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This article highlights a voltage instability when the bidirectional interlinking converter (BIC) of a hybrid ac–dc microgrid operates as a constant power load (CPL). The instability is attributed to the impedance interactions seen at the dc port of the BIC. The BIC is operated with two different controllers, viz., a PI controller and a model predictive controller (MPC). In order to avert the instability, prohibiting impedance interactions is proposed as a design objective while determining the bandwidth of the PI controller. However, since a flexible control over bandwidth is not available with MPC, an active damping technique is proposed to address the instability. The proposed technique works equally well for the PI controllers with fixed or predetermined bandwidths. An important feature of the proposed technique is that it does not interfere with the original objectives of the controllers, once the instability is addressed. The technique comprises only one tuning factor, which does not depend on the BIC's internal parameters. As a result, it can easily be implemented as a general stabilizing scheme in any BIC. The efficacy of the proposed technique is verified through simulations, frequency-domain impedance analyses as well as experiments on a laboratory prototype of the BIC. [ABSTRACT FROM AUTHOR]

This paper proposes a novel ancillary feature in bidirectional interlinking converter (BIC) for enhancing the transient performance of an islanded hybrid ac–dc microgrid. The system under consideration includes an ac microgrid with a mix of inertial and non-inertial sources integrated with a dc microgrid through a BIC. The existing BlC control schemes do not judiciously utilize the inertial sources [like the synchronous generator (SG)] as short-term storage for enhancing the transient performance of the system. Since both the microgrids are interfaced through a BIC, this can be achieved by adaptively varying its output frequency during disturbance in the ac microgrid. In the proposed scheme, the BIC is operated as a virtual synchronous generator (VSG) and its output frequency is deliberately increased/decreased during the disturbance. The change in BIC output frequency results in circulating current between the BIC and the SG. Since the BIC voltage phasor leads/lags the SG voltage phasor, it results in the utilization of the inertia of SG as storage. It provides a cost-effective solution by reducing the dependence of the scheme on storage, thereby minimizing the storage requirement while maintaining the transient stability of the system. The proposed control strategy is validated through simulations and experiments. [ABSTRACT FROM AUTHOR]

AbstractThe current work is devoted to a comparative analysis of enhanced co-factors in solidified floating organic drop microextraction methods (SFODME) and an environmental assessment. Also, the description of SFODME, with a focus on its applications in the determination of metals in different matrices, was explained. The impact of several parameters, developments, and greenness evaluations was introduced. Especially, the review provides a concise overview of the multiple approaches to SFODME, with an emphasis on environmentally friendly, supported co-factors. These mods include ultrasound, vortex, and air-assisted SFODME procedures. The selectivity and sensitivity increase when co-factors are added to SFODME. Lastly, the analysis also aims to select tools (Analytic GREEnness Metric Approach (AGREE), Red-Green-Blue (RGB12), and Blue Applicability Grade Index (BAGI)) that have been described as environmentally friendly. Additionally provide an explanation of the data collected, compare, and emphasize the advantages of certain characteristics in each tool. Furthermore, case studies and comparisons for three tools were shown. [ABSTRACT FROM AUTHOR]

