Pt(II)-bis(quinolinyl) complexes for photocatalytic hydrogen production

Three Pt(II)-bis(quinolinyl) complexes with varying electron densities were synthesized, structurally characterized and used for photocatalytic hydrogen production under different conditions. All the complexes were found to be active for hydrogen production giving a maximum turnover number (TON) of 1230 surpassing the conventionally used Pt-terpyridyl complexes.

Oncological Clearance Following Resection of the Carcinoma Rectum: A Comparison between Laparoscopic and Open Anterior Resection

Till the day the rectal cancer deaths in the world is in eighth position. For rectal cancer surgery, short-term benefits are expected to be similar for laparoscopic resection of rectum (LRR) and open resection of rectum (ORR). In Bangladesh though the rectal cancer is the sixteenth most common cause of cancer deaths, there is lack of data regarding outcomes of laparoscopic and open surgical approaches for carcinoma rectum. Purpose of study was to compare oncopathological outcomes by quality of surgical resection between LRR and ORR groups. The quasi experimental study was conducted among 46 subjects who attended in the Department of Colorectal Surgery, Bangabandhu Sheikh Mujib Medical University, Bangladesh from July 2020 to June 2021 with rectal adenocarcinoma within 15cm from the anal verge. Equal number of subjects were allocated for LRR and ORR group. Oncopathological end points such as circumferential resection margin (CRM), distal resection margin (DRM), lymph nodes and quality of mesorectal excision were assessed and compared. Here every patients have given their written consent for this study. Mean age of the subjects for LRR and ORR were 45.47±12.66 and 44.47±12.48 years respectively. Majority of the subjects were in age above 40 years (67.0%). The proportion of male (56.5%) were higher than those of female (43.5%). The complete resection was better in LRR (91.3%) than ORR (87.0%) group though statistically not significant. CRM was lower in LRR (0.0%) than ORR (13.0%) group in respect of frequency distribution. DRM was negative for both LRR and ORR group (95.7% each) and it was not statistically significant. ORR met the National Comprehensive Cancer Network (NCCN) criteria of harvesting 12 lymph nodes were as in LRR group 10 lymph nodes were harvested. The mean harvested lymph nodes were 12.2±5.55 and 10.1±5.55 in LRR and ORR group respectively. The study demonstrated that LRR is better (though statistically not significant) in respect of complete resection and CRM while in harvesting lymph nodes, ORR met the NCCN criteria but LRR does not. There is no difference observed regarding DRM in both groups. On oncopathological point of view both the group showed almost equally effective results. Laparoscopic surgery can be opted as the standard operative technique for surgical management of rectal cancer.

Effect of substitution on deep-blue Ir(III) N-heterocyclic carbene (NHC) emitters

The development of Ir(III)-NHC phosphors that display deep-blue luminescence without sacrificing the high photoluminescence quantum yield (PLQY) has become a pivotal area of research. In this respect, two novel deep-blue Ir-NHC emitters (C1 and C2) with strategically designed pro-carbenic imidazolium ligands (L1 and L2) incorporating a heavy bromine atom at the ligand-scaffold were synthesized in good yields (∼80% for L1, L2 and 65% for C1, C2). The ground and excited state properties of the complexes were photophysically determined and the results were found to be in accordance with theoretical calculations at the DFT and TD-DFT levels. Due to the strong σ-donation of the carbene ligands, complexes C1 and C2 displayed oxidation at low anodic potentials. Both the complexes showed deep-blue emission either in solution (λem ∼ 400-425 nm) or as PMMA-doped films of varying concentrations (λem ∼ 400 nm) with an ∼15 times enhanced PLQY with respect to benchmark Ir-NHC complexes. The strategy of incorporating the heavy bromine atom to reduce the molecular vibrations in C1 and C2 was further supported by ∼250 times reduced non-radiative decay constants (knr) and Huang-Rhys constants of C1 and C2 in comparison to those of the benchmark complexes. These facts were also supported by triplet frequency calculations of C1 and C2 to identify the absence of vibrations.

