Recent developments in the creation of a single molecular sensing tool for ternary iron (III), chromium (III), aluminium (III) ionic species: A review.

Rational design of a molecular sensing tool is an important topic in molecular recognition, signalling, and optoelectronics that has piqued the interest of chemists, biologists, and environmental scientists. Approximately 150 years have passed since the beginning of the fluorescent chemosensor sector. Due to the paramagnetic properties of Cr3+ and Al3+ , it is tough to prepare a photoluminescence plug-in detector. Most dye-based Al3+ sensors must be utilized in organic or mixed solvents for robust hydration of Al3+ in water. The sophisticated molecular design of sensors, conversely, allows for the detection of these metal ions in aqueous medium. The design of chemosensors using various fluorophores and their mechanisms of action have been thoroughly discussed. A literature survey covering the design of chemosensors and their mechanisms of action have been thoroughly discussed covering the period 2010-2022 and that was carried out including innovative and exemplary activities from numerous groups throughout the world that have significantly contributed to this sector. The most important advantages of these probes are their aqueous solubility and quick response with outstanding selectivity and sensitivity for temporal distribution with high fidelity of metals in living cells.

Rhodamine 6G-based efficient chemosensor for trivalent metal ions (Al3+, Cr3+ and Fe3+) upon single excitation with applications in combinational logic circuits and memory devices.

A new rhodamine 6G-based chemosensor (L3) was synthesized and characterized by 1H, 13C, IR and mass spectroscopy studies. It exhibited an excellent selective and sensitive CHEF-based recognition of trivalent metal ions M3+ (M = Fe, Al and Cr) over mono and di-valent and other trivalent metal ions with prominent enhancement in the absorption and fluorescence intensity for Fe3+ (669-fold), Al3+ (653-fold) and Cr3+ (667-fold) upon the addition of 2.6 equivalent of these metal ions in the probe in H2O/CH3CN (7 : 3, v/v, pH 7.2). The corresponding Kd values were evaluated to be 1.94 × 10-5 (Fe3+), 3.15 × 10-5 (Al3+) and 2.26 × 10-5 M (Cr3+). The quantum yields of L3, [L3-Fe3+], [L3-Al3+] and [L3-Cr3+] complexes in H2O/CH3CN (7 : 3, v/v, pH 7.2) were found to be 0.0005, 0.335, 0.327 and 0.333, respectively, using rhodamine-6G as the standard. The LODs for Fe3+, Al3+ and Cr3+ were determined by 3σ methods and found to be 2.57, 0.78 and 0.47 µM, respectively. The cyanide ion snatched Fe3+ from the [Fe3+-L3] complex and quenched its fluorescence via its ring-closed spirolactam form. Advanced level molecular logic devices using different inputs (2 and 4 input) and a memory device were constructed.

A differentially selective probe for trivalent chemosensor upon single excitation with cell imaging application: potential applications in combinatorial logic circuit and memory devices.

A new rhodamine 6G-benzylamine-based sensor (L1), having only hydrocarbon skeletons in the extended part, was synthesized and characterized by single-crystal X-ray crystallographic study. It exhibited excellent selective and sensitive recognition of trivalent metal ions M3+ (M = Fe, Al and Cr) over mono- and di-valent and other trivalent metal ions. A large enhancement of the fluorescence intensity for Fe3+ (41-fold), Al3+ (31-fold) and Cr3+ (26-fold) was observed upon the addition of 3.0 equivalent of these metal ions into the probe in H2O/CH3CN (4 : 1, v/v, pH 7.2) with naked eye detection. The corresponding Kf values were evaluated to be 9.4 × 103 M-1 (Fe3+), 1.34 × 104 M-1 (Al3+) and 8.7 × 103 M-1 (Cr3+). Quantum yields of the L1, [L1-Fe3+], [L1-Al3+] and [L1-Cr3+] complexes in H2O/CH3CN (4 : 1, v/v, pH 7.2) were found to be 0.012, 0.489, 0.376 and 0.310, respectively, using rhodamine-6G as standard. LODs for Fe3+, Al3+ and Cr3+ were determined by 3σ methods and found to be 1.28, 1.34 and 2.28 µM, respectively. Cyanide ion scavenged Fe3+ from the [Fe3+-L1] complex and quenched its fluorescence via its ring-closed spirolactam form. Advanced level molecular logic devices using different inputs (2 and 4 inputs) as advanced level logic gates and memory devices were constructed. The large enhancement in fluorescence emission of L1 upon complexation with M3+ metal ions makes the probe suitable for the bio-imaging of M3+ (M = Fe, Al and Cr) in living cells.