Abstract: Five new chiral MnIII complexes [Mn((1R, 2R)‐Salcy)N3]∞⋅CH3CN (1), [Mn((R,R)‐Salcy)N3]∞ (2), [Mn((R,R)‐Salcy)N3] (4), [Mn((R,R)‐Salcy)(H2O)N3]⋅C4H8O (5) and [Mn((R,R)‐Salcy)NCS] (6) have been synthesized and characterized by X‐ray structural analysis and magnetic measurements (Salcy=N,N′‐bis(salicylidene)‐1,2‐diaminocyclohexane}. The four azido complexes have been obtained from the previously known [Mn((R,R)‐Salcy)(CH3OH)N3] (3) by crystallization from various solvents. Compounds 1 and 2 are trans‐μ‐1,3‐azide bridged coordination polymers. While 1 forms helical chains, the chain in 2 is formed via translation of a dimeric helicate repeat unit. Compound 3 is a methanol coordinated mononuclear azido complex which forms a 2D‐network through H‐bonding. Compounds 4 and 6 are phenoxo‐bridged dimers without inversion center. Compound 5 is an aqua coordinated mononuclear azido complex, which forms a 1D‐chain through O−H⋅⋅⋅N hydrogen bonding involving axial ligands. In all six compounds MnIII exhibits a characteristic Jahn−Teller elongation. The magnetic coupling in 1 and 2 leads to antiferromagnetic interaction along the chain (2 J=−11.6 cm−1 for 1 and –11.9 cm−1 for 2) through the μ‐1,3‐azide bridge. Compound 3 is weakly antiferromagnetic due to hydrogen bonding interactions in the lattice. The phenoxo dimers (4 and 6) do not have measurable exchange interaction, the low temperature susceptibility being influenced mainly by zero‐field splitting. [ABSTRACT FROM AUTHOR]

The rotational spectrum of linear C 3 H + has been revisited in the millimeter-wave region using a cryogenic ion trap apparatus employing a double-resonance scheme based on leak-out action spectroscopy (LOS). Eight rotational transitions ( J ′ ← J ′ ′ = 4 ← 3 up to J ′ ← J ′ ′ = 11 ← 10) have been measured in the 85-250 GHz frequency range. With the laboratory measurements reported here, improved values for the ground-state spectroscopic constants of C 3 H + have been obtained. [Display omitted] • The 22-pole ion trap machine COLTRAP was used to investigate C 3 H+ at low temperature. • Applying a double-resonance scheme, 8 rotational lines have been recorded. • The spectroscopic constants could be refined, in particular the sextic centrifugal distortion constant. [ABSTRACT FROM AUTHOR]

Dental implants have become the preferred treatment option for missing teeth replacement due to their functional and restorative benefits. However, placing implants in the esthetic zone remains a challenge due to anatomical factors and the need for optimal emergence profile. The use of custom abutments and regenerative techniques in this case report resulted in a successful implantsupported restoration with excellent functional and aesthetic outcomes. The case highlights the importance of proper treatment planning and the use of advanced techniques in implant dentistry to achieve optimal results. [ABSTRACT FROM AUTHOR]

Two new NaI/CuI,II polynuclear compounds [(NaCu3((R,R)‐3‐MeOSalcy)2(NCO)2](1) and [(NaCu2(3‐MeOSalpn)(NCO)2] (2) have been synthesized using the Schiff base (SB) ligands, (R,R)‐3‐MeOSalcy=(R,R)–N,N′‐bis(3‐methoxysalicylidene)‐1,2‐diaminocyclohexane and 3‐MeOSalpn=N,N′‐bis(3‐methoxysalicylidene)‐1,3‐diaminopropane, respectively. Both complexes contain the rarely observed linear [Cu(NCO)2]− ion which links [{CuII(SB)}2Na]+ ions in 1 or [{CuII(SB)Na}2]2+ ions in 2 producing different linear chain topologies. The mixed valent CuI/IINa network in compound 1 allows for greater magnetic isolation of the paramagnetic ions as compared to compound 2, leading to differences in their EPR spectra. [ABSTRACT FROM AUTHOR]

