Do human leukocyte antigens have a role to play in differential manifestation of multibacillary leprosy: A study on multibacillary leprosy patients from North India

118 multibacillary leprosy patients with differential manifestations were studied for the antigens they expressed at MHC loci to investigate the role of human leukocyte antigens in the differential response to the same causative agent. While the lepromatous leprosy (LL) patients showed a significant increase of Bw60, DR2, DRw8 and DQw1, borderline lepromatous (BL) patients had Bw52, DR9 and DQw7 significantly more often as compared to the normal controls. A comparison of LL, BL and mid-borderline (BB) patients showed a significantly higher frequency of Bw60 in LL patients as compared to the BL. However, Bw52, Bw53, DR9 and DQw7 were found significantly more often in the BL patients as compared to the LL patients but the difference failed to reach significance after pc. A comparison of HLA antigens in BB patients with those of either the LL or BL patients did not show any significant differences.     

Association of HLA antigens with differential responsiveness toMycobacterium w vaccine in multibacillary leprosy patients

Leprosy patients undergoing phase II trials in two hospitals of New Delhi, India, were HLA typed to see the association of HLA with differential responsiveness toMycobacterium w vaccine. The vaccine comprises an atypical, nonpathogenic mycobacterium,Mycobacterium w, which has cross-reactive antigens withM. leprae. Multibacillary patients who are lepromin negative are vaccinated at an interval of 3 months. Considerable improvement is evident in the patients in terms of a decline in bacterial indices and histopathological and immunological upgrading. But all the patients do not respond to the vaccine in the same manner; some are slow responders, while others are good responders. HLA-A28 and DQw3 (DQw8+9) were found to be associated with slow responsiveness, while DQw1 and DQw7 were found to be associated with a more rapid responsiveness to theM. w vaccine. However, these associations were not significant afterP correction for the number of antigens tested for each locus except for HLA-DQw3 (DQw8 and DQw9) and DQw7. DQw7, a new defined split of HLA-DQw3, seems to be associated with the responsiveness toM. w vaccine.     

Highly diffusion-sensitized MRI of brain: dissociation of gray and white matter.

The brains of six healthy volunteers were scanned with a full tensor diffusion MRI technique to study the effect of a high b value on diffusion-weighted images (DWIs). The b values ranged from 500 to 5000 s/mm(2). Isotropic DWIs, trace apparent diffusion coefficient (ADC) maps, and fractional anisotropy (FA) maps were created for each b value. As the b value increased, ADC decreased in both the gray and white matter. Furthermore, ADC of the white matter became lower than that of the gray matter, and, as a result, the white matter became brighter than the gray matter in the isotropic DWIs. Quantitative analysis showed that these changes were due to nonmonoexponential diffusion signal decay of the brain tissue, which was more prominent in white matter than in gray matter. There was no significant change in relation to the b value in the FA maps. High b value appears to have a dissociating effect on gray and white matter in DWIs.     

Controlling the Wettability of ZnO Thin Films by Spray Pyrolysis for Photocatalytic Applications

Herein, we synthesized the zinc oxide (ZnO) thin films (TFs) deposited on glass substrates via spray pyrolysis (SP) to prepare self-cleaning glass. Various process parameters were used to optimize photocatalytic performance. Substrates were coated at room temperature (RT) and 250 °C with a 1 mL or 2 mL ZnO solution while maintaining a distance from the spray gun to the substrate of 20 cm or 30 cm. Several characterization techniques, i.e., XRD, SEM, AFM, and UV–Vis were used to determine the structural, morphological, and optical characteristics of the prepared samples. The wettability of the samples was evaluated using contact angle measurements. As ZnO is hydrophilic in nature, the RT deposited samples showed a hydrophilic character, whereas the ZnO TFs deposited at 250 °C demonstrated a hydrophobic character. The XRD results showed a higher degree of crystallinity for samples deposited on heated substrates. Because of this higher crystallinity, the surface energy decreased, and the contact angle increased. Moreover, by using 2 mL solution, better surface coverage and roughness were obtained for the ZnO TFs. However, by exploiting the distance of the spray to the samples size distribution and surface coverage can be controlled, the samples deposited at 30 mL showed a uniform particle size distribution from 30–40 nm. In addition, the photoactivity of the samples was tested by the degradation of rhodamine B dye. Substrates prepared with a 2 mL solution sprayed at 20 cm showed higher dye degradation than other samples, which can play a vital role in self-cleaning. Hence, by changing the said parameters, the ZnO thin film properties on glass substrates were optimized for self-cleaning diversity.     

