Analytical methods to determine and sense heavy metal pollutants using MXene and MXene-based composites: Mechanistic prophecy into sensing properties.

The presence of heavy metal ions in the biosphere is of grave concern, as these are toxic and impact living organisms. Lack of pure drinking water can spread waterborne diseases like cholera, dysentery, typhoid, etc. The presence of heavy metals like arsenic and radioactive materials can cause cancer. The detection and removal of these heavy metals are important for sustaining life. Herein, MXene comes to the rescue as a crucial and potential material, which can sense and adsorb heavy metal ions. Developed in 2011, MXenes are an emerging class of 2D nanomaterials that are appropriate substitutes for existing heavy metal ions sensing materials and have shown excellent efficiency due to their better hydrophilicity, capacity of transportation of electrons, functionalization, and a great variety in compositions as compared to the other nanomaterials properties. This work gives an insight into the chemistry and synthesis of MXenes for further utilization as a sensor in heavy metal ions toxicity and underlines the key future challenges to knowing the full prospective of MXenes in environmental systems.

From Paris to Montreal: disease regression is common during long term follow-up of paediatric Crohn's disease.

Introduction: Paediatric Crohn's disease (PCD) often presents with extensive and a frequent pan-enteric phenotype at onset. However, its long term evolution into adulthood, especially since the widespread use of biological agents, is not well characterised. We conducted a single centre cohort study of all PCD patients transitioned to adult care to assess the long term disease evolution in the era of biologic therapy.Methods: We conducted a retrospective observational, study of all PCD patients who were subsequently transferred to the care of an adult gastroenterology unit and had a minimum follow up of 2 years. We examined the case notes for evolution of disease location and behaviour. Disease location and behaviour was characterised using Paris classification at diagnosis and Montreal classification at last follow-up. In addition, we examined variables associated with complicated disease behaviour and the need for CD related intestinal resection.Results: In total, 132 patients were included with a median age at diagnosis of 13 (IQR 11-14) and a median follow up of 11 years (range 4-14). At diagnosis, 23 (17.4%), 39 (29.6%) and 70 (53%) patients had ileal, colonic and ileocolonic disease respectively. In addition, 31 (23.5%) patients had L4a or L4b disease at diagnosis (proximal or distal to the ligament of treitz respectively) and 13 patients (9.8%) had both whilst 27 (20.4%) patients had perianal disease. At diagnosis, 27 (20.4%) patients had complicated disease behaviour but 83 (62.9)% of patients had an extensive 'pan-enteric' phenotype. Of these patients only 55 (66.3%) retained the pan-enteric phenotype at last follow-up (p = .0002). Disease extension was noted in 25 (18.9%) of patients and regression was noted in 47 (35.6%) of patients, whereas upper GI disease was noted in significantly fewer patients at last follow-up (21, 15.9%) (p = .0001). More patients had complicated disease behaviour (46 patients, 34.9%, p = .0018) at last follow-up. There was a high exposure to both thiopurines 121 (91.7%) and biologics 84 (63.6%). The cumulative probability (95% CI) of surgery was 0.05 (0.02, 0.11) at 1 year, 0.17 (0.11, 0.24) at 3 years and 0.22 (0.15, 0.30) at 5 years. Neither disease location nor behaviour were associated with the need for intestinal resectional surgery.Conclusions: Over the course of an extended follow-up period, there appeared to be changes in both disease location and behaviour in PCD. Interestingly, a significant proportion of patients had disease involution which may be related to a high rate of exposure to thiopurines and biologics. We were unable to identify any variables associated with complicated disease course or the need for intestinal surgery.

Kinetics and Adsorption Studies of Mercury and Lead by Ceria Nanoparticles Entrapped in Tamarind Powder.

