Synergistic antibacterial and mosquitocidal effect of Passiflora foetida synthesized silver nanoparticles

Silver nanoparticles are opted to have various applications in different fields ranging from traditional medicines to culinary items. It is toxic and most effective against bacteria, fungi viruses, parasites, parasite carrying vectors such as mosquitoes and their larvae and other eukaryotic microorganisms at low concentration without any side effects and toxicity to humans. In view of these data, the present research has been investigated by synthesizing silver nanoparticles using 1mM silver nitrate and aqueous extract of Passiflora foetida. The variation of nanoparticles in size and shape concerning the concentration of extract prepared were analysed. The formation of silver nanoparticles was confirmed by colour changing from yellowish green to reddish-brown implicating the surface plasmon resonance. Further, it was concluded by obtaining an absorbance peak at 420 nm using UV-Visible spectrophotometer analysis. FTIR analysis was used to identify the capping ligands, which included alkanes, aromatic groups and nitro compounds. The average grain size of ~12 nm to 14 nm with crystalline phase was revealed by X-ray Diffraction studies. The SEM images depicted the surface morphology with agglomeration; TEM studies showed the shape of nanoparticles as spherical and hexagonal with sizes ranging from 40 nm to 100 nm and EDAX analysis confirmed the presence of elemental silver as the principal constituent. The characterized silver nanoparticles were then tested for synergistic antibacterial effects with tetracycline, and the results show that they are more active against E. coli and S. aureus, but moderately effective against B. cereus and K. pneumoniae . It also had a strong larval and pupal toxic effects on the dengue vector, Aedes aegypti with the highest mortality. As a result, silver nanoparticles could be a viable alternative for a variety of applications.

Degradation of Toxic Dye and Antimicrobial and Free Radical Potential of Environmental Benign Zinc Oxide Nanoparticles

Several industries have become major contributors to waterbody contamination due to the improper removal of dyes and effluents into water bodies. Due to their carcinogenic properties and low biodegradability, dye degradation is a considerable danger to people, animals, and the oceanic environment. As part of this study, Andrographis paniculata leaf extract was used as a reducing and stabilizing agent to synthesize zinc nanoparticles and degrade dyes such as methyl red and eosin. Zinc oxide nanoparticles (ZnONPs) showed a surface plasmon resonance peak at 430 nm in the UV spectrum. The FTIR result showed a band at 597.93 cm-1 that confirmed the formation of zinc nanoparticles. AFM results revealed spherical ZnONPs. The SEM results predicted an average particle size of 60 nm for crystalline particles. Biologically synthesized zinc nanoparticles exhibited greater antibacterial activity against Pseudomonas spp. and Proteus spp. but lesser activity against Klebsiella spp. and S. aureus. At 1000 μg/ml concentration, ZnONPs had the highest antioxidant activity of 45.34%. An ultraviolet-visible spectrophotometer measured dye degradation progress between 300 and 800 nm. For methyl red, the maximum absorption peak was measured at 415 nm, and for eosin, the maximum peak value was measured between 500 and 515 nm.

Curcumin-Chitosan Nanocomposite Formulation Containing Pongamia pinnata-Mediated Silver Nanoparticles, Wound Pathogen Control, and Anti-Inflammatory Potential

BACKGROUND

Because of its diverse range of use in several ethics of diagnosis and care of multiple diseases, nanotechnology has seen remarkable growth and has become a key component of medical sciences. In recent years, there has been rapid advancement in medicine and biomaterials. Nanomedicine aids in illness prevention, diagnosis, monitoring, and treatment.

AIM

The purpose of this work is to evaluate the antibacterial, anti-inflammatory, and cytotoxic capabilities of green produced silver nanoparticle with the addition of curcumin-assisted chitosan nanocomposite (SCCN) against wound pathogenic as reducing agents.

MATERIALS AND METHODS

The plant extract of Pongamia pinnata, silver nanoparticles, and its based curcumin nanoformulations was studied in this study utilizing UV visible spectrophotometer, selected area electron diffraction (SAED), and TEM. Anti-inflammatory, antimicrobial, and cytotoxic tests were performed on silver nanoparticles with the addition of curcumin-assisted chitosan nanocomposite (SCCN). Furthermore, these produced nanocomposites were coated on clinical silk and tested for antibacterial activity.

