Microwave-Assisted Rapid Synthesis of Luminescent Tryptophan-Stabilized Silver Nanoclusters for Ultra-Sensitive Detection of Fe(III), and Their Application in a Test Strip

A new preparation method for extreme fluorescent green emission tryptophan-stabilized silver nanoclusters (Tryp-AgNCs) is presented in this scientific research. The produced silver nanoclusters are dependent on tryptophan amino acid which contributes to normal growth in infants and the sublimation and recovery of human protein, muscles, and enzymes. Herein, we have introduced a green method by using microwave-assisted rapid synthesis. The subsequent silver nanoclusters (AgNCs) have excitation/emission peaks at 408/498 nm and display a considerable selectivity to Fe(III) ions. The tryptophan amino acid molecule was used in the synthesis process as a reducing and stabilizing agent. The Tryp-AgNCs’ properties were investigated in terms of morphology, dispersity, and modification of the synthesized particles using different advanced instruments. The luminescent nanoclusters traced the Fe(III) ions by the luminescence-quenching mechanism of the Tryp-AgNCs luminescence. Therefore, the extreme selectivity of the prepared nanoclusters was exhibited to the Fe(III) ions, permitting the sensitive tracing of ferric ions in the lab and in the real environmental samples. The limit of detection for Fe(III) ions based on Tryp-AgNCs was calculated to be 16.99 nM. The Tryp-AgNCs can be efficiently applied to a paper test strip method. The synthesized nanoclusters were used efficiently to detect the Fe(III) ions in the environmental samples. Moreover, we examined the reactivity of Tryp-AgNCs on various human tumor cell lines. The results show that the Tryp-AgNCs exhibited their activity versus the cancer cells in a dose-dependent routine for the perceived performance versus the greatest-used cancer cell lines.

An Eco-Friendly Synthetic Approach for Copper Nanoclusters and Their Potential in Lead Ions Sensing and Biological Applications

A new preparation route for high-luminescent blue-emission pepsin copper nanoclusters (Pep-CuNCs) is introduced in this work. The synthesized nanoclusters are based on a pepsin molecule, which is a stomach enzyme that works to digest proteins that exist in undigested food. Here, we have developed an eco-friendly technique through microwave-assisted fast synthesis. The resulting copper nanoclusters (CuNCs) exhibit significant selectivity towards Pb(II) ions. The pepsin molecule was utilized as a stabilizer and reducing agent in the production procedure of Pep-CuNCs. The characteristics of the resulting Pep-CuNCs were studied in terms of size, surface modification, and composition using various sophisticated techniques. The CuNCs responded to Pb(II) ions through the fluorescence quenching mechanism of the CuNCs' fluorescence. Thus, great selectivity of Pep-CuNCs towards Pb(II) ions was observed, allowing sensitive determination of this metal ion at lab-scale and in the environment. The CuNCs have detection limits for Pb(II) in very tenuous concentration at a nanomalar scale (11.54 nM). The resulting Pep-CuNCs were utilized significantly to detect Pb(II) ions in environmental samples. Additionally, the activity of Pep-CuNCs on different human tumor cell lines was investigated. The data for the observed behavior indicate that the Pep-CuNCs displayed their activity against cancer cells in a dose dependent manner against most utilized cancer cell lines.

Characterization, Antimicrobial and Anticancer Properties of Palladium Nanoparticles Biosynthesized Optimally Using Saudi Propolis

Due to their unique physicochemical characteristics, palladium nanoparticles (Pd-NPs) have shown tremendous promise in biological applications. The biosynthesis of Pd-NPs employing Saudi propolis has been designed to be environmental, fast, controlled, and cost-effective. The formation and stability of biosynthesized Pd-NPs by Saudi propolis extract were proved by ultraviolet-visible spectrophotometry (UV-Vis), Fourier-transform infrared spectroscopy (FT-IR), and Zeta potential analysis. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) findings show that the average particle size of Pd-NPs is between 3.14 and 4.62 nm, which is in quantum scale. The Saudi propolis enhanced the antimicrobial activity against B. subtilis, S. aureus, E. coli, K. pneumoniae, and C. albicans. Pd-NPs show effective anticancer activity against ductal carcinoma (MCF-7) with IC50 of 104.79 µg/mL.

