Comparative evaluation of antifungal activity of Sodium Hypochlorite, Calcium Hypochlorite and modified Salt Solution associated with passive ultrasonic irrigation against Candida albicans - An In-Vitro study

Aim

The study evaluated the antifungal activity of sodium hypochlorite (NaOCl), calcium hypochlorite (Ca(OCl)2), and modified salt solution (MSS) assisted with passive ultrasonic irrigation against Candida albicans.

Materials and Methods

One hundred and thirty-six single-rooted premolars were decoronated and enlarged up to a file #45, autoclaved, inoculated with C. albicans, and incubated for 72 h. The samples were randomly distributed into eight groups (n = 17) according to the protocol for decontamination G1: No treatment, G2: Distilled water (DW), G3: 2.5% NaOCl, G4: 2.5% NaOCl + ultrasonic activation (US), G5: 2.5% Ca(OCl)2, G6: 2.5% Ca(OCl)2 + US, G7: MSS, G8: MSS + US. Microbiological testing (Colony forming Unit [CFU] counting) was performed before and after the treatment.

Statistical Analysis

Data were subjected to the one-way analysis of variance followed by the Tukey's post hoc test (P < 0.05).

Results and Conclusion

Groups 1 and 2 showed the highest mean contamination (5.41 and 4.31 log10 CFU/mL, respectively), which was statistically different from all the other groups (P < 0.001). G4 showed the lowest mean contamination (0.24 log10 CFU/mL) with statistically significant value (P < 0.001). 2.5% NaOCl with ultrasonic activation can aid in significant fungal reduction. Ultrasonic activation of 2.5% NaOCl, 2.5% Ca(OCl)2, and MSS was also found to have improved antifungal activity against C. albicans.

Quantum-noise-limited microwave amplification using a graphene Josephson junction

Josephson junctions (JJs) and their tunable properties, including their nonlinearities, play an important role in superconducting qubits and amplifiers. JJs together with the circuit quantum electrodynamics architecture form many key components of quantum information processing¹. In quantum circuits, low-noise amplification of feeble microwave signals is essential, and Josephson parametric amplifiers (JPAs)² are the widely used devices. The existing JPAs are based on Al-AlO_x-Al tunnel junctions realized in a superconducting quantum interference device geometry, where magnetic flux is the knob for tuning the frequency. Recent experimental realizations of two-dimensional (2D) van der Waals JJs^3-5 provide an opportunity to implement various circuit quantum electrodynamics devices^6-8 with the added advantage of tuning the junction properties and the operating point using a gate potential. While other components of a possible 2D van der Waals circuit quantum electrodynamics architecture have been demonstrated, a quantum-noise-limited amplifier, an essential component, has not been realized, to the best of our knowledge. Here we implement a quantum-noise-limited JPA using a graphene JJ, that has a linear resonance gate tunability of 3.5 GHz. We report 24 dB amplification with 10 MHz bandwidth and -130 dBm saturation power, a performance on par with the best single-junction JPAs^2,9. Importantly, our gate-tunable JPA works in the quantum-limited noise regime, which makes it an attractive option for highly sensitive signal processing. Our work has implications for novel bolometers; the low heat capacity of graphene together with JJ nonlinearity can result in an extremely sensitive microwave bolometer embedded inside a quantum-noise-limited amplifier. In general, this work will open up the exploration of scalable device architectures of 2D van der Waals materials by integrating a sensor with the quantum amplifier.

Apical microleakage in root canals with separated rotary instruments obturated with different endodontic sealers

Aim

The aim of this study was to evaluate apical microleakage in root canals containing broken rotary instruments obturated with cold lateral condensation and thermoplasticized injectable gutta-percha, with different sealers, using glucose penetration leakage study.

Materials and Methods

In this in vitro study, 96 extracted human mandibular premolars were decoronated, and the roots were randomly divided into eight groups (n = 12). Root canals were instrumented with #30 4% taper rotary files. The files were scratched 3 mm from the tip by a high-speed handpiece, and they were intentionally broken in the apical third of the canals. The middle and coronal sections of the canals were obturated by cold lateral condensation and thermoplasticized technique, using ZOE, resin, CaOH, and bioceramic sealers. Apical microleakage was measured using the glucose penetration method.

Statistical Analysis

Independent Student's t-test and one-way ANOVA followed by Tukey's post hoc analysis were used for statistical analysis.

Results

Bioceramic sealer group showed the least apical microleakage and this was then followed by the resin and CaOH groups demonstrating lesser apical microleakage and the highest microleakage was with the ZOE group. Mean apical microleakage scores between lateral and thermoplastic condensation techniques in each group were statistically significant (P < 0.001).

