In vitro antileishmanial and antischistosomal activities of anemonin isolated from the fresh leaves of Ranunculus multifidus forsk

Leishmaniasis and schistosomiasis are neglected tropical diseases (NTDs) infecting the world's poorest populations. Effectiveness of the current antileishmanial and antischistosomal therapies are significantly declining, which calls for an urgent need of new effective and safe drugs. In Ethiopia fresh leaves of Ranunculus multifidus Forsk. are traditionally used for the treatment of various ailments including leishmaniasis and eradication of intestinal worms. In the current study, anemonin isolated from the fresh leaves of R. multifidus was assessed for its in vitro antileishmanial and antischistosomal activities. Anemonin was isolated from the hydro-distilled extract of the leaves of R. multifidus. Antileishmanial activity was assessed on clinical isolates of the promastigote and amastigote forms of Leishmania aethiopica and L. donovani clinical isolates. Resazurin reduction assay was used to determine antipromastigote activity, while macrophages were employed for antiamastigote and cytotoxicity assays. Antischistosomal assays were performed against adult Schistosoma mansoni and newly transformed schistosomules (NTS). Anemonin displayed significant antileishmanial activity with IC50 values of 1.33 nM and 1.58 nM against promastigotes and 1.24 nM and 1.91 nM against amastigotes of L. aethiopica and L. donovani, respectively. It also showed moderate activity against adult S. mansoni and NTS (49% activity against adult S. mansoni at 10 microM and 41% activity against NTS at 1 microM). The results obtained in this investigation indicate that anemonin has the potential to be used as a template for designing novel antileishmanial and antischistosomal pharmacophores

Global injury morbidity and mortality from 1990 to 2017 : results from the Global Burden of Disease Study 2017

Correction:Background Past research in population health trends has shown that injuries form a substantial burden of population health loss. Regular updates to injury burden assessments are critical. We report Global Burden of Disease (GBD) 2017 Study estimates on morbidity and mortality for all injuries. Methods We reviewed results for injuries from the GBD 2017 study. GBD 2017 measured injury-specific mortality and years of life lost (YLLs) using the Cause of Death Ensemble model. To measure non-fatal injuries, GBD 2017 modelled injury-specific incidence and converted this to prevalence and years lived with disability (YLDs). YLLs and YLDs were summed to calculate disability-adjusted life years (DALYs). Findings In 1990, there were 4 260 493 (4 085 700 to 4 396 138) injury deaths, which increased to 4 484 722 (4 332 010 to 4 585 554) deaths in 2017, while age-standardised mortality decreased from 1079 (1073 to 1086) to 738 (730 to 745) per 100 000. In 1990, there were 354 064 302 (95% uncertainty interval: 338 174 876 to 371 610 802) new cases of injury globally, which increased to 520 710 288 (493 430 247 to 547 988 635) new cases in 2017. During this time, age-standardised incidence decreased non-significantly from 6824 (6534 to 7147) to 6763 (6412 to 7118) per 100 000. Between 1990 and 2017, age-standardised DALYs decreased from 4947 (4655 to 5233) per 100 000 to 3267 (3058 to 3505). Interpretation Injuries are an important cause of health loss globally, though mortality has declined between 1990 and 2017. Future research in injury burden should focus on prevention in high-burden populations, improving data collection and ensuring access to medical care.Peer reviewe

Synthesis, characterization and application of WS₂ nanowire-nanoflake hybrid nanostructures

