Strong Bone Research Articles

Agronomic biofortification of calcium in cabbage (Brassica Oleracea var capitata) applied with different sources of liming in Ca deficient acidic soil of Coonoor, The Nilgiris (Typic Dystropept)

The human body needs calcium (Ca) to maintain strong bones and teeth and to build a strong structure, helping muscles contract and playing a crucial role in the structural and signalling process. However, low calcium consumption in the diet has related to a variety of disorders in humans, which can have long-term health repercussions. Therefore, this study aimed to evaluate the Ca biofortification capacity of cabbage (Brassica oleracea var capitata) supplied with different Ca-supplying inorganic fertilizer sources at various fixed levels based on soil liming potential grown in open field conditions where four hybrids of cabbage grown in Ca deficient acidic soil. Ca applied as Limestone (CaCO3) (150% and 175% liming potential) and Dolomitic limestone [CaMg(CO3)2]150% liming potential yield high Ca content in cabbage head and foliage (61.3 mg 100 g-1), high glucosinolates content (53.12 mg 100 g-1) and lower oxalate(0.31 mg 100 g-1) that produced firmer head as compared with Ca untreated control which also promoted high market value for Ca biofortified ones. On the other hand, Ca addition leads to lower Fe and Mg content in the cabbage tissues due to an antagonistic effect. All four hybrids of cabbage studied using the agronomic method of biofortification significantly(p≤0.05) improved Ca enrichment (20% more compared to control) without showing any toxicity symptoms making possibility to obtain Ca biofortified cabbage in acidic soil of a hilly ecosystem by application of liming.

Bone-Adhesive Anisotropic Tough Hydrogel Mimicking Tendon Enthesis.

Tendon consists of soft collagen, yet it is mechanically strong and firmly adhered to the bone owing to its hierarchically anisotropic structure and unique tendon-to-bone integration (enthesis), respectively. Despite the recent advances in biomaterials, hydrogels simultaneously providing tendon-like high mechanical properties and strong adhesion to bone-mimicking enthesis is still challenging. Here, a strong, stiff, and adhesive triple-network (TN) anisotropic hydrogel that mimics a bone-adhering tendon is shown. The tough adhesive TN hydrogel is developed by combining imidazole-containing polyaspartamide (providing multiple hydrogen bonds to the bone surface) and energy-dissipative alginate-polyacrylamide double-network. To mimic the anisotropic structure and high mechanical properties of tendons, the bone-adhered TN hydrogel is linearly stretched and subsequently fixed via secondary cross-linking. The resulting hydrogel exhibits high tensile modulus and strength while maintaining a high bone adhesion without chemical modification of the bone surface. Furthermore, a bone-ligament-bone structure with strong bone adhesion reminiscent of the natural ligament is realized.

Automatic lower limb bone segmentation in radiographs with different orientations and fields of view based on a contextual network.

Bone identification and segmentation in X-ray images are crucial in orthopedics for the automation of clinical procedures, but it often involves some manual operations. In this work, using a modified SegNet neural network, we automatically identify and segment lower limb bone structures on radiographs presenting various fields of view and different patient orientations. A wide contextual neural network architecture is proposed to perform a high-quality pixel-wise semantic segmentation on X-ray images presenting structures with a similar appearance and strong superposition. The proposed architecture is based on the premise that every output pixel on the label map has a wide receptive field. This allows the network to capture both global and local contextual information. The overlapping between structures is handled with additional labels. The proposed approach was evaluated on a test dataset composed of 70 radiographs with entire and partial bones. We obtained an average detection rate of 98.00% and an average Dice coefficient of 95.25 ± 9.02% across all classes. For the challenging subset of images with high superposition, we obtained an average detection rate of 96.36% and an average Dice coefficient of 93.81 ± 10.03% across all classes. The results show the effectiveness of the proposed approach in segmenting and identifying lower limb bone structures and overlapping structures in radiographs with strong bone superposition and highly variable configurations, as well as in radiographs containing only small pieces of bone structures.

Genetics of tibia bone properties of crossbred commercial laying hens in different housing systems.