Conclusion

Bioceramic sealer demonstrated the least apical leakage, whereas ZOE seal displayed the highest apical leakage.

A Brief Study on Trichomonas Vaginalis

In today's modern world women face too many challenges in front of them and in an country like India. There is still old system in which women can’t work. They are kept at home and indulged in household activities and their dreams don’t matter. they are not aware of the changes in their own body due to complete negligence or illiteracy. India is still one of the most illiterate countries in the world and its economy is still very low and beyond advancement.  India is a developing country and nowadays people are starting to get aware about problems of women. Now in today's society women are allowed to work and they are not kept at their household but are given an opportunity as equals. But still there are many places in India which are not aware about problems faced by women and they don’t know how to help them and we have to provide them education about their own healthy bodily practices. Women in the modern and ancient world were affected by many such diseases which causes harm not only to them but also to their young ones if untreated. In the modern culture, now a days a new trend of having multiple sexual partners have become common and therefore, due to unsafe and unprotected sex practices and poor awareness, a lot of diseases has been transmitted worldwide to both genders. Trichomoniasis vaginalis is one of the most common sexually transmitted disease in women caused by a parasite which transmitted during unsafe and unprotected during sexual practices.

Assessing suitability of commercial fibre reinforced plastic solar still for sustainable potable water production in rural India through detailed energy-exergy-economic analyses and environmental impacts

Fibre reinforced plastic (FRP) basin solar still is manufactured and marketed commercially in developing/underdeveloped nations. Unfortunately, these commercial units have not been widely adopted by the public due to its low water productivity. In the present investigation, an effort has been made to assess the performance and enviro-economic aspects of the commercial unit and its low-cost improved versions under Coimbatore climatic conditions through real-time experiments and mathematical models, respectively. The commercial unit has distillate productivity of about 2.76 L/d under cumulative solar radiation intensity of 24.37 MJ/m²d and it increased up to 6.03 L/d with the addition of black dye and thermocol insulation. Yearly average distillate production rate, thermal efficiency, and exergy efficiency of the improved version is about 4.36 L/d, 53.62%, and 6.89%, respectively. The greenhouse payback time of the commercial unit and insulated commercial unit with black dye is about 2.39 and 1.81 Years, respectively. Global warming potential, acidification potential and photochemical oxidant formation potential of the commercial unit decreased from 0.27 to 0.12 kg of carbon di-oxide eq/L of distillate, 2.40 to 1.05 g of sulphur di-oxide eq/L of distillate and 0.73 to 0.32 g of ethylene eq/L of distillate, respectively with the incorporation of low-cost improvement techniques. The sustainability index of the improved version is around 5.94% higher than the sustainability index of the commercial unit. The distillate production cost of improved version (1.32 INR/L) is closer to reverse osmosis (RO) water supplied to Indian houses (1.00 INR/L). The incorporation of low-cost improved techniques to the commercial unit makes it an attractive option for sustainable potable water production. However, proper marketing and awareness strategies must be adopted by stakeholders to make this improved version acceptable among the public.

Fight Against COVID-19: ARCI's Technologies for Disinfection

COVID-19 (SARS-CoV-2) is causing a huge concern to the global population due to its highly contagious properties. The SARS-CoV-2 is a new variant in the coronavirus family. The world is focussing on several methods to battle against this novel corona virus, including control of its spread. In this context, ARCI has quickly made efforts to develop disinfection systems including a UVC-based disinfection trolley, honeycomb air heater and a fogging chamber using UVC germicidal lamps, dry heat sterilization and HOCl-based chemical disinfectant to provide rapid and effective inactivation of microorganisms causing the pandemic. These systems have been successfully deployed at different hospitals for their validation.

Preparation and characterization of hybrid chitosan-silver nanoparticles (Chi-Ag NPs); A potential antibacterial agent

In this study, a novel ecofriendly chitosan- silver nanoparticles hybrid was developed. Biological method using leaf extract of T. portulacifolium was used as reducing agent for its synthesis and the antibacterial efficiency of these hybrid nanoparticles were evaluated against the bacteria E. coli and S. marcescens organisms. The intense peak observed around 419 nm in the UV-Vis indicates the formation of silver nanoparticles. The XRD analysis showed that the hybrid chitosan-silver nanoparticles have a polycrystalline and face-centered cubic configuration. FTIR spectrum hybrid chitosan-silver nanoparticles indicated speaks vibration of NH and OH. The EDS analysis confirmed the presence of Ag, O, C and N elements in the prepared sample. The spherical shape was obtained from TEM analysis and it indicated that with average particles around 3.24 nm to 44.80 nm. The prepared hybrid chitosan-silver nanoparticles showed significant antibacterial activities against E. coli and S. marcescens. In addition, the surface membrane damages and surface morphology of test pathogens were visualized using FESEM analysis.

