A fluorescence based dual sensor for Zn2+ and PO43- and the application of soft computing methods to predict machine learning outcomes.

A phenolphthalein-based Schiff base, 3,3-bis-{4-hydroxy-3-[(pyridine-2-ylmethylimino)-methyl]-phenyl}-3H-isobenzofuran-1-one (PAP), has been synthesized and used for selective fluorescence 'turn on' and 'turn off' sensing of Zn2+ and PO43- respectively. The limit of detection using the 3σ method for Zn2+ is found to be 19.3 nM and that for PO43- is 8.3 µM. The sensing mechanism of PAP for Zn2+ ions has been explained by 1H NMR, 13C NMR, TRPL, ESI-MS, FT-IR, and DFT based calculations. Taking advantage of this fluorescence 'on-off' behavior of PAP in the sequential presence of Zn2+ and PO43- a two input fuzzy logic (FL) operation has been constructed. The chemosensor PAP can thus act as a metal ion and anion responsive molecular switch, and its corresponding emission intensity is used to mimic numerous FL functions. To replace various expensive, time-consuming experimental procedures, we implemented machine learning soft computing tools, such as fuzzy-logic, artificial neural networks (ANNs), and adaptive neuro-fuzzy inference systems (ANFIS), to correlate as well as predict the fluorescence intensity in the presence of any equivalent ratio of Zn2+ and PO43-. The statistical performance measures (MSE and RMSE, for example) show that the projected values of the cation and anion sensing data by the ANFIS network are the best and closer to the experimental values.

Tunable CH/π Interactions within a Tryptophan Zipper Motif to Stabilize the Fold of Long ß-Hairpin Peptides.

The tryptophan zipper (Trpzip) is an iconic folding motif of ß-hairpin peptides capitalizing on two pairs of cross-strand tryptophans, each stabilized by an aromatic-aromatic stacking in an edge-to-face (EtF) geometry. Yet, the origins and the contribution of this EtF packing to the unique Trpzip stability remain poorly understood. To address this question of structure-stability relationship, a library of Trpzip hairpins was developed by incorporating readily accessible nonproteinogenic tryptophans of varying electron densities. We found that each EtF geometry was, in fact, stabilized by an intricate combination of XH/π interactions. By tuning the π-electron density of Trpface rings, CH/π interactions are strengthened to gain additional stability. On the contrary, our DFT calculations support the notion that Trpedge modulations are challenging due to their simultaneous paradoxical engagement as H-bond donors in CH/π and acceptors in NH/π interactions.

Super-Reducing Behavior of Benzo[b]phenothiazine Anion Under Visible-Light Photoredox Condition.

Herein we describe the anion of benzo[b]phenothiazine as a super reductant species upon excitation by visible light. In contrary to N-substituted phenothiazines or benzophenothiazines, this molecule holds extreme reducing power to promote single electron transfer-based reductive cleavage at a potential of -3.51 V vs SCE. As a proof, a plethora of aryl chloride substrates have been reductively cleaved to fabricate molecules of the class isoindolinone and oxindole. Moreover, an aryl-chloride bond has been homolytically cleaved to generate aryl radicals that have been utilized for C-C cross-coupling or C-P bond formation reactions. To prove its extreme reducing ability, some of the aryl fluoride bonds have been cleaved to generate aryl radicals. A detailed photophysical study including steady-state and time-resolved spectroscopic techniques explain the molecule's behavior upon light excitation, and that correlates with its reactivity pattern. Theoretical calculations disclose the benzophenothiazine anion to be slightly puckered at the ground state as the molecule is antiaromatic in nature. In contrast, the excited-state geometry is planar, which is also close to that of the intermediate after one electron transfer. Abating the antiaromaticity of the anionic species is partially responsible for its highly reducing behavior.

Does early-life migration experience determine health and health-risk behavior in later life? Evidence from elderly returns migrants in Kerala, India.

