Intertwining of Localized (d) and Delocalized (π) Spins in Magnetically Frustrated Two-Dimensional Metal-Organic Frameworks.

Two-dimensional metal-organic frameworks (2D MOFs) are emerging as a new class of multifunctional materials for diversified applications, although magnetic properties have not been widely explored. The metal ions and organic ligands in some of the 2D MOFs are arranged in the well-known Kagome lattice, leading to geometric spin frustration. Hence, such systems could be the potential candidates to exhibit an exotic quantum spin liquid (QSL) state, as was observed in Cu3(HHTP)2 (HHTP = hexahydroxytriphenylene), with no magnetic transition down to 38 mK. Hereto, we have investigated the spin intertwining in a bimetallic 2D MOF system, M3(HHTP)2 (M = Cu/Zn), arising from the localized (d-electron) and delocalized (π-electron) S = 1/2 spins from the Cu(II) ions and the HHTP radicals, respectively. The origin of the spin frustration (down to 5K) was critically examined by varying the metal composition in bimetallic systems, CuxZn3-x(HHTP)2 (x = 1, 1.5, 2), containing both S = 1/2 and S = 0 spins. Additionally, to gain a deeper understanding, we studied the spin interaction in the pristine Zn3(HHTP)2 system containing only S = 0 Zn(II) ions. In view of the quantitative estimate of the localized and delocalized spins, the d-π spin correlation appears essential in understanding the unusual magnetic and/or other physical properties of such hybrid organic-inorganic 2D crystalline solids.

Tridentate NacNac Tames T-Shaped Nickel(I) Radical.

The reaction of a nickel(II) chloride complex containing a tridentate ß-diketiminato ligand with a picolyl group [2,6-iPr2 -C6 H3 NC(Me)CHC(Me)NH(CH2 py)]Ni(II)Cl (1)] with KSi(SiMe3 )3 conveniently afforded a nickel(I) radical with a T-shaped geometry (2). The compound's metalloradical nature was confirmed through electron paramagnetic resonance (EPR) studies and its reaction with TEMPO, resulting in the formation of a highly unusual three-membered nickeloxaziridine complex (3). When reacted with disulfide and diselenide, the S-S and Se-Se bonds were cleaved, and a coupled product was formed through carbon atom of the pyridine-imine group. The nickel(I) radical activates dihydrogen at room temperature and atmospheric pressure to give the monomeric nickel hydride.

Robust Spin Liquidity in 2D Metal-Organic Framework Cu3 (HHTP)2 with S=1 /2 Kagome Lattice.

On one hand electron or hole doping of quantum spin liquid (QSL) may unlock high-temperature superconductivity and on the other hand it can disrupt the spin liquidity, giving rise to a magnetically ordered ground state. Recently, a 2D MOF, Cu3 (HHTP)2 (HHTP - 2,3,6,7,10,11-hexahydroxytriphenylene), containing Cu(II) S= 1 / 2 ${{ 1/2 }}$ frustrated spins in the Kagome lattice is emerging as a promising QSL candidate. Herein, we present an elegant in situ redox-chemistry strategy of anchoring Cu3 (HHTP)2 crystallites onto diamagnetic reduced graphene oxide (rGO) sheets, resulting in the formation of electron-doped Cu3 (HHTP)2 -rGO composite which exhibited a characteristic semiconducting behavior (5 K to 300 K) with high electrical conductivity of 70 S ⋅ m-1 and a carrier density of ~1.1×1018  cm-3 at 300 K. Remarkably, no magnetic transition in the Cu3 (HHTP)2 -rGO composite was observed down to 1.5 K endorsing the robust spin liquidity of the 2D MOF Cu3 (HHTP)2 . Specific heat capacity measurements led to the estimation of the residual entropy values of 28 % and 34 % of the theoretically expected value for the pristine Cu3 (HHTP)2 and Cu3 (HHTP)2 -rGO composite, establishing the presence of strong quantum fluctuations down to 1.5 K (two times smaller than the value of the exchange interaction J).

Impact of complete mouth rehabilitation following Pankey Mann Schuyler versus HOBO Philosophy on Oral Health-Related Quality of Life using Oral Health Impact Profile-14: A randomized clinical trial.