Wide-Bite-Angle Diphosphine Ligands in Thermally Activated Delayed Fluorescent Copper(I) Complexes: Impact on the Performance of Electroluminescence Applications

We report a series of seven cationic heteroleptic copper(I) complexes of the form [Cu(P^P)(dmphen)]BF₄, where dmphen is 2,9-dimethyl-1,10-phenanthroline and P^P is a diphosphine chelate, in which the effect of the bite angle of the diphosphine ligand on the photophysical properties of the complexes was studied. Several of the complexes exhibit moderately high photoluminescence quantum yields in the solid state, with Φ_PL of up to 35%, and in solution, with Φ_PL of up to 98%. We were able to correlate the powder photoluminescence quantum yields with the % V_bur of the P^P ligand. The most emissive complexes were used to fabricate both organic light-emitting diodes and light-emitting electrochemical cells (LECs), both of which showed moderate performance. Compared to the benchmark copper(I)-based LECs, [Cu(dnbp)(DPEPhos)]⁺ (maximum external quantum efficiency, EQE_max = 16%), complex 3 (EQE_max = 1.85%) showed a much longer device lifetime (t_1/2 = 1.25 h and >16.5 h for [Cu(dnbp)(DPEPhos)]⁺ and complex 3, respectively). The electrochemiluminescence (ECL) properties of several complexes were also studied, which, to the best of our knowledge, constitutes the first ECL study for heteroleptic copper(I) complexes. Notably, complexes exhibiting more reversible electrochemistry were associated with higher annihilation ECL as well as better performance in a LEC.

Limberg Flap in Pilonidal Sinus: Experience in Shaheed Suhrawardy Medical College Hospital

Pilonidal sinus disease is a common anorectal condition usually seen in young adult patients. Various methods have been described over the years and there is ongoing debate regarding the ideal method. This study was conducted to evaluate the advantages, results of rhomboid excision and Limberg flap reconstruction in the management of sacrococcygeal pilonidal sinus disease. This cross-sectional study was conducted in Surgery Unit-I of Department of Surgery, Shaheed Suhrawardy Medical College Hospital, Dhaka, Bangladesh a tertiary care centre from July 2016 to November 2017. It includes 19 patients who were treated for sacrococcygeal pilonidal sinus disease by Limberg (Rhomboid) flap. All patients that underwent the procedure had good postoperative outcome with minimal postoperative discomfort and were discharged in 3-4 days. There were 3 cases with complications. Limberg flap coverage is very effective for pilonidal disease with low complication rates, reduced hospital stay, low recurrence rates, earlier healing and shorter time off-work. This technique can be easily mastered and used as an indispensable tool for treating sacrococcygeal pilonidal sinus disease.

Panchromatic Ru(ii)-polypyridyl complexes as NIR emitters

Novel heteroleptic Ru(ii)-polypyridyl complexes were synthesised that exhibit panchromatic absorption up to 750 nm and ³MLCT NIR emission at λ_em > 830 nm.

Do It Better: Cross Mattress for Chest Drain Insertion Site Security Offers Quality Outcome in Chest Trauma Patients Required Tube Thoracostomy

We examined the hypothesis that the cross mattress for chest drain insertion site security is better than that of polypropylene horizontal mattress in chest trauma patient required tube thoracostomy at the Department of Casualty Surgery, Dhaka Medical College Hospital, Dhaka, Bangladesh from January 2016 to June 2016. Accordingly we prospectively studied 50 consecutive patients who needed chest tube insertion. In 25 consecutive cases chest drain insertion site was secured with polypropylene horizontal mattress technique (Control- Group A) and another 25 consecutive patients had a cross-mattress with non-absorbable suture materials (Experimental- Group B). All chest tubes were inserted into the triangle of safety to following the BTS guideline. A baseline x-ray chest was compared with post-procedure chest x-ray. Male preponderance and young adults were comprised in both the groups; mean age in Group A and Group B was 38.7±15.5 and 37.3±14.1 respectively. Haemo-pneumothorax was the most common cause of tube thoracostomy among the trauma victims. This study shows that, polypropylene horizontal mattress results in increased chest tube site infection 52% in Control Group vs. 12% in Experimental Group (p=0.002). Although there was similar incidence of blood loss between the groups, the length of Hospital stay was significantly higher in Control Group. We conclude that cross mattress for chest drain insertion site security showed a better clinical outcome, less wound complications and less hospitalization.