An in vivo comparative evaluation of antimicrobial efficacy of chitosan, chlorhexidine gluconate gel and their combination as an intracanal medicament against Enterococcus faecalis in failed endodontic cases using real time polymerase chain reaction (qPCR)

Aim

To evaluate the in vivo antibacterial efficacy of 2% chlorhexidine gel (CHX), 2% chitosan (CS) gel and their combination as an intracanal medicament against Enterococcus faecalis during endodontic retreatment procedure, with the use of qPCR.

Method

A total of 45 single rooted permanent teeth were selected from 28 systemically healthy patients (mean age of 43 years). After complete disinfection and access opening as well as gutta-percha (GP) removal, the first microbiological pretreatment sample (S1) was collected. After completion of instrumentation, a post-instrumentation sample (S2) was taken and the teeth were randomly divided into three experimental groups: 2% CHX gel; 2% CS gel; 2% CHX with CS; Fuji IX glass ionomer cement was used to seal the access; after 7 days, the post medication sample (S3) was collected and E. faecalis was quantified using qPCR.

Results

Maximum reduction in bacterial mean CFU (×10⁶) counts was observed between S1 and S2; S2 and S3; S1 and S3 in 2% CHX with chitosan group compared to other groups. Percentage reduction in CFU (×10⁶) counts at different time intervals (S1-S2; S2-S3; S1-S3) was maximum for the 2% CHX with the chitosan group. Comparison of the mean CFU (×10⁶) count within the 2% CHX gel group and the 2% CHX with chitosan group at different time intervals (S1,S2,S3) was found to be highly significant (P = 0.001); whereas in group II, it was significant (P = 0.002).

Conclusion

2% CHX with chitosan group showed the highest microbial reduction against E. faecalis during retreatment of failed endodontic cases.

Comparative study on alveolar bone healing in postextraction socket versus healing aided with autologous platelet-rich fibrin following surgical removal of bilateral mandibular impacted third molar tooth: A radiographic evaluation

Aim:

This study was to evaluate and compare the bone regeneration potential of autologous platelet-rich fibrin (PRF) placed in one of the extracted sockets after the surgical removal of bilateral impacted mandibular third molars.

Patients and Methods:

Twenty-five patients (10 females and 15 males; 18–35 years old) were taken for surgical removal of bilateral impacted mandibular third molar, performed in the same session. The autologous PRF was placed in one of the extracted sockets whereas the opposite side was taken as control side, and primary closure was done. Radiographic examination with orthopantomogram was done preoperatively and 1 month, 3 months, and 6 months postoperatively to assess the degree of bone regeneration at the extracted site and compare it with the control side using MATLAB software and the data are statistically analyzed using paired t-test.

Results:

PRF side had better healing and bone formation when compared with the control side as indicated by significant P values of (P = 0.06>5%) 1 month, (P = 0.00<1%) 3 month, and (P = 0.00<1%) 6 month postoperatively. The repeated-measures ANOVA showed a significant difference seen on 1^st, 3^rd, and 6^th months postoperatively on PRF side (P = 0.001).

Conclusion:

The autologous PRF improves and fastens the bone regeneration and healing in the extracted sockets.

Plasmodium DNA-mediated TLR9 activation of T-bet+ B cells contributes to autoimmune anaemia during malaria

Infectious pathogens contribute to the development of autoimmune disorders, but the mechanisms connecting these processes are incompletely understood. Here we show that Plasmodium DNA induces autoreactive responses against erythrocytes by activating a population of B cells expressing CD11c and the transcription factor T-bet, which become major producers of autoantibodies that promote malarial anaemia. Additionally, we identify parasite DNA-sensing through Toll-like receptor 9 (TLR9) along with inflammatory cytokine receptor IFN-γ receptor (IFN-γR) as essential signals that synergize to promote the development and appearance of these autoreactive T-bet+ B cells. The lack of any of these signals ameliorates malarial anaemia during infection in a mouse model. We also identify both expansion of T-bet+ B cells and production of anti-erythrocyte antibodies in ex vivo cultures of naive human peripheral blood mononuclear cells (PBMC) exposed to P. falciprum infected erythrocyte lysates. We propose that synergistic TLR9/IFN-γR activation of T-bet+ B cells is a mechanism underlying infection-induced autoimmune-like responses.

