Synthesis and characterization of some coordinated metal and charge transfer complexes of isonicotinic acid hydrazide ligand with 2-hydroxyacetophenonylidene.

A new series of coordinated metal (Fe(III), Co(II) and Cu(II)) and charge transfer complexes of Schiff base isonicotinic acid (2-hydroxy acetophenonylidene) hydrazide (L) have been synthesized. The ligand (L), its metals and CT complexes were characterized by UV-Vis spectra, FT-IR, 1HNMR and elemental analysis as well as conductance measurements. The pKa of L was determined in universal buffer solutions (20% v/v EtOH-H2O) with varying pH's values. The molar conductivity measurements prove the non-electrolytic nature of all metal complexes. Furthermore, the thermogravimetry (TG) and differential thermal analysis (DTA) of the synthesized complexes were carried out in the range of 30-1000 °C. In addition, interaction of (L) as an electron donor with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as π-type electron acceptor has been studied and characterized. The observed new band at 585 nm might be assigned as charge transfer (CT) absorption band. The electronic absorption spectrum of L-DDQ interaction is found to be dependent on time. The IR spectra of L with the coordinated metals and CT-complexes revealed new main IR bands, which strongly support the formation of complexes. The stoichiometry of the complexes was determined from photometric titration methods which are in accordance with the results of elemental analyses. The ratio were found to be 1:2 (metal:L) and 1:1 (L:DDQ). The spectra of L, its coordinated metals and CT complexes are fully discussed.

Ultrasound-guided Greater Occipital Nerve Block in Children Undergoing Posterior Fossa Craniotomy: A Randomized, Controlled Trial.

BACKGROUND: Posterior fossa surgery is commonly associated with severe postoperative pain. This study assessed the impact of ultrasound-guided greater occipital nerve (GON) block on postoperative pain and hemodynamic profiles in pediatric posterior fossa craniotomy. MATERIALS AND METHODS: Children aged 2 to 12 years undergoing elective posterior fossa craniotomy with general anesthesia were randomly allocated to a control group receiving standard care (n=18) or a GON block group receiving standard care plus bilateral ultrasound-guided GON block (=17). Outcomes were postoperative pain assessed using the objective pain scale, time to first postoperative analgesia, intraoperative fentanyl consumption, perioperative blood pressure and heart rate, incidence of nausea and vomiting, and nerve-block-related complications. RESULTS: Objective pain scale scores were lower in the GON block group than in the control group at 2, 4, 6, 8 (all P =0.0001), 12 ( P =0.001), 16 ( P =0.03), and 24-hour ( P =0.004) postoperatively. The time to first analgesic request was 13.4±7.4 hours in the GON block group and 1.8±1.5 hours in the control group ( P <0.001). Intraoperative fentanyl consumption was 2.68±0.53 µg/kg -1 in the GON block group and 4.1±0.53 µg/kg -1 in the control group ( P =0.0001). Systolic blood pressure was lower in the GON block group at several intraoperative and postoperative time points, whereas heart rate was similar in the two groups at most time points. The incidence of postoperative nausea and vomiting was similar between groups ( P =0.38), and there were no nerve-block-related complications. CONCLUSIONS: In children undergoing posterior fossa craniotomy, GON block was associated with superior quality and duration of postoperative analgesia and better hemodynamic profile compared with standard care.

Effective and selective electroreduction of aqueous nitrate catalyzed by copper particles on multi-walled carbon nanotubes.