High-Efficiency Deep-Blue-Emitting Organic Light-Emitting Diodes Based on Iridium(III) Carbene Complexes

High-efficiency pure blue phosphorescent organic light-emitting diodes (OLEDs) remain one of the grand challenges, principally because the emissive complexes employed either do not possess sufficiently high photoluminescence quantum yields or exhibit unsatisfactory Commission International de l'Éclairage (CIE) coordinates. Here two deep-blue-emitting homoleptic iridium(III) complexes are reported and OLEDs are demonstrated with CIE coordinates of (0.15, 0.05) and maximum external quantum efficiency of 13.4%, which decreases slightly to 12.5% at 100 cd m^-2 . They represent examples of the most efficient OLEDs surpassing the CIEy requirement of the National Television System Committee (NTSC) and the European Broadcasting Union (EBU). Emitter orientation contributes to the excellent device performance.

Sloppy Hinge Prosthetic Replacement in Old Healed Side Swipe Injuries of Elbow - Long term Results

BACKGROUND

Sideswipe injuries of elbow often poses significant functional loss resulting from devastating injuries involving osseoligamentous structures as well as multilevel soft tissue injuries around the elbow. Inspite of treatment, no conscientious treatment opinion is available in the literature to provide optimum functional outcome. The objective of this study is to evaluate the results of prosthetic replacement of old healed sideswipe injuries of elbow with gross dysfunctional disabilities resulting from loss of bones and muscles around the joint.

MATERIALS AND METHODS

Fourteen patients of 2-3 years old healed sideswipe injuries of the elbow, treated by Baksi sloppy hinge (original version in seven and recent version in seven) prosthetic replacement were evaluated. All had normal neurovascular status except two; one having ulnar nerve deficit the other median nerve in another. The mean age was 42.7 years (range 32-61 years).

RESULTS

The average followup period was 13.5 years (range 5.11-23.11 years). Ten patients regained stable 0° to 130° elbow flexion, and four had restricted terminal flexion with arc 10°-115° following V-Y plasty of contracted triceps. Mean supination was 22° and mean pronation was 35°. According to Mayo Elbow Performance Score (MEPS), excellent results were in five (35.7%), good in six (42.8%), and fair in one (7.1%). Two patients (14.2%) needed removal of prosthesis due to intractable delayed infection and considered failure. Following removal, the resected elbow retained relatively stable motions due to mature fibrous tissues connecting the adjacent bone ends and reorientation of muscle balance. Postoperative improvement of MEPS (mean 84) was significant (P = 0.0037) compared to preoperative value (mean 41.7). Two patients had superficial wound infection and five aseptic loosening of which one was symptomatic.

CONCLUSION

Prosthetic replacement of elbow is an effective salvage procedure in old healed sideswipe injuries.

A Bisamide Ruthenium Polypyridyl Complex as a Robust and Efficient Photosensitizer for Hydrogen Production

A photosensitizer based on a ruthenium complex of a bisamide-polypyridyl ligand gives rise to a large improvement in photocatalytic stability, rate of activity, and efficiency in photocatalytic H₂ production compared to [Ru(bpy)₃ ]²⁺ (bpy=2,2'-bpyridine). The bisamide ruthenium polypyridyl complex combined with a cobaltoxime-based photocatalyst was found to be highly efficient under blue-light (turnover number (TON)=7800) and green-light irradiation (TON=7200) whereas [Ru(bpy)₃ ]²⁺ was significantly less effective with a TON of 2600 and 1100, respectively. The greatest improvement was under red-light-emitting diodes, with bisamide ruthenium polypyridyl complex and cobaltoxime exhibiting a TON of 4200 compared to [Ru(bpy)₃ ]²⁺ and cobaltoxime at a TON of only 71.

Bay-Region Functionalisation of Ar-BIAN Ligands and Their Use Within Highly Absorptive Cationic Iridium(III) Dyes

We report the synthesis, UV-vis absorption, electrochemical characterisation, and DFT studies of five panchromatic, heteroleptic iridium complexes (four of which are new) supported by Ar-BIAN ligands. In particular, the synthesis of an ester-functionalised Ar-BIAN ligand was carried out by a mechanochemical milling approach, which was advantageous over conventional metal templating solution methods in terms of reaction time and product purity. The introduction of ester and carboxylate functionalities at the bay region of the acenaphthene motif increases each ligand’s π-accepting capacity and imparts grafting capabilities to the iridium complexes. These complexes have absorption profiles that surpass the renowned N3 dye [Ru(dcbpy)₂(NCS)₂] (dcbpy = 4,4′-dicarboxy-2,2′-bipyridine), making them of interest for solar-energy-harvesting applications.