Scanning electron microscopic evaluation of the influence of manual and mechanical glide path on the surface of nickel-titanium rotary instruments in moderately curved root canals: An in-vivo study

Aim:

The aim of this study was to evaluate the influence of manual versus mechanical glide path (GP) on the surface changes of two different nickel-titanium rotary instruments used during root canal therapy in a moderately curved root canal.

Materials and Methods:

Sixty systemically healthy controls were selected for the study. Controls were divided randomly into four groups: Group 1: Manual GP followed by RaCe rotary instruments, Group 2: Manual GP followed by HyFlex rotary instruments, Group 3: Mechanical GP followed by RaCe rotary instruments, Group 4: Mechanical GP followed by HyFlex rotary instruments. After access opening, GP was prepared and rotary instruments were used according to manufacturer's instructions. All instruments were evaluated for defects under standard error mean before their use and after a single use. The scorings for the files were given at apical and middle third.

Statistical Analysis Used:

Chi-squared test was used.

Results:

The results showed that there is no statistical difference between any of the groups. Irrespective of the GP and rotary files used, more defects were present in the apical third when compared to middle third of the rotary instrument.

Conclusion:

Within the limitations of this study, it can be concluded that there was no effect of manual or mechanical GP on surface defects of subsequent rotary file system used.

Dynamical strong coupling and parametric amplification of mechanical modes of graphene drums

Mechanical resonators are ubiquitous in modern information technology. With the possibility of coupling them to electromagnetic and plasmonic modes, they hold promise as the key building blocks in future quantum information technology. Graphene-based resonators are of interest for technological applications due to their high resonant frequencies, multiple mechanical modes and low mass. The tension-mediated nonlinear coupling between various modes of the resonator can be excited in a controllable manner. Here we engineer a graphene resonator with large frequency tunability at low temperatures, resulting in a large intermodal coupling strength. We observe the emergence of new eigenmodes and amplification of the coupled modes using red and blue parametric excitation, respectively. We demonstrate that the dynamical intermodal coupling is tunable. A cooperativity of 60 between two resonant modes of ∼100 MHz is achieved in the strong coupling regime. The ability to dynamically control the coupling between the high-frequency eigenmodes of a mechanical system opens up the possibility of quantum mechanical experiments at low temperatures.

Experimental Quantum Randomness Processing Using Superconducting Qubits

Coherently manipulating multipartite quantum correlations leads to remarkable advantages in quantum information processing. A fundamental question is whether such quantum advantages persist only by exploiting multipartite correlations, such as entanglement. Recently, Dale, Jennings, and Rudolph negated the question by showing that a randomness processing, quantum Bernoulli factory, using quantum coherence, is strictly more powerful than the one with classical mechanics. In this Letter, focusing on the same scenario, we propose a theoretical protocol that is classically impossible but can be implemented solely using quantum coherence without entanglement. We demonstrate the protocol by exploiting the high-fidelity quantum state preparation and measurement with a superconducting qubit in the circuit quantum electrodynamics architecture and a nearly quantum-limited parametric amplifier. Our experiment shows the advantage of using quantum coherence of a single qubit for information processing even when multipartite correlation is not present.

Observation of measurement-induced entanglement and quantum trajectories of remote superconducting qubits

The creation of a quantum network requires the distribution of coherent information across macroscopic distances. We demonstrate the entanglement of two superconducting qubits, separated by more than a meter of coaxial cable, by designing a joint measurement that probabilistically projects onto an entangled state. By using a continuous measurement scheme, we are further able to observe single quantum trajectories of the joint two-qubit state, confirming the validity of the quantum Bayesian formalism for a cascaded system. Our results allow us to resolve the dynamics of continuous projection onto the entangled manifold, in quantitative agreement with theory.

Single-quasiparticle trapping in aluminum nanobridge Josephson junctions

We present microwave measurements of a high quality factor superconducting resonator incorporating two aluminum nanobridge Josephson junctions in a loop shunted by an on-chip capacitor. Trapped quasiparticles (QPs) shift the resonant frequency, allowing us to probe the trapped QP number and energy distribution and to quantify their lifetimes. We find that the trapped QP population obeys a Gibbs distribution above 75 mK, with non-Poissonian trapping statistics. Our results are in quantitative agreement with the Andreev bound state model of transport, and demonstrate a practical means to quantify on-chip QP populations and validate mitigation strategies in a cryogenic environment.