Gossypiboma mimicking posterior urethral stricture

INTRODUCTIONForeign bodies in the urogenital tract are not uncommon. Hairpins, glass rods, umbilical tapes, ball point pen are described in lower urogenital tract. Retained gauze piece (gossypiboma) in posterior urethra may cause diagnostic dilemma. Symptoms and investigations may mimic stricture of posterior urethra.PRESENTATION OF CASETwo cases of retained gauze pieces in the urethra are described here. The micturating cystourethrogram was suggestive of posterior urethral stricture.DISCUSSIONTwo cases described here had retained gauze piece as a cause of filling defect and abnormal appearance in the micturating cystourethrogram. Gossypiboma may be a possibility where posterior urethral stricture are seen after previous surgery in paediatric age group.CONCLUSIONIn the setting of previous urogenital surgery gossypiboma should be kept in the differential diagnosis where posterior urethral stricture are seen in the paediatric age group.     

Ferumoxytol Is Not Retained in Kidney Allografts in Patients Undergoing Acute Rejection

Purpose

To evaluate whether ultrasmall superparamagnetic iron oxide nanoparticle (USPIO)-enhanced magnetic resonance imaging (MRI) can detect allograft rejection in pediatric kidney transplant patients.

Procedures

The USPIO ferumoxytol has a long blood half-life and is phagocytosed by macrophages. In an IRB-approved single-center prospective clinical trial, 26 pediatric patients and adolescents (age 10–26 years) with acute allograft rejection (n = 5), non-rejecting allografts (n = 13), and normal native kidneys (n = 8) underwent multi-echo T2* fast spoiled gradient-echo (FSPGR) MRI after intravenous injection (p.i.) of 5 mg Fe/kg ferumoxytol. T2* relaxation times at 4 h p.i. (perfusion phase) and more than 20 h p.i. (macrophage phase) were compared with biopsy results. The presence of rejection was assessed using the Banff criteria, and the prevalence of macrophages on CD163 immunostains was determined based on a semi-quantitative scoring system. MRI and histology data were compared among patient groups using t tests, analysis of variance, and regression analyses with a significance threshold of p < 0.05.

Results

At 4 h p.i., mean T2* values were 6.6 ± 1.5 ms for native kidneys and 3.9 ms for one allograft undergoing acute immune rejection. Surprisingly, at 20–24 h p.i., one rejecting allograft showed significantly prolonged T2* relaxation times (37.0 ms) compared to native kidneys (6.3 ± 1.7 ms) and non-rejecting allografts (7.6 ± 0.1 ms). Likewise, three additional rejecting allografts showed significantly prolonged T2* relaxation times compared to non-rejecting allografts at later post-contrast time points, 25–97 h p.i. (p = 0.008). Histological analysis revealed edema and compressed microvessels in biopsies of rejecting allografts. Allografts with and without rejection showed insignificant differences in macrophage content on histopathology (p = 0.44).

Conclusion

After ferumoxytol administration, renal allografts undergoing acute rejection show prolonged T2* values compared to non-rejecting allografts. Since histology revealed no significant differences in macrophage content, the increasing T2* value is likely due to the combined effect of reduced perfusion and increased edema in rejecting allografts.

     

Magnetic phase transition from paramagnetic in Nb2AlC-MAX to superconductivity-like diamagnetic in Nb2C-MXene: an experimental and computational analysis

Transition metal carbides (TMCs) have recently emerged as competent members among the family of two-dimensional (2D) materials, owing to their promising applications. There are many promising applications of MXenes; however, their magnetic properties lack a wide margin, both experimentally as well as theoretically, which needs to be investigated for potential use in spintronics. In this study, we carried out a comprehensive etching process via selective extraction of Al layers from Nb₂AlC-MAX using a wet electrochemical route under well-optimized conditions to obtain fine 2D-Nb₂C MXene sheets. Structural analysis using X-ray diffraction (XRD) confirms the effective removal of Al followed by confirmation of a 2D layered structure from morphological analysis using scanning electron microscopy (SEM). Zero-field-cooled (ZFC) and field-cooled (FC) measurements of MAX and MXene at different field strengths were performed using a superconducting quantum interference device (SQUID). Magnetic measurements reveal the paramagnetic nature of Nb₂AlC-MAX measured under 5 mT; however, this changes to a clear superconductor-like diamagnetic behavior with a shift of the magnetization from positive to negative values at low temperatures when measured under 5 mT and 10 mT for Nb₂C MXene. The diamagnetism, however, is changed to paramagnetism at 100 mT, which shows the existence of critical fields known typically for a type-II superconductor. To gain an insight into this unusual behavior in MXene, density functional theory (DFT) first-principles calculation was also performed in Wein2K software using spin-polarized generalized gradient approximation (sp-GGA). The magnetic moment of the compound is calculated to be negative, which corresponds well with the experimental finding and suggests that the negative magnetic moment originated from the d-orbital of Nb₂C. The present report provides a pathway to deeply understanding the existence of superconductivity-like diamagnetic behavior in Nb₂C MXene, which is useful for future magnetic applications.

Transition metal carbides (TMCs) have recently emerged as competent members among the family of two-dimensional (2D) materials, owing to their promising applications.

