Efficient Source Research Articles

Effect of Recycling Chicken Eggshell Waste as a Pore-Forming Mineral Source in Low-Water-Absorption Bi-Layered Red Ceramic Tiles

This work evaluated the effects of incorporating chicken eggshell waste in a low-water-absorption bi-layered red ceramic tile composition, focusing on its porosity. Red ceramic tile formulations were prepared with incorporations of 0, 5, 10, 15, 20 and 25 wt.% of chicken eggshell waste. The bi-layered red floor tile processing method consisted of dry powder granulation, double uniaxial pressing and firing at 1220 °C using a fast-firing cycle. The physical properties and microstructural development of the tile specimens were investigated. It was found that chicken eggshell waste exhibited good chemical compatibility for use in red ceramic tile formulations, enabling its recycling. The novel bi-layered red ceramic tiles presented water absorption between 0.34 and 0.97% and apparent density between 2.09 and 2.14 g/cm3. The results demonstrated that chicken eggshell waste, when incorporated up to 15 wt.%, can be used as an efficient pore-forming carbonate source to manufacture low-water-absorption bi-layered red ceramic tiles (BIa and BIb groups—ISO 13006), which allows use in ventilated façades. It was concluded that the proposed approach is suitable for recycling chicken eggshell waste into red ceramic tile formulations, with relevant repercussions for the circular economy.

Telegram-канал Главы Республики Мордовия «Здунов здесь» как инструмент медиа

Mordovia is a small national republic with a low level of social conflicts. Mordovia has few regional mass media sources, which makes digital sources important for its residents. As a result, Governor Artyom A. Zdunov launched his own Telegram channel called Zdunov Zdes (i.e., Zdunov is here), which has become a valuable source of information and communication. The authors used the methods of qualitative and quantitative content analysis to study the posts published from 2022, when the channel was opened, to the present day. The channel proved to be an efficient source of relevant information that can compete with other regional media. Not only does it promote A. A. Zdunov as an active politician, but it also represents Mordovia as a region with good economic prospects and touristic potential. In addition, the channel initiates an indirect dialogue between the authorities and the population. The content-makers rely on such techniques as data prioritization, creolization, emotional contagion, interviews with influencers, eyewitness accounts, etc. The positive image of the Governor includes his hard-working nature, professionalism, competence, kindness, toughness, sociability, good health, youth, energy, patriotism, and personal involvement.

TERMOELEKTRIK GENERATOR DAN FUNGSINYA

This article summarizes and reviews various journals on the performance, applications, and development of Thermoelectric Generators (TEG) that convert temperature differences into electrical energy through the Seebeck effect. The aim of this review is to provide a comprehensive overview of advancements in TEG technology and its potential in enhancing energy efficiency and renewable energy utilization. The methodology includes a literature review of research methods applied in previous studies, including simulations and experiments aimed at improving TEG efficiency. Some studies also integrate TEG with phase change materials (PCM) to harvest energy from ambient temperature fluctuations. The review findings indicate that innovations in TEG materials and design can significantly improve the efficiency and sustainability of this technology. Additionally, this article discusses the applications of TEG in various fields, such as waste heat recovery from industrial processes and vehicles, as well as in wearable devices to harvest energy from body heat. A table presenting research methods and comparisons of previous studies is included to offer a thorough view of current developments in TEG technology. The conclusion of this review is that TEG has significant potential as a solution for waste heat recovery, wearable device applications, and as an efficient renewable energy source. The article also provides recommendations for future research, including the development of new materials and more optimal designs, to address existing challenges and maximize the potential of TEG.

Optimal conditions for efficient ion acceleration and neutron production in deuterium gas-puff z-pinches