Blue-to-Green Emitting Neutral Ir(III) Complexes Bearing Pentafluorosulfanyl Groups: A Combined Experimental and Theoretical Study

A structure-property relationship study of neutral heteroleptic (1 and 2, [Ir(C^∧N)₂(L^∧X)]) and homoleptic (3 and 4, fac-[Ir(C^∧N)₃]) Ir(III) complexes (where L^∧X = anionic 2,2,6,6-tetramethylheptane-3,5-dionato-κO³,κO⁶ (thd) and C^∧N = a cyclometalating ligand bearing a pentafluorosulfanyl (-SF₅) electron-withdrawing group (EWG) at the C₄ (HL1) and C₃ (HL2) positions of the phenyl moiety) is presented. These complexes have been fully structurally characterized, including by single-crystal X-ray diffraction, and their electrochemical and optical properties have also been extensively studied. While complexes 1 ([Ir(L1)₂(thd)]), 3 (Ir(L1)₃), and 4 (Ir(L2)₃) exhibit irreversible first reduction waves based on the pentafluorosulfanyl substituent in the range of -1.71 to -1.88 V (vs SCE), complex 2 ([Ir(L2)₂(thd)]) exhibits a quasi-reversible pyridine_C^∧N-based first reduction wave that is anodically shifted at -1.38 V. The metal + C^∧N ligand oxidation waves are all quasi-reversible in the range of 1.08-1.54 V (vs SCE). The optical gap, determined from the lowest energy absorption maxima, decreases from 4 to 2 to 3 to 1, and this trend is consistent with the Hammett behavior (σ_m/σ_p with respect to the metal-carbon bond) of the -SF₅ EWG. In degassed acetonitrile, for complexes 2-4, introduction of the -SF₅ group produced a blue-shifted emission (λ_em 484-506 nm) in comparison to reference complexes [Ir(ppy)₂(acac)] (R1, where acac = acetylacetonato) (λ_em 528 nm in MeCN), [Ir(CF₃-ppy) (acac)] (R3, where CF₃-ppyH = 2-(4-(trifluoromethyl)phenyl)pyridine) (λ_em 522 nm in DCM), and [Ir(CF₃-ppy)₃] (R8) (λ_em 507 nm in MeCN). The emission of complex 1, in contrast, was modestly red shifted (λ_em 534 nm). Complexes 2 and 4, where the -SF₅ EWG is substituted para to the Ir-C_C^∧N bond, are efficient phosphorescent emitters, with high photoluminescence quantum yields (Φ_PL = 58-79% in degassed MeCN solution) and microsecond emission lifetimes (τ_ε = 1.35-3.02 μs). Theoretical and experimental observations point toward excited states that are principally ligand centered (³LC) in nature, but with a minor metal-to-ligand charge-transfer (³MLCT) transition component, as a function of the regiochemistry of the pentafluorosulfanyl group. The ³LC character is predominant over the mixed ³CT character for complexes 1, 2, and 4, while in complex 3, there is exclusive ³LC character as demonstrated by unrestricted density functional theory (DFT) calculations. The short emission lifetimes and reasonable Φ_PL values in doped thin film (5 wt % in PMMA), particularly for 4, suggest that these neutral complexes would be attractive candidate emitters in organic light-emitting diodes.

Simple design to achieve red-to-near-infrared emissive cationic Ir(iii) emitters and their use in light emitting electrochemical cells

Two cationic Ir(iii) complexes bearing bithiazole-type ancillary ligands have been synthesised and tested as deep red-to-near-infrared emitters in solution-processed electroluminescent devices.

Dietary protein enhances non-specific immunity, anti-oxidative capability and resistance to Aeromonas hydrophila in Labeo rohita fingerlings pre-exposed to short feed deprivation stress