Rehabilitation of complicated crown-root fracture by fragment reattachment and intraradicular splinting: case reports

This paper describes the rehabilitation of two traumatised teeth in two patients namely; A maxillary left central incisor with a relatively rare combination of multiple fractures- uncomplicated crown fracture, complicated crown-root fracture along with an oblique fracture in middle third of the root and A traumatised mandibular central incisor with a horizontal fracture in cervical third of the root and complete separation of the fragments. In both cases, initially the fractured crown fragments were extracted which was followed by pulpectomy and placement of fiber posts luted with resin cement. The fractured fragments were then reattached to the respective teeth using resin cement. In the first case, the fractured incisal edge of the fragment was built up with a hybrid composite. Teeth were splinted with fibre splint (Ribbond) in both the cases. The patient was recalled regularly for follow ups for six months in first case. The patient presented with normal clinical and radiographic findings at each visit. In the second case, follow ups were carried out for 3 weeks and being continued and both the cases are still under observation by regular recalls. How to cite this article: Ruchi Arora, B Shivakumar, H Murali Rao, R Vijay. Rehabilitation of Complicated Crown-Root Fracture by Fragment Reattachment and Intraradicular Splinting: Case Reports. J Int Oral Health 2013; 5(5):129-38.

Unprecedented relationship between the size of spherical chiral micellar aggregates and their specific optical rotations

Transmission electron microscopy (TEM) images and fluorescence quenching methods indicated that lauryl ester of L-phenylalanine (LEP) and lauryl ester of L-tyrosine (LET) form spherical chiral micelles in the 50-200 mM range and their size increases with concentration. The number of molecules present in these spherical chiral aggregates varied from 80 to 160 for LEP and 80-100 for LET. The specific optical rotation, representing circular birefringence, for LEP at 405 nm and 32 °C is found to increase linearly from 37 deg cc g(-1) dm(-1) for an isolated molecule to 56 deg cc g(-1) dm(-1) for ∼200 nm size aggregate. A similar trend was found for temperatures up to 70 °C and at other visible wavelengths. A linear relation between specific optical rotation and the size of aggregate is also observed for LET. Circular dichroism, as measured in both the visible and infrared wavelength regions, however did not reveal any concentration dependent changes. The unique sensitivity uncovered for specific optical rotation as a function of the size of spherical chiral aggregates is unprecedented and opens new areas of enquiry for physical chemists.

Evaluation of micronutrient status in serum and saliva of oral submucous fibrosis patients: A clinicopathological study

BACKGROUND

Oral submucous fibrosis (OSMF) is one of the most commonly occurring potentially malignant disorders in India and south East Asian countries where betel chewing is common practice. Iron and ascorbic acid are important agents for collagen synthesis.

AIMS

The aims of this study were to estimate the levels of iron and ascorbic acid in serum and saliva in patients with OSMF and to correlate change in levels of iron and ascorbic acid with the histopathological grading of OSMF.

MATERIALS AND METHODS

The study group comprised of 65 clinically diagnosed and histopathologically confirmed cases of OSMF; 21 age- and sex-matched controls were also enrolled in the study. Serum and salivary ascorbic acid were analyzed by the dintrophenyl hydrazine method whereas serum and salivary iron were analyzed by the dipyridyl method.

RESULTS

The serum and salivary ascorbic acid levels consistently decreased with the progression of histopathologiocal grading of OSMF. Serum and salivary iron levels were also decreased in OSMF patients, but this was not significant.

CONCLUSION

Ascorbic acid and iron may have been used for the excessive collagen synthesis occurring during progression of OSMF. Hence, serum and salivary monitoring may play a crucial role in the early diagnosis and prognosis of OSMF.

Measurement-induced qubit state mixing in circuit QED from up-converted dephasing noise

We observe measurement-induced qubit state mixing in a transmon qubit dispersively coupled to a planar readout cavity. Our results indicate that dephasing noise at the qubit-readout detuning frequency is up-converted by readout photons to cause spurious qubit state transitions, thus limiting the nondemolition character of the readout. Furthermore, we use the qubit transition rate as a tool to extract an equivalent flux noise spectral density at f~1 GHz and find agreement with values extrapolated from a 1/f(α) fit to the measured flux noise spectral density below 1 Hz.

Malondialdehyde levels in oral sub mucous fibrosis: a clinicopathological and biochemical study

BACKGROUND

Oral submucous fibrosis is one of the most commonly occurring potentially malignant disorders in the South-East Asia. Levels of lipid peroxidation product malondialdehyde have been recently correlated with clinical grades of oral Submucous fibrosis.

AIMS

The aims of this study were to estimate the levels of malondialdehyde in serum, saliva and tissue in patients with oral submucous fibrosis, to correlate change in levels of malodialdehyde with the histopathological grading.

MATERIALS AND METHODS

The study group comprised of 65 clinically diagnosed and histopathologically confirmed cases of oral submucous fibrosis, 21 age and sex matched controls were also enrolled into the study. The serum saliva and tissue samples in the study groups were evaluated by the thiobarbutric acid reactive substances.