A dual response fluorescent sensor for HNO and S2- ions using a Cu(ii) complex based probe assisted by detailed DFT studies.

A Cu(ii) based sensor (1) prepared by the complexation between (quinolin-8-ylamino)-acetic acid hydrazide (L2) and Cu2+ ions has been developed for a highly sensitive and selective recognition of HNO and S2- over other biologically abundant anions with prominent enhancement in absorption and emission intensities. The sensor (1) shows weak fluorescence due to ET (electron transfer) but upon addition of HNO and S2- a large enhancement in the fluorescence intensity (F.I.) was observed over other possible competitive anions on the basis of reduction of Cu(ii) to Cu(i) and formation of CuS, respectively. The 1 : 1 complexation was characterized by mass spectrometry (MS), elemental analysis and Job's plot. The corresponding Kf value was evaluated to be (4.934 ± 0.05) × 104 M-1 for Cu2+ from UV-Vis absorption titration. Quantum yields of L2 and [Cu-L2 + S2-] and [Cu-L2 + HNO] complexes in acetonitrile (CH3CN) are found to be 0.107, 0.09 and 0.07, respectively, using quinine sulphate as the standard.

A rhodamine-based turn-on nitric oxide sensor in aqueous medium with endogenous cell imaging: an unusual formation of nitrosohydroxylamine.

A new sensor (L3) based on Rhodamine-B-en (2) and 2-(pyridin-2-ylmethoxy)benzaldehyde (1) has been developed for highly sensitive and selective recognition of NO in purely aqueous medium where the reaction of NO with the fluorophore leads to an unusual formation of nitrosohydroxylamine with the selective opening of the spirolactam ring over different cations, anions, amino-acids and other biological species with prominent enhancement in absorption and emission intensities. A large enhancement of fluorescence intensity for NO (11 fold) was observed upon addition of 3 equivalents of NO into the sensor in aqueous HEPES buffer (20 mM) at pH 7.20, µ = 0.05 M NaCl with naked eye detection. The corresponding Kf value was evaluated to be (7.55 ± 2.04) × 104 M-1 from the fluorescence titration plot. Quantum yields of L3 and the [L3 + NO] compound are found to be 0.07 and 0.77, respectively, using Rhodamine-6G as the standard. The LOD for NO was determined by the 3σ method and found to be 83.4 nM. The L3 sensor has low cytotoxicity, and is cell permeable and suitable for in vitro NO sensing. The in vivo compatibility of the sensor was also checked on zebrafish.

Thalassemias in South Asia: clinical lessons learnt from Bangladesh.

Thalassemias are emerging as a global public health concern. Due to remarkable success in the reduction of childhood mortality by controlling infectious diseases in developing countries, thalassemias are likely to be a major public health concern in the coming decades in South Asia. Despite the fact that Bangladesh lies in the world's thalassemia belt, the information on different aspects (epidemiology, clinical course, mortality, complications and treatment outcomes) of thalassemias is lacking. In this comprehensive review, the aim is to to depict the epidemiological aspects of thalassemias, mutation profile and current treatment and management practices in the country by sharing the experience of dealing with 1178 cases over 2009-2014 time periods in a specialized thalassemia treatment centre. We have also discussed the preventative strategies of thalassemias from the context of Bangladesh which could be effective for other developing countries.

Pattern of Injuries and Treatment Given to Victims of Rana Plaza Tragedy in a Level II Armed Forces Medical Facility in Bangladesh.

BACKGROUND: Rana Plaza building collapse is the worst industrial disaster of Bangladesh so far. The 9-storied structure collapsed suddenly on April 24, 2013, with more than 4000 people inside. Bangladesh Armed Forces played a key role in the massive rescue operations. METHODS: We conducted a cross-sectional study with 423 victims who were treated at a Combined Military Hospital to review the pattern of injuries and management provided. RESULTS: Middle-aged (35±12.75 years) females (68.32%) were the majority of the victims. Among the injured, 42.35% had soft tissue injury, 22.55% had abrasions, 18.79% had fractures, 3.75% had facial injuries, and 2.5% each had head and abdominal injuries. We treated the injured with various surgical approaches, such as soft tissue debridement (38.84%), fasciotomy (18.79%), amputation (3.75%), and other procedures. We had to refer 8.27% of the patients to different advanced centers. The mortality rate was 5.91%, including 1 volunteer rescuer. CONCLUSION: Pattern of injuries and modalities of management needed in an industrial disaster is a valuable experience which can be utilized in preparing to face disasters in the future and beyond. Death of a voluntary rescuer once again warrants the necessity of using a helmet and safety gear during any rescue operation. (Disaster Med Public Health Preparedness. 2017;11:21-24).