In this study, novel adsorbent ceria nanoparticles (CeNPs) entrapped in tamarind powder (Tm@CeNPs) were efficiently utilized for the simultaneous adsorption of aqueous mercury [Hg(II)] and aqueous lead [Pb(II)]. Surface interactions between the adsorbent and heavy metal ions play an important role in the adsorption process, and the surface morphology can significantly improve the adsorption capacity of the adsorbent. The Langmuir adsorption capacity of Tm@CeNPs for Hg(II) and Pb(II) was found to be 200 and 142.85 mg/g, respectively. The surface area of utilized adsorbent was found to be very high, that is, 412 m2/g. The adsorption kinetics of Tm@CeNPs for both ions follow pseudo-second-order, and the adsorption process is also thermodynamically feasible. Column study favors multilayer adsorption of the heavy metal ion. The spectral analysis of the adsorbent revealed that hydroxyl, carboxylic, and ester groups, as well as CeNPs, are responsible for Hg(II) and Pb(II) adsorption. The cost-benefit analysis confirms the economic viability of the synthesized Tm@CeNPs composite for heavy metal removal. The adsorbent is best suited for Hg(II) adsorption as compared to Pb(II). This is a novel study on the utilization of tamarind leaf powder with CeNPs for heavy metal ion adsorption and its adsorption mechanism, which has not been reported to date.

Synthesis, spectral and extended spectrum beta-lactamase studies of transition metal tetraaza macrocyclic complexes.

Urinary tract infections commonly occur in humans due to microbial pathogens invading the urinary tract, which can bring about a range of clinical symptoms and potentially fatal sequelae. The present study is aimed at addressing the development of a new antimicrobial agent against extended spectrum beta lactamase (ESBL) producing E. coli bacteria. We have synthesised some biologically potent (NNNN) donor macrocycles (L 1  = dibenzo[f,n]dipyrido[3,4-b:4',3'-j][1,4,9,12]tetraazacyclohexadecine-6,11,18,23(5H,12H, 7H, 24H)-tetraone, and L 2  = 6,12,19,25-tetraoxo-4,6,11,12,16,18,23,24-octahydrotetrabenzo [b,g,k,p][1,5,10,14]tetra azacyclooctadecine-2,13-dicarboxylic acid) and their Ti and Zr metal complexes in alcoholic media using microwave protocol. Macrocyclic ligands were synthesised by incorporating of 3,5-diaminobenzoic acid, phthalic acid and 3,4-diaminopyridine in 1:1:1 molar ratio. The macrocyclic ligands and their metal complexes have been characterised by elemental analysis, conductance measurement, magnetic measurement and their structure configurations have been determined by various spectroscopic (FTIR, 1H/13C NMR, UV-Vis, LC-MS mass, XRD and TGA) techniques. [ZrL2Cl2]Cl2 metal complex shows excellent antibacterial activity against ESBLs. A zone of inhibition and minimum inhibitory concentration was determined by McFarland and the dilution method, respectively. The spectral studies confirm the binding sites of the nitrogen atom of the macrocycles. An octahedral geometry has been assigned to the metal complexes based on the findings.

Excellent fluoride decontamination and antibacterial efficacy of Fe-Ca-Zr hybrid metal oxide nanomaterial.

The aim of the present study is to develop an efficient nanomaterial for the removal of fluoride and disinfection of harmful bacteria in order to make water potable according to Environmental Protection Agency (EPA) guidelines. Hydrous hybrid Fe-Ca-Zr oxide nanoadsorbent presented a marked fluoride adsorption capacity of 250 mg/g at pH 7.0 (±0.1) much greater than other commercially accessible adsorbents for both synthetic and real water samples. The adsorption isotherms, Freundlich and Dubinin-Radushkevich (D-R) fitted reasonably well fine having high coefficient of regression values. The adsorption of fluoride was established well using pseudo-second-order kinetics. The fluoride loaded adsorbent was efficiently regenerated by using an alkali solution. Interestingly, the developed nanomaterial not only showed excellent fluoride removal capacity but also demonstrated good antibacterial activity against Escherichia coli with IC50 (25 µg/mL).

Hypomelanosis of ito.

Four-year-old boy presented with hypopigmented skin lesions since birth and seizure of recent onset. He had psychomotor retardation and hemi hypertrophy of left half of body. Computerised tomography scan findings were suggestive of hemimegalencephaly. On clinical grounds, a diagnosis of Hypomelanosis of Ito was made.