Dim-light colour vision in the facultatively nocturnal Asian giant honeybee, Apis dorsata

We discovered nocturnal colour vision in the Asian giant honeybee Apis dorsata-a facultatively nocturnal species-at mesopic light intensities, down to half-moon light levels (approx. 10-2 cd m-2). The visual threshold of nocturnality aligns with their reported nocturnal activity down to the same light levels. Nocturnal colour vision in A. dorsata is interesting because, despite being primarily diurnal, its colour vision capabilities extend into dim light, while the 'model' European honeybee Apis mellifera is reported to be colour-blind at twilight. By employing behavioural experiments with naturally nesting A. dorsata colonies, we show discrimination of the trained colour from other stimuli during the day, and significantly, even at night. Nocturnal colour vision in bees has so far only been reported in the obligately nocturnal carpenter bee Xylocopa tranquebarica. The discovery of colour vision in these two bee species, despite differences in the extent of their nocturnality and the limitations of their apposition compound eye optics, opens avenues for future studies on visual adaptations for dim-light colour vision, their role in pollination of flowers at night, and the effect of light pollution on nocturnal activity in A. dorsata, a ubiquitous pollinator in natural, agricultural and urban habitats in the Asian tropics and sub-tropics.

Clinical outcome of anterior cruciate ligament reconstruction with modified transtibial and anteromedial portal

Arthroscopic ACL reconstruction is the current standard care of treatment for anterior cruciate ligament (ACL) injuries. Modified transtibial (mTT) and anteromedial portal (AMP) techniques aim at the anatomical placement of femoral tunnel. Controversy existed in the literature with regard to the outcome of these techniques. Hence, we designed a retrospective comparative study to analyse the clinical and functional outcomes of mTT and AMP techniques. We hypothesized that there would be no difference between the clinical and functional outcomes in mTT and AMP techniques. This retrospective observational study was conducted in consecutive patients who underwent arthroscopic ACL reconstruction using semitendinosus-gracilis (STG) quadrupled graft in our tertiary care centre with a minimum follow-up of two years. Out of 69 patients, 37 had undergone ACL reconstruction by mTT technique and remaining by AMP technique. All the patients were assessed clinically by anterior drawer, Lachman's, pivot shift and single-legged hop test. Lysholm Knee Scoring Scale and International Knee Documentation Committee (IKDC) subjective knee evaluation score were used for the functional status. Knee instability was assessed objectively by KT-1000 arthrometer. There was no statistically significant difference in baseline demographic characteristics between mTT and AMP groups. At the end of 2 years, no statistically significant difference was noted in the anterior drawer and Lachman's test. Though not significant, IKDC scores and Lysholm's scores showed a better outcome in the AMP group when compared to the mTT group. AMP group showed significantly better outcome with KT-1000 arthrometer. Based on the results obtained, we presume that overall both mTT and AMP have similar functional outcome. However, as AMP technique offers significantly improved subjective rotational stability on pivot shift test, better hop limb symmetry index and KT 1000 readings compared to mTT, we suggest AMP over mTT.

Bifocal Stabilisation of Acute Acromioclavicular Joint Dislocation using Suture Anchor and Temporary K-Wires: A Retrospective Analysis

Introduction

The acromioclavicular joint (ACJ) is a major link connecting the upper limb to the torso. The acromioclavicular and coracoclavicular (CC) ligaments help in stabilising the joint. We feel it is prudent to address both these ligament injuries, to achieve optimum result. This study was undertaken to analyse the results of a simple frugal surgical technique we used to deal with this injury considering stabilisation for both these ligaments.

Materials and methods

In this retrospective study, skeletally mature patients with Type III, IV or V ACJ dislocations who underwent open reduction and stabilisation of the joint with temporary K-wires, repair of the capsule and augmentation of CC ligaments with suture anchors were included. Clinico-radiological and functional outcome was evaluated. Functional assessment of the upper limb was analysed using the Disabilities of Arm, Shoulder, and Hand Score (DASH), Constant shoulder score (CSS) and Oxford shoulder score (OSS).