Present experiment was conducted to study the effect of dietary protein levels on growth, immunity and anti-oxidative status of Labeo rohita fingerlings during feed deprivation followed by refeeding. Fish (5.44 ± 0.10 g) were deprived of feed for 3 weeks and then re-fed to satiation for 5 weeks with one of the diets containing 25 (25P), 30 (30P), 35 (35P) or 40 (40P) percent crude protein (CP) level. In addition to these groups, a control group (C) was also maintained by feeding to satiation level twice daily with a diet containing 30% CP throughout the experimental period. At the end of 8-weeks' trial, fish were challenged with Aeromonas hydrophila and survival was recorded for the next 7 days. Complete recovery of growth in terms of weight gain percentage was achieved in the fish fed 35 and 40% protein during refeeding. The body indices (condition factor and hepatosomatic index), haematological parameters and serum protein contents at the end of the experimental trial were not significantly different (P > 0.05) among different groups suggesting that the overall health of the fish was not compromised. However, respiratory burst activity and serum lysozyme activity were indicative of a better immune function in the higher protein fed groups (35P and 40P) than the lower protein groups (25P and 30P). Following challenge with Aeromonas hydrophila, survival rate, blood monocyte%, respiratory burst activity, serum lysozyme activity, serum protein and globulin were significantly higher (P < 0.05) in the 35P and 40P groups compared to the other groups. Further, fish fed lower dietary protein were not able to restore the activities of anti-oxidative enzymes (superoxide dismutase and catalase) in the liver. Conclusively, an improved disease resistance capability and immune status was observed in the fish fed a higher dietary protein (35-40%), even out-performing the daily-fed fish.

Synthesis and photophysical properties of C3-symmetric tris(pyridyl)truxene scaffolds of Ru(ii) and Re(i)

Facial Ru(ii)- and Re(i)-complexes of a novel face-capping tris(pyridyl)truxene ligand were synthesised and characterised by various analytical techniques including single crystal XRD. The Ru(ii) complex exhibits unusual green phosphorescence with a long excited-state lifetime.

Synthesis, Properties, and Light-Emitting Electrochemical Cell (LEEC) Device Fabrication of Cationic Ir(III) Complexes Bearing Electron-Withdrawing Groups on the Cyclometallating Ligands

The structure–property relationship study of a series of cationic Ir(III) complexes in the form of [Ir(C^N)₂(dtBubpy)]PF₆ [where dtBubpy = 4,4′-di-tert-butyl-2,2′-bipyridine and C^N = cyclometallating ligand bearing an electron-withdrawing group (EWG) at C₄ of the phenyl substituent, i.e., −CF₃ (1), −OCF₃ (2), −SCF₃ (3), −SO₂CF₃ (4)] has been investigated. The physical and optoelectronic properties of the four complexes were comprehensively characterized, including by X-ray diffraction analysis. All the complexes exhibit quasireversible dtBubpy-based reductions from −1.29 to −1.34 V (vs SCE). The oxidation processes are likewise quasireversible (metal + C^N ligand) and are between 1.54 and 1.72 V (vs SCE). The relative oxidation potentials follow a general trend associated with the Hammett parameter (σ) of the EWGs. Surprisingly, complex 4 bearing the strongest EWG does not adhere to the expected Hammett behavior and was found to exhibit red-shifted absorption and emission maxima. Nevertheless, the concept of introducing EWGs was found to be generally useful in blue-shifting the emission maxima of the complexes (λ_em = 484–545 nm) compared to that of the prototype complex [Ir(ppy)₂(dtBubpy)]PF₆ (where ppy = 2-phenylpyridinato) (λ_em = 591 nm). The complexes were found to be bright emitters in solution at room temperature (Φ_PL = 45–66%) with microsecond excited-state lifetimes (τ_e = 1.14–4.28 μs). The photophysical properties along with density functional theory (DFT) calculations suggest that the emission of these complexes originates from mixed contributions from ligand-centered (LC) transitions and mixed metal-to-ligand and ligand-to-ligand charge transfer (LLCT/MLCT) transitions, depending on the EWG. In complexes 1, 3, and 4 the ³LC character is prominent over the mixed ³CT character, while in complex 2, the mixed ³CT character is much more pronounced, as demonstrated by DFT calculations and the observed positive solvatochromism effect. Due to the quasireversible nature of the oxidation and reduction waves, fabrication of light-emitting electrochemical cells (LEECs) using these complexes as emitters was possible with the LEECs showing moderate efficiencies.

A series of heteroleptic cationic Ir(III) complexes bearing electron-withdrawing groups −CF₃ (1), −OCF₃ (2), −SCF₃ (3), −SO₂CF₃ (4) on the cyclometallating ligands have been synthesized, and their optoelectronic properties have been characterized. Though clear trends were found for the ground-state properties, anomalous behavior was observed for the emission maxima. Thus, this study demonstrates that the common design paradigm for blue-shifting emission through addition of EWGs on the C^N ligands is not always operative.

