PEI functionalized NaCeF4:Tb3+/Eu3+ for photoluminescence sensing of heavy metal ions and explosive aromatic nitro compounds

This work reports an eco-friendly hydrothermal approach for the synthesis of hexagonal NaCeF₄:Tb³⁺/Eu³⁺ nanophosphors. The phase, morphology and optical properties were characterized by Powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy and photoluminescence (PL) spectroscopy respectively. Herein, the as-synthesized nanophosphor was functionalized with amine rich polyethylenimine (PEI) resulting in development of a luminescent nanoprobe bearing dual sensing functions for hazardous nitroaromatics and heavy metal ions. The strong photoluminescence emission of Eu³⁺ ions was selectively quenched upon addition of toxic analytes at concentrations from 10 to 100 ppm due to complex formation between the analytes and PEI functionalized nanostructure. The synthesized nanomaterial shows sharp emission peaks at 493, 594, 624, 657 and 700 nm. Significantly, the peak at 594 nm shows a noticeable quenching effect on addition of toxic analytes to the aqueous solution of the nanocrystals. The nanophosphors are sensitive and efficient for the PA and Fe³⁺ ion detection with an LOD of 1.32 ppm and 1.39 ppm. The Stern–Volmer (SV) quenching constant (K_SV) is found to be 2.25 × 10⁵ M⁻¹ for PA and 3.8 × 10⁴ M⁻¹ for Fe³⁺ ions. The high K_SV value and low LOD suggest high selectivity and sensitivity of the nanosensor towards PA and Fe³⁺ ions over other analytes. Additionally, a reduced graphene oxide and nanophosphor based nanocomposite was also synthesized to investigate the role of energy transfer involving delocalized energy levels of reduced graphene oxide in regulating the luminescence properties of the nanophosphor. It was observed that PEI plays central role in inhibiting the quenching effect of reduced graphene oxide on the nanophosphor.

This work reports an eco-friendly hydrothermal approach for the synthesis of hexagonal NaCeF₄:Tb³⁺/Eu³⁺ nanophosphors.     

The concept of social dignity as a yardstick to delimit ethical use of robotic assistance in the care of older persons

Medicine, Health Care and Philosophy - With robots being introduced into caregiving, particularly for older persons, various ethical concerns are raised. Among them is the fear of replacing human...     

Y-STR diversity in the Himalayas

Linguistic and ethnic diversity throughout the Himalayas suggests that this mountain range played an important role in shaping the genetic landscapes of the region. Previous Y-chromosome work revealed that the Himalayas acted as a biased bidirectional barrier to gene flow across the cordillera. In the present study, 17 Y-chromosomal short tandem repeat (Y-STR) loci included in the AmpFlSTR? Yfiler kit were analyzed in 344 unrelated males from three Nepalese populations (Tamang, Newar, and Kathmandu) and a general collection from Tibet. The latter displays the highest haplotype diversity (0.9990) followed by Kathmandu (0.9977), Newar (0.9570), and Tamang (0.9545). The overall haplotype diversity for the Himalayan populations at 17 Y-STR loci was 0.9973, and the corresponding values for the extended (11 loci) and minimal (nine loci) haplotypes were 0.9955 and 0.9942, respectively. No Y-STR profiles are shared across the four Himalayan collections at the 17-, 11-, and nine-locus resolutions considered, indicating a lack of recent gene flow among them. Phylogenetic analyses support our previous findings that Kathmandu, and to some extent Newar, received significant genetic influence from India while Tamang and Tibet exhibit limited or no gene flow from the subcontinent. A median-joining network of haplogroup O3a3c-M134 based on 15 Y-STR loci from our four Himalayan populations suggests either a male founder effect in Tamang, possibly from Tibet, or a recent bottleneck following their arrival south of the Himalayas from Tibet leading to their highly reduced Y single-nucleotide polymorphism and Y-STR diversity. The genetic uniqueness of the four Himalayan populations examined in this study merits the creation of separate databases for individual identification, parentage analysis, and population genetic studies.     

Progress and delivery of health care in Bhutan, the Land of the Thunder Dragon and Gross National Happiness

The Himalayan Kingdom of Bhutan is rapidly changing, but it remains relatively isolated, and it tenaciously embraces its rich cultural heritage. Despite very limited resources, Bhutan is making a concerted effort to update its health care and deliver it to all of its citizens. Healthcare services are delivered through 31 hospitals, 178 basic health unit clinics and 654 outreach clinics that provide maternal and child health services in remote communities in the mountains. Physical access to primary health care is now well sustained for more than 90% of the population. Bhutan has made progress in key health indicators. In the past 50 years, life expectancy increased by 18 years and infant mortality dropped from 102.8 to 49.3 per 1000 live births between 1984 and 2008. Bhutan has a rich medical history. One of the ancient names for Bhutan was 'Land of Medicinal Herbs' because of the diverse medicinal plants it exported to neighbouring countries. In 1967, traditional medicine was included in the National Health System, and in 1971, formal training for Drungtshos (traditional doctors) and sMenpas (traditional compounders) began. In 1982, Bhutan established the Pharmaceutical and Research Unit, which manufactures, develops and researches traditional herbal medicines. Despite commendable achievements, considerable challenges lie ahead, but the advances of the past few decades bode well for the future.