Results

Clinical and radiological evaluation of the 32 patients who had completed two years from the index surgery, was done. Out of the 37 patients included initially, five were lost in follow-up. Majority of the subjects included were males and type V was the most common injury. Mean pre-operative CC distance on the affected side was 13.92±4.94mm. In the immediate post-operative radiograph, it was 7.63±2.08mm and in the final follow- up was 9.36±2.75mm. Measurements were taken by two independent investigators and inter, and intra-observer reliability were analysed by Interclass correlation coefficient. Excellent functional outcome was noted despite the 1.81±1.50mm average loss of correction. At final follow-up, mean DASH score was 4.67±4.18, Oxford shoulder score was 44.06±2.44 and Constant shoulder score was 86.37±5.81. The severity of the injury had no significant effect on the functional outcome post our method of stabilisation and rehabilitation.

Conclusion

Bifocal fixation restores the multidirectional stability of the disrupted ACJ. Adequate radiological reduction, good functional outcome and simplicity of execution make this technique an undemanding one for use in regular practice.

Defensive shimmering responses in Apis dorsata are triggered by dark stimuli moving against a bright background

Giant honeybees, including the open-nesting Asian giant honeybee Apis dorsata, display a spectacular collective defence behaviour - known as "shimmering" - against predators, which is characterised by travelling waves generated by individual bees flipping their abdomens in a coordinated and sequential manner across the bee curtain. We examined if shimmering is visually-mediated by presenting moving stimuli of varying sizes and contrasts to the background (dark or light) in bright and dim ambient light conditions. Shimmering was strongest under bright ambient light, and its strength declined under dim-light in this facultatively nocturnal bee. A. dorsata shimmered only when presented with the darkest stimulus against a light background, but not when this condition was reversed (light stimulus against dark background). This response did not attenuate with repeated exposure to the stimuli, suggesting that shimmering behaviour does not undergo habituation. We suggest that this is an effective anti-predatory strategy in open-nesting A. dorsata colonies which are exposed to high ambient light, as flying predators are more easily detected when they appear as dark moving objects against a bright sky. Moreover, the stimulus detection threshold (smallest visual angular size) is much smaller in this anti-predatory context (1.6o - 3.4o) than in the context of foraging (5.7o), indicating that ecological context affects visual detection threshold.

Experimental investigation and mechanism analysis: Effect of concentration and temperature on the heat transfer characteristics of novel MWCNT-mustard oil nanofluid

ABSTRACT. The bio-oils as alternative lubricating fluid are potential solution for the automotive and industrial mechanical systems. The development of novel renewable and non-toxic bio-oils with better heat transfer distinctiveness will strengthen the economy of farmers in the agricultural based countries. The most innovative approach to improve the heat transfer characteristics of bio-oils is converting it into nanofluids by dispersing nanomaterials which has extremely high heat transfer characteristics. In this study, MWCNT-Mustard oil nanofluids were formulated through ultrasonication and their dispersion stability was estimated through Zeta-potential technique.  The thermal stability of the MWCNT-Mustard oil nanofluids are estimated through thermogravimetric analysis and concentration and temperature dependent density, thermal conductivity and specific heat capacity of MWCNT-Mustard oil nanofluids are also determined and their characteristics are discussed. The heat transfer characteristics of MWCNT-Mustard oil nanofluids observed through the heat pipe test rig at different inlet temperatures, mass flow rate of nanofluids and Reynolds number. The results exhibits that the dispersion of MWCNT enhances the heat transfer characteristics of MWCNT-Mustard oil nanofluids.   KEY WORDS: Non-toxic bio-oils, Nanomaterials, Nanofluids, Thermogravimetric analysis, MWCNT, Mustard oil Bull. Chem. Soc. Ethiop. 2022, 36(3), 675-686.                                                                DOI: https://dx.doi.org/10.4314/bcse.v36i3.16

TB case fatality and recurrence in a private sector cohort in Mumbai, India

BACKGROUND: Half of India´s three million TB patients are treated in the largely unregulated private sector, where quality of care is often poor. Private provider interface agencies (PPIAs) seek to improve private sector quality of care, which can be measured in terms of case fatality and recurrence rates.METHODS: We conducted a retrospective cohort survey of 4,000 private sector patients managed by the PATH PPIA between 2014 and 2017. We estimated treatment and post-treatment case-fatality ratios (CFRs) and recurrence rates. We used Cox proportional hazards models to identify predictors of fatality and recurrence. Patient loss to follow-up was adjusted for using selection weighting.RESULTS: The treatment CFR was 7.1% (95% CI 6.0-8.2). At 24 months post-treatment, the CFR was 2.4% (95% CI 1.7-3.0) and the recurrence rate was 1.9% (95% CI 1.3-2.5). Treatment fatality was associated with age (HR 1.02, 95% CI 1.02-1.03), clinical diagnosis (HR 0.61, 95% CI 0.45-0.84), treatment duration (HR 0.09, 95% CI 0.06-0.10) and adherence. Post-treatment fatality was associated with treatment duration (HR 0.87, 95% CI 0.79-0.91) and adherence.CONCLUSIONS: We found a moderate treatment phase CFR among PPIA-managed private sector patient with low rates of post-treatment fatality and recurrence. Routine monitoring of patient outcomes after treatment would strengthen PPIAs and inform future post TB interventions.