RESULTS

The produced silver nanoparticle with the addition of curcumin-assisted chitosan nanocomposite (SCCN) has significant antibacterial activities against Pseudomonas aeruginosa and staphylococcus aureus. They are as well as possess anti-inflammatory activity and furthermore prove to be biocompatible.

CONCLUSION

This advancement in the field of biomaterials, which means nanocomposite, not only helps to reduce the harmful effects of pathogenic organisms while representing an environmentally benign material but it also shows to be a material with zero danger to humans and the environment.

Systematic review: Acculturation strategies and their impact on the mental health of migrant populations

Objectives

This study aims to examine the correlation between the different types of migrant acculturation strategies according to Berry’s model of acculturation (integration, assimilation, separation, and marginalisation) and their effects on mental health conditions, such as depression, anxiety and PTSD.

Study design

Systematic Review.

Methods

Three databases (PubMed, Ovid and Ebsco) were searched using different combinations of search terms to identify relevant articles to be included. The search terms were pre-identified using relevant synonyms for “migrants”, “mental health” and “integration”. The list of article titles from these searches were then filtered using predefined inclusion and exclusion criteria. The mental health consequences included a range of common conditions including suicide/self-harm, depressive disorders, psychosis, as well as substance misuse.

Results

21 primary studies were included in the review, which assessed 61,885 migrants in total (Fig. 1 and Supplemental File 1). Of these, seven were cohort studies and fourteen were cross-sectional studies.

Most studies showed that marginalisation was associated with worse depression symptoms, compared to integration, assimilation and separation, while integration was associated with the least depressive symptoms.

Marginalisation more than triples the likelihood of anxiety-related symptoms compared to integration. Similarly, separation increased the likelihood of anxiety-related symptoms nearly six-fold.

Conclusions

Our review found out that marginalisation had the worst effects on mental health of the migrant populations while integration had the most positive effects. The study also identified three key sources which may contribute to acculturation stress and worse mental health: low education or skill set, proficiency of the host country’s language, and financial hardships.

Acculturation strategies and their impact on the mental health of migrant populations

Objectives

This systematic review examined the correlation between the different types of migrant acculturation strategies according to Berry's model of acculturation (integration, assimilation, separation, marginalisation) and their effects on mental health.

Methods

Three databases (PubMed, Ovid and Ebsco) were searched using different combinations of terms to identify relevant articles. Search terms included relevant synonyms for “migrants”, “mental health” and “integration”. The list of article titles from these searches were filtered using inclusion and exclusion criteria. Common mental health conditions including suicide/self-harm, depressive disorders, psychosis, as well as substance misuse were analysed.

Results

21 primary studies were examined, which assessed 61,885 migrants in total. Of these, 7 were cohort studies and 14 were cross-sectional studies. Most studies showed that marginalisation was associated with worse depression symptoms, compared to integration, assimilation and separation, while integration was associated with the least depressive symptoms. Marginalisation triples the likelihood of anxiety-related symptoms compared to integration. Similarly, separation increased the likelihood of anxiety-related symptoms nearly six-fold. Our study has also identified 16 factors that negatively impact level of migrant acculturation, 19 factors that adversely impact general mental health of migrants, and 22 factors that increases risks of depressive symptoms in migrants.

Conclusions

Our review found out that marginalisation had the worst effects on migrant mental health while integration had the most positive effects. The study also established multiple factors associated with low levels of acculturation and poor mental health in migrants. Given the problem of limited public resources, governments can identify at-risk individuals using factors highlighted and channel these scarce resources to develop targeted mental health interventions for them.

Key messages

Our review found out that marginalisation had the worst effects on migrant mental health while integration had the most positive effects. The study identified factors associated with low levels of acculturation and poor mental health in migrants. Governments can develop targeted mental health interventions for these at-risk individuals.