Osteoporosis and bone fractures are a severe problem for the welfare of laying hens, with genetics and environment, such as housing system, each making substantial contributions to bone strength. In this work, we performed genetic analyses of bone strength, bone mineral density, and bone composition, as well as body weight, in 860 commercial crossbred laying hens from 2 different companies, kept in either furnished cages or floor pens. We compared bone traits between housing systems and crossbreds and performed a genome-wide association study of bone properties and body weight. As expected, the 2 housing systems produced a large difference in bone strength, with layers housed in floor pens having stronger bones. These differences were accompanied by differences in bone geometry, mineralization, and chemical composition. Genome scans either combining or independently analyzing the 2 housing systems revealed no genome-wide significant loci for bone breaking strength. We detected 3 loci for body weight that were shared between the housing systems on chromosomes 4, 6, and 27 (either genome-wide significant or suggestive) and these coincide with associations for bone length. In summary, we found substantial differences in bone strength, content, and composition between hens kept in floor pens and furnished cages that could be attributed to greater physical activity in pen housing. We found little evidence for large-effect loci for bone strength in commercial crossbred hens, consistent with a highly polygenic architecture for bone strength in the production environment. The lack of consistent genetic associations between housing systems in combination with the differences in bone phenotypes could be due to gene-by-environment interactions with housing system or a lack of power to detect shared associations for bone strength.

Calcium and phosphorous insight of local chicken, broiler and old layer bones and their ratios for optimal bone health and development

In developing countries like Nigeria, milk and dairy products which are major sources of calcium and phosphorous are rarely taken by most adults due to high cost. This therefore resulted in osteomalacia, osteoporosis and other related diseases to some elderly persons. Domestic birds which bones are rich in minerals, readily available and cheaper than mineral supplements become the next available option despite their hardness to chew. This study therefore investigated the calcium and phosphorous contents of commonly relished local, old layer and broiler chicken bone ashes and their ratios. Standard analytical procedures were used for the analyses while their ratios were calculated. The results revealed that their calcium content ranged from 30.42 to 49.01 mg/100g, phosphorous 17.67 to19.23 mg/100g and ratios 1.64 to 2.55. Old layers’ bones had the best dietary mineral content while local chickens’ bones had the least. Their ratios were higher than that recommended for human by the nutritionist for healthy and strong bone formation.

Illuminating the Complexity of Biology in Syndesmotic Injuries with Ankle Fractures: The Downfalls of Strong Bones

Category: Ankle Introduction/Purpose: Injury to the syndesmotic ligaments can lead to prolonged functional limitations and thus, long-term ankle mobility dysfunction if not diagnosed and treated appropriately. Obesity has been studied in relation to syndesmotic instability but there is a paucity of literature investigating syndesmotic risk associated with other bone fragility characteristics. Additionally, ankle injury complexity associated with risk of Charcot in patients with a syndesmotic injury remains unstudied. Methods: This is a large retrospective, database study with structured query of a national insurance claims database (PearlDiver Technologies) for patients treated with ankle fixation from 2015 through 2020 as identified by ICD-10 codes. Patient characteristics associated with obtaining a syndesmotic injury with ankle fracture were analyzed using multivariable logistic regression analysis. In addition to corroborating the increased risk seen with elevated BMI, data included age at time of operation, sex, smoking record, diabetes, and osteoporosis. Likelihood of developing Charcot in patients with an ankle fracture and unstable syndesmosis was also analyzed using univariable logistic regression. Results: Our query yielded 168,359 patients who underwent ankle fixation; 32,502 (23.9%) were treated for syndesmotic injury. On multivariable analysis, obese and male patients had a higher probability of syndesmotic injury (OR 1.39 [95% CI, 1.36-1.43] and OR 1.55 [95% CI, 1.52-1.59], respectively; P<0.001); osteoporotic patients had lower probability of syndesmotic injury (OR 0.64 [95% CI, 0.62-0.67]; P<0.001). Of 13,275 diabetic patients, 2,822 (21.3%) were treated for syndesmotic injury. Diabetic patients had increased probability of developing Charcot (OR 1.54 [95% CI, 1.19-2.00]; P=0.001). A total of 36,883 patients were treated with ankle fixation and unstable syndesmosis. While statistically insignificant, compared to patients with syndesmotic injury treated with bimalleolar ORIF, patients undergoing isolated fibular ORIF had lower probability of developing Charcot (OR 0.71 [95% CI, 0.50-0.99]) versus undergoing trimalleolar ORIF had higher probability (OR 1.24 [95% 0.91-1.69]). Conclusion: Among this population derived from a large all-claims database using ICD-10 coding, higher probability of syndesmotic injury was associated with male or obese patients; lower syndesmotic injury probability was associated with osteoporotic patients. This suggests that injuries obtained with a greater force or patients with stronger bone strength are more likely to sustain a syndesmotic disruption while weaker bones are more susceptible to fracture, leaving the syndesmotic structures intact. These findings suggest purposeful evaluation for syndesmotic disruption in patients with these higher risk characteristics. Increasing ankle injury complexity demonstrates a gradient in Charcot risk in patients with syndesmotic instability.