Drinking-water contamination with nitrate ions is inevitable and wide spreading, which demands feasible removal. Water de-nitration by potentiostatic electroreduction is described here. A novel electrocatalyst based on nano-copper particles, supported onto multi-walled carbon nanotubes (MWCNTs), and spray-deposited onto fluorine doped tin oxide-glass substrates, is described. The Cu/MWCNT/FTO electrode has been characterized by several methods and assessed as a working electrode in aqueous nitrate ion electroreduction, in comparison with MWCNT sprayed on FTO (MWCNT/FTO) with no copper. Comparison with earlier reported electrodes is also described. XRD patterns confirm the presence of nano-copper crystallites, in the electrode, with average size ⁓45 nm. Within 2 h of electrolysis, Cu/MWVNT/FTO exhibits more than 65% removal of nitrate at -1.80 V (vs. SCE). In longer time (7 h) the electrode completely converts the nitrate into N2 (∼65%) and (NH4+) ∼35% with no NO2- ions. The kinetics show 0.76 order with respect to nitrate, and a rate constant 4.53 × 10-2 min-1 higher than earlier counterparts. The new electrode functions under various conditions of temperature, pH, electrolyte type and concentration and inter-electrode spacing, only at ambient applied potential. Moreover, the electrode exhibits stability under nitrate electroreduction conditions, and can be recovered and reused for multiple times without efficiency loss. XRD and EDS results also confirm the electrode stability after multiple reuse. Compared to earlier systems, the Cu/MWCNT/FTO is environmentally stable, safe, non-costly with high nitrate removal efficiency and selectivity.

Transmuscular Quadratus Lumborum Block versus Suprainguinal Fascia Iliaca Block for Hip Arthroplasty: A Randomized, Controlled Pilot Study.

BACKGROUND: This study aimed to investigate the analgesic efficacy and motor block profile of single-shot transmuscular quadratus lumborum block (QLB) in comparison with those of suprainguinal fascia iliaca block (FIB) in patients undergoing hip arthroplasty. METHODS: This randomized, double-blinded, controlled trial included adult patients undergoing hip arthroplasty under spinal anesthesia. Patients were allocated to one of two groups according to the regional block received: FIB group (n=19) or QLB group (n=17). Both study groups were compared with regard to the duration of analgesia (primary outcome), block performance time, pain during positioning for spinal anesthesia, total morphine consumption in the first postoperative 24-h period, quadriceps muscle power, and static and dynamic visual analog scale. RESULTS: Thirty-six patients were included in the final analysis. Both study groups had comparable durations of analgesia. Postoperative visual analog scale (static and dynamic) values were comparable between the two groups in most readings. The block performance time was shorter in the FIB group. The number of patients with pain during positioning for the subarachnoid block was lower in the QLB group. The total morphine requirement during the first 24 h was marginally lower in the FIB group, whereas the quadriceps motor grade was higher in the FIB group than in the QLB group at 4 h and 6 h after surgery. CONCLUSION: Both single-shot blocks, namely the suprainguinal FIB and transmuscular QLB, provide effective postoperative analgesia after hip arthroplasty. FIB showed slightly lower 24-h morphine consumption, while QLB showed better quadriceps motor power. CLINICAL TRIAL REGISTRATION: The study was registered at clinical trials registry system before enrollment of the first participant (NCT04005326; initial release date, 2 July 2019; https://clinicaltrials.gov/ct2/show/NCT04005326).

Effects of nitroglycerin versus labetalol on peripheral perfusion during deliberate hypotension for sinus endoscopic surgery: a randomized, controlled, double-blinded trial.