Abstract Deuterium gas-puff z-pinches are researched primarily as efficient sources of DD fusion neutrons. The first experiment with a deuterium gas jet was carried out in 1978 (J. Shiloh, A. Fisher, and N. Rostoker, Phys. Rev. Lett. 40, 515518, 1978). Since then, several D2 gas-puff experiments have been performed on various pulsed-power generators. The highest, so far published, DD neutron yields of 4×1013 were observed on the Z-machine at Sandia National Laboratories around 2005 (C.A. Coverdale, et al. Phys. Plasmas 14, 022706, 2007). More recently, z-pinch experiments with a plasma shell on a deuterium gas puff were carried out on GIT-12 higher-impedance pulsed-power generator at 3 MA currents. On GIT-12, unique results were high neutron and ion energies, which approached 60 MeV. Comparison of deuterium gas-puff experiments on different generators allows the identification of the parameters essential for optimizing neutron production. These parameters include the optimal mass, preionization, short deuterium gas-injection time, and zippering towards a cathode. Neutron yields appear to depend not only on a current, but also on other parameters of a generator, such as an impedance and the energy stored in a capacitor bank. Our conclusions regarding the optimal conditions were tested on the Hawk generator (NRL, Washington, DC). At a current of 0.7 MA, Hawk accelerated deuterons up to 15 MeV producing one neutron pulse with the yield of the order of 1010 and a broad energy spectrum in the axial and radial direction. These results show that ion acceleration mechanisms in deuterium gas-puff z-pinches could be very efficient and attractive, with a variety of potential applications in high-energy-density physics, materials science, and controlled thermonuclear fusion research.

Operation of a hybrid heating system based on heat pumps using a photovoltaic installation

In Poland, heating systems using renewable energy sources have gained importance in construction projects, especially in newly designed buildings. This is mainly due to the Regulation of the Minister of Infrastructure, which sets technical conditions for buildings. As of December 31, 2020, the primary energy index for newly designed single-family buildings should not exceed 70 kWh/(m2year). This requires efficient energy sources in building design. Renewable energy installations have significantly lower primary energy utilization rates than fossil fuel systems, making them the preferred choice. In a facility in Batowice near Krakow, a hybrid energy system with ground-source and air-source heat pumps has been installed. These pumps are powered by electricity from a photovoltaic installation connected to the grid. The study aims to determine the optimal heat pump choice based on the facility’s conditions and optimize electricity consumption from the photovoltaic installation. Both heat pumps showed similar efficiencies during the heating season from December 2022 to March 2023: the ground-source heat pump achieved an annual coefficient of performance of 2.69, and the air-source heat pump achieved a seasonal coefficient of perfor-mance of 2.63. Given the high non-renewable primary energy factor for grid electricity, the feasibility of replacing gas boilers with heat pumps requires careful evaluation. The results indicate that integrating a heat pump with a photovoltaic installation substantially reduces the primary energy utilization index, supporting climate protection and the advancement of renewable energy sources. However, heat pumps alone may not be sufficiently efficient without the support of a PV installation.

The effects of different hormone combinations on the growth of Panax notoginseng anther callus based on metabolome analysis

Panax notoginseng saponins (PNS), the primary active components of Panax notoginseng (Burk.) F.H.Chen, a traditional and precious Chinese medicinal herb, are mainly derived from the roots of the plant. However, due to the long cultivation period and specific environmental requirements, the PNS supply is often limited. And, callus cultures of P. notoginseng, which grow rapidly, have short production cycles, and can be cultured under controlled conditions, provide a more efficient source for the quick acquisition of saponins. In this study, anthers of P. notoginseng were used as explants, and twelve hormone combinations were tested to induce callus formation. Eight kinds of hormone combinations successfully induced P. notoginseng anther callus. Among these, callus induced by combinations 5 and 7 had the highest saponin content, while those induced by combinations 1 and 3 exhibited the highest relative growth rates. Metabolomic analysis of these four callus types revealed that there were a total of 99 differential metabolites between combinations 5 and 7, 30 between combinations 1 and 3, 123 between combinations 3 and 7, and 116 between combinations 1 and 5. Further analysis showed that the tricarboxylic acid (TCA) cycle metabolites in callus induced by combinations 1 and 3 were significantly upregulated, with corresponding genes showing high expression levels, increased ATP accumulation, and low responses of the auxin response factor PnARF-3 and cytokinin response factor PnCRF-3. The abundance of metabolites in the PNS biosynthesis pathway in callus induced by combinations 5 and 7 increased significantly, with related genes showing high expression levels, increased IPP accumulation, and high responses of PnARF-3 and PnCRF-3. Overexpression of PnARF-3 and PnCRF-3 in callus induced by combination 3 promoted the production of IPP and saponins while reducing ATP production. In conclusion, different hormone combinations affect the distribution of Acetyl-CoA through PnARF-3 and PnCRF-3, resulting in the relative growth rate and saponin of P. notoginseng anther callus differences.