Periosteum-inspired in situ CaP generated nanocomposite hydrogels with strong bone adhesion and superior stretchability for accelerated distraction osteogenesis

BackgroundDistraction osteogenesis (DO) is an efficacious but lengthy procedure to reconstruct segmental bone defects under the principle of tension-stress, during which the periosteum-mediated mechanical stimulation plays a pivotal role. Inspired by the dynamic process of DO and the mechanical stimulation of periosteum, a new design of bionic periosteum was developed to simulate the mechanical transduction of natural periosteum for the application in DO procedure.MethodsIn this study, an injectable organic-inorganic hybrid hydrogel was developed based on a novel combination of the PEGylated poly (glycerol sebacate) (PEGS) polymer network and in situ formed CaP nanoparticles (ICPNs). Rat bone marrow mesenchymal stem cells (rBMSCs) and human umbilical vein endothelial cells (HUVECs) were cultured and tested in vitro to evaluate biocompatibility, cell adhesion, proliferation, and pro-osteogenic and pro-angiogenic activity. In vivo experiments were conducted in the rat tibial model of distraction osteogenesis.ResultsThe developed nanocomposite hydrogels exhibited excellent injectability, robust bone adhesion, superior stretchability, and enhanced osteogenic activity. The results of in vitro and in vivo studies showed that PEGS/ICPN hydrogels could promote new bone formation and mineralization during the dynamic distraction process through the synergistic effects of angiogenesis and osteogenesis.ConclusionsThis periosteum-inspired nanocomposite hydrogel represents a mechanobiology approach for effectively restoring large bone defects through the dynamic DO process.

SYNTHESIS OF CALCIUM CARBONATE (CaCO3) FROM EGGSHELL BY CALCINATION METHOD

Calcium is an essential nutrient the human body needs to control blood pressure and maintain strong bones and teeth. One type of calcium that is often consumed and safe for health is calcium carbonate. It can obtain this material from chicken eggshell waste, where it is known that the CaCO3 content is 95%. Therefore, it conducted this research to see the phase, functional group, absorbance level, and energy band gap of CaCO3 samples. CaCO3 was synthesized using the calcination method, in which the egg shells were first soaked in sodium hypochlorite, then dried at 250°C for 10 minutes, and CaCO3 powder was obtained. Then the powder was characterized by XRD, FTIR, and UV-Vis. The results of XRD analysis showed that the calcite phase of CaCO3 was 100% according to the JCPDS PDF of calcite (96-901-6707) with a crystalline size of CaCO3 of 22.6 nm. The results of FTIR of CaCO3 samples at the absorption peak of 4000-500 cm-1 identified the functional groups of Ca-O, C-O, -CH2, and O-H. CaCO3 samples can absorb light at wavelengths of 237.1 nm, 251.5 nm, and 289.7 nm, which have an energy band gap of 3.91 eV. Thus, using this simple calcination method, the CaCO3 sample obtained from the extraction of chicken egg shells can later be applied in the medical field.

Morphometric Study of Proximal End of the Fully Ossified Human Femur: A Cross-Sectional Study.