Drying characteristics of mint leaves (Mentha arvensis) dried in a solid desiccant dehumidifier system

In this present study, solid desiccant-based pressure-swing adsorption (PSA) dehumidifier was developed and the process parameters were optimized to deliver the air continuously at 0.1% relative humidity. Mint (Mentha arvensis) leaves are tested to study the drying characteristics at varied flow rates of dehumidified air in the drying chamber. The initial moisture content of 5.059 g water/g dry matter have been reduced to a safe storage level in 360 min at 0.160 m³/min volume low rate. The effective moisture diffusivity of the mint leaves was found in the range of 2.07534 × 10^-11m²/s to 3.45817 × 10^-11m²/s. The percentage of retention of ascorbic acid in dried mint leaves is increased by an increase in the volume flow rate of dry air and a maximum of 70.11% is achieved by 0.160 m³/min. The colour measurement and chlorophyll content of the dried samples indicated that the desiccant dehumidified air dryers are suitable for heat sensitive green leafy vegetables.

0124 A Prefrontal-Amygdala Network Model of the Cellular and Circuit-Level Mechanisms of Emotional Memory Consolidation During the Awake State and REM Sleep

Introduction

Rapid eye movement (REM) sleep has been implicated in the consolidation of emotional memories. Our recent work found a candidate system for REM-related memory consolidation. We showed that during REM sleep, the frontal cortices are dominated by theta (4–8 Hz) oscillations and bursts of beta (15–35 Hz) activity. Studies suggest that rhythmic interactions between the frontal cortices and limbic structures, in particular the amygdala, play a critical role in the consolidation of emotional memories. However, the mechanisms responsible for memory consolidation during these rhythmic interactions during REM sleep remain unknown.

Methods

We used biophysically based neural models to build a large-scale network model of the prefrontal cortex (PFC) and amygdala (AMY) and incorporated synaptic plasticity mechanisms, such as spike-timing dependent plasticity (STDP), into the connections between these two regions. Norepinephrine (NE) and serotonin (SE) levels were manipulated to mimic the different physiological conditions during the awake state and REM sleep.

Results

We were able to reproduce the oscillatory dynamics observed in experimental studies and identify cell-type specific synaptic changes caused by STDP. During the awake state, PFC connections to all cell types of the AMY become strengthened when PFC neurons provide theta frequency inputs, with the connections strengthening to a greater extent when inputs are in burst mode rather than single spike mode. When the PFC provides beta inputs, we see the exact opposite relationship: synaptic strengths become weaker when inputs are in burst mode rather than single spike mode. During REM sleep conditions, the connections to all principal cell types of the AMY become strengthened, with synaptic connections to some subtypes of pyramidal cells becoming stronger than others. Surprisingly, however, the synaptic connections to the interneurons become weaker in response to theta frequency inputs.

Conclusion

Using our large-scale network model, we show how the levels of the neurotransmitters NE and SE during the awake state and REM sleep affect oscillatory dynamics and in turn influence the strengthening or weakening of connections related to emotional memories.

Support

United States Army Research Office, Award number ARO W91lNF-17-1-0300

Haploinsufficiency of X-linked intellectual disability gene CASK induces post-transcriptional changes in synaptic and cellular metabolic pathways

