Harnessing ZnCr2O4/g-C3N4 nanosheet heterojunction for enhanced photocatalytic degradation of rhodamine B and ciprofloxacin.

Utilizing semiconductors for photocatalytic processes in water bodies as an approach to environmental remediation has gained considerable attention. Theoretical band position calculations revealed a type-II step-scheme charge flow mechanism for ZnCr2O4/g-C3N4 (ZCr/gCN), emphasizing effective heterojunction formation due to synergies between the materials. A composite of agglomerated nanoparticle ZnCr2O4 (Zinc chromium oxide - ZCr)/g-C3N4 (graphitic carbon nitride - gCN) nanosheets was synthesized using the ultrasonication and leveraging the heterojunction to enhance degradation efficiency and active sites participation. The synthesized sample was characterized by XRD, XPS, FTIR, BET, HRSEM, EDX, HRTEM, EIS PL, and UV-visible spectroscopy. XRD analysis confirmed the successful formation of pure ZnCr2O4, g-C3N4 (gCN), and their composite without any secondary phases. Optical investigations demonstrated a red shift (444-470 nm) in UV-visible spectra as ZnCr2O4 content increased. Morphological assessment via HRSEM unveiled agglomerated nanoparticle and nanosheet structures. FTIR analysis indicated the presence of gCN with the tri-s-triazine breathing mode at 807 cm-1, and the identification of octahedral Zn-O (598.11 cm-1) and tetrahedral Cr-O (447.01 cm-1) metal bonds within the spinel structure of ZnCr2O4. A Surface area of 134.162 m2/g was noticed with a microporous structure of pore radius 1.484 nm. Notably, the 15% ZCr/gCN composite achieved a remarkable 93.94 % (Rhodamine B-RhB) and 74.36 % (Ciprofloxacin - CIP) within 100 and 120 min, surpassing the performance of pure gCN. Improved degradation was attributed to higher charge separation (photo-excited electrons and holes), reducing charge recombination, as supported by photoluminescence and photoelectrochemical analyses. The presence of active species like superoxide during degradation was confirmed through a scavenger test. The stability analysis confirms the sample's stable nature (without secondary phase formation) after degradation. This work underscores the potential of ZnCr2O4 based metal-free compounds intended for effective environmental remediation.

Influence of heat input on the mechanical characteristics, corrosion and microstructure of ASTM A36 steel welded by GTAW technique.

The Gas Tungsten Arc Welding process weld for the 4 mm thickness of the ASTM A36 steel plate with varied heat input parameters of 0.608 kJ/mm, 0.900 kJ/mm and 1.466 kJ/mm, respectively. The effect of different heat inputs on microstructure, corrosion, and mechanical characteristics of developed weld joints are examined by three zones: heat-affected zone, welded zone, and base metal zone. The optical microscopic results of weld joints illustrate that fine grain structure leads to enhance welding strength. It is revealed that the increased heat input parameter on the weld joint shows a decreased tensile strength and hardness of the weld joint. The corrosion resistance of the weld joint is evaluated by Potentio-dynamic polarization. It facilitates that the corrosion rate of the weld joint is decreased with increasing heat input, which results indicate the best and worst corrosion micrograph of the polygonal ferrite and ferrite plus polygonal ferrite. However, the weld joint prepared with 0.900 kJ/mm heat input found maximum corrosion resistance.

The Role of HMGB1 in Traumatic Brain Injury-Bridging the Gap Between the Laboratory and Clinical Studies.

PURPOSE OF REVIEW: Traumatic brain injury (TBI) is amongst the leading causes of mortality and morbidity worldwide. However, several pharmacological strategies in the clinical setting remain unsuccessful. Mounting evidence implicates High Mobility Group Box protein 1 (HMGB1) as a unique alternative target following brain injury. Herein, we discuss current understanding of HMGB1 in TBI and obstacles to clinical translation. RECENT FINDINGS: HMGB1 plays a pivotal role as a 'master-switch' of neuro-inflammation following injury and in the regulation of neurogenesis during normal development. Animal models point towards the involvement of HMGB1 signalling in prolonged activation of glial cells and widespread neuronal death. Early experimental studies demonstrate positive effects of HMGB1 antagonism on both immunohistochemical and neuro-behavioural parameters following injury. Raised serum/CSF HMGB1 in humans is associated with poor outcomes post-TBI. HMGB1 is a promising therapeutic target post-TBI. However, further studies elucidating receptor, cell, isoform, and temporal effects are required prior to clinical translation.