Introduction The femur or thigh bone is the longest and strongest bone in the body. It provides skeletal support for the thigh. Weight-bearing and stability of gait are the essential functions of the femur. Aim To construct the baseline data on different dimensions of the proximal end of the fully ossified human femur and determine any significant differences between the right and left femora. Objective To measure the total length of the femur, proximal breadth, vertical diameter of the head, transverse diameter of the head, the circumference of the head, the vertical diameter of the neck, the transverse diameter of the neck, the circumference of the neck, anterior length of the neck, neck-shaft angle, length of the intertrochanteric crest and correlate the different dimensions of the proximal end with the total length of the femur. Result The variables of the proximal end of the left femora like proximal breadth (PB), the circumference of the head (CH), vertical diameter (VDN), the transverse diameter of the neck (TDN), the circumference of the neck (CN), neck length (NL), neck-shaft angle (NSA), length of an intertrochanteric crest (LITC) showed highly significant positive linear correlation with the length of the femur. Circumference of the neck showed the highest degree of correlation with the length of the femur (correlation coefficient 0.839). Conclusion The statistically significant difference between right and left femora was found between the length of the femur, the vertical diameter of the neck of the femur, the transverse diameter of the neck of the femur, and the length of the intertrochanteric crest of the femur. The mean value of proximal breadth, the vertical diameter of the head, the transverse diameter of the head, the circumference of the head, the circumference of the neck, anterior length of the neck of the femur, and neck-shaft angle of the right and left femora to have no statistically significant differences.

Influence of hydroxyapatite composite coating on the textured surface of patient specific dental implant: An in silico 3D finite element study

Titanium dental implants are one of the best replacements for the natural teeth. It can reduce early failures compared to other implant materials. During mastication, generally, implant loosening occurs between the bone and the implant surface. Therefore, to resolve this issue, surface modification of the implant surface was done which can provide better bonding between the implant and the bone. In this study, we designed five different types of surface texture on the implant and compared them with the solid non-textured implant. In addition to that, we used four different hybrid composite coating materials along with hydroxyapatite, for better osseointegration and bone formation. Thus, we modeled a bony structure like mandible using solid modeling technique. We considered average biting force of 250 N with different bone conditions. After the analysis, it has been observed that ‘U’ and ‘V’ shape textures exhibited the optimized textures for dental implant with coating combination of HA1.5TO1.5SR and HA3Sr for weak and very weak bone conditions. The coating for straight and dome shaped textures for strong and very strong bone conditions showed better results, whereas ‘U’ shaped and dome shaped textures showed better results for normal bone condition.

Activity Preference, Demographic Characteristics, and Attitudes of the Students toward Physical Education at the University of Eastern Philippines

The study aimed to determine the activity preference, demographic characteristics, and attitudes of the students toward Physical Education at the University of Eastern Philippines. Specifically, it tried to determine the demographic characteristics of the respondents in terms of age, sex, income level, year level, and body build. It also identified the students’ activity preferences and level of attitudes towards physical education activities. Furthermore, it tried to find out if there was a significant relationship between the demographic characteristic and the preference of the students in physical education. It also investigated the significant relationship between the demographic characteristics of the respondents and their attitudes towards physical education activities. Finally, it attempted to find out if a significant relationship existed between the students’ preference and their attitudes toward physical education activities. The descriptive-correlational survey design was used in this study. A research instrument patterned from Jean Marie Cando was used in gathering the data which were tabulated and analyzed using frequency counts, percentage, weighted mean, and multiple regression analysis. The findings revealed that most of the college students who were 16-17 years of age were dominated by females and were in the second-year level. Most of the students were ectomorphs. Hence, it can be said that they can be trained in a physical education activity. The UEP college students slightly preferred the activities in physical education. However, the preferred physical fitness and Philippine games considering that they can help develop strong bones and muscles needed for their growth. They slightly preferred rhythmic activities, individual/dual sports/games, team sports, and outdoor recreation. The rhythmic activities were more on folk dances, ballroom, and modern dance. They need artistry and skill in body movement. Those who had limited talents in dancing refrained from performing it. Most of the college student respondents favored physical education activities such as training for the women's Olympic team, physical fitness, callisthenic, and regular physical activities. However, some highly favored the value of physical activity as a skilled movement, as a way of participating in group activities, and to release emotional stress. This implies a favorable attitude toward physical education activities. Normally a bodybuilder needs to be trained in any form of physical body activities for a healthy and productive manpower resource.