Smallholder Inclusion Through Cooperative Contract Farming of Cavendish Banana Farmers in Davao del Norte, Philippines: A Meta‐Frontier Analysis

ABSTRACTAs the third‐highest global supplier of Cavendish bananas, the Philippine banana industry has a vital role in rural development. We compared farmers' technical efficiency (TE) and production performance across different contract farming arrangements: individual contracts, cooperative contracts, and growers without a contract. Using a random sample of 186 farmers in Davao del Norte, Philippines, we used meta‐frontier Data Envelopment Analysis to calculate TE scores and then use a truncated regression with bootstrapping to model the efficiency sources. We applied propensity score matching to minimize observable bias resulting from self‐selection among farmers participating in contract farming. The results across returns‐to‐scale assumptions and matching methods reveal that cooperative contract farmers have significantly higher TE and revenue performance than individual and noncontract farmers, primarily due to high export‐quality production and associated premium prices. Individual contract farmers were also more technically efficient and had higher returns than noncontract farmers. Smallholder farmers tend to participate more in cooperative contract farming. Thus, cooperative contracts should include smallholder farmers in export value chains to improve smallholder farmer income. This strategy will lead to the formation of inclusive agrifood value chains in Mindanao, Philippines.

Fructose-mediated AGE-RAGE axis: approaches for mild modulation.

Fructose is a valuable and healthy nutrient when consumed at normal levels (≤50 g/day). However, long-term consumption of excessive fructose and elevated endogenous production can have detrimental health impacts. Fructose-initiated nonenzymatic glycation (fructation) is considered as one of the most likely mechanisms leading to the generation of reactive species and the propagation of nonenzymatic processes. In the later stages of glycation, poorly degraded advanced glycation products (AGEs) are irreversibly produced and accumulated in the organism in an age- and disease-dependent manner. Fructose, along with various glycation products-especially AGEs-are present in relatively high concentrations in our daily diet. Both endogenous and exogenous AGEs exhibit a wide range of biological effects, mechanisms of which can be associated with following: (1) AGEs are efficient sources of reactive species in vivo, and therefore can propagate nonenzymatic vicious cycles and amplify glycation; and (2) AGEs contribute to upregulation of the specific receptor for AGEs (RAGE), amplifying RAGE-mediated signaling related to inflammation, metabolic disorders, chronic diseases, and aging. Therefore, downregulation of the AGE-RAGE axis appears to be a promising approach for attenuating disease conditions associated with RAGE-mediated inflammation. Importantly, RAGE is not specific only to AGEs; it can bind multiple ligands, initiating a complex RAGE signaling network that is not fully understood. Maintaining an appropriate balance between various RAGE isoforms with different functions is also crucial. In this context, mild approaches related to lifestyle-such as diet optimization, consuming functional foods, intake of probiotics, and regular moderate physical activity-are valuable due to their beneficial effects and their ability to mildly modulate the fructose-mediated AGE-RAGE axis.

Advanced in Socioproductive Inclusion: The Protection of Tangible and Intangible Assistances of the Quilombola Community Traditional of Cachoeira Dos Forros - Passa Tempo/MG

Objective: The objective of this study is to investigate the development of a sustainable and collective business model, by and for the community, aiming, in principle, at its economic emancipation. Theoretical Framework: Today, cooperation is recognized as a source of efficiency and well-being, opposing competition, rational selfishness and neoliberal individualism. However, the simple normative constitution or even the defense of the collective based on moral values ​​is insufficient to develop real cooperation. Therefore, traditional knowledge, understood as communal material and immaterial resources, reveals itself as resources capable of guiding community-based enterprises. Method: The methodology adopted for this research comprises a study in the Traditional Quilombola Community of Cachoeira dos Forros (CTQCF/MG), located in Passa Tempo, in the state of Minas Gerais. Results and Discussion: The results obtained revealed that it is possible to outline perspectives for communal development, based on the appreciation of traditional knowledge, from the perspective of community enterprise. However, for this approach to be viable, it is necessary to recognize the obstacles that may interfere with the path to be taken by this community, towards its autonomy as an Afro-diasporic culture. Research Implications: The practical and theoretical implications of this research are discussed, providing insights into how the results can be applied or influence practices in the field of intellectual property. These implications may include contributing to the emancipatory process of the CTQCF/MG, already underway. Originality/Value: This study contributes to the originality of the research, whether through an innovative approach, new discoveries or practical contributions. The relevance and value of this research are evidenced by adversities to be overcome, highlighting the discredit and lack of engagement of a portion of its members in achieving the common project, which permeates the compelling need to develop methodologies capable of creating enabling conditions in the process of building trust and cooperation among its actors.