Crystal structure, spectral investigations, DFT and antimicrobial activity of brucinium benzilate (BBA).

The unreported brucinium benzilate (BBA) crystal and Hirshfeld surface analysis indicated the influence of intramolecular hydrogen bonding network on the crystal structure. Protonation occurs at the tertiary nitrogen as it is the most basic site. The protonated N-H+ proton was observed at 7.08 ppm and the benzilate carbon COO- at 178.41 ppm. Molecular electrostatic potential (MEP) studies showed the electron-rich and electron-deficient sites in the molecule for understanding BBA interaction with an enzyme. Frontier molecular orbital (FMO) studies indicated that BBA molecule is thermodynamically stable and the HOMO-LUMO energy gap was found to be 4.454 eV. The highest interaction has the energy (322.86 kcal/mol) between tertiary ammonium N(LP) and H+. Inhibition tests showed that brucinium benzilate inhibits Bacillus cereus and Salmonella typhimurium bacteria. ADMET properties indicated that BBA has drug characteristics in binding plasma protein.

Endoscope-assisted techniques for evacuation of acute subdural haematoma in the elderly: The lesser of two evils? A scoping review of the literature.

INTRODUCTION: Surgical evacuation of acute subdural haematoma (ASDH) in the elderly remains a point of contention due to the significant associated mortality. Therefore, there is a dire need for alternative treatment options. Endoscope-assisted techniques (EAT) have been increasingly reported over the last decade with variable outcomes. In this scoping review, we identify studies reporting the use of EAT for ASDH evacuation in elderly patients. Outcomes and patient selection criteria are discussed to identify patients that may benefit from EAT. METHODS: A multi-database literature search was performed between January 1990 and January 2021. Studies including patients aged 60 years or above who underwent EAT for ASDH evacuation with reported outcomes were included. RESULTS: A total of 13 studies and 122 patients were eligible for inclusion. Patient age ranged from 65 to 101 years, and average age from 78.6 to 87.4 years. High comorbidity burden, advanced age, absence of adverse imaging features, and pre-operative neurological status were the most common eligibility criteria for EAT. 52% of all procedures were performed under local anaesthetic (LA). Mortality rates ranged between 0% and 40%, whilst favourable outcomes ranged between 26.7% and 96.4%. Re-bleed was the most commonly reported complication, ranging between 0% and 13%. CONCLUSIONS: EAT pose a viable compromise for elderly patients with ASDH that may be unfit for GA. Heterogeneity of patient selection criteria prevents meaningful comparison between EAT and other approaches, and there is a clear impact of patient selection on outcome among studies reporting EAT. Further studies are required to identify the patient cohort that may benefit from this approach.

A Novel Technique of Approach in a Skeletally Immature Case of Chondroblastoma - A Case Report.

INTRODUCTION: Chondroblastoma is a rare benign cartilaginous neoplasm arising in the epiphysis of long bones in young patients. It is an uncommon benign but locally aggressive tumor, mostly located in the secondary centers of ossification. These tumors arise near a joint or growth plate and surgical excision is always challenging. CASE REPORT: A 13-year-old boy presented with intermittent knee pain, swelling, and limitation of movements for 1 year. On examination, magnetic resonance imaging revealed a hyperintense lesion in distal femoral epiphysis with superior transphyseal extension and inferior thinning of cortex with cartilage breach. Histopathological examination confirmed the diagnosis of chondroblastoma of distal femur. We report a novel technique of approach in a case of distal femoral chondroblastoma in a skeletally immature individual. CONCLUSION: The technique we incorporated had an adequate exposure to reach the lesion for a complete curettage and bone grafting. It also reduced further injury to cartilage and physeal plate.

Management of neurotrauma during COVID-19: a single centre experience and lessons for the future.