Oxime Based Selective Fluorescent Sensor for Arsenate Ion in a Greener Way with Bio-Imaging Application.

A newly designed oxime based probe, 2,4-dihydroxyacetophenone-oxime (DHAO), was found to recognize H2AsO4- selectively with ∼3 fold "turn-on" fluorescence enhancement and LOD of 29 µM, K = (2.10 ± 0.54) × 104 M-1 in purely aqueous medium. The structures of the DHAO and its adduct with H2AsO4- were optimized by DFT calculations. Intracellular imaging of As(V) in HepG2 cells demonstrate the possibilities of in vitro/in vivo applications for selective monitoring of such species.

Morphology-directing synthesis of rhodamine-based fluorophore microstructures and application toward extra- and intracellular detection of Hg(2+).

A new, easily synthesizable rhodamine-based chemosensor with potential N2O2 donor atoms, L(3), has been characterized by single-crystal X-ray diffraction together with (1)H NMR and high-resolution mass spectrometry (HRMS) studies. L(3) was found to bind selectively and reversibly to the highly toxic Hg(2+) ion. The binding stoichiometry and formation constant of the sensor toward Hg(2+) were determined by various techniques, including UV-vis, fluorescence, and Job's studies, and substantiated by HRMS methods. None of the biologically relevant and toxic heavy metal ions interfered with the detection of Hg(2+) ion. The limit of detection of Hg(2+)calculated by the 3σ method was 1.62 nM. The biocompatibility of L(3) with respect to its good solubility in mixed organic/aqueous media (MeCN/H2O) and cell permeability with no or negligible cytotoxicity provides good opportunities for in vitro/in vivo cell imaging studies. As the probe is poorly soluble in pure water, an attempt was made to frame nano/microstructures in the absence and in the presence of sodium dodecyl sulfate (SDS) as a soft template, which was found to be very useful in synthesizing morphologically interesting L(3) microcrystals. In pure water, micro-organization of L(3) indeed occurred with block-shaped morphology very similar to that in the presence of SDS as a template. However, when we added Hg(2+) to the solution of L(3) under the above two conditions, the morphologies of the microstructures were slightly different; in the first case, a flowerlike structure was observed, and in second case, a simple well-defined spherical microstructure was obtained. Optical microscopy revealed a dotlike microstructure for L(3)-SDS assemblies, which changed to a panicle microstructure in the presence of Hg(2+). UV-vis absorption and steady-state and time-resolved fluorescence studies were also carried out in the absence and presence of Hg(2+), and also the SDS concentration was varied at fixed concentrations of the receptor and guest. The results revealed that the fluorescence intensity increased steadily with [SDS] until it became saturated at ∼7 mM SDS, indicating that the extent of perturbation to the emissive species increases with the increase in [SDS] until it becomes thermodynamically stable. There was also an increase in anisotropy with increasing SDS concentration, which clearly manifests the restriction of movement of the probe in the presence of SDS.

Di-oxime based selective fluorescent probe for arsenate and arsenite ions in a purely aqueous medium with living cell imaging applications and H-bonding induced microstructure formation.

A 2-hydroxy-5-methyl-benzene-1,3-dicarboxaldehyde di-oxime based turn-on blue emission fluorescent probe was found to recognize both AsO2(-) and H2AsO4(-) in a purely aqueous medium in intra and extra-cellular conditions. Self-organization of the ligand in the absence and presence of AsO2(-) and H2AsO4(-) was investigated by DLS, optical microscopy, optical fluorescence microscopy and FE-SEM methods.

A novel chromo- and fluorogenic dual sensor for Mg(2+) and Zn(2+) with cell imaging possibilities and DFT studies.