RESULTS

There was a significant difference between the serum and salivary malondialdehyde among the histopathological grades of oral submucous fibrosis. Tissue malonaldehyde levels were significantly higher as the grading progressed but tissue levels in grade 3 oral submucous fibrosis were lower than the controls.

CONCLUSION

This decrease in tissue malonaldehyde could possibly be associated to collagen cross linking occurring during the advanced stages of oral submucous fibrosis.

Heralded state preparation in a superconducting qubit

We demonstrate high-fidelity, quantum nondemolition, single-shot readout of a superconducting flux qubit in which the pointer state distributions can be resolved to below one part in 1000. In the weak excitation regime, continuous measurement permits the use of heralding to ensure initialization to a fiducial state, such as the ground state. This procedure boosts readout fidelity to 93.9% by suppressing errors due to spurious thermal population. Furthermore, heralding potentially enables a simple, fast qubit reset protocol without changing the system parameters to induce Purcell relaxation.

Formation of self-aggregated structures of different types in water of chiral polymerizable amphiphiles from L-tyrosine and L-phenylalanine

Sodium salts of maleamic acid derivatives from lauryl esters of L-tyrosine (MTNa) and L-phenylalanine (MPNa) were synthesized and characterized. The aggregated structures of MTNa and MPNa in water were investigated, employing several independent methods. MPNa showed secondary aggregated structures in contrast to MTNa at concentrations of >1 × 10(-3) M. The results from dynamic light scattering, transmittance, conductivity, and viscosity measurements suggested the formation of aggregated structures of different types in MTNa and MPNa solutions. The measured fluorescence anisotropy (r) at 0.180 of the fluoroprobe, 1,6-diphenyl-1,3,5-hexatriene (DPH), and the d spacing of 38 Å from small-angle X-ray diffraction (SAXD) experiments confirmed the bilayer structures in MPNa. Scanning electron microscope (SEM) images provided the morphological features. The emulsion produced using MPNa solution was more stable. The confocal fluorescence microscopy image of the emulsion from MPNa confirmed the entrapment of water-soluble dye, rhodamine. The models of MTNa and MPNa molecules and the aggregated structures are presented.

Observation of quantum jumps in a superconducting artificial atom

We continuously measure the state of a superconducting quantum bit coupled to a microwave readout cavity by using a fast, ultralow-noise parametric amplifier. This arrangement allows us to observe quantum jumps between the qubit states in real time, and should enable quantum error correction and feedback--essential components of quantum information processing.

1H NMR spectroscopic investigations on the conformation of amphiphilic aromatic amino acid derivatives in solution: effect of chemical architecture of amphiphiles and polarity of solvent medium

In this study, the conformation of the amphiphilic lauryl esters of L-tyrosine (LET) and L-phenylalanine (LEP) in water and dimethyl sulfoxide is established. The alkyl chain protons of LEP in D(2)O appear at δ 1.010-1.398 and show an upfield shift and large line width, suggesting the proximity of the phenyl ring to the alkyl chain in contrast to that of LET. Quite interestingly, in DMSO-d(6), the (1)H NMR spectra of LET and LEP show a strong similarity that is suggestive of an orientation that positions the aromatic ring and aliphatic chain away from each other. These results are substantiated with two-dimensional nuclear Overhauser enhancement spectroscopy (2D NOSEY). Theoretical molecular models of the conformation at the interface corroborate the experimental findings. Investigations of the solvent polarity and chemical structure-dependent conformation are discussed.

Determination of processes affecting groundwater quality in the coastal aquifer beneath Puri city, India: a multivariate statistical approach

Variability of groundwater quality parameters is linked to various processes such as weathering, organic matter degradation, aerobic respiration, iron reduction, mineral dissolution and precipitation, cation exchange and mixing of salt water with fresh water. Multivariate statistical analyses such as principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied to the standardized data set of eleven groundwater quality parameters (i.e. pH, Ca2+, Mg2+, Na+, K+, Fe3+, alkalinity, NO3-, Cl-, SO4(2-), TDS) collected during the post-monsoon and the summer seasons in order to elicit hydrologic and biogeochemical processes affecting water quality in the unconfined aquifer beneath Puri city in eastern India. The application of PCA resulted in four factors explaining 73% variance in post-monsoon and 81% variance in summer. The HCA using Ward's method and squared Euclidean distance measure classified the parameters into four clusters based on their similarities. PCA and HCA allowed interpretation of processes. During both post-monsoon and summer seasons, anthropogenic pollution and organic matter degradation/Fe(III) reduction were found dominant due to contribution from on-site sanitation in septic tanks and soak pits in the city. Cation exchange and mineral precipitation were possible causes for increase in Na+ and decrease in Ca2+ concentration in summer. Fresh water recharge during monsoon and Sea water intrusion in summer are attributed as significant hydrologic processes to variations of the groundwater quality at the study site.