INTRODUCTION: Traumatic brain injury (TBI) is amongst the leading causes of morbidity and mortality worldwide. The unprecedented emergence of COVID-19 has mandated neurosurgeons to limit viral spread and spare hospital resources whilst trying to adapt management plans for TBI. We aimed to characterize how this affects decision-making on TBI management and drive strategies to cope with future expected waves. METHODS: Retrospective TBI data collection from a single tertiary referral unit was performed between: 01/04/2019 - 30/06/2019 ('Pre-Epidemic') and 01/04/2020 - 30/06/20 ('Epidemic'). Demographics, mechanism of injury, TBI severity, radiological findings, alcohol/anticoagulants/antiplatelets use, and management decisions were extracted. RESULTS: 646 TBI referrals were received in 'Pre-Epidemic' (N = 317) and 'Epidemic' (N = 280) groups. There was reduction in RTA-associated TBI (14.8 vs 9.3%; p = .04) and increase in patients on anticoagulants (14.2 vs 23.6%; p = .003) in the 'Epidemic' group. Despite similarities between other TBI-associated variables, a significantly greater proportion of patients were managed conservatively in local referring units without neurosurgical services (39.1 vs 56.8%; p < .0001), predominantly constituted by mild TBI. CONCLUSION: Despite COVID-19 public health measures, the burden of TBI remains eminent. Increases in local TBI management warrant vigilance from primary healthcare services to meet post-TBI needs in the community.

Disulfide HMGB1 acts via TLR2/4 receptors to reduce the numbers of oligodendrocyte progenitor cells after traumatic injury in vitro.

Traumatic brain injury (TBI) is associated with poor clinical outcomes; autopsy studies of TBI victims demonstrate significant oligodendrocyte progenitor cell (OPC) death post TBI; an observation, which may explain the lack of meaningful repair of injured axons. Whilst high-mobility group box-1 (HMGB1) and its key receptors TLR2/4 are identified as key initiators of neuroinflammation post-TBI, they have been identified as attractive targets for development of novel therapeutic approaches to improve post-TBI clinical outcomes. In this report we establish unequivocal evidence that HMGB1 released in vitro impairs OPC response to mechanical injury; an effect that is pharmacologically reversible. We show that needle scratch injury hyper-acutely induced microglial HMGB1 nucleus-to-cytoplasm translocation and subsequent release into culture medium. Application of injury-conditioned media resulted in significant decreases in OPC number through anti-proliferative effects. This effect was reversed by co-treatment with the TLR2/4 receptor antagonist BoxA. Furthermore, whilst injury conditioned medium drove OPCs towards an activated reactive morphology, this was also abolished after BoxA co-treatment. We conclude that HMGB1, through TLR2/4 dependant mechanisms, may be detrimental to OPC proliferation following injury in vitro, negatively affecting the potential for restoring a mature oligodendrocyte population, and subsequent axonal remyelination. Further study is required to assess how HMGB1-TLR signalling influences OPC maturation and myelination capacity.

(2E)-2-(4-ethoxybenzylidene)-3,4-dihydro-2H-naphthalen-1-one single crystal: Synthesis, growth, crystal structure, spectral characterization, biological evaluation and binding interactions with SARS-CoV-2 main protease.

A new α-Tetralone based chalcone compound, (2E)-2-(4-ethoxybenzylidene)-3,4-dihydro-2H-naphthalen-1-one (EBDN) has been synthesized by Claisen-Schmidt condensation reaction of α-Tetralone (1) with 4-Ethoxybenzaldehyde (2) in basic medium. Then it was allowed to grow through slow evaporation solution growth technique. The molecular structure of grown EBDN has been systematically characterized by SCXRD, FT-IR, 1H NMR and 13C NMR spectroscopic studies. The micro-hardness, thermal (TGA & DTA) and photoluminence studies of the synthesized EBDN were also examined. The EBDN was screened for its anti-inflammatory, antidiabetic and anti-oxidant activity. It has shown admirable anti-inflammatory and antidiabetic activity. Protein-Ligand interactions of EBDN with SARS-CoV-2 main protease (PDB code: 6yb7) also performed.

Neurogenesis after traumatic brain injury - The complex role of HMGB1 and neuroinflammation.