Heterozygous mutations in the X-linked gene CASK are associated with intellectual disability, microcephaly, pontocerebellar hypoplasia, optic nerve hypoplasia and partially penetrant seizures in girls. The Cask^+/- heterozygous knockout female mouse phenocopies the human disorder and exhibits postnatal microencephaly, cerebellar hypoplasia and optic nerve hypoplasia. It is not known if Cask^+/- mice also display seizures, nor is known the molecular mechanism by which CASK haploinsufficiency produces the numerous documented phenotypes. 24-h video electroencephalography demonstrates that despite sporadic seizure activity, the overall electrographic patterns remain unaltered in Cask^+/- mice. Additionally, seizure threshold to the commonly used kindling agent, pentylenetetrazol, remains unaltered in Cask^+/- mice, indicating that even in mice the seizure phenotype is only partially penetrant and may have an indirect mechanism. RNA sequencing experiments on Cask^+/- mouse brain uncovers a very limited number of changes, with most differences arising in the transcripts of extracellular matrix proteins and the transcripts of a group of nuclear proteins. In contrast to limited changes at the transcript level, quantitative whole-brain proteomics using iTRAQ quantitative mass-spectrometry reveals major changes in synaptic, metabolic/mitochondrial, cytoskeletal, and protein metabolic pathways. Unbiased protein-protein interaction mapping using affinity chromatography demonstrates that CASK may form complexes with proteins belonging to the same functional groups in which altered protein levels are observed. We discuss the mechanism of the observed changes in the context of known molecular function/s of CASK. Overall, our data indicate that the phenotypic spectrum of female Cask^+/- mice includes sporadic seizures and thus closely parallels that of CASK haploinsufficient girls; the Cask^+/- mouse is thus a face-validated model for CASK-related pathologies. We therefore surmise that CASK haploinsufficiency is likely to affect brain structure and function due to dysregulation of several cellular pathways including synaptic signaling and cellular metabolism.

Survival of Extremotolerant Bacteria from the Mukundpura Meteorite Impact Crater

Carbonaceous meteorites provide clues with regard to prebiotic chemistry and the origin of life. Geological Survey of India recorded a carbonaceous chondrite meteorite fall in Mukundpura, India, on June 6, 2017. We conducted a study to investigate the microbial community that survived the meteorite impact. 16S rRNA metagenomic sequencing indicates the presence of Actinobacteria, Proteobacteria, and Acidobacteria in meteorite impact soil. Comparative phylogenetic analysis revealed an intriguing abundance of class Bacilli in the impact soil. Bacillus thermocopriae IR-1, a moderately thermotolerant organism, was isolated from a rock, impacted by the Mukundpura meteorite. We investigated the resilience of B. thermocopriae IR-1 to environmental stresses and impact shock in a Reddy shock tube. Bacillus thermocopriae IR-1 survived (28.82% survival) the effect of shock waves at a peak shock pressure of 300 kPa, temperature 400 K, and Mach number of 1.47. This investigation presents the first report on the effect of impact shock on B. thermocopriae IR-1. The study is also the first report on studying the microbial diversity and isolation of bacteria from impact crater soil immediately after meteorite impact event.

Revision cartilage cell transplantation for failed autologous chondrocyte transplantation in chronic osteochondral defects of the knee

The management of failed autologous chondrocyte implantation (ACI) and matrix-assisted autologous chondrocyte implantation (MACI) for the treatment of symptomatic osteochondral defects in the knee represents a major challenge. Patients are young, active and usually unsuitable for prosthetic replacement. This study reports the results in patients who underwent revision cartilage transplantation of their original ACI/MACI graft for clinical or graft-related failure. We assessed 22 patients (12 men and 10 women) with a mean age of 37.4 years (18 to 48) at a mean of 5.4 years (1.3 to 10.9). The mean period between primary and revision grafting was 46.1 months (7 to 89). The mean defect size was 446.6 mm(2) (150 to 875) and they were located on 11 medial and two lateral femoral condyles, eight patellae and one trochlea. The mean modified Cincinnati knee score improved from 40.5 (16 to 77) pre-operatively to 64.9 (8 to 94) at their most recent review (p < 0.001). The visual analogue pain score improved from 6.1 (3 to 9) to 4.7 (0 to 10) (p = 0.042). A total of 14 patients (63%) reported an 'excellent' (n = 6) or 'good' (n = 8) clinical outcome, 5 'fair' and one 'poor' outcome. Two patients underwent patellofemoral joint replacement. This study demonstrates that revision cartilage transplantation after primary ACI and MACI can yield acceptable functional results and continue to preserve the joint.

