Current Biomedical Applications of 3D-Printed Hydrogels

Three-dimensional (3D) printing, also known as additive manufacturing, has revolutionized the production of physical 3D objects by transforming computer-aided design models into layered structures, eliminating the need for traditional molding or machining techniques. In recent years, hydrogels have emerged as an ideal 3D printing feedstock material for the fabrication of hydrated constructs that replicate the extracellular matrix found in endogenous tissues. Hydrogels have seen significant advancements since their first use as contact lenses in the biomedical field. These advancements have led to the development of complex 3D-printed structures that include a wide variety of organic and inorganic materials, cells, and bioactive substances. The most commonly used 3D printing techniques to fabricate hydrogel scaffolds are material extrusion, material jetting, and vat photopolymerization, but novel methods that can enhance the resolution and structural complexity of printed constructs have also emerged. The biomedical applications of hydrogels can be broadly classified into four categories-tissue engineering and regenerative medicine, 3D cell culture and disease modeling, drug screening and toxicity testing, and novel devices and drug delivery systems. Despite the recent advancements in their biomedical applications, a number of challenges still need to be addressed to maximize the use of hydrogels for 3D printing. These challenges include improving resolution and structural complexity, optimizing cell viability and function, improving cost efficiency and accessibility, and addressing ethical and regulatory concerns for clinical translation

Study of thyroid dysfunction and dyslipidemia in chronic kidney diseases

Background: Though there are many studies on thyroid dysfunction and dyslipidemia in Chronic Kidney Disease (CKD), no study is conclusive. Aim of this study was to correlate abnormalities in thyroid function and lipid profile with the severity of renal failure and also to observe the difference of these abnormalities between patients on conservative management verses hemodialysis.Methods: Hundred consecutive CKD cases admitted to Medicine Department were taken up for the study. They were divided into two groups as Group-A [on conservative management] and Group-B [on regular Hemodialysis (HD)]. Hundred healthy persons were taken as control in Group-C. After evaluation of thyroid function and lipid profile statistical analysis was done by students t-test, chi-square and regression analysis.Results: Hundred CKD cases with 74% male (n=74) and 26% female (n=26) in a M: F ratio of 2.9:1 were found to be in different stages CKD (0, 2, 20, 28 and 50 in stage-1 to stage-5 respectively). In 50 cases of stage-5 CKD, 30 were on HD and 20 on conservative management. Diabetes Mellitus (DM) (40%) was the commonest etiology of CKD followed by Hypertension (HTN), obstructive uropathy, chronic glomerulonephritis (CGN) and polycystic kidney disease (PKD). Thyromegaly was not found in a single case. In all CKD cases (Group-A+B) TT3 (TT3) was significantly low (P =0.0011) when compared with control (Group-C) and no difference was found between Group-A and Group-B. Fall in TT3 worsened with increasing severity of CKD. Lipid profile study revealed Decreased High-Density Lipoprotein Cholesterol (HDLc) and increased Triglyceride (TG), Total Cholesterol (TC), Low Density Lipoprotein Cholesterol (LDLc), TC/HDLc and LDLc/HDLc in Group-A than Group-B but only TG and TC increase was statistically significant. The levels of TG and TC and TC/HDLc increased as the stage of CKD progressed and was statistically significant (P= 0.035).Conclusions: There occurs a state of biochemical hypothyroidism without overt clinical hypothyroid state in CKD, the extent of which correlates with the severity of CKD. Increased cardiovascular complications occur due to accelerated atherosclerosis in CKD. This study confirmed that atherogenic lipid profile and thyroid dysfunction worsen with the progression of disease. Difference between patients on conservative management and HD was not found

Valence electronic structure of Mn in undoped and doped lanthanum manganites from relative K x-ray intensity studies

Relative $K$ x-ray intensities of $Mn$ in $Mn$, $MnO_{2}$, $LaMnO_{3}$ and $La_{0.7}B_{0.3}MnO_{3}$ ($B$ = $Ca$, $Sr$, and $Ce$) systems have been measured following excitation by 59.54 keV $\gamma$-rays from a 200 mCi $^{241}$Am point-source. The measured results for the compounds deviate significantly from the results of pure $Mn$. Comparison of the experimental data with the multiconfiguration Dirac-Fock (MCDF) effective atomic model calculations indicates reasonable agreement with the predictions of ionic model for the doped {manganites except} that the electron doped $La_{0.7}Ce_{0.3}MnO_{3}$ and hole doped $La_{0.7}Ca_{0.3}MnO_{3}$ compounds show some small deviations. The results of $MnO_{2}$ and $LaMnO_{3}$ deviate considerably from the predictions of the ionic model. Our measured $K\beta/K\alpha$ ratio of $Mn$ in $La_{0.7}Ca_{0.3}MnO_{3}$ cannot be explained as a linear superposition of $K\beta/K\alpha$ ratios of $Mn$ for the end members which is in contrast to the recent proposal by Tyson et al. from their $Mn$ $K\beta$ spectra.Comment: 14 pages, 4 figures. to appear in NIM-B.Please send an e-mail for figure