INTRODUCTION: Traumatic brain injury (TBI) is amongst the leading causes of morbidity and mortality worldwide. Despite evidence of neurogenesis post-TBI, survival and integration of newborn neurons remains impaired. High Mobility Group Box protein 1 (HMGB1) is an 'alarmin' released hyper-acutely following TBI and implicated in hosting the neuro-inflammatory response to injury. It is also instrumental in mediating neurogenesis under physiological conditions. Given its dual role in mediating neuro-inflammation and neurogenesis, it serves as a promising putative target for therapeutic modulation. In this review, we discuss neurogenesis post-TBI, neuro-pharmacological aspects of HMGB1, and its potential as a therapeutic target. METHODS: PubMed database was searched with varying combinations of the following search terms: HMGB1, isoforms, neurogenesis, traumatic brain injury, Toll-like receptor (TLR), receptor for advanced glycation end-products (RAGE). RESULTS: Several in vitro and in vivo studies demonstrate evidence of neurogenesis post-injury. The HMGB1-RAGE axis mediates neurogenesis throughout development, whilst interaction with TLR-4 promotes the innate immune response. Studies in the context of injury demonstrate that these receptor effects are not mutually exclusive. Despite recognition of different HMGB1 isoforms based on redox/acetylation status, effects on neurogenesis post-injury remain unexplored. Recent animal in vivo studies examining HMGB1 antagonism post-TBI demonstrate predominantly positive results, but specific effects on neurogenesis and longer-term outcomes remain unclear. CONCLUSION: HMGB1 is a promising therapeutic target but its effects on neurogenesis post-TBI remains unclear. Given the failure of several pharmacological strategies to improve outcomes following TBI, accurate delineation of HMGB1 signalling pathways and effects on post-injury neurogenesis are vital.

Numerical approach to minimize mercury contamination by geometric and parametric optimization.

Due to high vapour pressure at ambient conditions, exposed mercury contributes significant vapour concentration in working atmosphere. Ventilation is a conventional, cheap and very effective method to bring down the concentration of hazardous materials like mercury vapour below permissible limit. In this work a numerical model was developed to obtain intuitive understandings of the spatial distribution of mercury vapors from an exposed surface. The model was validated with experimental data generated using a precinct ventilation system with 8.14% absolute average error. a Validated model was used to study the effect of air flow rate (100-1200 LPM) and impact of architectural design of the containment for fixed exposed mercury surfaceon the final (diluted) mercury concentration. Comparative analysis shows that modification in structural design offers a reduced volume averaged exit mercury concentration and also the reduced peak mercury concentration(Cpeak) in the computational domain. Computational approach outlined in this work can be used to estimate spatial variation of mercury vapor concentration and to locate and quantify regions of high local concentration of mercury in various geometries.

The efficacy of endoscopic third ventriculostomy in children 1 year of age or younger: A systematic review and meta-analysis.

PURPOSE: Hydrocephalus is a major cause of morbidity in the pediatric population, with potentially severe consequences if left untreated. Two viable strategies for management of non-communicating hydrocephalus are endoscopic third ventriculostomy (ETV) and ventriculoperitoneal shunting. However, there is uncertainty over the safety and efficacy of ETV in younger infants aged 1 year or below. In this systematic review, we aim to elucidate the success rate and procedural risks of ETV in this age group. METHODS: A multi-database (PubMed, Embase, Web of Science) literature search between January 1990 and April 2018 was performed in accordance with PRISMA guidelines. Eligible studies were included if they (i) examined non-communicating hydrocephalus; (ii) quantified the success/failure rates of ETV; and (iii) assessed outcomes in children 1 year of age or younger. RESULTS: A total of 19 articles with 399 patients were eligible for inclusion. Mean age at procedure was 4.2 months (range 34 weeks gestation to 12 months), with 116 females and 143 males. Commonest underlying aetiology was congenital aqueductal stenosis (AS) (60.4%). Remaining causes included post-haemorrhagic, post-infection, Chiari malformations, malignancies and others. Overall and AS mean success rates were 51.6% and 56.5% respectively. Overall complication rate was 10.0%, consisting mainly of CSF leak, infection, and haemorrhage. Younger age was significantly associated with poorer ETV success rate when divided into <6 months and 6-12 months of age (44.4 vs 66.7%; p = 0.0007). Underlying pathology had no significant association with ETV outcome when divided into AS and other pathologies (p = 0.53). CONCLUSIONS: Age is significantly associated with ETV success rates. Pathology-dependent effects were not found in this age group. Despite a lower ETV success rate at younger ages (44.4 vs 66.7%), it offers a comparable safety profile that is independent of age. ETV remains a viable treatment option for non-communicating hydrocephalus for infants aged 1 year or younger.