Becoming elderly is an intrinsic part of life, and the burden of disease increases with age. However, the early life migration experience and occupational hazards at the destination can lead to serious health problems later in life. This study aims to understand the association between early life migration and the health and risky behavior of elderly return migrants using data from the Kerala Migration Survey in 2018. The results of bivariate and multivariate analyses show that the majority of migrants return due to retirement and ill health at the average age of 51 and suffer from poor health and multiple diseases. More than half (55%) of elderly returnees reported poor health, and among them, 70% have at least one chronic disease. The early life migration experience and injuries at the destination are the main determinants of poor self-rated health and chronic disease. Furthermore, elderly return migrants have high-risk health behaviours such as smoking and alcohol consumption, as well as less access to health schemes. Despite some shortcomings, this study identifies the most vulnerable groups among the elderly and their health characteristics. This will help to promote healthy aging in Kerala, India, or areas with increasing numbers of elderly and return migrants around the world.

Strategic Synthesis of Heptacoordinated FeIII Bifunctional Complexes for Efficient Water Electrolysis.

In this research, highly efficient heterogeneous bifunctional (BF) electrocatalysts (ECs) have been strategically designed by Fe coordination (CR ) complexes, [Fe2 L2 (H2 O)2 Cl2 ] (C1) and [Fe2 L2 (H2 O)2 (SO4 )].2(CH4 O) (C2) where the high seven CR number synergistically modifies the electronic environment of the Fe centre for facilitation of H2 O electrolysis. The electronic status of Fe and its adjacent atomic sites have been further modified by the replacement of -Cl- in C1 by -SO4 2- in C2. Interestingly, compared to C1, the O-S-O bridged C2 reveals superior BF activity with extremely low overpotential (η) at 10 mA cm-2 (140 mVOER , 62 mVHER ) and small Tafel slope (120.9 mV dec-1 OER , 45.8 mV dec-1 HER ). Additionally, C2 also facilitates a high-performance alkaline H2 O electrolyzer with cell voltage of 1.54 V at 10 mA cm-2 and exhibits remarkable long-term stability. Thus, exploration of the intrinsic properties of metal-organic framework (MOF)-based ECs opens up a new approach to the rational design of a wide range of molecular catalysts.

A survey on rumor detection and prevention in social media using deep learning.

In the current digital era, massive amounts of unreliable, purposefully misleading material, such as texts and images, are being shared widely on various web platforms to deceive the reader. Most of us use social media sites to exchange or obtain information. This opens a lot of space for false information, like fake news, rumors, etc., to spread that could harm a society's social fabric, a person's reputation, or the legitimacy of a whole country. Therefore, preventing the transmission of such dangerous material across platforms is a digital priority. However, the main goal of this survey paper is to thoroughly examine several current state-of-the-art research works on rumor control (detection and prevention) that use deep learning-based techniques and to identify major distinctions between these research efforts. The comparison results are intended to identify research gaps and challenges for rumor detection, tracking, and combating. This survey of the literature makes a significant contribution by highlighting several cutting-edge deep learning-based models for rumor detection in social media and critically evaluating their effectiveness on recently available standard datasets. Furthermore, to have a thorough grasp of rumor prevention to spread, we also looked into various pertinent approaches, including rumor veracity classification, stance classification, tracking, and combating. We also have created a summary of recent datasets with all the necessary information and analysis. Finally, as part of this survey, we have identified some of the potential research gaps and challenges that need to be addressed in order to develop early, effective methods of rumor control.

Surgical Treatment Modalities in Pediatric Monostotic Fibrous Dysplasia of Proximal Femur - A Case Series.