A facile methodology for the design of functionalized hollow silica spheres

A new amino acid derived amphiphile, lauryl ester of tyrosine (LET) is shown to provide a facile methodology for the preparation of hollow silica spheres. In a previous study on the interface adsorption, it was shown that phenolic OH group in LET plays a key role in the formation and stabilization of close packed structures, typically at the oil/water interface. Drawing an analogy between the air/water and the oil/water interface, we detail here a procedure where air droplets are capped with LET aggregated structures, and in turn they are utilized as viable templates in the production of hollow silica spheres. We demonstrate that hollow silica spheres are formed at pH 4.0 specifically under conditions of vortexing within a short period of time (ca. 15 min). The dimensions of the structures are 0.43±0.15 μm in diameter and they have then subsequently been used as templates for directing the synthesis of silica-silver and silica-polyanthranilic composite hollow spheres.

Amphiphilic lauryl ester derivatives from aromatic amino acids: significance of chemical architecture in aqueous aggregation properties

Lauryl esters of L-tyrosine (LET) and L-phenylalanine (LEP) were, in a previous interface adsorption study, found to adopt very different interfacial conformations. The present study is an investigation of their aqueous aggregation properties with the goal of elucidating the effects of the presence in LET and absence in LEP of the phenolic OH group on their aqueous aggregate structures and micellar conformations of the surfactant monomers. The measured properties included aggregation numbers from time-resolved fluorescence quenching (TRFQ), interface hydration index and microviscosity by electron spin resonance (ESR), chemical shifts of (1)H resonance lines by NMR, and Krafft temperatures and enthalpies of structural transitions by differential scanning calorimetry (DSC). The TRFQ, ESR, and NMR experiments were conducted at various temperatures from 23 to 70 degrees C for various surfactant concentrations from 0.050 to 0.200 M. Markedly different temperature dependences of aggregation number and (1)H NMR chemical shifts are exhibited by LET and LEP micelles. LET and LEP form ionic micelles. The aggregation number of LEP decreases as is characteristic of ionic micelles, but that of LET increases slightly with temperature. The changes with temperature in the NMR chemical shifts and width of the resonance lines are significantly greater for the various LEP protons than for those of LET. The differences in these properties and other fluorescence decay characteristics of fluorophores incorporated into the micelles could be attributed to the difference in the micellar conformations of LET and LEP which are postulated to be similar to that at oil-water interfaces. The phenolic group is hypothesized to be in the micelle-water interface as part of the headgroup in LET micelles, and its location does not change with temperature. On the other hand, in LEP micelles, the phenyl ring is folded into the core overlapping with the flexible hydrophobic chains. The resulting closer proximity between the phenyl ring and the flexible hydrocarbon chain causes interdependence of the phenyl ring and chain proton resonances, leading to the observed temperature dependence of the chemical shifts in LEP. The TRFQ and ESR data are combined together in a molecular space-filling model, referred to as the polar shell model, to derive the geometrical properties of the micelle. The DSC scans in the temperature range 10-55 degrees C showed the presence of distinctly different endotherms for LET and LEP. The Krafft temperatures, K(T), and the enthalpies were determined. The higher K(T) and broader peak of the DSC endotherm of LET as compared to LEP are attributed to the stabilization of fiberlike structures below the Krafft temperature due to its chirality and the hydrogen bonding capability of the phenolic OH and also to the ion-dipole interactions. Thus, all of the observed differences between LET and LEP could be attributed to the difference in their chemical architecture.

Laparoscopic management of urachal cyst associated with umbilical hernia

The urachal cyst is a rare clinical entity of a urachal remnant. It is usually asymptomatic but can present with haematuria, tumour, urachal stone and infection. We present a case of a 63-year-old lady with a body mass index (BMI) of 49 who presented with a painful swelling in the umbilical region associated with an umbilical hernia. An ultrasound and computed tomography (CT) scan showed a suspected herniation of an umbilical remnant cyst through a paraumbilical defect. Laparoscopy confirmed the urachal cyst of 3 cm in size with a band connected with the cyst down to the urinary bladder associated with a 3-cm paraumbilical hernia. We removed the cyst and repaired the hernia laparoscopically uneventfully, after which her recovery was perfect. Radiological and laparoscopic pictures have not been reported in the English literature before. Although this condition is very rare, we suggest that it should be considered in the differential diagnosis of painful paraumbilical swelling. CT scanning and laparoscopy seems to be valuable, especially in obese patients.