Patient advice regarding participation in sport in children with disorders of cerebrospinal fluid (CSF) circulation: a national survey of British paediatric neurosurgeons.

BACKGROUND: Management of children with disorders of cerebrospinal fluid (CSF) circulation is a common aspect of paediatric neurosurgical practice. Sport and physical activity play an integral role in the lives of patients in this age group. However, there is little evidence to support the dissemination of appropriate advice to children regarding such activities. The aim of this study was to evaluate the perspectives of clinicians across the UK regarding the participation of children with disorders of CSF circulation in sports. METHODS: Questionnaires were distributed to Consultant Paediatric Neurosurgeons practising across the UK via the Society of British Neurological Surgeons (SBNS). Five different patient scenarios were supplied, and participants were asked to choose whether they would advise participation in the following sports: Taekwondo, rugby, skiing, and football. RESULTS: An overall response rate of 66.7% (36 out of 54 paediatric neurosurgeons) was achieved. The following percentages of clinicians advocated football, rugby, Taekwondo, and skiing across all scenarios: 96%, 75%, 77%, and 97%, respectively. The majority of responders (91.2%) relied on personal experience when providing advice, whilst 50% used available literature and 19.4% used available guidelines. CONCLUSIONS: There is a paucity of evidence in the literature to support the dissemination of appropriate advice to children with disorders of CSF circulation regarding participation in sports. Our findings demonstrate that the majority of clinicians rely on personal experience to make such decisions, emphasizing the necessity of larger scale studies to inform evidence-based guidelines.

Demographics, presentation, and clinical outcomes after traumatic bifrontal contusions: a systematic review.

Traumatic bifrontal contusions (TBC) form a recognised clinical entity among patients with traumatic brain injury (TBI). This study aims to systematically review current literature on demographics, management, and predictors of outcomes of patients with TBC. A multi-database literature search (PubMed, Cochrane, OVID Medline/Embase) was performed using PRISMA as a search strategy. Studies were selected by predefined selection criteria (PROSPERO: CRD42018055390), and risk of bias was assessed using an adapted form of ROBINS-I tool. Of the 275 studies yielded by the literature search, seven articles met the criteria for inclusion, all of which were level III evidence. Total cohort consisted of 468 patients; predominantly male (n = 5; 303/417 patients) with average age 44.3 years (range, 7-81). Falls (44.9%) and road traffic accidents (46.6%) were the commonest mechanisms of injury with an average presentation GCS of 9.2 (n = 3, 119 patients). GCS on admission of ≤ 13.1 and contusion volume at day 2 post-injury of ≥ 62.9cm3 were associated with increased risk of deterioration needing surgical interventions (n = 1, 7 patients). The majority of patients underwent surgery; the average GOS was 4, at an average follow-up duration of 11.7 months (n = 6, 356 patients). The currently available evidence on the management of TBC is scarce. Larger multicentre well-designed studies are needed to further delineate the factors behind acute deterioration, the effectiveness of management options. Once in place, this can be used to develop and test an algorithmic approach to management of TBC resulting in consistently improved outcomes.

Subdural haematoma in neonates following forceps-assisted delivery: case series and review of the literature.