A diformyl-p-cresol (DFC)-8-aminoquinoline based dual signaling probe was found to exhibit colorimetric and fluorogenic properties on selective binding towards Mg(2+) and Zn(2+). Turn-on fluorescent enhancements (FE) as high as 40 fold and 53 fold in 9 : 1 MeCN/water (v/v) at pH 7.2 in HEPES buffer for Mg(2+) and Zn(2+), respectively, were observed. The binding constants determined from the fluorescence titration data are: K = (1.52 ± 0.21) × 10(5) M(-1) and (9.34 ± 4.0) × 10(3) M(-2) at n = 1 and 0.5, for Mg(2+) and Zn(2+), respectively. The L : M binding ratios were also determined by Job's method, which support the above findings. This is further substantiated by HRMS analysis. Due to solubility in mixed organo-aqueous solvents as well as cell permeability it could be used for the in vitro/in vivo cell imaging of Mg(2+) and Zn(2+) ions with no or negligible cytotoxicity. This probe could be made selective towards Mg(2+) over Zn(2+) in the presence of TPEN, both under intra- and extracellular conditions and is superior to other Mg(2+) probes which suffer from selectivity of Mg(2+) over Ca(2+) or Zn(2+). Furthermore the dissociation constant (Kd = 6.60 µM) of the Mg(2+)-() complex is far lower than the so far reported Mg(2+) probes which fall in the mM range.

A novel copper(II) complex as a nitric oxide turn-on fluorosensor: intracellular applications and DFT calculation.

We report, herein, the development of an easily synthesizable novel dansyl-based turn-on NO sensor L2. The UV-Vis titration data of L2 with Cu(2+) display a gradual increase in absorbance at 418 nm with [Cu(2+)], which were analyzed by using a non-linear least-squares computer-fit program yielding K = (1.16 ± 0.36) × 10(6) M(-1) and n = (1.28 ± 0.03) indicating a 1 : 1 complexation. The ground state geometries of L2 as well as its complex [Cu(L2)Cl](+) (1) were optimized by DFT calculations which showed that in complex 1 the central metal ion is in distorted tetrahedral geometry with bond distances very close to those found in analogous Cu(2+) complexes. The fluorescence of L2 was dramatically quenched (∼60-fold) through complexation with paramagnetic Cu(2+) to form [Cu(L2)Cl](+) in MeCN-H2O (9 : 1, v/v) at pH 7.2 in HEPES buffer, which on further treatment with Angeli's salt (Na2N2O3) restores its fluorescence property by ∼15-fold due to the reduction of Cu(2+) to Cu(+) by NO generated in solution from Na2N2O3. The lifetime measurements displayed a substantial decrease in the lifetime of free ligand L2 (τ0 = 12 ns) on complexation with Cu(2+) (τ0 = 2.1 ns). The detection limit of NO calculated by the 3σ method gives a value of 1.6 nM. The NO induced fluorescence enhancement of [Cu(II)(L2)Cl](+) was due to the reduction of [Cu(II)(L2)Cl](+) (1) to [Cu(I)(L2)](+) (2) and is supported by the disappearance of the d-d transition band at 850 nm as well as the X-band EPR signal of 1. The selective "turn on" fluorogenic behavior of L2 was examined on HeLa cells of human cervical cancer origin by fluorescence microscopy which showed very intense intracellular fluorescence that was strongly suppressed by the addition of Cu(2+) but it regains its fluorescence property on further incubation with Angeli's salt (Na2N2O3). The existence of [Cu(II)(L2)Cl](+) and [Cu(I)(L2)](+) in solution was confirmed by ESI-MS(+) (m/z) analysis. The effect of different biologically relevant cations and anions on the fluorescence property of L2 indicates that it was only the [Cu(II)(L2)Cl](+) which displayed high selectivity for NO, indicating its suitability for intracellular application without much worry about its cytotoxicity in a specified dose.

A 7-nitrobenz-2-oxa-1,3-diazole based highly sensitive and selective turn-on chemosensor for copper(II) ion with intracellular application without cytotoxicity.

A 7-nitrobenz-2-oxa-1,3-diazole (NBD) derived turn-on fluorescent probe (1) exhibits a reversible binding to Cu(2+) ion in presence of other metal ions, giving ~20 fold increase in fluorescence intensity. The apparent association constant (K(a)) for Cu(2+) was found to be 2.62 × 10(4) M(-1). The intracellular Cu(2+) imaging behaviour of chemosensor 1 on HeLa cells studied by fluorescence microscopy revealed that after incubation with 1 cells exhibited intensive fluorescence when exogenous Cu(2+) was introduced into the cell. Thus this probe features the ready availability, high sensitivity and selectivity towards Cu(2+) in MeCN-H(2)O (1:1, v/v) with cell imaging possibilities with no or negligible cytotoxicity.

Chemistry of transition metal carbene complexes: nucleophilic substitution reactions of cyanamide anion to Fischer carbene complexes.