Transwoman Elite Athletes: Their Extra Percentage Relative to Female Physiology.

There is increasing debate as to whether transwoman athletes should be included in the elite female competition. Most elite sports are divided into male and female divisions because of the greater athletic performance displayed by males. Without the sex division, females would have little chance of winning because males are faster, stronger, and have greater endurance capacity. Male physiology underpins their better athletic performance including increased muscle mass and strength, stronger bones, different skeletal structure, better adapted cardiorespiratory systems, and early developmental effects on brain networks that wires males to be inherently more competitive and aggressive. Testosterone secreted before birth, postnatally, and then after puberty is the major factor that drives these physiological sex differences, and as adults, testosterone levels are ten to fifteen times higher in males than females. The non-overlapping ranges of testosterone between the sexes has led sports regulators, such as the International Olympic Committee, to use 10 nmol/L testosterone as a sole physiological parameter to divide the male and female sporting divisions. Using testosterone levels as a basis for separating female and male elite athletes is arguably flawed. Male physiology cannot be reformatted by estrogen therapy in transwoman athletes because testosterone has driven permanent effects through early life exposure. This descriptive critical review discusses the inherent male physiological advantages that lead to superior athletic performance and then addresses how estrogen therapy fails to create a female-like physiology in the male. Ultimately, the former male physiology of transwoman athletes provides them with a physiological advantage over the cis-female athlete.

Design of patient specific basal dental implant using Finite Element method and Artificial Neural Network technique.

The bone conditions of mandibular bone vary from patient to patient, and as a result, a patient-specific dental implant needs to be designed. The basal dental implant is implanted in the cortical region of the bone since the top surface of the bone narrows down because of aging. Taguchi designs of experiments technique are used in which 25 optimum solid models of basal dental implants are modeled with variable geometrical parameters, viz. thread length, diameter, and pitch. In the solid models the implants are placed in the cortical part of the 3D models of cadaveric mandibles, that are prepared from CT data using image processing software. Patient-specific bone conditions are varied according to the strong, weak, and normal basal bone. A compressive force of 200 N is applied on the top surface of these implants and using finite element analysis software, the microstrain on the peri-implant bone ranges from 1000 to 4000 depending on the various bone conditions. According to the finite element data, it can be concluded that weak bone microstrain is comparatively high compared with normal and strong bone conditions. A surrogate artificial neural network model is prepared from the finite element analysis data. Surrogate model assisted genetic algorithm is used to find the optimum patient-specific basal dental implant for a better osseointegration-friendly mechanical environment.

Modeling, design and tailoring of a tough, strong and stiff multilayered bone graft material

Damage tolerance, stiffness, and strength are critical mechanical properties that are difficult to achieve concurrently in synthetic monolithic materials. This limits the range of certain applications, including in bone graft materials where bone-like mechanical reliance is desired. For example, calcium sulfate (CS) is a biologically compatible ceramic that possesses several properties of an ideal bone graft material, but its applications in medicine is limited by its brittleness. Brittleness may be alleviated by the addition of stronger and more ductile reinforcements, with the best mechanical improvements obtained when the layered architecture and the interfaces for these reinforcements are tailored. Here we propose a systematic modeling and design approach to tailor the architecture and properties of a multilayered bone graft material composed of a brittle ceramic and a more ductile material such as metals. More specifically, the volume fraction, moduli, number of layers, and the toughness of the interfaces between the different phases are tailored to maximize overall stiffness, strength, and energy absorption capacity. Our model predicts that when the stiffness of the reinforcement is higher (lower) than the ceramic, the beams with lower (higher) number of layers and higher (lower) volume fraction of metal are stronger. However, while the higher number of layers is always desired in terms of energy dissipation, the effects of other variables is more complex to understand and should thus be studied in conjunction with each other.