BACKGROUND: Deliberate hypotension is used to provide a bloodless field during functional endoscopic sinus surgery; however, the impact of controlled hypotension during anesthesia on peripheral tissue perfusion has not been extensively evaluated. The aim of this study was to compare the impact of nitroglycerin- versus labetalol-induced hypotension on peripheral perfusion. METHODS: The present randomized, double-blinded, controlled trial included adult patients undergoing endoscopic sinus surgery. Patients were allocated to one of two groups according to the drug received for induction of deliberate hypotension: nitroglycerin (n = 20) or labetalol (n = 20). Mean arterial pressure was maintained at 55-65 mmHg in both groups. Both study groups were compared according to pulse oximeter-derived peripheral perfusion index (primary outcome), serum lactate level, mean arterial pressure, heart rate, surgical field score, and intraoperative blood loss. RESULTS: Forty patients were included in the final analysis. The nitroglycerin group exhibited a higher peripheral perfusion index at nearly all records (p < 0.0001) and lower postoperative serum lactate levels (1.3 ± 0.2 mmol/L vs. 1.7 ± 0.4 mmol/L; p = 0.001) than the labetalol group. The peripheral perfusion index was higher in the nitroglycerin group than at baseline at most intraoperative readings. The median surgical field score was modestly lower in the labetalol group than in the nitroglycerin group in the first 20 min (2 [interquartile range (IQR) 2-2.5] versus 1.5 [IQR 1-2]; p = 0.001). Both groups demonstrated comparable and acceptable surgical field scores in all subsequent readings. CONCLUSION: Nitroglycerin-induced deliberate hypotension was accompanied by higher peripheral perfusion index and lower serum lactate levels than labetalol-induced deliberate hypotension during sinus endoscopic surgery. TRIAL REGISTRATION: The study was registered at clinicaltrials registry system with trial number: NCT03809065. Registered at 19 January 2019. This study adheres to CONSORT guidelines.

Sonographic Evaluation of Internal Jugular Vein Diameter and Cross-sectional Area Measurements in Correlation with Left Ventricular End Diastolic Area as a Tool for Perioperative Assessment of Volume Status in Pediatric Patients Undergoing Cardiac Surgery.

AIM: The aim of this study is to compare the ultrasound estimation of the cross-sectional area (CSA) and diameter of internal jugular vein (IJV) with left ventricular end diastolic area (LVEDA) for the assessment of intravascular volume in pediatric patients during cardiac surgery. PATIENTS AND METHODS: The CSA and diameter of the left IJV were defined, using ultrasound machine, and compared with LVEDA, estimated by transesophageal echo, in four times intervals (immediately after induction [T1], before the start of cardiopulmonary bypass [CPB] [T2], immediately after weaning of CPB [T3], and at the end of surgery before transfer to the Intensive Care Unit [T4]) as a tool for intravascular volume assessment in 16 pediatric patients undergoing cardiac surgery. RESULTS: There was a poor correlation between IJV CSA and diameter with LVEDA. r values were 0.158, 0.265, 0.449, and 0.201 at the four time intervals (T1, T2, T3, and T4), respectively. CONCLUSION: Estimation of the CSA and diameter of the left IJV using ultrasound is not reliable and cannot be used alone to decide further management.

Perfusion indices revisited.

Monitoring of tissue perfusion is an essential step in the management of acute circulatory failure. The presence of cellular dysfunction has been a basic component of shock definition even in the absence of hypotension. Monitoring of tissue perfusion includes biomarkers of global tissue perfusion and measures for assessment of perfusion in non-vital organs. The presence of poor tissue perfusion in a shocked patient is usually associated with worse outcome. Persistently impaired perfusion despite adequate resuscitation is also associated with worse outcome. Thus, normalization of some perfusion indices has become one of the resuscitation targets in patients with septic shock. Although the collective evidence shows the clear relation between impaired peripheral perfusion and mortality, the use of different perfusion indices as a resuscitation target needs more research.

Collagen based barrier membranes for periodontal guided bone regeneration applications.

Certain cell populations within periodontal tissues possess the ability to induce regeneration, provided they have the opportunity to populate the wound or defect. Guided regeneration techniques have been investigated for regenerating periodontal tissues and such therapies usually utilize barrier membranes. Various natural and synthetic barrier membranes have been fabricated and tested to prevent epithelial and connective tissue cells from invading while allowing periodontal cells to selectively migrate into the defect. This paper focuses on the literature relevant to the use and potential of resorbable collagen membranes in GBR procedures, sites of periodontal and intrabony defects, in cases of socket and alveolar ridge preservation and at implant sites. The results of their use in GBR procedures has shown them to be effective and comparable with non-resorbable membranes with regards to clinical attachment gain, probing depth reduction and defect bone filling. They have also shown to prevent epithelial ingrowth into the defect space during the initial wound healing phase postsurgically. Collagen membranes have also been used for root coverage and GBR procedures and have shown good success rates comparable to subepithelial connective tissue grafts and expanded-polytetrafluoroethylene (e-PTFE) membranes. The future for periodontal tissue engineering is very exciting with the use of barrier membranes expected to continue playing a critical role. However, long-term clinical trials are required to further evaluate and confirm the efficacy of the available collagen barrier membranes for periodontal and bone regeneration use.