Simulation and optimization of strained GeSn laser with SiN-induced stress

By modifying Germanium (Ge) material, direct bandgap emission can be achieved, improving light emission efficiency. This paper proposes a strain-engineered GeSn laser based on SiN stress. The stress distribution within the device and its optoelectronic characteristics were analyzed through simulation. The laser is predicted to emit light at a wavelength of approximately 2252 nm, with a threshold current density around 220 kA/cm2. By introducing a multi-quantum well (MQW) structure, the threshold current density is reduced to about 90 kA/cm2. The work in this paper provides a feasible technical solution for the design of efficient silicon-based light sources.

Doped-δ-doped transferred electron device for sustained terahertz signal generation

Abstract The performance of a novel transferred electron device structure aimed at sustaining high-frequency signals in the terahertz (THz) range is investigated. The device uses a highly doped δ-layer to split the n-doped device into two distinct regions, forming a doped-δ-doped configuration. The first region generates high-speed electrons toward the δ-layer, while the second region utilizes negative differential resistance to modulate electron speeds and sustain oscillations. An ensemble self-consistent Monte Carlo model is employed to analyze electron dynamics and THz signal generation in this structure under a constant bias. The design demonstrates superior performance, achieving a fundamental operating frequency of 427 GHz in a 600 nm length InP device, nearly a 50% increase over conventional notch-doped design, while maintaining the current harmonic amplitude. This design achieves higher frequencies without reducing device length and increasing doping density, effectively addressing the trade-off of the Kroemer criterion. The study of the effects of varying doping densities and region lengths on device performance, highlighting the importance of optimizing these parameters to sustain current oscillations and efficiently generate THz signals. This design offers a promising solution for a compact and efficient THz source.

Copper-Catalyzed Asymmetric Nucleophilic Substitutions of TsSCF3: Synthesis of Chiral SCF3-Containing Compounds.

By employing electrophilic TsSCF3 as an efficient SCF3 source, we reported Cu/SOP (chiral sulfoxide-phosphine ligand)-catalyzed enantioselective nucleophilic substitutions. Under this protocol, α-pyridyl-α-fluoro esters as latent carbon nucleophiles, compounds containing a C-SCF3 stereocenter along with azacycles and fluorine atoms, were obtained in good yields and enantioselectivities under mild conditions (up to 68% yield, 92% ee).

A Review of Energy Harvesting Techniques for Self-Powered IoT Devices

The Internet of Things (IoT) manages a vast network of interconnected smart devices that collect, transmit, and analyze data from their environment using embedded components like processors, sensors, and communication equipment. These devices, which require efficient power sources, often rely on batteries that limit their operational lifespan and increase environmental impact. This paper provides a comprehensive review of energy harvesting techniques aimed at enhancing the longevity and sustainability of IoT devices. The methodology involves a comparative analysis of various energy harvesting sources such as solar, thermal, RF, and mechanical energy focusing on their efficiency, applicability, and integration within wireless sensor networks (WSNs). Key contributions include the identification of current limitations in energy harvesting technologies, such as low energy conversion efficiency and intermittency, and the proposal of solutions to optimize energy capture and storage. The results demonstrate that integrating multiple energy sources can significantly improve power availability and reduce dependence on conventional batteries. This review concludes by outlining the ongoing challenges and future research directions needed to develop efficient, reliable, and cost-effective energy harvesting systems for IoT applications.