Introduction: Monostotic fibrous dysplasia is a rare genetic non-inherited orthopedic condition presenting at any age with variable presentation. Proximal femur being the most common site, the mechanical factor predisposes it to increased chances of pathological fracture, which makes it challenging to choose an appropriate treatment modality and implant selection in children. Case Presentation: In this retrospective case series, six children aged 7-12 years with monostotic fibrous dysplasia with or without fracture were treated with different treatment modalities from 2015 to 2020. Extended curettage and bone grafting and stabilization were done with extramedullary implants such as locking plates and DHS. Autograft alone or combination with allograft was chosen according to size of lesion. Patients without fracture were treated with curettage and artificial bone graft substitute with hip spica. Patients were followed up to 12 months. Revised Musculoskeletal Tumor Society (MSTS) score at each follow-up and Toronto Extremity Salvage Score (TESS) at final follow-up. Results: Mean fracture healing time was 14.8 ± 2.28 weeks. in patients with fracture. Full weight-bearing was started at average 15.67 ± 2.94 weeks. One patient had shortening of 1 cm but none had any surgical site infection, loss of correction, or varus collapse more than 5°. Mean revised MSTS at 12 months was 24.2 ± 2.28 in patients with curettage, bone grafting, and internal fixation, while it was 27 in patients with curettage, grafting with hip spica. Mean TESS was found to be 90 ± 9.41 in internal fixation group, while it was 95 in patient with curettage, grafting with hip spica. Conclusion: Treatment modality should be chosen wisely after analyzing pre-operative radiograph, lesion size, presence of pathological fracture, and each patient profile. Extramedullary fixation devices can be an alternate choice of implant in children and adolescents for monostotic fibrous dysplasia. Long duration follow-up and patient counseling should be done for recurrence of lesion and deformities.

Preclinical validation and treatment of volumetric modulated arc therapy based total bone marrow irradiation in Halcyon™ ring gantry linear accelerator.

AIM: This study aims​ to report preclinical validation, and the first clinical treatment of total bone marrow irradiation (TMI) and total bone marrow and lymph nodal irradiation (TMLI) using Volumetric modulated arc therapy in Halcyon-E ring gantry linear accelerator. Preclinical validation includes simulation, planning, patient-specific QA, and dry run. MATERIAL AND METHOD: Four patients, two female and two male, with body weights of 116 kg, 52 kg, 64 kg, and 62 kg; with two with chronic myeloid leukemia, one each with acute lymphoblastic leukemia and acute myeloid leukemia (AML) were simulated and planned for TMI/TMLI. Patients were immobilized with a full-body vacuum bag. Head first supine (HFS) and Feet first supine (FFS) CT scans were acquired from head to knee and knee to toe. Planning target volume (PTV) was created with a uniform margin of 6 mm over the total bone marrow/bone marrow + lymph nodes. HFS and FFS PTVs were optimized independently using 6MV unflatten energy for 12 Gy in 6 fractions. Plans were merged to create the resultant dose distribution using a junction bias dose matching technique. The total number of isocenters was ≤ 10 per CT set, and two to four full arcs were used for each isocenter. A junction dose gradient technique was used for dose feathering between arcs between adjacent isocenters. RESULT: Only one female patient diagnosed as AML received the TMLI treatment, while the other three patients dropped out due to clinical complications and comorbidities that developed in the time between simulation and treatment. The result presented has been averaged over all four patients. For PTV, 95% dose was normalised to 95% volume, PTV_V107% receiving 3.3 ± 3.1%. Total lung mean and V12Gy were 1048.6 ± 107.1 cGy and 19.5 ± 12.1%. Maximum lens doses were 489.5 ± 35.5 cGy (left: L) and 497 ± 69.2 cGy (right: R). The mean cardiac and bilateral kidney doses were 921.75 ± 89.2 cGy, 917.9 ± 63.2 cGy (L), and 805.9 ± 9.7 cGy (R). Average Monitor Unit was 7738.25 ± 1056.6. The median number of isocenters was 17(HFS+FFS), average MU/Dose (cGy) ratio per isocenter was 2.28 ± 0.3. CONCLUSION: Halcyon-E ring gantry linear accelerator capable of planning and delivering TMI/TMLI.​​.

Dioxygen Activation and Mandelate Decarboxylation by Iron(II) Complexes of N4 Ligands: Evidence for Dioxygen-Derived Intermediates from Cobalt Analogues.