Water quality assessment of Malad Creek, Mumbai, India: an impact of sewage and tidal water

The aim of the study was to carry out water quality assessment and to identify sources responsible for deterioration of quality in the Malad creek, Mumbai, India. Creek receives sewage and wastewater from various drains and partially treated effluent from Malad and Versova treatment facilities. To assess the water quality, sampling locations were identified in the creek based on discharges of wastewater and sewage. Identified locations were traced in physical space by a global positioning system. Samples were collected during low and high tides and analyzed for physical, chemical and bacteriological parameters such as pH, Turbidity, DO, BOD, NH(3)-N, PO(4) and FC and compared with SW-II Standards. Parameters were also analyzed statistically and correlated to determine the relationship amongst the parameters using SPSS software. The idea was to determine the probable causes contributing to the pollution in the creek. Various options were suggested for improvement in the creek quality based on water quality assessment.

Water quality simulation of sewage impacts on the west coast of Mumbai, India

Most coastal cities use the ocean as a site of waste disposal where pollutant loading degrades the quality of coastal waters. Presently, the west coast of Mumbai receives partially treated effluent from wastewater treatment facilities through ocean outfalls and discharges into creeks as well as wastewater/sewage from various open drains and nallahs which affect the water quality of creek and coastal water. Therefore, the objective of this paper is to simulate and assess the hydrodynamic behaviour and water quality due to impact of sewage and wastewater discharges from the west coast of Mumbai. Hydrodynamics and water quality were simulated based on present conditions and validated by using measured tide, current data and observed DO, BOD and FC. Observed and simulated results indicated non compliance to standards in Malad, Mahim creeks and the impact zones of ocean outfalls. The developed model could be used for generating various conditions of hydrodynamics and water quality considering the improvement in wastewater collection systems, treatment levels and proper disposal for proper planning and management of creeks and coastal environment.

Invited review article: The Josephson bifurcation amplifier

We review the theory, fabrication, and implementation of the Josephson bifurcation amplifier (JBA). At the core of the JBA is a nonlinear oscillator based on a reactively shunted Josephson junction. A weak input signal to the amplifier couples to the junction critical current I(0) and results in a dispersive shift in the resonator plasma frequency omega(p). This shift is enhanced by biasing the junction with a sufficiently strong microwave current I(rf) to access the nonlinear regime where omega(p) varies with I(rf). For a drive frequency omega(d) such that Omega=2Q(1-omega(d)/omega(p))>3, the oscillator enters the bistable regime where two nondissipative dynamical states O(L) and O(H), which differ in amplitude and phase, can exist. The sharp I(0) dependent transition from O(L) to O(H) forms the basis for a sensitive digital threshold amplifier. In the vicinity of the bistable regime (Omega<3), analog amplification of continuous signals is also possible. We present experimental data characterizing amplifier performance and discuss two specific applications--the readout of superconducting qubits (digital mode) and dispersive microwave magnetometry (analog mode).

Optimizing anharmonicity in nanoscale weak link Josephson junction oscillators

We compute the current phase relation for superconducting weak links, with dimensions comparable to the zero temperature coherence length, connected to two and three dimensional superconducting electrodes. Our results indicate that 50-100 nm long aluminum nanobridges with three dimensional banks have sufficient anharmonicity for realizing low noise amplifiers and quantum bits. Such weak link junctions thus present a practical new route for realizing sensitive quantum circuits with potentially higher quality factor than tunnel junction devices due to the absence of a lossy oxide layer.

Doped nanocrystalline ZnO powders for non-linear resistor applications by spray pyrolysis method

Homogeneous and doped nanocrystalline ZnO powders (30-200 nm) were synthesized by spray pyrolysis technique. The spray pyrolysed powders were calcined in the temperature range of 500-750 degrees C. Formation of insulating pyrochlore phase started from 700 degrees C during the calcination itself. The calcined powders were compacted and sintered at different temperatures ranging from 900-1200 degrees C for 0.5-4 h. The densification behavior was found to be dependent on calcination temperature of the nanopowder. The resulting discs were found to have density (5.34-5.62 g/cc) in the range of 96-99% of theoretical density. The breakdown voltage value obtained for the nanopowder based non-linear resistor is 10.3 kV/cm with low leakage current density of 0.7 microA/cm2 and coefficient of nonlinearity as high as 193. The activation energy for grain growth of the doped ZnO nanopowder powders is 449.4 +/- 15 kJ/mol.