In two-dimensional (2D) materials, magnetism at the nanoscale is at the forefront of many cutting-edge technological applications, such as spintronic devices. Naguib et al. have synthesized a new class of two-dimensional materials, known as MXenes (M_nX_n+1), discovered in 2011, giving a possibility of magnetism in such 2D materials and their promising uses in spintronic devices.¹ These 2D layer structured early transition metal carbides and/or nitrides are known as MXenes, so named to indicate their structural similarities with graphene.² MXenes are derived from 3D MAX phases (space group P6₃/mmc) in which “M” is an early transition metal, e.g., Ti, Ta, V, etc.; “A” is mainly a group 13 or group 14 element (group III-A or IV-A), e.g., Si, Al; “X” is a carbide, nitride or can be both; and n = 1, 2, 3 represents the number of layers, forming 211, 312 and 413 phases.^3–5 Over the past decade, this new material has gained enormous attention, thus developing an entirely new research field to disclose the properties of the 2D state of this material. The materials in the 2D regime own a cluster of astonishing physical properties as compared to the 3D nature, but intrinsic two-dimensional magnetism has proved to be challenging. As 2D semiconductors have revamped the field of electronics, similarly, magnetism in 2D materials could remodel spintronic devices that can employ a spin degree of freedom.^6,7Nb₂C MXene was first synthesized by Naguib et al., but they just reported its electrochemical activity as a promising electrode material.⁴ Further work has been reported in Nb₂C with various biomedical applications, energy storage, supercapacitors, and nanoelectronics.^9–19 As far as the magnetism in such 2D MXenes is concerned, it remains less investigated, and this research void needs to be filled. Recently, Babar et al. reported the observation of superconductivity in as-prepared powdered Nb₂C for the first time, with the highest onset transition temperature T_c,onset = 12.5 K among the MXene family. However, the authors did not discuss the magnetic nature of the parent Nb₂AlC MAX itself and did not reason for the presence of unusual magnetic effects in MXene.⁸ MXenes are favorable members of 2D magnetism, and different magnetic natures are computationally predicted in various carbide and nitride MXenes.^7,20 The existence of novel room-temperature ferromagnetic order in doped MXene and the coexistence of different magnetic phases in MXene, along with experimental evidence, indicate its potential of hosting diverse magnetic natures.^21,22 Considerable research has been focused on these 2D structures due to their importance and favorable applications, such as spintronics. MXene could provide a vast platform for exploring the magnetic properties and is one of the best candidates that can host superconductivity as compared to other members of the 2D family. Experimental studies are generally dependent upon numerous variables, thus affecting the research pace. However, density functional theory-based first principles calculation and theoretical simulations are a successful way to examine and foresee the properties of low-dimensional materials. This provoked us to theoretically explore superconductivity in Nb₂C and their validation through superconductivity measurements of experimentally synthesized Nb₂C MXene. In this work, we report a systematic etching mechanism of Nb₂C MXene to obtain fine 2D sheets via a chemical etching route using hydrofluoric (HF) acid. Structural and morphological studies using the X-ray diffraction technique (XRD), scanning electron microscopy (SEM) and elemental analysis by energy-dispersive X-ray spectroscopy (EDX) show the effective removal of Al from the parent 3D-Nb₂AlC MAX, thus revealing an accordion-like sheet structure. Optical analysis indicates a significant reduction in bandgap after chemical etching. Magnetic properties were carried out to observe the signatures of superconductivity (a perfect diamagnetic state, negative magnetic moment) and its magnetic nature at room temperature. To study the magnetic nature of as-prepared powder-form Nb₂C, density functional theory (DFT) first principles calculation was carried out through Wein2K using spin-polarized generalized gradient approximation (sp-GGA). The magnetic moment of the compound is calculated to be −0.00485, which although but small is important, as the value is negative, which is an indication of the presence of diamagnetism in Nb₂C. Here, the detailed chemical etching process, magnetic properties of Nb₂AlC MAX and its effect on magnetic phase of Nb₂C MXene, and the density functional theory calculation are reported, which were not discussed by Babar et al. in ref. 8.     

Dental management of a patient fitted with subcutaneous Implantable Cardioverter Defibrillator device and concomitant warfarin treatment

Automated Implantable Cardioverter Defibrillators (AICD), simply known as an Implantable Cardioverter Defibrillator (ICD), has been used in patients for more than 30 years. An Implantable Cardioverter Defibrillator (ICD) is a small battery-powered electrical impulse generator that is implanted in patients who are at a risk of sudden cardiac death due to ventricular fibrillation, ventricular tachycardia or any such related event. Typically, patients with these types of occurrences are on anticoagulant therapy. The desired International Normalized Ratio (INR) for these patients is in the range of 2–3 to prevent any subsequent cardiac event. These patients possess a challenge to the dentist in many ways, especially during oral surgical procedures, and these challenges include risk of sudden death, control of post-operative bleeding and pain.This article presents the dental management of a 60 year-old person with an ICD and concomitant anticoagulant therapy. The patient was on multiple medications and was treated for a grossly neglected mouth with multiple carious root stumps. This case report outlines the important issues in managing patients fitted with an ICD device and at a risk of sudden cardiac death.