The isolation, characterization, and dioxygen reactivity of monomeric [(TPA)MII(mandelate)]+ (M = Fe, 1; Co, 3) and dimeric [(BPMEN)2MII2(µ-mandelate)2]2+ (M = Fe, 2; Co, 4) (TPA = tris(2-pyridylmethyl)amine and BPMEN = N1,N2-dimethyl-N1,N2-bis(pyridin-2-yl-methyl)ethane-1,2-diamine) complexes are reported. The iron(II)- and cobalt(II)-mandelate complexes react with dioxygen to afford benzaldehyde and benzoic acid in a 1:1 ratio. In the reactions, one oxygen atom from dioxygen is incorporated into benzoic acid, but benzaldehyde does not derive any oxygen atom from dioxygen. While no O2-derived intermediate is observed with the iron(II)-mandelate complexes, the analogous cobalt(II) complexes react with dioxygen at a low temperature (-80 °C) to generate the corresponding cobalt(III)-superoxo species (S), a key intermediate implicated in the initiation of mandelate decarboxylation. At -20 °C, the cobalt(II)-mandelate complexes bind dioxygen reversibly leading to the formation of µ-1,2-peroxo-dicobalt(III)-mandelate species (P). The geometric and electronic structures of the O2-derived intermediates (S and P) have been established by computational studies. The intermediates S and P upon treatment with a protic acid undergo decarboxylation to afford benzaldehyde (50%) with a concomitant formation of the corresponding µ-1,2-peroxo-µ-mandelate-dicobalt(III) (P1) species. The crystal structure of a peroxide species isolated from the cobalt(II)-carboxylate complex [(TPA)CoII(MPA)]+ (5) (MPA = 2-methoxyphenylacetate) supports the composition of P1. The observations of the dioxygen-derived intermediates from cobalt complexes and their electronic structure analyses not only provide information about the nature of active species involved in the decarboxylation of mandelate but also shed light on the mechanistic pathway of two-electron versus four-electron reduction of dioxygen.

Towards the Experimentally-Informed In Silico Nozzle Design Optimization for Extrusion-Based Bioprinting of Shear-Thinning Hydrogels.

Research in bioprinting is booming due to its potential in addressing several manufacturing challenges in regenerative medicine. However, there are still many hurdles to overcome to guarantee cell survival and good printability. For the 3D extrusion-based bioprinting, cell viability is amongst one of the lowest of all the bioprinting techniques and is strongly influenced by various factors including the shear stress in the print nozzle. The goal of this study is to quantify, by means of in silico modeling, the mechanical environment experienced by the bioink during the printing process. Two ubiquitous nozzle shapes, conical and blunted, were considered, as well as three common hydrogels with material properties spanning from almost Newtonian to highly shear-thinning materials following the power-law behavior: Alginate-Gelatin, Alginate and PF127. Comprehensive in silico testing of all combinations of nozzle geometry variations and hydrogels was achieved by combining a design of experiments approach (DoE) with a computational fluid dynamics (CFD) of the printing process, analyzed through a machine learning approach named Gaussian Process. Available experimental results were used to validate the CFD model and justify the use of shear stress as a surrogate for cell survival in this study. The lower and middle nozzle radius, lower nozzle length and the material properties, alone and combined, were identified as the major influencing factors affecting shear stress, and therefore cell viability, during printing. These results were successfully compared with those of reported experiments testing viability for different nozzle geometry parameters under constant flow rate or constant pressure. The in silico 3D bioprinting platform developed in this study offers the potential to assist and accelerate further development of 3D bioprinting.

Results of modified thread technique for the treatment of wrist ganglion.

BACKGROUND: Ganglion cyst is the commonest swelling around the wrist. It usually presents as a painless swelling. There is no consensus as to the exact cause and the ideal modality of its treatment. Surgical excision has the best cure rates but has its share of complications. The aim of this study was to evaluate whether a modified thread technique can give reasonably good results with a low complication rate in patients with wrist ganglion. MATERIAL AND METHODS: One hundred and sixteen patients with wrist ganglion underwent a modified thread technique in which a sterile silk suture was passed through the ganglion, the contents of the ganglion were expressed out completely by firm pressure and the thread was tied over a sterile gauze piece forming a single loop. The thread was removed once serosanginous discharge was seen at entry point of the thread into the cyst. RESULTS: One hundred and eight patients were available for final analysis with minimum six months follow up. There was no recurrence in ninety eight patients giving success rate of ninety one percent. Recurrence was only seen in patients where complete evacuation of the contents of ganglion could not be achieved. Nine patients had minor complications in the form of superficial infection in two patients and mild pain around thread entry point in seven patients. CONCLUSION: Modified thread technique for the treatment of wrist ganglion is a minimally invasive, low cost, day care procedure which can give reasonably good results with a very low complication rate.