Vitamin D and its Relationship with Female Outfit Dressing Style

Background: Vitamins, minerals, and other important nutrients we get from food can keep our bodies healthy, and to get strong bones, we need calcium and vitamin D. Vit D3 titled the “sunshine vitamin,” is one of the important nutrients needed for a female’s health. Vit D had a constant function in adaptive and inherent immunity. Exposure to sunlight has a major role in providing adequate Vit D for most people in the world. Aim of the study: Our study aims to evaluate Vit D and calcium levels in healthy young females of child-bearing age and to inspect the effects of their outfit dressing. Methods: A total of 108 women were included, those wearing full cover outfit style clothing covering all body leaving the face area and hand exposed group I (74 women), and uncovered women with exposed head, arms, and legs group II (34 women). A quantitative test was used to determine 25-hydroxy Vit D in human serum using minividase and for total calcium measurement atomic absorption spectrophotometry. Results: All women in both groups had a blood test for calcium (Ca) and Vit D3 level levels, and a calculation of body mass index (BMI) was done. Using t-test for the comparison between (group I and group II).A significant difference (p is less than 0.005) was found in serum Vit D3, which was lower in group I with a mean (12.09 ± 7.59), and for group II, it was (16.56 ± 7.61). Serum calcium was slightly elevated in group II than in group I, but there was no significant between the two groups. The mean serum calcium level was (9.41) in group I and (9.56) (p is less than 0.3) in group II. Although body mass index was higher in group I mean (28.73 ± 0.61) than group II mean (27.25 ± 4.88), it was statistically not significant (p is less than 0.2). Conclusion: The finding of this study revealed that many factors could affect Vit D levels, like clothing styles and lifestyle. Inadequate Vit D intake and covered dress style can lead to low Vit D levels. A recommendation that has been suggested when there is no Vit D intake is to expose the face area, arms, and hands for a short duration in the middle of the day many times a week to have normal Vit D levels.

Ilizarov Ankle Arthrodesis: A Simple Salvage Solution for Failed and Neglected Ankle Fractures.

Infection around theankle joint after fracture fixation, or septic arthritis with active discharging sinuses is often challenging to manage with conventional procedures of arthrodesis. The Ilizarov method of arthrodesis gives a better alternative for salvage in such cases. This was a retrospective study including 20 patients who were subjected to tibiotalar arthrodesis with Ilizarov method. The major pathologies included internal fixation of ankle fractures complicated by infection, posttraumatic infected ankle arthritis, and osteomyelitis. The patients were evaluated on the basis of Association for the Study and Application of the Method of Ilizarov (ASAMI) criteria. The aim of the surgery was to achieve plantigrade, stable, and painless foot with no signs of infection. A total of 20 patients were operated and reviewed at our institute. The study comprised of 15 male and 5 female patients with a mean age of 43.9years (range 33-55years). Out of 20 patients, 4 patients had complications of pin-tract infection and one had wire breakage of the forefoot ring. According to the ASAMI criteria, 17 patients had excellent bone scores and 18 patients had good functional scores. Union was achieved in all patients with resolution of infection and the mean limb length discrepancy was 1.92cm (range 1-2.5cm). The Ilizarov fixator for ankle arthrodesis provides an excellent way for strong bone fusion, infection eradication, early weight-bearing, and the added benefits of compression atthe arthrodesis site post-operatively.

Synthesis, Structure-Property Evaluation and Biological Assessment of Supramolecular Assemblies of Bioactive Glass with Glycyrrhizic Acid and Its Monoammonium Salt.

Medical nutrients obtained from plants have been used in traditional medicine since ancient times, owning to the protective and therapeutic properties of plant extracts and products. Glycyrrhizic acid is one of those that, apart from its therapeutic effect, may contribute to stronger bones, inhibiting bone resorption and improving the bone structure and biomechanical strength. In the present study, we investigated the effect of a bioactive glass (BG) addition to the structure–property relationships of supramolecular assemblies formed by glycyrrhizic acid (GA) and its monoammonium salt (MSGA). FTIR spectra of supramolecular assemblies evidenced an interaction between BG components and hydroxyl groups of MSGA and GA. Moreover, it was revealed that BG components may interact and bond to the carboxyl groups of MSGA. In order to assess their biological effects, BG, MSGA, and their supramolecular assemblies were introduced to a culture of human bone-marrow-derived mesenchymal stromal cells (BMSCs). Both the BG and MSGA had positive influence on BMSC growth, viability, and osteogenic differentiation—these positive effects were most pronounced when BG1d-BG and MSGA were introduced together into cell culture in the form of MSGA:BG assemblies. In conclusion, MSGA:BG assemblies revealed a promising potential as a candidate material intended for application in bone defect reconstruction and bone tissue engineering approaches.