Mechanistic insights into the use of flotation tail coal for enhanced water electrolysis in hydrogen production

Coal-assisted water electrolysis for hydrogen production (CAWE) is a promising method for the efficient utilization of coal resources and the sustainable generation of hydrogen. However, identifying a cost-effective and efficient carbon source remains a critical and ongoing challenge. This study proposes the use of flotation tail coal as a novel and efficient carbon source for water electrolysis. Through a combination of electrochemical experiments, thermodynamic analysis, and comprehensive material characterization techniques, this research explores the effectiveness of tail coal-assisted water electrolysis for hydrogen production (TCAWE) in enhancing hydrogen production efficiency. It is found that the catalytic effect of minerals, particularly iron and manganese ions, is instrumental in significantly reducing energy consumption and enhancing the anodic oxidation reactions in the CAWE process. Flotation tail coal, with its high content of these catalytic minerals and favorable hydrophilic surface properties, not only lowers the electrolysis voltage but also increases the hydrogen yield compared to traditional coal sources. This research innovatively demonstrates that utilizing flotation tail coal in water electrolysis offers a dual benefit: it provides a cost-effective, abundant carbon source while promoting a more efficient and sustainable hydrogen production process. Additionally, this approach is expected to facilitate the resource utilization of waste flotation tail coal.

Giant Photoluminescence Enhancement of Ga-Doped ZnO Microwires by X-Ray Irradiation.

Ga-doped zinc oxide (ZnO) microwires hold great promise for developing highly efficient light sources because of the wide bandgap with proper exciton binding energy. However, most microwires grown from one mainstream approach, i.e., chemical vapor deposition (CVD), are morphologically and crystallographically defective, exhibiting limited photoluminescence performances. Herein, a simple and effective X-ray irradiation strategy is demonstrated for enhancing the photoluminescence of Ga-doped ZnO microwire in ambient conditions. Under moderate doses (≤ 150Gy), the photoluminescence monotonically rockets up with X-ray dose increment and achieves nine-fold enhancement at a dose of ≈150Gy, recording high photoluminescence improvement of ZnO microwires to date. The elemental characteristics under different controlled irradiation atmospheres suggest the elimination of surface oxygen vacancy and the cross-section transmission electron microscope reveals prominent lattice relaxations after mild X-ray irradiation. In addition, the X-ray irradiated microwires further exhibit elevated electroluminescence by over three times. The enhanced photoluminescence and electroluminescence as well as long-term stability enable us to imagine the super-rapid applications of ZnO microwires in modern optoelectronic devices.

(Invited) Electrically Pumped GeSn/SiGeSn Lasers

Si-based photonic integrated circuits, where optical components are monolithically integrated on Si Integrated Circuits, are expected to dominate the future information and communication technology infrastructure. The Si photonic (SiPh) technology, consisting of both active- and passive components, is already widely used in a wealth of applications, ranging from datacom to detection systems. Recently, SiPh entered the technology platform for cryogenic applications in the emerging fields of integrated quantum technologies, optical computing, and artificial intelligence. Nonetheless, an efficient, electrically pumped light source that can be manufactured using solely group-IV semiconductors remains a major challenge. The novel GeSn and SiGeSn semiconductors obtained by the substitutional incorporation of Sn, a semi-metal, into the Ge lattice, offer a few advantages over other group-IV semiconductor alloys: by properly selecting the alloy composition and epitaxial strain, these materials are turned into fundamental direct bandgap semiconductors. This property normally missing in Group IV makes the (Si)GeSn system very attractive for efficient light sources. Using this material system, major milestones in group-IV lasing were reached in recent years like optically pumped bulk and Multi-Quantum Wells (MQW) lasers working up to room temperature. Building on an extensive experimental activity on optically pumped GeSn heterostructures, here we will discuss electrically pumped lasing. The accent is put on two key features: CW operation and low threshold currents. Both of these milestones are simultaneously reached in SiGeSn/GeSn MQW micro disk cavity laser diodes. We will also discuss the material design in SiGeSn/GeSn heterostructures and a possibility of strain engineering to push the electrically pumped lasing to room temperatures.

Decentralized Energy Systems and the Circular Economy: Business Models for Sustainable Energy Transitions

To address current rising northern environmental concerns, and a remarkable increase in energy demand, this research aims to investigate the feasibility of implementing both decentralized energy systems and circular economy approach for successful sustainable energy transformations. As a general goal of this research, the aim is to compare different business models of agent-based decentralized energy production according to circular economy principles of efficiency, waste reduction, and secure sources of supply chains. It adopted both quantitative treatment of energy data pertaining to decentralized systems in European and Asian countries and qualitative findings generated from industry case studies. The study shows that business models include energy as a service and community power which plays an important role in energy saving resulting in operational efficiency after the application of the analyzed models leading to a decrease in energy losses ranging between 1530%. The major contribution of this study is to provide an integrative framework that not only emphasises the possibility of decentralised scenarios but also reveals how they can contribute to circular economy aims such as resource circulation and low carbon. Based on the findings of this study, there are insights drawn that speaker to policymakers, business strategists, and environmental organizations as these details a coherent explanation of models of sustainable energy as well as coming up with practical models that can be adopted in largescale manner. The approach of this research within its quantitative and practical methodologies provides valuable insights to inform the analysis of decentralised energy as it contributes to international agenda towards sustainability.