A series of thirty six complexes obtained from acetonitrile solutions of Cu(NO3)2, Ln(NO3)3 and 2,2‐biyridine or 5,5‐dimethyl‐2,2‐bipyridine (Ln=La‐Yb excluding Pm) have been characterized. The crystals may be grouped into six types: Type‐I, [Cu(bpy)3][La(NO3)5(OH2)]; Type‐II, [Cu(bpy)3][Ln(NO3)5(OH2)] ⋅ 2CH3CN (Ln=Ce, Pr); Type‐IIa, [Cu(5,5‐dmbpy)3][Ln(NO3)5(OH2)] ⋅ 2CH3CN (Ln=La, Ce); Type‐III, [Cu(bpy)3][Ln(NO3)5] (Ln=Nd, Sm–Lu); Type‐IIIa [Cu(5,5‐dmbpy)3][Ln(NO3)5] (Ln=Pr, Nd, Sm‐Lu); Type‐IV, [Cu(5,5‐dmbpy)2(NO3)]2[Ln(NO3)5(OH2)]⋅CH3CN [Ln=La‐Nd, Sm‐Tb). The coordination numbers of the nitrato and aquonitrato lanthanide anions are 10 and 11, respectively. The tris‐chelates in Types I, II and IIIa undergo static Jahn‐Teller distortion while Types IIa and III support fluxional tris‐chelate ions. Type‐IV contains distortion isomers of [Cu(5,5‐dmbpy)2NO3]+. The structural trends are analysed in terms of lanthanide contraction and non‐covalent interactions in the crystals. EPR and electronic spectral characteristics are discussed for the six types of compounds. [ABSTRACT FROM AUTHOR]

Five new polybromide compounds containing tris-chelates of 1,10-phenanthroline and 2, 2-bipyridine as counter cations are described: [Mn(phen)3](Br3)2 (1), [Co(phen)3](Br3)3 (3) and [M- (phen)3](Br3)(Br8)1 =2 where, M=Fe (2), Cu(4) or Zn(5). All are obtained by self assembly in solution starting from divalent transition metal bromides and bromine along with the ligand. In the case of CoBr2, bromine acts as a tribromide precursor as well as oxidising agent. The Mn compound is isomorphous with the corresponding triodide and analogously contains one short and one normal trihalide ion. The Co compound contains one bent but symmetric Br3 ion. The three compounds containing the Z-shaped octabromide ion are isostructural. While the cation in 1 has a crystallographically imposed C3 symmetry, the tris chelates in the other four compounds have near trigonal symmetry. Unusually, the trigonally compressed octahedral cation in 4 has six almost equal Cu N bond distances. Attempts to prepare bpy analogs of 1 resulted in a new dibromo-bridged compound [Mn2Br2(bpy)4](Br3)2 (6) and a dioxo-bridged compound [Mn2O2(bpy)4](Br3)3 (7). The mixed valence cation in 7 formed by bromine oxidation of MnBr2, followed by disproportionation, is well known with other anions. All the paramagnetic compounds (1, 4, 6, 7) give resolved EPR spectra since the bulky anions help to magnetically isolate the cations. The unsymmetric dibromo bridges in 6 produce a net, albeit weak, ferromagnetic coupling between the two [Mn(bpy)2] ²+ fragments. Raman as well as electronic spectra are reported for all compounds. Raman bands, though significantly different even for isostructural compounds, may be understood in terms of Br3 ions and Br2 molecules. All compounds give luminescence from phen and bpy both in solid and solution states, modulated by the coordinated metal io [ABSTRACT FROM AUTHOR]

Patients with rheumatic disorders treated with TNF inhibitors are at increased risk of developing TB. There is no 'gold-standard' for the diagnosis of latent TB prior to initiation of biologic agents. We report our own experience of comparing two interferon gamma release assays (IGRAs) in screening for latent TB in a 'high-risk' TB area in patients with rheumatic disorders. The study demonstrated good concordance between the two tests. We believe the additional cost of these assays is justified in high-risk populations prior to biologic agents, with 16 % of the current study population with at least one positive IGRA assay. [ABSTRACT FROM AUTHOR]