Phytosynthesis of silver nanoparticles using the leaves extract of Ficus talboti king and evaluation of antioxidant and antibacterial activities

The present study, the synthesis of silver nanoparticles (AgNPs) at 90 °C temperature using an aqueous extract from Ficus talboti leaf and the antioxidant and antibacterial activities of the AgNPs obtained. The devised method is simple and cost-effective, and it produces spherical AgNPs of size 11.9 ± 2.3 nm. The synthesized AgNPs was characterized as UV-vis spectrum and obtain a peak at 438 nm. The phytochemical study result shows that the secondary metabolites such as alkaloids, saponins, phenolic compounds, tannin, flavonoids, phytosterol, and glycosides may be responsible for reducing as well as capping silver ions into AgNPs. Transmission electron microscopic (TEM) studies of the particles revealed a dominance of spherical particle AgNPs. The face centered cubic structure of the AgNPs was confirmed by X-ray diffraction (XRD) peaks at 111°, 200°, 220°, and 311°; SAED patterns confirms the plane of silver nanoparticle planes with clear circular spots on the selected area electron diffraction (SAED). Elemental analysis was done by energy dispersive X-ray analysis (EDX). In addition, this study evaluated the in vitro antioxidant and antibacterial properties of the biosynthesized AgNPs that were found to be significant.

Design and analysis of finite element based sensors for diagnosis of liver disorders using biocompatible metals

BACKGROUND

Analysis of liver tissue in normal and abnormal conditions is essential for disease research, medical device design and treatment planning. Currently cirrhosis and malignancies of liver are among the major causes of mortality, worldwide.

OBJECTIVE

The objective of this work is to design an efficient capacitive sensor using Finite Element Methods (FEM), for diagnosis of cirrhotic and malignant liver.

METHODS

In this work, 3D geometric FEM models (N=120) of normal, cirrhotic and malignant liver were generated using Comsol 3.5a. A set of 'E' shaped metallic plates, each with a dimension of 1 × 1 × 1 mm were modeled and mounted on the developed liver models. Four different bio-compatible metals namely Gold, Silver, Palladium and Platinum were used for analysis. Further, the observed capacitance values were converted into voltage using a De Sauty's bridge circuit implemented using Proteus 8. Finally, the statistical significance of the results was analyzed using the ANOVA test.

RESULTS

Results demonstrate that the observed voltages show significant variations between different liver pathologies. The developed sensor characteristic was found to be linear and the sensitivity of the sensor was found to be high when platinum electrodes were used. The diagnostic ability of the developed sensors for the adopted biocompatible metals was found to be highly statistically significant (P < 0.001).

CONCLUSIONS

The proposed sensor design is compact with small dimensions and can be placed in contact with the human liver using endoscopic techniques. Hence, the developed sensor may provide a minimally invasive technique for liver diagnosis. This study appears to be of high clinical relevance since modelling of normal and abnormal liver, as well as design of suitable sensors for identification of liver abnormalities is required for improving the present diagnostic techniques.

Non-invasive vesicoureteral reflux detection: heating risk studies for a new device

OBJECTIVE

To investigate a novel non-invasive device developed to warm bladder urine and to measure kidney temperature to detect vesicoureteral reflux.

MATERIALS AND METHODS

Microwave antennas focused energy within the bladder. Phantom experiments measured the results. The heating protocol was optimized in an in-vivo porcine model, and then tested once, twice and three times consecutively in three pigs followed by pathologic examinations.

RESULTS

Computer simulations showed a dual concentric conductor square slot antenna to be the best. Phantom studies revealed that this antenna easily heated a bladder phantom without over heating intervening layers. In-vivo a bladder heating protocol of 3 min with 30 W each to two adjacent antennas 45 s on 15 s off followed by 15 min of 15 s on and 45 s off was sufficient. When pigs were heated once, twice and three times with this heating protocol, pathologic examination of all tissues in the heated area showed no thermal changes. More intensive heating in the animal may have resulted in damage to muscle fibers in the anterior abdominal wall.

CONCLUSIONS

Selective warming of bladder urine was successfully demonstrated in phantom and animals. Localized heating for this novel vesicoureteral reflux device requires low-power levels and should be safe for humans.

