed by sequencing the nuclear gene IRBP (interphotoreceptor retinoid-binding protein) and the mtDNA gene ND4 (NADH dehydrogenase subunit 4). Despite the low density of wildcats, this combined protocol proved to be an applicable tool for detecting the presence of elusive wildcats and other mesocarnivore species in this remote region of southern Europe. In addition, non-invasive hair trapping contributes to the collection of genetic material from current wildcat populations. This procedure could enhance future management actions focused on collecting quality individualized biological material.

ВОЛНОВОДНО ДИЭЛЕКТРИЧЕСКИЙ МЕТОД И УСТРОЙСТВА ДЛЯ ИЗМЕРЕНИЯ КОНЦЕНТРАЦИИ ВОДНЫХ РАСТВОРОВ И ОБЛУЧЕНИЯ БИОЛОГИЧЕСКИХ ОБЪЕКТОВ

A technique for studying the absorption of microwave radiation of biological objects in a thin dielectric capillary is proposed. The results of experimental studies are presented and the mechanism of the detected effects of the biological action of microwave radiation is proposed. It was found that at a certain ratio between the dimensions of the waveguide, the diameter and thickness of the walls of the capillary, the dielectric parameters of the biological material that fills the capillary and the wavelength of microwave radiation in the waveguide, a significant increase in the absorbed power in a rather narrow frequency band (waveguide-dielectric resonance) is possible. This phenomenon must be taken into account in biotechnological experiments on the irradiation of suspensions. As a result of the work done on the study of the absorption of microwave radiation by hydrocarbon mixtures and models of biological objects in aquatic environments, new designs of measuring devices were created and a technique for hydrocarbon aquametry was developed. The created products are protected by the authors of this work by a patent for an invention.

Optimizing functionally graded tibial components for total knee replacements: a finite element analysis and multi-objective optimization study

The optimal design of complex engineering systems requires tracing precise mathematical modeling of the system’s behavior as a function of a set of design variables to achieve the desired design. Despite the success of current tibial components of knee implants, the limited lifespan remains the main concern of these complex systems. The mismatch between the properties of engineered biomaterials and those of biological materials leads to inadequate bonding with bone and the stress-shielding effect. Exploiting a functionally graded material for the stem of the tibial component of knee implants is attractive because the properties can be designed to vary in a certain pattern, meeting the desired requirements at different regions of the knee joint system. Therefore, in this study, a Ti6Al4V/Hydroxyapatite functionally graded stem with a laminated structure underwent simulation-based multi-objective design optimization for a tibial component of the knee implant. Employing finite element analysis and response surface methodology, three material design variables (stem’s central diameter, gradient factor, and number of layers) were optimized for seven objective functions related to stress-shielding and micro-motion (including Maximum stress on the cancellous bone, maximum and mean stresses on predefined paths, the standard deviation of mean stress on paths, maximum and mean micro-motions at the bone-implant interface and the standard deviation of mean micro-motion). Then, the optimized functionally graded stem with 6 layers, a central diameter of 5.59 mm, and a gradient factor of 1.31, was compared with a Ti6Al4V stem for various responses. In stress analysis, the optimal stem demonstrated a 1.92% improvement in cancellous bone stress while it had no considerable influence on the maximum, mean, and standard deviation of stresses on paths. In micro-motion analysis, the maximum, mean, and standard deviation of mean micro-motion at the interface were enhanced by 24.31%, 39.53%, and 19.77%, respectively.

A device for rapid calorimetric measurements on small biological tissue samples

AbstractA new calorimetric technique is described that allows high-throughput heat production rate measurements on small biological tissue samples. The technique is based on the widely used thermopile chip technology combined with an innovative method for precise transport and positioning of samples of different biological materials at the thermal power detector inside the calorimeter. The new transport and positioning technique is a combination of fluidic and mechanical transport, where the latter is realized by a magneto-motor drive. The transport facility ensures good diffusive oxygen penetration into the sample, which is essential for highly metabolically active materials. The proper functioning of the device is demonstrated by measuring the heat production of metabolically active brown adipose tissue, biopsied tegu lizard muscle, and live Drosophila larvae at different stages and temperatures.