Autologous chondrocyte implantation for osteochondral lesions in the knee using a bilayer collagen membrane and bone graft: a two- to eight-year follow-up study

Matrix-induced autologous chondrocyte implantation (MACI) is an established technique used to treat osteochondral lesions in the knee. For larger osteochondral lesions (> 5 cm(2)) deeper than approximately 8 mm we have combined the use of two MACI membranes with impaction grafting of the subchondral bone. We report our results of 14 patients who underwent the 'bilayer collagen membrane' technique (BCMT) with a mean follow-up of 5.2 years (2 to 8). There were 12 men and two women with a mean age of 23.6 years (16 to 40). The mean size of the defect was 7.2 cm(2) (5.2 to 12 cm(2)) and were located on the medial (ten) or lateral (four) femoral condyles. The mean modified Cincinnati knee score improved from 45.1 (22 to 70) pre-operatively to 82.8 (34 to 98) at the most recent review (p < 0.05). The visual analogue pain score improved from 7.3 (4 to 10) to 1.7 (0 to 6) (p < 0.05). Twelve patients were considered to have a good or excellent clinical outcome. One graft failed at six years. The BCMT resulted in excellent functional results and durable repair of large and deep osteochondral lesions without a high incidence of graft-related complications.

Minimum ten-year results of a prospective randomised study of autologous chondrocyte implantation versus mosaicplasty for symptomatic articular cartilage lesions of the knee

Autologous chondrocyte implantation (ACI) and mosaicplasty are methods of treating symptomatic articular cartilage defects in the knee. This study represents the first long-term randomised comparison of the two techniques in 100 patients at a minimum follow-up of ten years. The mean age of the patients at the time of surgery was 31.3 years (16 to 49); the mean duration of symptoms pre-operatively was 7.2 years (9 months to 20 years). The lesions were large with the mean size for the ACI group being 440.9 mm(2) (100 to 1050) and the mosaicplasty group being 399.6 mm(2) (100 to 2000). Patients had a mean of 1.5 previous operations (0 to 4) to the articular cartilage defect. Patients were assessed using the modified Cincinnati knee score and the Stanmore-Bentley Functional Rating system. The number of patients whose repair had failed at ten years was ten of 58 (17%) in the ACI group and 23 of 42 (55%) in the mosaicplasty group (p < 0.001). The functional outcome of those patients with a surviving graft was significantly better in patients who underwent ACI compared with mosaicplasty (p = 0.02).

Enhanced antifungal and insect α-amylase inhibitory activities of Alpha-TvD1, a peptide variant of Tephrosia villosa defensin (TvD1) generated through in vitro mutagenesis

TvD1 is a small, cationic, and highly stable defensin from the weedy legume, Tephrosia villosa with demonstrated in vitro antifungal activity. We show here peptide modifications in TvD1 that lead to enhanced antifungal activities. Three peptide variants, S32R, D37R, and Alpha-TvD1 (-G-M-T-R-T-) with variations in and around the β2-β3 loop region that imposes the two β-strands, β2 and β3 were generated through in vitro mutagenesis. Alpha-TvD1 exhibited enhanced antifungal activity against the fungal pathogens, Fusarium culmorum and Fusarium oxysporum with respective IC(50) values of 2.5 μM and 3.0 μM, when compared to S32R (<5.0 μM and >5.0 μM), D37R (5.5 μM and 4.5 μM), and the wild type TvD1 (6.5 μM). Because of the enhanced antifungal activity, this variant peptide was characterized further. Growth of F. culmorum in the presence of Alpha-TvD1 showed deformities in hyphal walls and nuclear damage. With respect to the plant pathogenic bacterium, Pseudomonas syringae pv. tomato strain DC3000, both Alpha-TvD1 and the wild type TvD1 showed comparable antibacterial activity. Both wild type TvD1 and Alpha-TvD1 displayed inhibitory activity against the α-amylase of the mealworm beetle, Tenebrio molitor (TMA) with the latter showing enhanced activity. The human salivary as well as barley α-amylase activities were not inhibited even at concentrations of up to 50 μM, which has been predicted to be due to differences in the pocket size and the size of the interacting loops. Present study shows that the variant Alpha-TvD1 exhibits enhanced antifungal as well as insect α-amylase inhibitory activity.

Multimodality imaging of exuberant mitral annular calcification in a patient presenting with transient ischaemic attack

We report an unusual case of calcification of mitral valve annulus imaged with multiple non-invasive modalities in a patient who suffered a transient ischaemic attack, probably from thrombus overlying the mitral annular calcification. Both this mode of presentation and the imaging features of the annular calcification were relatively unusual, and the images obtained are remarkably clear and diagnostic.