A series of thirteen complexes which may be formally considered as assembled from Cu(bpy)2(NO3)2 and Ln(NO3)3 (Ln=La−Yb excluding Pm, bpy=2,2'‐bipyridine) have been characterized. The crystals may be grouped into four classes: A, [Cu2(bpy)4(μ‐NO3)][Ln(NO3)6] (Ln=La−Nd); B, [Cu(bpy)2(NO3)]2[Ln(NO3)4(OH2)2](NO3) (Ln=Sm−Dy); C, [Cu(bpy)2(NO3)]2[Ln(NO3)5] (Ln=Ho−Tm); D, [Cu(bpy)2(NO3)]2 [Ln(NO3)3(OH2)3](NO3)2⋅2H2O (Ln=Yb). The coordination numbers of the nitrato or aquonitrato lanthanide anions range from 9 to 12. The dinuclear cation in Class A having a linear monoatomic nitrate bridge is new and is seen to produce weak antiferromagnetic coupling in these compounds. The other classes contain distortion isomers of [Cu(bpy)2NO3]+. The structural trends are analysed in terms of lanthanide contraction and non‐covalent interactions in the crystals. EPR and electronic spectral characteristics are discussed for the four classes of compounds. Self assembly from acetonitrile solutions containing 2,2‐bipyridine and hydrates of Cu(NO3)2 and Ln(NO3)3 results in 13 CuII‐LnIII compounds belonging to four classes. The structural trends including the formation of the new dinuclear Cu(II) complex having linear monoatomic nitrato bridge as well as the unusual cocrystal of neutral lanthanide aquanitrate with Cu(II) complex salt are analysed in terms of lanthanide contraction and non‐covalent interactions in the crystals. Magnetic properties, EPR and electronic spectral characteristics are also discussed. [ABSTRACT FROM AUTHOR]

Two new triply bridged Cu(II) compounds [Cu3(bpy)2(μ‐ClCH2COO)6] (1) and [Cu2(bpy)2(μ‐OH)(μ‐OH2)(μ‐ClCH2COO)](ClO4)2 (2) (where, bpy=2,2'‐bipyridine) have been synthesized and their magnetic properties have been measured and correlated with structure. Compound 1 is a novel centrosymmetric tricopper compound with only carboxylate bridges. The terminal Cu2+ ions have [5 + 1] coordination while the central ion has [4 + 2] coordination. The three centres are antiferromagnetically coupled, the exchange parameters for the neighbouring and distant pairs of Cu(II) atoms being 2 J=–28.6 cm–1 and 2 J'=–1.0 cm–1, respectively. In compound 2 three types bridging modes are observed, viz., hydroxo, aquo and carboxylato. The two Cu(II) centers are ferromagnetically coupled (2 J=73.8 cm–1) as previously observed for several di‐copper complexes with the same bridges. DFT calculations are in reasonable agreement with the magnetic exchange parameters for both dinuclear and trinuclear compounds. [Cu3(bpy)2(μ‐ClCH2COO)6] (1) and [Cu2(bpy)2(μ‐OH)(μ‐OH2)(μ‐ClCH2COO)](ClO4)2 (2) are two new triply bridged Cu(II) compounds. Compound 1 is a novel centrosymmetric tricopper compound with only carboxylate bridges and is antiferromagnetic while 2 is ferromagnetic. Their magnetic properties are correlated with structure and modeled well using DFT calculations. [ABSTRACT FROM AUTHOR]

The broadband luminescence of isolated Cr+3 ions in the title lattices is investigated. The 4T2g lowest excited state is found to undergo Jahn–Teller distortion in the eg coordinate, in addition to expanding along the a1g. Quantitative determination of these displacements is made by analysis of extremely rich fine structure, the Ham quenched spin-orbit splitting of the electronic origins, and the Stokes shifts. The Jahn–Teller effect is found to influence the temperature dependence of lifetimes at less than 50 K. In the yttrium containing hosts, nonradiative deactivation of the 4T2g is observed above 200 K. Analysis of lifetime data with four models for nonradiative decay indicates that the active vibrations are again the a1g and eg. The trends observed among the host materials are rationalized on the basis of the freedom of the 4T2g to relax along the a1g and eg directions. [ABSTRACT FROM AUTHOR]

The article offers updates related to dental research. A study showed that people with HIV infections and periodontal disease have higher levels of the virus in the saliva. A biomaterial was developed to rebuild worn enamel and lower tooth sensitivity permanently. A study revealed that memory and walking speed of adults without teeth decline significantly.