Aim: Aim of this in vivo study was to assess the impact of two rehabilitation philosophies namely; Pankey Mann Schuyler (PMS) & Hobo Twin Stage (HOBO) on Oral Health-related Quality of life (OHRQoL) using Oral Health Impact Profile (OHIP 14). Settings and Design: This was a randomized clinical trial. Material and Methods: This study was designed based on the PICOT model. 40 patients were selected who need to undergo complete mouth rehabilitation. The intervention performed was complete mouth rehabilitation therapy and the results were compared with that of no intervention. The outcome was assessed in terms of improvement in mastication, phonetics, esthetics and overall OHRQoL (OHIP-14) over a period of 01 year at intervals of 48 hrs, 01 mon, 6 mon and 12 months. Patients were unaware of the treatment philosophy being used and were given a questionnaire (OHIP-14); at baseline (pre-treatment) and 48 hrs, 1, 6 and 12 months after completion of treatment (post-treatment) to evaluate OHRQoL. The data was collected by independent reviewers blinded to the regimen followed making the participants and the outcome assessors blinded to the procedure. Statistical Analysis: Independent Student's t-test and Chi-Square test were used for analysis. Result: Analysis illustrated significant differences in scores obtained pre-treatment and post-treatment in both groups at 12 months (P < 0.05). At 12 months, OHIP-14 scores showed a mean percentage change of 51% in Group A (PMS); (P = 0.001) and a mean percentage change of 49% in group B (Hobo). Conclusion: Complete mouth rehabilitation therapy for management of generalized attrition or mutilated dentition is a viable and effective treatment option and brings about definitive improvement in Oral Health Related Quality of Life (OHRQoL) and overall health status of an individual.

Rehabilitation of acquired mandibular defect with two-piece, magnet-retained salivary reservoir.

Resection of large tumors involving mandible is the most common reason for mandibulectomy in patients. Adjunct therapies complicate the clinical situation and advocates innovations in conventional design concepts and treatment protocols. Xerostomia is one of the most common complications arising post-radiotherapy. Incorporation of a salivary reservoir in the design has been frequently used in xerostomia patients using acrylic dentures. The purpose of the article is to highlight a technique and steps in rehabilitation of a large acquired mandibular defect using a two-piece, magnet-retained acrylic removable partial denture with salivary reservoir.

First-Row Transition Metal Complexes of a Phosphine-Silylene-Based Hybrid Ligand.

We have prepared two new silylene-phosphine-based hybrid ligands Si{N(R)C6H4(PPh2)}{PhC(NtBu)2} [R = TMS {trimethylsilyl} (1) and TBDMS {tert-butyldimethylsilyl} (2)], which possess two donor sites. Furthermore, the treatment of the bidentate ligand 1 with base metal halides {FeBr2, CoBr2, NiCl2·dme [nickel chloride(II) ethylene glycol dimethyl ether]} and 2 with NiBr2·dme [nickel bromide(II) ethylene glycol dimethyl ether] afforded four-coordinate six-membered metal complexes 3-6, respectively, which feature coordination from both Si(II) and P(III) sites. Subsequently, complexes 3 [(FeBr2)Si{N(SiMe3)C6H4(PPh2)}{PhC(NtBu)2}], 4 [(CoBr2)Si{N(SiMe3)C6H4(PPh2)}{PhC(NtBu)2}], 5 [(NiCl2)Si{N(SiMe3)C6H4(PPh2)}{PhC(NtBu)2}], and 6 [(NiBr2)Si{N(SitBuMe2)C6H4(PPh2)}{PhC(NtBu)2}] are studied for their redox and magnetic properties with the help of UV-vis spectroscopy, cyclic voltammetry, SQUID magnetometry, and theoretical calculations. Complexes 3-6 were found to display a paramagnetic behavior. All the compounds are well established by single-crystal X-ray diffraction studies.

Custom-fabricated nasal conformers and surgical stents in the management of midfacial acid burn injuries: A clinical report.

Acid burn injuries in the midfacial region cause contracture of the skin and nasal aperture, which can lead to nasal airway obstruction. Management of such complicated situations requires a multidisciplinary approach, including prosthetic intervention. This article describes a clinical treatment for fabricating a custom nasal conformer for a 28-year-old man who presented with a history of an acid burn injury leading to obstructed external nares and fusion of the tip and columella of the nose with the philtrum of the upper lip. The prosthesis served the dual function of maintaining the nasal airway passage and preventing the contracture of the graft placed over the upper lip during reconstructive surgery.