The Need for Solar Power Energy Utilization in the Northern Part of Nigeria for Sustainability and Economic Growth (A case study of Nigeria)

Northern Nigeria is one of the most recognizable areas, having vast amounts of solar radiation and rapidly growing populations. Thus, there is an opportunistic aspect of the use of solar power in this region. Since this region enjoys all-year sunshine, it is one of the best places for the integration of solar energy. With huge problems of energy she presently faces such as irregular supply of electricity, people's growth and thus demand, solar power presents an immediate usable, reliable, and sustainable solution. The energy demand in northern Nigeria is expected to sharply increase from about 48 billion kWh in 2024 to 64.5 billion kWh by 2034. This escalated energy requirement directly puts a demand for an efficient and sustainable source of energy, and as such, the promise of steady and renewable energy supply through solar power makes it very appealing. The average regional solar radiation exceeds 6 kWh/m2 per day, which points towards a very vast potential for solar energy generation. But to meet the energy requirements that will arise in the future from solar, it would call for a tremendous investment in infrastructure. This is because it is estimated that approximately 246,000 km2 of solar panels might be needed by 2034 in order to be able to cover the energy needs of the country. However, this massive area is required, but the benefits of solar energy do not stop there at solving shortages of energy. Solar power would increase economic activities due to job creation, stimulation of local industries, and the end reliance on fossil fuels. It has implications on environmental sustainability as it reduces greenhouse gas emissions and promotes cleaner practices of energy consumption. Northern Nigeria will unlock a stable and reliable source of power through investment in this infrastructure. This is important for economic development, thereby eventually improving the quality of life. Indeed, the integration of solar power addresses the immediate needs of satisfying energy challenges but builds a foundation for sustainable growth and environmental stewardship over the long term. Solar power in northern Nigeria is important for ensuring future demands for energy and significant economic development while emphasizing sustainability within the environment. A lot still has to be tapped into by tapping into the solar resources that are available. Key words: Solar Energy,Sustainability,Economic Growth,Energy Demand,Renewable Resources

Nanoring Tamm cavity in the telecommunications O band

Quantum and classical telecommunications require efficient sources of light. Semiconductor sources, owing to the high refractive index of the medium, often exploit photonic cavities to enhance the external emission of photons into a well-defined optical mode. Optical Tamm States (OTSs) in which light is confined between a distributed Bragg reflector and a thin metal layer have attracted interest as confined Tamm structures are readily manufactureable broadband cavities. Their efficiency is limited however by the absorption inherent in the metal layer. We propose a nanoring Tamm structure in which a nanoscale patterned annular metasurface is exploited to reduce this absorption and thereby enhance emission efficiency. To this end, we present designs for a nanoring Tamm structure optimized for the telecommunications O band and demonstrate a near doubling of output efficiency (35%) over an analogous solid disk confined Tamm structure (18%). Simulations of designs optimized for different wavelengths are suggestive of annular coupling between the Tamm state and surface plasmons. These designs are applicable to the design of single photon sources, nano-LEDs, and nanolasers for communications.

Magnetic hexagram micro soft robot

Abstract. This research focuses on the development of a hexagram-shaped multimodal magnetic soft robot for biomedical applications. This micro-robot utilizes principles of soft robotics and magnetic control mechanisms to achieve precise manipulation and maneuverability within biological environments at the micrometer to millimeter scale. Its advantages include precise navigation through physiological fluids via magnetic fields, enabling targeted drug delivery, diagnostic imaging enhancement, and minimally invasive surgical interventions. The hexagram shape ensures stable and controlled movements, overcoming instability seen in alternative robotic systems. However, these magnetic robots also face challenges such as size constraints, navigating turbulent flows and anatomical obstacles, sustaining operations with an efficient energy source, and biocompatibility concerns.