The article offers dentistry news briefs. Topics discussed include the discovery of a tooth protein that could assist in bone regeneration, a science exhibition which will showcase stem cells turned into new teeth, and 232 denticles removed from a 17 year old Indian student Ashik Gavai's mouth, which were embedded in a bone in his lower right jaw.

The reaction of CuII halides with 4,5-diazaflouren-9-one (dafone) in acetonitrile and in the presence of halogens gave four novel compounds: [Cu(dafone)2Cl2]Br2 (1), [Cu(dafone)2Br2]Br2 (2), [Cu(dafone)2(CH3CN)2](IBr2)2 (3), and [Cu(dafone)2(CH3CN)2](Br3)2(Br2)2 (4). The well-known preference of dafone to form an unsymmetrical chelate with Cu2+ directs the halide ion and acetonitrile to the equatorial plane of the octahedral complex. In 1 and 2, dibromine links the neutral halo complex molecules to form infinite chains of the previously known neutral molecules. The acetonitrile complex in 3 has the symmetrical mixed trihalide (IBr2–) as a counterion, while in 4 the cation is surrounded by a tribromide-dibromine network. Raman, EPR, optical absorption, and luminescence characteristics are discussed. The dibromine molecules in 1 and 2 provide a pathway for weak magnetic coupling along the chain polymer. [ABSTRACT FROM AUTHOR]

Two new iodobromides [I2Br62- (analogue of I82- and Br82-) and IBr4- (analogue of Br5- and I2Br3-)] and new chains formed from Br3-, Br2 and IBr4- have been obtained in three compounds all containing the same CuII tris-chelate cation Cu(dafone)32+ {[Cu(dafone)3](Br3)(Br5) ( 1), [Cu(dafone)3](Br5)(Br8)0.5·CH3CN ( 2) and [Cu(dafone)3](IBr4)(I2Br6)0.5·CH3CN ( 3)} by a procedure employing bromine, iodine, CuII bromide and dafone in acetonitrile. The formation of chains and isolated polyhalide ions is facilitated by templating with the tris-chelate cation. The Raman spectra of the polyhalides and EPR and other spectral characteristics of the fluxional CuII complex cation are presented. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to clinically evaluate the use of biodegradable chlorhexidine chip when used as an adjunct to scaling and root planing (SRP) in the treatment of moderate to severe periodontitis patients. The study also intended to compare the combined therapy (SRP and Chlorhexidine chip) with chlorhexidine chip alone in individuals with periodontitis. Materials and Methods: Fifteen patients with three sites having a probing depth of 5-8mm were considered for the study. Sites were numbered 1, 2, 3 randomly. The clinical parameters assessed were the Plaque Index (PI), gingival index (GI), Bleeding on probing (BOP), Clinical attachment level (CAL) and Probing pocket depth (PPD). Following baseline evaluation, on two sites scaling and root planing (SRP) was performed, no treatment was carried out in the third site. Chlorhexidine chips were placed on one site with SRP and another without SRP. A periodontal pack was placed on the site to prevent dislodgement of the CHX chip. Clinical parameters were recorded at baseline, one month and three months. Duration of the study was for three months. Statistical Analysis: T-test and Analysis of variance (ANOVA) has been carried out in the present study. Results: All three groups presented with an improvement in the clinical parameters compared to baseline. There was no statistically significant difference between the SRP and SRP + CHIP group in all parameters. There was a significant difference when these two groups were compared to the chip alone group. The mean reductions in PPD were 2.8mm (SRP group), 2.6 (SRP+CHIP group), 0.8 (chip alone group) The mean gain in CAL were 2.8mm (SRP group), 2.5 (SRP+CHIP group), 0.7 (chip alone group). Reduction in bleeding on probing were significant for the SRP and SRP +CHIP group but not for the chip alone group. Conclusion: The CHX chip did not provide any clinical benefit beyond that achieved with conventional scaling and rootplaning after a three month period. [ABSTRACT FROM AUTHOR]