Incidence of Retinopathy of Prematurity and Its Association with Oxygen Therapy in Preterm Low Birth Weight Babies

Introduction: The objectives of this study were to study the incidence and risk factors of retinopathy of prematurity (ROP) among preterm low birth weight babies and its association with oxygen therapy.Material and Methods: During one year study period, 50 neonates, who had fulfilled the inclusion criteria (born at gestational age ≤ 35 wks), were included in the present study. They were examined by indirect ophthalmoscopy by an ophthalmologist in NICU or ophthalmology outdoor. Staging of ROP was done according to the International classification. Data obtained from this study were entered in Microsoft Excel and subsequently analysed in SPSS version 20.0.Results: Among study population, 12 neonates (24%) showed evidence of retinopathy of prematurity, and Stage 2 ROP was most common (41.7%) within this group. Those neonates who had born ≤28 wks gestational age, showed more incidence (75%) of ROP. There was significant association between ROP and prematurity, low birth weight, mechanical ventilation, duration and concentration of oxygen therapy.Conclusion: Apart from prematurity and low birth weight, oxygen therapy also carries significant risk for ROP. Thus, judicious use of oxygen in premature babies can reduce incidence of ROP significantly.J Nepal Paediatr Soc 2015;35(3):247-252

Osteosynthesis of ununited femoral neck fracture by internal fixation combined with iliac crest bone chips and muscle pedicle bone grafting

BACKGROUND

Ununited femoral neck fracture is seen commonly in developing countries due to delayed presentation or failure of primary internal fixation. Such fractures, commonly present with partial or total absorption of femoral neck, osteonecrosis of femoral head in 8-30% cases with upward migration of trochanter posing problem for osteosynthesis, especially in younger individuals. Several techniques for treatment of such conditions are described like osteotomies or nonvascularied cortical or cancellous bone grafting provided varying degrees of success in terms of fracture union but unsatisfactory long term results occurred due to varying incidence of avascular necrosis (AVN) of femoral head. Moreover, in presence of AVN of femoral head neither free fibular graft nor cancellous bone graft is satisfactory. The vascularied bone grafting by deep circumflex iliac artery based on iliac crest bone grafting, free vascularied fibular grafting and muscle pedicle periosteal grafting showed high incidence of success rate. Osteosynthesis is the preferred treatment of choice in ununited femoral neck fracture in younger individuals.

MATERIALS AND METHODS

Of the 293 patients operated during the period from June 1977 to June 2009, 42 were lost to followup. Seven patients with gluteus medius muscle pedicle bone grafting (MPBG) were excluded. Thus, out of 244 patients, 208 (85.3%) untreated nonunion and 36 (14.7%) following failure of primary internal fixation were available for studies. Time interval between the date of injury and operation in untreated nonunion cases was mean 6.5 months and in failed internal fixation cases was mean 11.2 months. Ages of the patients varied from 16 to 55 years. Seventy patients had partial and 174 had subtotal absorption of the femoral neck. Evidence of avascular necrosis (AVN) femoral head was found histologically in 135 (54.3%) and radiologically in 48 (19.7%) patients. The patients were operated by open reduction of fracture, cannulated hip screw fixation, iliac crest bone chips and quadratus femoris MPBG.

RESULTS

The mean followup is 12.5 years (range 3-35). The union of fractures occurred in 202 (82.8%), delayed union in 18 (7.3%), and established nonunion in 24 (9.8%) patients. Full weight bearing was permitted at 16-22 weeks after union of fractures. Mean Harris hip score at the longest followup was 85.5. Among the complications, superficial wound infection occurred in 20 (8.2%), deep infection in seven (2.9%), and coxa vara in 39 (16%) patients. Preoperative radiodensity of femoral head disappeared mostly after the union of fracture whereas fresh radiodensity of femoral head appeared in 20 (8%) patients; nine (45%) of them developed segmental collapse.

CONCLUSION

Ununited femoral neck fractureis characterized by absorption of femoral neck, posterior cortical defect, smoothening and overriding of fracture surfaces with intervening fibrous tissues associated with or without AVN of femoral head. The above method of osteosynthesis rectified the above pathology and provided satisfactory results with union of fractures in 90.1% patients at long term followup.