Possibility of controlling the conduction mechanism by choosing a specific doping element in a praseodymium manganite system

Electrical properties of Pr0.7Ca0.3Mn0.9X0.1O3 (X = Co, Ni, Cr and Fe) systems have been investigated using impedance spectroscopy measurements. The reported results confirmed the role of cationic disorder on the transport properties of the doped Pr0.7Ca0.3MnO3 system. For the case of the substitution by Co and Ni and Fe transition metals, the lower temperature side has been marked by the activation of the hopping conductivity over the nearest sites. Moreover, the Shklovskii-Efros-variable range hopping conductivity mechanism has been observed in the case of the substitution by Cr element. In the high temperature range, the evolution of the resistance with temperature confirmed the activation of a hopping process. In such a temperature range, the conduction process of all the studied compounds is dominated by a thermally activated small polaron hopping mechanism. For the Pr0.7Ca0.3Mn0.9Cr0.1O3 compound, AC studies have confirmed that the electrical conductance should be investigated in terms of an activated quantum mechanical tunneling process. At higher frequencies, the Pr0.7Ca0.3Mn0.9Fe0.1O3 compound is characterized by the existence of a high frequency plateau. For the Pr0.7Ca0.3Mn0.9Fe0.1O3 ceramic, the dispersive region of the spectrum has confirmed the activation of the correlated barrier hopping mechanism. Thus, the conductance is found to follow the double Jonscher power law only for the temperature range of [80 K, 200 K]. For the Pr0.7Ca0.3Mn0.9Ni0.1O3 compound, the evolution of the frequency exponent has confirmed the activation of two conduction mechanisms. The non small polaron tunneling mechanism was activated at lower temperatures. Accordingly, the activation of the correlated barrier hopping mechanism was detected for the high temperature range. For Pr0.7Ca0.3Mn0.9Co0.1O3 manganite, the coexistence of two conduction mechanisms (correlated barrier hopping and the non small polaron tunneling) is noticed. The latter's were activated in the whole of the explored temperature range. Using the scaling model, the spectra of both Pr0.7Ca0.3Mn0.9Cr0.1O3 and Pr0.7Ca0.3Mn0.9Ni0.1O3 compounds merge into a single master curve, which confirms the validity of the time temperature superposition principle.

Obstetric referrals to the regional maternity of Kasserine (Tunisia)

Background

A large proportion of maternal deaths are related to the health care system, including the failure of the referral system between maternity wards. The objectives of this study were to determine the frequency and the indications of obstetric referrals in a Tunisian regional care maternity and to assess the conformity of referral mechanisms with the National Perinatality Programme guidelines.

Methods

A descriptive study was carried out at the regional maternity facility of the regional Hospital of Kasserine in 2018, among parturients referred during a period of three months. Data collection was carried out prospectively from medical records, transfer documents, interviews with parturients and with the nursing staff of the reference maternity hospital. The ICD-10 was used to code recorded indications and diagnoses for referrals.

Results

A total of 234 parturients were included. Referrals represented 15.1% of the obstetric activity in this facility. There were 26 reasons for referrals and the most common was Maternal care for pelvic organ abnormalities (19.7%) and premature rupture of membranes (12.8%). 34.4% of the referrals were unclassifiable according to ICD-10. Most of the indications for referrals (71.4%) did not conform to the list of referral indications of the NPP. Twenty-eight diagnoses were retained after referrals: the most common was Maternal care for pelvic organ abnormalities (15.8%). In 42% of women, reasons for referral did not match with diagnoses established at the time of the patients' admission to hospital.

Conclusions

The referral system must be analyzed in order to ensure a maximum level of safety for the mother-child couple through the formalization of the protocols and the promotion of the role of peripheral maternity facilities, which are the structures of first recourse.

Key messages

The current referral system in the region of Kasserine still faces several challenges that need to be addressed in order to make it more effective. Maternal referral systems are an effective measure to help to reduce preventable maternal deaths, they should be continuously assessed and revised.