Coordination Flexibility Aided CO2 -specific Gating in an Iron Isonicotinate MOF.

Coordination flexibility assisted porosity has been introduced into an Iron-isonicotinate metal-organic framework (MOF), (Fe(4-PyC)2 ⋅ (OH). The framework showed CO2 -specific gate opening behavior, which gets tuned as a function of temperature and pressure. The MOF's physisorptive porosity towards CO2 , CH4 , and N2 was investigated; it adsorbed only CO2 via a gate opening phenomenon. The isonicotinate, representing a borderline soft base, is bound to the hard Fe3+ centre through monodentate carboxylate and pyridyl nitrogen. This moderately weak binding enables isonicotinate to spin like a spindle under the CO2 pressure opening the gate for a sharp increase in CO2 uptake at 333 mmHg (At 298 K, the CO2 uptake increases from 0.70 to 1.57 mmol/g). We investigated the MOF's potential for CO2 /N2 and CO2 /CH4 gas separation aided by this gating. IAST model reveals that the CO2 /N2 selectivity jumps from 325 to 3131 when the gate opens, while the CO2 /CH4 selectivity increases three times. Interestingly, this Fe-isonicotinate MOF did not follow the trend set by our earlier reported Hard-Soft Gate Control (established for isostructural M2+ -isonicotinate MOFs (M=Mg, Mn)). However, we account for this discrepancy using the different oxidation state of metals confirmed by X-ray photoelectron spectroscopy and magnetism.

Utility versus futility of facebow in the fabrication of complete dentures: A systematic review.

AIM: The aim of this review was to investigate utility or futility of facebow for fabrication of complete denture prosthesis to maximise clinical efficiency and acceptability of complete dentures. SETTINGS AND DESIGN: Systematic review following PRISMA guidelines. MATERIALS AND METHODS: A study question was designed based on PICOT model which was used to evaluate whether facebow transfer is required or not for fabrication of complete denture prosthesis. An extensive search was carried out manually and using electronic databases such as PubMed-Medline, Cochrane, Google Scholar, and Clinicaltrials.gov. Parameters under review included patient satisfaction, masticatory efficiency, occlusal adjustments, clinician time, stability and retention. Boolean operators, MeSH terms and limiters were applied to develop the search and reach to conclusive studies pertaining to study design. Literature dated between 1950 and 2019 were selected. The data extraction and assessment of the studies was done by two independent investigators. STATISTICAL ANALYSIS USED: No meta-analysis was conducted due to heterogeneity of data obtained. RESULTS: 13690 studies were shortlisted, 13672 were excluded based on title and abstract. By the end of search phase, 07 RCTs were considered relevant. 04 studies concluded comparable/ no differences in outcome with and without use of facebow for fabrication of complete denture prostheses, whereas 03 studies concluded better results without the use of facebow. CONCLUSION: The use of facebow results in fabrication of complete denture prostheses with similar results in terms of clinical efficiency and patient acceptability as compared to simplified techniques using anatomical landmarks. Variations in assessment criteria, non uniform distribution of sample size amongst different clinical trials and subjective questionnaire based criteria are the weaker links in the review. Extensive research and long term standardised studies with objective criteria for assessment are required for comprehensive and conclusive results to establish the need for change in clinical practice.

Ferromagnetic Order at Room Temperature in Monolayer WSe2 Semiconductor via Vanadium Dopant.

Diluted magnetic semiconductors including Mn-doped GaAs are attractive for gate-controlled spintronics but Curie transition at room temperature with long-range ferromagnetic order is still debatable to date. Here, the room-temperature ferromagnetic domains with long-range order in semiconducting V-doped WSe2 monolayer synthesized by chemical vapor deposition are reported. Ferromagnetic order is manifested using magnetic force microscopy up to 360 K, while retaining high on/off current ratio of ≈105 at 0.1% V-doping concentration. The V-substitution to W sites keeps a V-V separation distance of 5 nm without V-V aggregation, scrutinized by high-resolution scanning transmission electron microscopy. More importantly, the ferromagnetic order is clearly modulated by applying a back-gate bias. The findings open new opportunities for using 2D transition metal dichalcogenides for future spintronics.