Thermal characteristics of thermobrachytherapy surface applicators for treating chest wall recurrence

The aim of this study was to investigate temperature and thermal dose distributions of thermobrachytherapy surface applicators (TBSAs) developed for concurrent or sequential high dose rate (HDR) brachytherapy and microwave hyperthermia treatment of chest wall recurrence and other superficial diseases. A steady-state thermodynamics model coupled with the fluid dynamics of a water bolus and electromagnetic radiation of the hyperthermia applicator is used to characterize the temperature distributions achievable with TBSAs in an elliptical phantom model of the human torso. Power deposited by 915 MHz conformal microwave array (CMA) applicators is used to assess the specific absorption rate (SAR) distributions of rectangular (500 cm(2)) and L-shaped (875 cm(2)) TBSAs. The SAR distribution in tissue and fluid flow distribution inside the dual-input dual-output (DIDO) water bolus are coupled to solve the steady-state temperature and thermal dose distributions of the rectangular TBSA (R-TBSA) for superficial tumor targets extending 10-15 mm beneath the skin surface. Thermal simulations are carried out for a range of bolus inlet temperature (T(b) = 38-43 degrees C), water flow rate (Q(b) = 2-4 L min(-1)) and tumor blood perfusion (omega(b) = 2-5 kg m(-3) s(-1)) to characterize their influence on thermal dosimetry. Steady-state SAR patterns of the R- and L-TBSA demonstrate the ability to produce conformal and localized power deposition inside the tumor target sparing surrounding normal tissues and nearby critical organs. Acceptably low variation in tissue surface cooling and surface temperature homogeneity was observed for the new DIDO bolus at a 2 L min(-1) water flow rate. Temperature depth profiles and thermal dose volume histograms indicate bolus inlet temperature (T(b)) to be the most influential factor on thermal dosimetry. A 42 degrees C water bolus was observed to be the optimal choice for superficial tumors extending 10-15 mm from the surface even under significant blood perfusion. Lower bolus temperature may be chosen to reduce the thermal enhancement ratio (TER) in the most sensitive skin where maximum radiation dose is delivered and to extend the thermal enhancement of radiation dose deeper. This computational study indicates that well-localized elevation of tumor target temperature to 40-44 degrees C can be accomplished by large surface-conforming TBSAs using appropriate selection of coupling bolus temperature.

Clinical Utility of Magnetic Resonance Thermal Imaging (MRTI) For Realtime Guidance of Deep Hyperthermia

A critical need has emerged for volumetric thermometry to visualize 3D temperature distributions in real time during deep hyperthermia treatments used as an adjuvant to radiation or chemotherapy for cancer. For the current effort, magnetic resonance thermal imaging (MRTI) is used to measure 2D temperature rise distributions in four cross sections of large extremity soft tissue sarcomas during hyperthermia treatments. Novel hardware and software techniques are described which improve the signal to noise ratio of MR images, minimize motion artifact from circulating coupling fluids, and provide accurate high resolution volumetric thermal dosimetry. For the first 10 extremity sarcoma patients, the mean difference between MRTI region of interest and adjacent interstitial point measurements during the period of steady state temperature was 0.85°C. With 1min temporal resolution of measurements in four image planes, this non-invasive MRTI approach has demonstrated its utility for accurate monitoring and realtime steering of heat into tumors at depth in the body.

Characterization of a digital microwave radiometry system for noninvasive thermometry using a temperature-controlled homogeneous test load

Microwave radiometry has been proposed as a viable noninvasive thermometry approach for monitoring subsurface tissue temperatures and potentially controlling power levels of multielement heat applicators during clinical hyperthermia treatments. With the evolution of technology, several analog microwave radiometry devices have been developed for biomedical applications. In this paper, we describe a digital microwave radiometer with built-in electronics for signal processing and automatic self-calibration. The performance of the radiometer with an Archimedean spiral receive antenna is evaluated over a bandwidth of 3.7-4.2 GHz in homogeneous and layered water test loads. Controlled laboratory experiments over the range of 30-50 degrees C characterize measurement accuracy, stability, repeatability and penetration depth sensitivity. The ability to sense load temperature through an intervening water coupling bolus of 6 mm thickness is also investigated. To assess the clinical utility and sensitivity to electromagnetic interference (EMI), experiments are conducted inside standard clinical hyperthermia treatment rooms with no EM shielding. The digital radiometer provided repeatable measurements with 0.075 degrees C resolution and standard deviation of 0.217 degrees C for homogeneous and layered tissue loads at temperatures between 32-45 degrees C. Within the 3.7-4.2 GHz band, EM noise rejection was good other than some interference from overhead fluorescent lights in the same room as the radiometer. The system response obtained for ideal water loads suggests that this digital radiometer should be useful for estimating subcutaneous tissue temperatures under a 6 mm waterbolus used during clinical hyperthermia treatments. The accuracy and stability data obtained in water test loads of several configurations support our expectation that single band radiometry should be sufficient for sub-surface temperature monitoring and power control of large multielement array superficial hyperthermia applicators.