The correlation of cardiovascular risk factors and angiographic findings with serum vitamin D levels in patients undergoing coronary angiography

Background: Studies regarding correlation of various conventional risks factors for Coronary Artery Disease (CAD) are many. Keeping in mind the scarcity of studies regarding Vit-D Deficiency (VDD), a new risk factor in CAD, present study was conducted to correlate Vit-D level with conventional risk factors and Coronary Angiography (CAG).Methods: Hundred adult patients admitted to Medicine and Cardiology undergoing CAG with suspected or established CAD were kept in study. Patients having renal, hepatic, parathyroid disease, osteomalacia and patients taking drugs interfering with Vitamin D (Vit-D) metabolism were excluded. After detailed history and thorough clinical examination, routine investigations and 25-(OH) D level was estimated. Subsequently patients underwent CAG. Statistical analysis by Mann Whitey test and Chi-square Test was done and inference was drawn.Results: 100 patients in different age groups had hypertension (HTN) in 53, diabetics mellitus (DM) 39, dyslipidemia 62, smokers 38 and family history of CAD 19. CAG showed normal coronaries in 4, Single Vessel Disease (SVD) in 30, double vessel diseases (DVD) 43 and triple vessel disease (TVD) 22. Vit-D level 30ng/ml (normal) in 10. VDD was profound in 51-60 and 61-70 years age groups. Statistical correlation of VDD was not significant with conventional risk factors, but statistically significant correlation of VDD was observed with dyslipidemia and CAG findings in our study.Conclusions: Like earlier studies we observed significant correlation of Vit-D levels with CAD. Though dyslipidemia was significantly correlated with VDD, correlation of other conventional risk factors like age, sex, HTN, DM, smoking and family history was not found. We conclude from this study presence of significant association of VDD with severe CAD. DVD and TVD by CAG were common with low Vit-D levels

Effect of neutron alignments on the structure of Tl 197

The excited states of 197Tl have been studied via 19 Au(4He, 4n)197 Tl reaction at a beam energy of 50 MeV from the K-130 cyclotron at the Variable Energy Cyclotron Centre (VECC). The γ rays were detected using the VECC array for Nuclear Spectroscopy (VENUS) with six Compton-suppressed clover HPGe detectors. An improved level scheme of 197 Tl has been proposed from this work, which has been extended to 5.1 MeV of excitation energy and 39/2 ℏ of spin from the placement of 28 new γ-ray transitions. Band crossings in the known one- and three-quasiparticle (qp) bands have been identified for the first time in this work. Two new bands, based on 3-qp and 5-qp configurations, have been observed for the first time in this nucleus; both of which are identified as the magnetic rotational (MR) in nature. The excitation energies of these bands are similar to that of the doubly degenerate bands observed for the similar 3-qp and 5-qp configurations in 195 Tl. These indicate a transition from an aplanar geometry of the neutron, proton, and the core angular momentum vectors to a planar one for neutron number N≥116 in Tl isotopes. The total Routhian surface calculations suggest a change in shape from oblate for the 1-qp configuration to a near-spherical one for the 3- and 5-qp configurations. This is consistent with the observed MR nature of the bands with multi-qp configuration. The MR bands are well reproduced by a model calculations in the frame work of the shears mechanism with the principal axis cranking.One of the authors (H.P.) is grateful for the support from the Ramanujan Fellowship Research Grant under SERB-DST Grant No. SB/S2/RJN-031/2016

New high precision study on the decay width of the Hoyle state in C-12

Precise estimation of the rare direct 3α decay of the Hoyle state of 12C has been made to unveil its unusual α-cluster configurations ranging from linear 3α chain structure to diffuse Bose gas as well as Bose Einstein condensate. The present new high precision, nearly zero background experimental study with Hoyle events has converged on the upper limit for direct decay at ∼0.019% with 95% confidence limit, which is more than a factor of 2 lower than the limit obtained in the previous studies.Two of the authors (S.B. and A.R.) acknowledge the financial support received as Raja Ramanna Fellowship from the Department of Atomic Energy, Government of India

Complete Break Up of Ortho Positronium (Ps)- Hydrogenic ion System

The dynamics of the complete breakup process in an Ortho Ps - He+ system including electron loss to the continuum (ELC) is studied where both the projectile and the target get ionized. The process is essentially a four body problem and the present model takes account of the two centre effect on the electron ejected from the Ps atom which is crucial for a proper description of the ELC phenomena. The calculations are performed in the framework of Coulomb Distorted Eikonal Approximation. The exchange effect between the target and the projectile electron is taken into account in a consistent manner. The proper asymptotic 3-body boundary condition for this ionization process is also satisfied in the present model. A distinct broad ELC peak is noted in the fully differential cross sections (5DCS) for the Ps electron corroborating qualitatively the experiment for the Ps - He system. Both the dynamics of the ELC from the Ps and the ejected electron from the target He+ in the FDCS are studied using coplanar geometry. Interesting features are noted in the FDCS for both the electrons belonging to the target and the projectile.Comment: 14 pages,7 figure