Rate constants for the reactions of cyanamide anion N≡C-NH(-) with Fischer carbene complexes of the type (CO)(5)M=C(XR)C(6)H(4)Z with M = Cr and W, XR = SMe and OMe, Z = NMe(2), OMe, Me, H, F, Cl and CF(3) in 50% MeCN-50% water (v/v) at 25 °C are reported. N≡C-NH(-) shows a much higher reactivity towards these carbene complexes than OH(-), primary aliphatic amines (e.g. n-butylamine) or secondary alicyclic amines (e.g. piperidine) but is slightly less reactive than thiolate ions (e.g. HOCH(2)CH(2)S(-)). The alkoxy carbene complexes were found to react faster than the thiomethyl derivatives, consistent with previous findings for alkoxide ion, CH(CN)(2)(-), OH(-), amine and thiolate ion nucleophiles. Hammett ρ values are 3.00 ± 0.08 (k(1)) and 2.98 ± 0.08 (k(2)) for Cr-OMe-Z-N≡C-NH(-) reactions and 0.94 ± 0.05 (k(1)) for Cr-SMe-Z-N≡C-NH(-) reactions. The ρ values for the reaction of Cr-OMe-Z and Cr-SMe-Z with CH(CN)(2)(-) and DABCO (1,4-diazabicyclo[2.2.2]octane) (in 50% MeCN-50% H(2)O (v/v) are comparable to the present reactions. The much higher reactivity and hence much higher ρ value for methoxy carbene complexes over the corresponding thiomethyl derivatives is best explained by considering the substituent effects not only on the transition state (TS) but also on the reactant, and consistent with the previously observed pattern. Higher k(1)(W)/k(1)(Cr) ratios for (thiomethyl)carbene complexes as well as methoxy and ethoxycarbene complexes are related to the intrinsic rate constant which is higher for tungsten-carbene complexes than the corresponding Cr ones resulting in an enhanced ratio. This can also be explained by considering the electronegativity of Cr and W, which is higher for the latter; as a result the negative charge on the central metal atom is more localized in case of W causing destabilization of the TS and hence higher reactivity.

A brief retrospective review of medical records comparing outcomes for inpatients treated via telehealth versus in-person protocols: is telehealth equally effective as in-person visits for treating neutropenic fever, bacterial pneumonia, and infected bacterial wounds?

The incidence of infectious diseases in the United States has been increasing since 1980. Re-emergent conditions, multidrug-resistant bacteria, newly identified infections, and bioterrorism have prompted public health surveillance and control initiatives, including the use of telehealth technology. Infectious diseases, such as West Nile Virus, pose a particular threat to rural areas, where access to infectious disease specialists (IDS) is limited. Initial, in-patient IDS consultations are reimbursed by Centers for Medicare & Medicaid Services for in-person and for telehealth services. Follow-up consultation and subsequent care visits are reimbursed when delivered via in-person care, but not reimbursed when delivered via telehealth. The purpose of this study is to investigate the efficacy of telehealth technology (interactive videoconferencing) in providing timely, efficient, and prudent infectious disease care for rural patients. We conducted a retrospective, comparative review of medical records (n = 107) from inpatients at a metropolitan hospital (n = 59) in a rural state who received in-person IDS treatment, with records from inpatients at nonmetropolitan, rural, and frontier hospitals (n = 48) in the same state who received telehealth IDS treatment. Outcome measures, including number of days hospitalized, number of days receiving intravenous antibiotic, survival, and transfer to another hospital, were compared for three commonly occurring infectious diseases: neutropenic fever, bacterial pneumonia, or bacterial wound infection. Patients treated via telehealth had fewer days on antibiotics and fewer days hospitalized than patients treated via in-person intervention. Survival rates did not differ significantly between groups, but were lower for telehealth patients. Fewer in-person patients required transfer to hospitals offering a higher level of care. Ninety percent of telehealth patients were able to remain at their local hospital for treatment. Results were statistically significant only for selected outcomes and conditions. IDS treatment for the conditions studied is equally effective when delivered via telehealth as when delivered via in-person methods.

Thrombocytopenia associated with linezolid therapy.

We evaluated the incidence and clinical characteristics of linezolid-induced thrombocytopenia in 19 patients who were treated with linezolid. Overall, thrombocytopenia (platelet count, <100,000 platelets/mm(3)) was observed in 32% of patients who received linezolid for >10 days; gastrointestinal bleeding was observed in 1 patient and 4 patients required platelet transfusions. These data suggest that even patients who are not considered to be at risk for development of thrombocytopenia should be monitored closely if linezolid therapy is continued for >10 days.