Performance evaluation of a conformal thermal monitoring sheet sensor array for measurement of surface temperature distributions during superficial hyperthermia treatments

PURPOSE

This paper presents a novel conformal thermal monitoring sheet (TMS) sensor array with differential thermal sensitivity for measuring temperature distributions over large surface areas. Performance of the sensor array is evaluated in terms of thermal accuracy, mechanical stability and conformity to contoured surfaces, probe self-heating under irradiation from microwave and ultrasound hyperthermia sources, and electromagnetic field perturbation.

MATERIALS AND METHODS

A prototype with 4 x 4 array of fiber-optic sensors embedded between two flexible and thermally conducting polyimide films was developed as an alternative to the standard 1-2 mm diameter plastic catheter-based probes used in clinical hyperthermia. Computed tomography images and bending tests were performed to evaluate the conformability and mechanical stability respectively. Irradiation and thermal barrier tests were conducted and thermal response of the prototype was compared with round cross-sectional clinical probes.

RESULTS

Bending and conformity tests demonstrated higher flexibility, dimensional stability and close conformity to human torso. Minimal perturbation of microwave fields and low probe self-heating was observed when irradiated with 915 MHz microwave and 3.4 MHz ultrasound sources. The transient and steady state thermal responses of the TMS array were superior compared to the clinical probes.

CONCLUSIONS

A conformal TMS sensor array with improved thermal sensitivity and dimensional stability was investigated for real-time skin temperature monitoring. This fixed-geometry, body-conforming array of thermal sensors allows fast and accurate characterization of two-dimensional temperature distributions over large surface areas. The prototype TMS demonstrates significant advantages over clinical probes for characterizing skin temperature distributions during hyperthermia treatments of superficial tissue disease.

Enhancement of natural immune function by dietary consumption of Bifidobacterium lactis (HN019)

OBJECTIVE

To determine the effects of dietary consumption of Bifidobacterium lactis (strain HN019, DR10TM) on natural immunity.

DESIGN

A randomized, double blind, placebo-controlled clinical trial.

SETTING

Janeway Medical Centre, Memorial University, St Johns, Newfoundland.

SUBJECTS

Twenty-five healthy elderly volunteers (median age 69 y; range 60-83 y).

INTERVENTIONS

Twelve control subjects consumed 180 ml low-fat/low-lactose milk twice daily for a period of 6 weeks; 13 test subjects consumed milk supplemented with 1.5x1011 colony-forming units of B. lactis twice daily. Indices of natural immunity, including interferon production, phagocytic capacity and phagocyte-mediated bactericidal activity, were determined via peripheral blood at 0, 3, 6 and 12 weeks post-trial commencement.

RESULTS

Subjects who consumed milk containing B. lactis for 6 weeks produced significantly enhanced levels of interferon-alpha, upon stimulation of their peripheral blood mononuclear cells in culture, in comparison to the placebo control group who received milk alone. There were also significant increases in polymorphonuclear cell phagocytic capacity among test group subjects, following consumption of milk supplemented with B. lactis, while individuals who consumed B. lactis-supplemented milk or milk alone showed enhanced phagocyte-mediated bactericidal activity.

CONCLUSIONS

The results demonstrate that dietary consumption of B. lactis HN019 can enhance natural immunity in healthy elderly subjects, and that a relatively short-term dietary regime (6 weeks) is sufficient to impart measurable improvements in immunity that may offer significant health benefits to consumers.

SPONSORS

Financial support for this project was provided by the New Zealand Dairy Board.