Abstract Transition metal dichalcogenide (TMD) materials crystalize in a layered structure with a stoichiometry MX₂ where M is a transition metal (Mo, W, Tc, Re, V, Nb, Ta, Ti, Zr, Hf) and X is a chalcogen (S, Se, Te). While there is a strong covalent bond between the chalcogen and the metal atoms in each 2-dimensional (2D) sheet, the bulk 3-dimensional crystals are held together by weak van der Waals forces acting on the adjacent 2D sheets allowing for micromechanical and liquid phase exfoliation into nanostructures composed of either a single layer or a few layers. Since the electronic band structure depends not only on the chemistry but also on the number of layers, a whole new range of metal, semimetal and semiconductor materials may be achieved. These properties, among many other advantages (e.g. tunable band structure, high mobility of carriers, easy intercalation with ions), make TMDs appealing and timely for applications in solar cells and photodetectors, heterogeneous catalysis, electrocatalytic electrodes, energy storage and in (electro) chemical sensing. Motivated by the anticipated fascinating properties of TMDs, this research work focuses on the synthesis, characterization and application of a novel hybrid WS₂ nanomaterial. While the original goal of the research work was to develop a simple method to synthesize WS₂ nanowires, it became clear that instead of nanowires a hybrid nanowire-nanoflake (NW-NF) structure could be synthesized by a simple thermal sulfurization of hydrothermally grown WO₃ nanowires. The structure, morphology and composition of the new materials were analyzed by X-ray diffraction, Raman spectroscopy, electron microscopy and X-ray photoelectron spectroscopy. Temperature dependent electrical measurements carried out on random networks of the nanostructures showed nonlinear characteristics and a negative temperature coefficient of resistance indicating that the hybrids were semiconducting. Resistive gas sensors were prepared and exposed to H₂S, CO, NH₃, H₂ and NO and to which the devices displayed ultra-high sensitivity (0.043 ppm⁻¹) towards H₂S with a detection limit of 20 ppb. The results suggest further exploration of gas sensing with TMDs as potential competitive alternatives to the classical metal oxide based devices. Moreover, photodetector devices with excellent visible light response were also demonstrated using an individual WS₂ NW-NF hybrid as well as its random networks having photoresponsivity of up to 400 mAW⁻¹. This was two orders of magnitude higher than that measured for other 2D materials based devices. Overall, the WS₂ nanowire-nanoflake hybrid is a truly multipurpose and multifunctional semiconductor making it a promising material for advanced micro, nano and optoelectronics devices.Tiivistelmä Siirtymämetallidikalkogenidistä (transition metal dichalcogenide, TMD) olevat materiaalit kiteytyvät kerroksittaisiksi rakenteiksi, joiden stoikiometria on MX₂, missä M on siirtymämetalli (Mo, W, Tc, Re, V, Nb, Ta, Ti, Zr, Hf) ja X on kalkogeeni (S, Se, Te). 2-ulotteisessa (2D) tasossa kalkogeenin ja metallin välillä on voimakas kovalenttinen sidos, mutta suuremmassa kolmiulotteisessa kiteessä viereisiä tasoja sitoo toisiinsa vain heikot van der Waals-voimat, jolloin tasot on mahdollista erottaa mikromekaanisesti ja nestefaasikuorinnalla yksittäisiksi tai muutamasta kerroksesta koostuvaksi nanorakenteeksi. Koska elektronivyörakenne ei riipu ainoastaan kemiallisesta koostumuksesta vaan myös kerrosten lukumäärästä, voidaan muodostaa täysin uusia metallisia, puolimetallisia tai puolijohdemateriaaleja. Nämä ominaisuudet monien muiden lisäksi (esim. räätälöity vyörakenne, korkeanliikkuvuuden varauksen kuljettajat, helppo ionien interkelaatio) tekevät TMD-materiaaleista kiinnostavia ja ajankohtaisia aurinkokennoihin, valokennoihin, heterogeeniseen katalyysiin, sähkökatalyyttisiin elektrodeihin, energiavarastoihin ja sähkökemiallisiin antureihin. TDM-materiaalien oletettavasti kiehtovien ominaisuuksien motivoimana tämä tutkimus keskittyy uusien hybridi-WS₂-nanomateriaalien synteesiin, karakterisoimiseen ja sovellutuksiin. Tutkimuksen alkuperäinen tavoite oli kehittää yksinkertainen menetelmä WS₂-nanolankojen syntetisoimiseksi, mutta kävi ilmi että nanolankojen sijaan syntyi nanolanka-nanohiutale -hybridirakenne (nanowire-nanoflake, NW-NF), kun hydrotermisesti kasvatettuja WO₃-nanolankoja rikitettiin termisesti. Näiden uusien materiaalien rakenne, morfologia ja koostumus on analysoitu röntgendiffraktiolla, Raman-spekstrokopialla, elektronimikroskoopilla ja röntgenfotoelektronispektroskopialla. Valikoimattomista nanorakenteista koostuvien verkostojen lämpötilasta riippuvien sähköisten ominaisuuksien mittaukset osoittavat epälineaarisia piirteitä ja negatiivinen resistanssin lämpötilakerroin viittaa hybridien puolijohtavuuteen. Materiaalista valmistettiin resistiivisiä kaasuantureita, jotka altistettiin H₂S:lle, CO:lle, NH₃:lle, H₂:lle ja NO:lle, näistä anturi osoitti erittäin suurta herkkyyttä H₂S:lle (0.043 ppm) havaintorajan ollessa 20 ppb. Tulokset kannustavat TMD-materiaalien kaasuanturisovellutusten jatkotutkimukseen tarjoten potentiaalisesti kilpailukykyisen vaihtoehdon perinteisille metallioksidi-pohjaisille laitteille. Lisäksi, yksittäisillä WS₂-nanolanka-nanohiutalepartikkeleilla sekä valikoimattomilla nanolanka-nanohiutalehybridiverkostoilla demonstroitiin valokenno, jonka vaste näkyvään valoon oli jopa 400 mAW⁻¹ ollen kaksi kertaluokkaa korkeampi kuin muilla 2D-materiaaleihin perustuvilla kennoilla. Kaiken kaikkiaan, WS₂-nanolanka-nanohiutalehybridi on todella monikäyttöinen ja monipuolinen puolijohde ollen lupaava materiaali kehittyneille mikro-, nano- ja optoelektronisille laitteille

Essential Oil Composition, Antibacterial and Antioxidant Activities of Four Mentha Species Growing in Ethiopia

The essential oils obtained by hydrodistillation from the leaves of Mentha arvensis L., M. longifolia L., M. piperita L., and M. spicata L., were analyzed by gas chromatography (GC-FID) and gas chromatography/ mass spectrometry (GC/MS). In addition, the antibacterial activities of the oils were evaluated against 20 bacterial strains and their radical scavenging potentials were determined in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and deoxyribose degradation assays. Oxygenated monoterpenes were found to be major constituents of all the oils. The essential oil of M. spicata exhibited a significant wide spectrum antibacterial activity against all test strains including multiresistant strains of Pseudomonas aeruginosa and Escherichia coli. The essential oil of M. piperita displayed powerful in vitro radical scavenging activities in both DPPH and deoxyribose degradation assays, with IC50 values of 5.96 μl/ml and 0.57 μl/ml, respectively. The other essential oils also produced concentraion dependant radical scavenging activities with IC50 values ranging between 5.96 and 37.01 μl/ml, and 0.57 and 3.88 μl/ml, in DPPH and deoxyribose degradation assays, respectively. The present study revealed that all the essential oils have the potential to be used as naturally occurring antibacterial and antioxidant agents. Keywords: essential oils, Mentha spp, capillary gas chromatography-mass spectrometry, radical scavenging activity, antibacterial activityEthiopian Pharmaceutical Journal Vol. 25 (2) 2007: pp. 91-10