"Low cost, modified negative pressure wound therapy in infected orthopaedic wounds: can it be as effective as its costly counterparts?"

BACKGROUND: Infected wounds pose a great financial burden on our healthcare system. Negative pressure wound therapy (NPWT) has brought a paradigm shift in the management of these wounds. However, availability and high cost of a conventional NPWT system remains a challenge. We carried out this study to assess whether we can replicate functioning of the conventional NPWT system using resources which are easily available in most hospitals and determine the clinical efficacy and cost effectiveness of the same. MATERIAL AND METHODS: A prospective study was conducted in the orthopaedic department at our tertiary care institute from January 2018 to December 2019. Fifty six patients with contaminated or infected orthopaedic wounds were included in the study. Wound dressings were carried out by modified negative pressure therapy and their results were studied. RESULTS: The study group consisted of 41 males and 15 females. Duration of stay in hospital ranged from 6 to 37 days, with average duration of 14.05 days. Wound closure was achieved by secondary suturing in 18 (32.2%) of the cases and split thickness skin grafting in 38 (67.8%) of the cases. Wound assessment done using the revised Photographic wound assessment tool revealed an average of 60% reduction in scores, post procedure. The average cost of the dressing could be considerably reduced during the study by the use of available material. CONCLUSION: Through our study we describe a simple and effective method of application of negative pressure dressings which may be beneficial in low resource settings. Our method is easily reproducible and does not require expertise for its application, at the same time it is cost effective and efficient in wound care.

Adolescent girls' attitudes toward female genital mutilation: a study in seven African countries.

Background: The study's aim is to examine adolescent girls' attitudes toward the continuation or discontinuation of female genital mutilation (FGM) in association with their demographics in seven different countries in Africa. Methods: Data from the women's survey of the Demographic and Health Surveys (DHS) conducted by the respective ministries (of Health and Family Welfare) in Egypt, Guinea, Kenya, Mali, Niger, Senegal and Sierra Leone were used. Adolescent girls (15-19 years) were included in the current analysis: Egypt (N=636), Guinea (N=1994), Kenya (N= 1767), Mali (N=2791), Niger (N=1835), Senegal (N=3604), Sierra Leone (N=1237). Results: Prevalence of supporting the continuation of FGM among adolescent girls was in Egypt 58%, Guinea 63%, Kenya 16%, Mali 72%, Niger 3%, Senegal 23%, and Sierra Leone 52%. Being Muslim and having low economic status were significantly associated with supporting the continuation of FGM in five of the participating countries. Girls having no education or only primary education in Guinea, Kenya, Mali and Sierra Leone exhibited a higher likelihood of supporting FGM than girls with secondary or higher education. In Egypt, Niger and Senegal there was no association between education and supporting FGM. The girls who stated that they had no exposure to media showed the higher likelihood of supporting FGM in Guinea, Kenya, and Senegal than those with exposure to media. Conclusions: The current study argues that increasing media coverage and education, and reducing poverty are of importance for shifting adolescent girls' attitudes in favor of discontinuation of FGM.

3D powder printed tetracalcium phosphate scaffold with phytic acid binder: fabrication, microstructure and in situ X-Ray tomography analysis of compressive failure.

One of the important aspects in 3D powder printing (3DPP) is the selection of binder for a specific material composition to produce scaffolds with desired microstructure and physico-chemical properties. To this end, a new powder-binder combination, namely tetracalcium phosphate (TTCP) and phytic acid (IP6) was investigated at ambient temperature, for low load bearing application. A minimal deviation (<200 µm, w.r.t. computer aided design) was observed in the final sample through optimization of 3DPP process, along with minimum strut and macro-pore size of 200 and 750 µm, respectively. Importantly, the printed scaffolds exhibited compressive strength of 4-8.5 MPa (in the range of cancellous bone) and in vitro dissolution experiments in phosphate buffered saline (PBS) upto one month revealed gradual degradation in strength property. The TTCP scaffolds are characterized to be moderately porous (~40%) with high interconnectivity, which is essential for vascularization and good osteoconductivity. Another major aim of this study was to demonstrate the failure mechanism of 3D powder-printed scaffolds using monotonic and intermittent compression coupled with micro-computed tomography (µCT) imaging. Analyzing these results, we have demonstrated the origin of crack generation and propagation under compressive loading in relation to the unique microstructure, obtained through 3DPP. These findings enable us to acquire a deeper insight of the relationship between structural attributes and failure behavior, to further tailor the 3D powder printing process for ceramic biomaterials.