Transition Metal Complexes of Bidentate and Tridentate Ligands: From Optoelectronic Studies to Supramolecular Assemblies

This article depicts an overview of some of the research in supramolecular chemistry performed by the author over the past few years. This work includes the synthesis of building blocks, bidentate and tridentate 'super donor' ligands that are comprised of H-hpp (where H-hpp = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a] pyrimidine) coupled with various N-heterocycles as well as the synthesis and characterization of the transition metal complexes in self-assembled superstructures. The article also includes the studies of photophysical, electrochemical and density functional theory calculation of the complexes. Thus, the work relies on a combination of synthetic work and optoelectronic studies, and the results are relevant in the greater context of supramolecular chemistry, solar energy harvesting, and its conversion to chemical energy, photovoltaics and inorganic light-emitting device applications.

Effect of sub-lethal concentration of endosulfan on lipid and fatty acid metabolism of spotted murrel, Channa punctatus

The spotted murrel, Channa punctatuswere exposed to sub-lethal concentration of endosulfan (8.1 microg l(-1)) for 12, 24, 48, 72 and 96 hrto elucidate the impact of pesticide on fatty acid composition of liver and muscle. After endosulfan exposure, fish from each control and experimental tanks were randomly sampled anesthetized, sacrificed and then the liver and muscle were dissected out for lipid and fatty acid (FA) profile. Results showed that total lipid, cholesterol, and triglyceride and FA in liver and muscle, and phospholipid in liver were significantly affected due to pesticide exposure. In liver and muscle tissues, 28.09 and 32.57% reduction of the total lipid, and 42.82 and 49.75% reduction in triglyceride and FAwere observed at the end of 96 hrs of exposure. Reduction of total lipid, triglyceride and FA may be due to their mobilization for energy production to combat stress. In FA, oleic (25.46 to 22.48% in liver and 25.75 to 21.87% in muscle) and linoleic acids (8.04 to 6.83% in liver and 9.88 to 8.09%) were reduced in both the tissues at the end of 96 hr of exposure. It may be concluded that exposure of fish to sub-lethal concentration of endosulfan had influenced the lipid and fatty acid metabolism of Channa punctatus.

Blue-green emissive cationic iridium(iii) complexes using partially saturated strongly-donating guanidyl-pyridine/-pyrazine ancillary ligands

A new class of cationic iridium(iii) complexes of the form [(C^∧N)₂Ir(N^∧N)][PF₆] is reported, where C^∧N = cyclometallating 2-phenylpyridinato, ppy, or 2-(2,4-difluorophenyl)-5′-methylpyridinato, dFMeppy, and N^∧N = guanidyl-pyridine, gpy, or -pyrazine, gpz, as the ancillary ligand.

Palladium(II)-directed self-assembly of a neutral molecular triangle as a heteroditopic receptor for ion pairs

A molecular triangle, based on the self-assembly of 4,7-phenanthroline by a neutral palladium complex, has been synthesized and characterized by a combination of techniques: (1)H NMR and UV-vis absorption spectroscopies, mass spectrometry, elemental analysis, and gel permeation chromatography. This new neutral metallocavitand has demonstrated the capacity to host both anionic and cationic guests, thus acting as an open-shaped heteroditopic receptor. Density functional theory calculations have shown that (i) there is no overtension in the assembly of the discrete triangle, which is more stable than open-chain oligomers, (ii) the adducts formed between the triangle and some salts (modeled in the gas phase) are thermodynamically stable, and (iii) two types of cavities coexist in the triangle, which host ions and ion pairs. This easily accessible triangular unit extends further the rational design of model nanoarchitectures in host-guest chemistry with applications in analytical chemistry and multifunctional molecular materials.

Stress mitigating and growth enhancing effect of dietary tryptophan in rohu (Labeo rohita, Hamilton, 1822) fingerlings

An experiment was conducted to study the stress mitigation and growth enhancing role of dietary L-tryptophan (TRP) under thermal stress in rohu, Labeo rohita fingerlings for 45 days. Seven hundred and twenty fishes were distributed in three major groups that are ambient temperature (26 °C), 34 and 38 °C in triplicate following a complete randomized design. Acclimation of fishes to 34 and 38 °C over average ambient temperatures were carried out at 1 °C/day. Each group was fed with a diet supplemented with 0, 0.36, 0.72 or 1.42 % L-TRP. Results showed that blood glucose and serum cortisol level were found to be significantly higher (p < 0.05) in the higher temperature groups than the ambient temperature group. Similarly, aminotransferase, lactate dehydrogenase, malate dehydrogenase, CAT, superoxide dismutase activities were found to be significantly higher (p < 0.05) in the control groups (0 % L-TRP) and decreasing activities of these enzymes were observed with the increasing level of dietary L-TRP. In different temperature groups, L-TRP-supplemented groups were found to have higher (p < 0.05) growth, RGR and PER. The results obtained in the present study indicate that dietary L-TRP mitigates thermal stress and enhances growth. From the present study, we can conclude that dietary supplementation of L-TRP at the 0.72 % level in the diet is found to be optimum to reduce thermal stress even up to 38 °C in rohu, L. rohita. The baseline data obtained here could be useful for the farmers to formulate feeds to culture the fish in different agro-climatic zones.