Resolving the Conflict between Strength and Toughness in Bioactive Silica-Polymer Hybrid Materials.

Simultaneously improving the strength and toughness of materials is a major challenge. Inorganic-polymer hybrids offer the potential to combine mechanical properties of a stiff inorganic glass with a flexible organic polymer. However, the toughening mechanism at the atomic scale remains largely unknown. Based on combined experimental and molecular dynamics simulation results, we find that the deformation and fracture behavior of hybrids are governed by noncovalent intermolecular interactions between polymer and silica networks rather than the breakage of covalent bonds. We then attempt three methods to improve the balance between strength and toughness of hybrids, namely the total inorganic/organic (I/O) weight ratio, the size of silica nanoparticles, and the ratio of -C-O vs -C-C bonds in the polymer chains. Specifically, for a hybrid with matched silica size and I/O ratio, we demonstrate optimized mechanical properties in terms of strength (1.75 MPa at breakage), degree of elongation at the fracture point (31%), toughness (219 kPa), hardness (1.08 MPa), as well as Young's modulus (3.0 MPa). We also demonstrate that this hybrid material shows excellent biocompatibility and ability to support cell attachment as well as proliferation. This supports the possible application of this material as a strong yet tough bone scaffold material.

Dietary protein requirement for captive juvenile green turtles (Chelonia mydas).

Head-starting programs are extremely important for restoring the population of sea turtles in wild whereas husbandry conditions and feeding regimens of captive turtles are still limited. In the current study, the optimal dietary protein requirement for green turtle (Chelonia mydas) was investigated to support rearing in head-starting programs. Twenty-five-day-old turtles (44.5-46.2 g body weight, n = 45) were randomly distributed into 15 experimental plastic tanks, comprising three treatment replications of 3 turtles each. They were fed fishmeal-based feeds containing different levels of protein (30%, 35%, 40%, 45%, and 50%) for 8 weeks. At the end of feeding trial, growth performance (specific growth rate = 1.86% body weight/day) and feed utilization (protein efficiency ratio = 3.30 g gain/g protein) were highest in turtles fed with 40% protein in feed (p < .05). These nutritional responses were significantly supported by specific activities of fecal digestive enzymes, especially trypsin, chymotrypsin, amylase, and the amylase/trypsin ratio. Also, this dietary level improved the deposition of calcium and phosphorus in carapace, supporting a hard carapace and strong healthy bones. There were no negative effects in general health status of reared turtles, as indicated by hematological parameters. Based on a broken-line analysis between dietary protein levels and specific growth rate, the optimal protein level for green turtles was estimated as 40.6%. Findings from the current study support the use of artificial diets of specific protein levels to rear captive green turtle before release to natural habitats.

Antibacterial Vancomycin@ZIF-8 Loaded PVA Nanofiber Membrane for Infected Bone Repair.

Bone substitutes with strong antibacterial properties and bone regeneration effects have an inherent potential in the treatment of severe bone tissue infections, such as osteomyelitis. In this study, vancomycin (Van) was loaded into zeolitic imidazolate framework-8 (ZIF-8) to prepare composite particles, which is abbreviated as V@Z. As a pH-responsive particle, ZIF-8 can be cleaved in the weak acid environment caused by bacterial infection to realize the effective release of drugs. Then, V@Z was loaded into polyvinyl alcohol (PVA) fiber by electrospinning to prepare PVA/V@Z composite bone filler. The drug-loading rate of V@Z was about 6.735%. The membranes exhibited super hydrophilicity, water absorption and pH-controlled Van release behavior. The properties of anti E. coli and S. aureus were studied under the pH conditions of normal physiological tissues and infected tissues (pH 7.4 and pH 6.5, respectively). It was found that the material had good surface antibacterial adhesion and antibacterial property. The PVA/V@Z membrane had the more prominent bacteria-killing effect compared with the same amount of single antibacterial agent containing membrane such as ZIF-8 or Van loaded PVA, and the antibacterial rate was up to 99%. The electrospun membrane had good biocompatibility and can promote MC3T3-E1 cell spreading on it.