ZrO2-toughened Al2O3-based near-net shaped femoral head: Unique fabrication approach, 3D microstructure, burst strength and muscle cell response.

The development of reliable biomedical devices demands the use of an integrated manufacturing protocol with comprehensive understanding of prototype characterization in terms of 3D microstructural analysis along with biocompatibility. While addressing these issues for ZrO2 (3mol% Y2O3 stabilized)-toughened Al2O3-based femoral head prototypes, the present work reports a unique fabrication protocol involving a sequence of uniaxial compaction followed by pre-sintering, machining, final sintering and polishing to ensure dimensional tolerance with respect to the design of patient-specific femoral head. The prototypes are characterized by a clinically relevant surface finish (Ra ~0.2µm) with good geometric circularity (±50µm). Extensive µCT analysis at different regions of interest confirms a homogeneous distribution and 3D spatial orientation of ZrO2 across the volume of the defect-free prototype. Further, an in vitro cell culture with a murine myoblast cell line (C2C12) over a period of 72h showed an increase in the number of mitochondrially-active cells and good cellular attachment with oriented cellular bridge formation, which confirms the excellent cytocompatibility. The as-machined ZTA femoral heads fracture at a load of 15.3kN during burst tests, conducted following ISO guidelines. Taken together, this novel fabrication approach can be effectively utilised in the development of near-net shaped bioceramic-based femoral ball heads.

Microstructure and compression properties of 3D powder printed Ti-6Al-4V scaffolds with designed porosity: Experimental and computational analysis.

The osseointegration of metallic implants depends on an effective balance among designed porosity to facilitate angiogenesis, tissue in-growth and bone-mimicking elastic modulus with good strength properties. While addressing such twin requirements, the present study demonstrates a low temperature additive manufacturing based processing strategy to fabricate Ti-6Al-4V scaffolds with designed porosity using inkjet-based 3D powder printing (3DPP). A novel starch-based aqueous binder was prepared and the physico-chemical parameters such as pH, viscosity, and surface tension were optimized for drop-on-demand (DOD) based thermal inkjet printing. Micro-computed tomography (micro-CT) of sintered scaffolds revealed a 57% total porosity in homogeneously porous scaffold and 45% in the gradient porous scaffold with 99% interconnectivity among the micropores. Under uniaxial compression testing, the strength of homogeneously porous and gradient porous scaffolds were ~47MPa and ~90MPa, respectively. The progressive failure in homogeneously porous scaffold was recorded. In parallel to experimental measurements, finite element (FE) analyses have been performed to study the stress distribution globally and also locally around the designed pores. Consistent with FE analyses, a higher elastic modulus was recorded with gradient porous scaffolds (~3GPa) than the homogenously porous scaffolds (~2GPa). While comparing with the existing literature reports, the present work, for the first time, establishes 'direct powder printing methodology' of Ti-6Al-4V porous scaffolds with biomedically relevant microstructural and mechanical properties. Also, a new FE analysis approach, based on the critical understanding of the porous architecture using micro-CT results, is presented to realistically predict the compression response of porous scaffolds.

Strength reliability and in vitro degradation of three-dimensional powder printed strontium-substituted magnesium phosphate scaffolds.