Stoichiometrically controlled revocable self-assembled "spiro" versus quadruple-stranded "double-decker" type coordination cages

The simple combination of Pd(II) with the tris-monodentate ligand bis(pyridin-3-ylmethyl) pyridine-3,5-dicarboxylate, L, at ratios of 1:2 and 3:4 demonstrated the stoichiometrically controlled exclusive formation of the "spiro-type" Pd1L2 macrocycle, 1, and the quadruple-stranded Pd3L4 cage, 2, respectively. The architecture of 2 is elaborated with two compartments that can accommodate two units of fluoride, chloride, or bromide ions, one in each of the enclosures. However, the entry of iodide is altogether restricted. Complexes 1 and 2 are interconvertible under suitable conditions.

Acclimation of brackish water pearl spot (Etroplus suratensis) to various salinities: relative changes in abundance of branchial Na(+)/K (+)-ATPase and Na (+)/K (+)/2Cl (-) co-transporter in relation to osmoregulatory parameters

The present study was conducted to elucidate the osmoregulatory ability of the fish pearl spot (Etroplus suratensis) to know the scope of this species for aquaculture under various salinities. Juvenile pearl spot were divided into three groups and acclimated to freshwater (FW), brackish water (BW) or seawater (SW) for 15 days. The fish exhibited effective salinity tolerance under osmotic challenges. Although the plasma osmolality and Na(+), K(+) and Cl(-) levels increased with the increasing salinities, the parameters remained within the physiological range. The muscle water contents were constant among FW-, BW- and SW-acclimated fish. Two Na+/K+-ATPase α-isoforms (NKA α) were expressed in gills during acclimation in FW, BW and SW. Abundance of one isoform was up-regulated in response to seawater acclimation, suggesting its role in ion secretion similar to NKA α1b, while expression of another isoform was simultaneously up-regulated in response to both FW and SW acclimation, suggesting the presence of isoforms switching phenomenon during acclimation to different salinities. Nevertheless, NKA enzyme activities in the gills of the SW and FW individuals were higher (p < 0.05) than in BW counterparts. Immunohistochemistry revealed that Na(+)/K(+)-ATPase immunoreactive (NKA-IR) cells were mainly distributed in the interlamellar region of the gill filaments in FW groups and in the apical portion of the filaments in BW and SW groups. The number of NKA-IR cells in the gills of the FW-acclimated fish was almost similar to that of SW individuals, which exceeded that of the BW individuals. The NKA-IR cells of BW and SW were bigger in size than their FW counterparts. Besides, the relative abundance of branchial Na(+)/K(+)/2Cl(-) co-transporter showed stronger evidence in favor of involvement of this protein in hypo-osmoregulation, requiring ion secretion by the chloride cells. To the best of our knowledge, this is the first study reporting the wide salinity tolerance of E. suratensis involving differential activation of ion transporters and thereby suggesting its potential as candidate for fish farming under different external salinities.

A light-harvesting polyoxometalate-polypyridine hybrid induces electron transfer as its Re(I) complex

A derivative of the Dawson polyoxometalate [P2V3W15O62](9-) functionalized with one remote bipyridine coordination site (2) has been synthesized and combined with the neutral {Re(CO)3Br} moiety. The new Re(I)-hybrid (3) was characterized by various analytical techniques. Hybrid 3 exhibits several redox processes on a wide range of potentials with reductions centered on V(V), W(VI) and the organic ligand in order of decreasing potential. Both units, the polyoxometalate and the transition metal complex, retain their intrinsic properties in the hybrid 3, which displays photosensitization in the UV region with tailing into high-energy visible region.

Enhanced stereoselectivity in a di-Ru(ii) complex of an achiral bis-bidentate ligand

The diastereoselective formation of a meso-dinuclear Ru(ii) complex of a novel bis-bidentate ligand is reported along with its electrochemical and photophysical properties.