PURPOSE: Subdural haematoma (SDH) is a recognised complication of forceps-assisted delivery (FAD). There are no guidelines regarding its management. This study aims to provide a better insight into the management and outcomes of neonatal SDH post-FAD. METHODS: Retrospective review of our neonatal database and systematic review of the literature for neonatal cases that presented with SDH after FAD. Retrospective neurosurgical database search for cases of neonatal SDH post-FAD managed in our unit between January 2007 and January 2017. Systematic review of the literature was performed using PRISMA guidelines. The inclusion criteria are as follows: (1) neonates; (2) forceps-assisted delivery; (3) evidence of SDH on imaging, with or without other traumatic lesions. RESULTS: A literature search yielded nine studies with 30 patients meeting our inclusion criteria. In addition, four cases were identified from our institutional database. Forty-two percent (n = 14) had their SDH managed surgically, with subsequent full neurological recovery in 57%. In comparison, 95% (n = 18) of the conservatively managed patients made a full recovery. Hydrocephalus was present in 1/19 and 11/14 of the conservatively managed and surgically managed patients respectively. CONCLUSIONS: Conservative management can lead to a full neurological recovery in SDH following FAD in neonates. However, a significant minority may still need neurosurgical intervention for the SDH or subsequent hydrocephalus; therefore, we advocate early transfer to a specialist neuroscience centre.

Decontamination of Microorganisms and Pesticides from Fresh Fruits and Vegetables: A Comprehensive Review from Common Household Processes to Modern Techniques.

Fresh fruits and vegetables are a rich source of micronutrients. However, many foodborne illnesses have been linked to the consumption of fresh fruits and vegetables as they are reported to harbor contaminants such as microorganisms and pesticides. Recently reported foodborne outbreaks have been linked to a diverse group of fruits and vegetables due to the presence of various pathogens including Salmonella, Escherichia coli, and Listeria monocytogenes. Also, the increased use of pesticides has resulted in the deposition of chemical residues on the surface of fruits and vegetables, which has led to the adverse health conditions such as cancer, birth defects, and neurodevelopmental disorders. Fresh commodities are subjected to various treatments to prevent or minimize these outbreaks, and the main targets of such treatments have been the elimination of pathogens and degradation of toxic chemical residues. Here, we have discussed various decontamination methods including simple household washing, chemical treatments, and modern technologies with their mode of action for microbial and pesticide removal. The simple household processes are not very effective in the removal of pathogenic organisms and pesticides. The use of modern techniques like cold plasma, ozone, high hydrostatic pressure, and so on, showed better efficacy in the removal of microorganisms and pesticides. However, their industrial use is limited considering high installation and maintenance cost. In this review, we suggest combined methods based on their mode of decontamination and suitability for a selected fruit or vegetable for effective decontamination of microbes and pesticide together to reduce the treatment cost and enhance food safety.

Augmentation of pyrethrins content in callus of Chrysanthemum cinerariaefolium and establishing its insecticidal activity by molecular docking of NavMS Sodium Channel Pore receptor.

Pyrethrins are effective food-grade bio-pesticides obtained from the flowers of Chrysanthemum cinerariaefolium and this crop cannot be cultivated widely in India due to its specific agro-climatic requirement. Hence pyrethrins are mostly imported from Kenya. Therefore, the present study aims to develop a process for augmentation of pyrethrin contents in C. cinerariaefolium callus and establish the correlation between early knockdown effects through docking on grain storage insect. In vitro seedlings were used as explants to induce callus on MS medium with different concentrations of auxins and cytokinins. Pyrethrin extracted from the callus was estimated by RP-HPLC. In callus, total pyrethrin was found to be 17.5 µg/g, which is higher than that found in natural flowers of certain Pyrethrum cultivars. The concentrations of cinerin II, pyrethrin II and jasmoline II were quite high in callus grown on solid medium. Bio-efficacy of pyrethrum extracts of flower and callus on insect Tribolium sp., showed higher repellency and early knock-down effect when compared with pure compound pestanal. Further, the rapid knockdown effect of all pyrethrins components was established by molecular docking studies targeting NavMS Sodium Channel Pore receptor docking followed by multiple ligands simultaneous docking, performed to investigate the concurrent binding of different combinations of pyrethrin. Among the six pyrethrin components, the pyrethrin I and II were found to be a more efficient, binding more firmly to the target, exhibiting higher possibilities of insecticidal effect by an early knockdown mechanism.

Potential of pyrethroid-synergised pyrethrum on stored product insects and implications for use as prophylactic sprays.