Strontium ions (Sr(2+)) are known to prevent osteoporosis and also encourage bone formation. Such twin requirements have motivated researchers to develop Sr-substituted biomaterials for orthopaedic applications. The present study demonstrates a new concept of developing Sr-substituted Mg3(PO4)2 - based biodegradable scaffolds. In particular, this work reports the fabrication, mechanical properties with an emphasis on strength reliability as well as in vitro degradation of highly biodegradable strontium-incorporated magnesium phosphate cements. These implantable scaffolds were fabricated using three-dimensional powder printing, followed by high temperature sintering and/or chemical conversion, a technique adaptable to develop patient-specific implants. A moderate combination of strength properties of 36.7MPa (compression), 24.2MPa (bending) and 10.7MPa (tension) were measured. A reasonably modest Weibull modulus of up to 8.8 was recorded after uniaxial compression or diametral tensile tests on 3D printed scaffolds. A comparison among scaffolds with varying compositions or among sintered or chemically hardened scaffolds reveals that the strength reliability is not compromised in Sr-substituted scaffolds compared to baseline Mg3(PO4)2. The micro-computed tomography analysis reveals the presence of highly interconnected porous architecture in three-dimension with lognormal pore size distribution having median in the range of 17.74-26.29µm for the investigated scaffolds. The results of extensive in vitro ion release study revealed passive degradation with a reduced Mg(2+) release and slow but sustained release of Sr(2+) from strontium-substituted magnesium phosphate scaffolds. Taken together, the present study unequivocally illustrates that the newly designed Sr-substituted magnesium phosphate scaffolds with good strength reliability could be used for biomedical applications requiring consistent Sr(2+)- release, while the scaffold degrades in physiological medium. STATEMENT OF SIGNIFICANCE: The study investigates the additive manufacturing of scaffolds based on different strontium-substituted magnesium phosphate bone cements by means of three-dimensional powder printing technique (3DPP). Magnesium phosphates were chosen due to their higher biodegradability compared to calcium phosphates, which is due to both a higher solubility as well as the absence of phase changes (to low soluble hydroxyapatite) in vivo. Since strontium ions are known to promote bone formation by stimulating osteoblast growth, we aimed to establish such a highly degradable magnesium phosphate ceramic with an enhanced bioactivity for new bone ingrowth. After post-processing, mechanical strengths of up to 36.7MPa (compression), 24.2MPa (bending) and 10.7MPa (tension) could be achieved. Simultaneously, the failure reliability of those bioceramic implant materials, measured by Weibull modulus calculations, were in the range of 4.3-8.8. Passive dissolution studies in vitro proved an ion release of Mg(2+) and PO4(3-) as well as Sr(2+), which is fundamental for in vivo degradation and a bone growth promoting effect. In our opinion, this work broadens the range of bioceramic bone replacement materials suitable for additive manufacturing processing. The high biodegradability of MPC ceramics together with the anticipated promoting effect on osseointegration opens up the way for a patient-specific treatment with the prospect of a fast and complete healing of bone fractures.

Assessment of the Antioxidant and Reactive Oxygen Species Scavenging Activity of Methanolic Extract of Caesalpinia crista Leaf.

"Oxidative stress" is initiated by reactive oxygen species (ROS), which are responsible for majority of the diseases. However, antioxidants with ROS scavenging ability may have great relevance in the prevention of oxidative stress. The present study was undertaken, using a 70% methanolic extract of Caesalpinia crista leaves, to examine different in vitro tests in diversified fields including total antioxidant activity, scavenging activities for various ROS, iron chelating activity and phenolic and flavonoid contents. Total antioxidant activity was evaluated as trolox equivalent antioxidant capacity value of 0.546 ± 0.014. The extract was investigated for different ROS scavenging activities and IC(50) values were found to be 0.44 ± 0.1 mg/ml, 24.9 ± 0.98 µg/ml, 33.72 ± 0.85 µg/ml, 61.13 ± 3.24 µg/mL and 170.51 ± 4.68 µg/mL for hydroxyl, superoxide, nitric oxide, singlet oxygen and hypochlorous acid, respectively; however, no significant results were obtained in scavenging of hydrogen peroxide and peroxynitrite anion. The extract was found to be a potent iron chelator with IC(50) = 279.85 ± 4.72 µg/mL. The plant extract (100 mg) yielded 50.23 ± 0.003 mg/mL gallic acid equivalent phenolic content and 106.83 ± 0.0003 mg/mL quercetin equivalent flavonoid content. In the in vivo experiments, the extract treatment showed significant increase in the level of superoxide dismutase, catalase, glutathione-S-transferase and reduced glutathione. In a word, it may be concluded that 70% methanol extract of C. crista leaves acts as an antioxidant and ROS scavenger; which may be due to the presence of phenolic and flavonoid compounds.