Interaction of thiazolidine-2-thione with 2,3,5,6-tetrabromo-1,4-benzoquinone: a set of sequential interactions involving redox and substitution reactions after an initial charge transfer complexation.

Interaction between thiazolidine-2-thione (T2T) as an electron donor and 2,3,5,6-tetrabromo-1,4-benzoquinone (p-bromanil, BRL) as a π-electron acceptor has been studied by using several spectral techniques, viz. UV/visible, IR, (1)H NMR and Mass spectra. A substitution reaction has been occurred after an initial formation of a CT complex, meanwhile a redox reaction has been occurred, in situ, too in which the interacting donor (T2T) has been oxidized to the corresponding thiazole. Thus, the stoichiometric ratio of this interaction has been found to be 2:1, T2T:BRL. However, the most interesting finding is that unexpectedly neither the SH group of the thiol form nor the NH group of the thione form of the T2T has shared in the substitution reaction with BRL. This finding has been confirmed by the different applied spectral tools, whereas a plausible reaction pathway has been illustrated and discussed.

Multiple and sequential charge transfer interactions occurring in situ: A redox reaction of thiazolidine-2-thione with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone.

Interaction of thiazolidine-2-thione (T2T) as an electron donor with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as an electron π-acceptor has been studied. Electronic absorption spectra of the system T2T-DDQ in several organic solvents of different polarities have been measured. A charge transfer (CT) complexation has occurred between T2T and DDQ. This CT interaction has led to a redox reaction in which T2T has been oxidized to the corresponding dehydrogenated T2T (T2T-2H), meanwhile DDQ has been fully reduced to the corresponding hydroquinone (DDQH2). However, the two new species, resulting in situ, have been interacted, whereas a CT complex having the formula (T2T-2H·DDQH2) has occurred. IR, 1H NMR and mass spectra were used for ascertaining the structural formula of the synthesized CT complex. Formation constants (KCT), molar absorption coefficients (ɛCT) and thermodynamic properties of this CT interaction in various organic solvents were determined and discussed. The obtained KCT and ɛCT values have indicated that T2T-2H is a weak CT donor, whereas the formed CT complex has a low stability and it is classified as a contact-type CT complex.

In vitro simulation of the chemical scenario of the action of an anti-thyroid drug: charge transfer interaction of thiazolidine-2-thione with iodine.

Thiazolidine-2-thione (T2T) has been studied spectrophotometrically by UV-visible and IR spectra. The spectral studies have indicated that T2T has two tautomeric forms, namely thione and thiole forms, in addition to the dimeric thioamide complex existing as a hydrogen-bonded dimer of two thione forms. Interaction of the T2T as an electron donor with iodine as a typical σ-type acceptor has been studied spectrophotometrically. Electronic absorption spectra of the system T2T-I2 in several organic solvents of different polarities have performed a clear charge transfer (CT) band in each spectrum. Formation constants (KCT) and molar absorption coefficients (ɛCT) and thermodynamic properties, ΔH, ΔS, and ΔG, of this system in various organic solvents were determined and discussed. The stoichiometric ratio of the T2T-I2 system in solutions was found to be 1:1 T2T:I2, whereas the elemental analysis of the prepared solid CT complex has illustrated the same stoichiometry. The obtained KCT and ɛCT values have indicated that T2T is a donor of moderately strength capable of interacting with the iodine just to form the corresponding CT complex with an iodine molecule without further reducing of the iodine to either of the corresponding poly-iodide ions viz. I3-, I5-, etc. This action of spongy trapping of iodine simulates in vitro the chemical scenario of the anti-thyroid action of this compound.