The study was conducted to evaluate the synergistic effects of 2% pyrethrum extract with synthetic pyrethroids on the mortality of stored product insects. Contact toxicity was performed at variable concentrations observing mortality at 12, 24 and 48 h durations. The results of the present study indicated that, pyrethrum + deltamethrin combination (25:1 ratio) was effective on the adults of Rhyzopertha dominica (F.) and Tribolium castaneum (Herbst). On the other hand, pyrethrum + cypermethrin combination proved effective against Sitophilus oryzae (L.). The efficacy of the tested combination showed reasonable increase in mortality response in treated insects over increasing exposures. At 48 h, 450 ppm pyrethrum + deltamethrin combination induced 25, 90 and 97% mortalities in S. oryzae, T. castaneum and R. dominica adults; while, pyrethrum-cypermethrin combination recorded 75, 45 and 75% mortalities respectively. On the other hand, it was observed that, among the pyrethrum alone treatments i.e. at 300, 450 and 600 ppm concentrations, maximum mortality (62.5%) was observed in S. oryzae exposed to 600 ppm pyrethrum for 48 h. The effective LC50 concentrations for pyrethrum (600 ppm) + deltamethrin combination was estimated to be as 0.1987 and 0.7039 µl/cm2 for R. dominica and T. castaneum adults respectively. Contrastingly, for treatments with S. oryzae, a LC50 value of 0.8673 µl/cm2 was recorded for pyrethrum (600 ppm) + cypermethrin mixture. This investigation strengthens the fact that pyrethrum along with pyrethroids is effective against storage insect pests which can be promisingly a safer insecticidal combination.

Phytochemical residue profiles in rice grains fumigated with essential oils for the control of rice weevil.

In the present study, we investigated the fumigant potential of five edible essential oils (EOs) against Sitophilus oryzae and their phytochemical residues in treated grains. Among the tested EOs, peppermint oil proved significantly effective (P ≤ 0.05) on S.oryzae at 400 µl/L air concentration, inducing 83 and 100% mortalities in with-food and without-food conditions respectively over 72 h exposure. In addition, it was also observed that the binary mixtures of peppermint + lemon oil (1:1 ratio) produced an equivalent effect to that of peppermint oil alone treatments. The phytochemical residue analysis by GC-MS revealed the presence of six compounds upon 72 h exposure to EOs. Further, the analysis of physico-chemical properties of the compounds indicated a positive correlation between polar surface area (PSA) and its residual nature. The residue levels of eugenol were significantly elevated corresponding to its high PSA value (29) in clove and cinnamon oils. On the other hand, the compounds with zero PSA value imparted very less or no (D-Limonene, caryophyllene, pinene and terpinolene) residues in treated grains. With respect to the most active peppermint oil, L-menthone, menthyl acetate and eucalyptol residues were at 67, 41 and 23% levels respectively. The outcome of the present study indicate the peppermint oil as a potent fumigant against S. oryzae, and although the residues of phytochemicals in treated grains is higher; they belong to the generally recognised as safe (GRAS) status leaving no harmful effect.

Toxicity of phosphine on the developmental stages of rust-red flour beetle, Tribolium castaneum Herbst over a range of concentrations and exposures.

The susceptibility of the developmental stages of rust-red flour beetle, Tribolium castaneum to a range of concentrations of phosphine over varying durations from 24 to 168 h was reconnoitered in the laboratory at 25 ± 2 °C. Responses of the life stages exposed to phosphine were compared with those of un-treated controls over 24, 48, 72, 96, 120, 144 and 168 h exposures and mortality was assessed after 14 days. Among the life stages tested, pupae were more tolerant to phosphine followed by the egg and the larval instars. At 24 h, the maximum LC50 value was observed in case of egg; 1.571 mgL(-1); followed by the pupae, 6(th) instar, 4(th) instar and 2(nd) instar larvae with LC50 values of 1.184, 0.336, 0.212 and 0.081 mgL(-1) respectively. However, continued exposure of the developmental stages to phosphine, recorded maximum LC values in the pupae followed by egg and the larval instars. A linear increase in the mortality response was witnessed in all the insect stages when the exposure periods were extended from 24 to 168 h with increasing concentrations of phosphine, conversely significant increase in mortality was greatly apparent during the initial treatment periods.