Assessment of optimal strategies in a two-patch dengue transmission model with seasonality

Emerging and re-emerging dengue fever has posed serious problems to public health officials in many tropical and subtropical countries. Continuous traveling in seasonally varying areas makes it more difficult to control the spread of dengue fever. In this work, we consider a two-patch dengue model that can capture the movement of host individuals between and within patches using a residence-time matrix. A previous two-patch dengue model without seasonality is extended by adding host demographics and seasonal forcing in the transmission rates. We investigate the effects of human movement and seasonality on the two-patch dengue transmission dynamics. Motivated by the recent Peruvian dengue data in jungle/rural areas and coast/urban areas, our model mimics the seasonal patterns of dengue outbreaks in two patches. The roles of seasonality and residence-time configurations are highlighted in terms of the seasonal reproduction number and cumulative incidence. Moreover, optimal control theory is employed to identify and evaluate patch-specific control measures aimed at reducing dengue prevalence in the presence of seasonality. Our findings demonstrate that optimal patch-specific control strategies are sensitive to seasonality and residence-time scenarios. Targeting only the jungle (or endemic) is as effective as controlling both patches under weak coupling or symmetric mobility. However, focusing on intervention for the city (or high density areas) turns out to be optimal when two patches are strongly coupled with asymmetric mobility.ope

Agar dilution method for susceptibility testing of Neisseria gonorrhoeae

The antibiotic susceptibilities of Neisseria gonorrhoeae isolates obtained from patients attending a clinic for sexually transmitted diseases in Tucumán, Argentina, were determined by the agar dilution method (MIC). 3.5% of the isolates produced ²-lactamase. A total of 96.5% of ²-lactamase negative isolates tested were susceptible to penicillin (MIC < 2 µgml-1); 14.03% of the tested isolates were resistant to tetracycline (MIC < 2 µgml-1), and 98% of the tested isolates were susceptible to spectinomycin (MIC < 64 µgml-1). The MICs for 95% of the isolates, tested for other drugs were: < 2 µgml-1 for cefoxitin, < 0.06 µgml-1 for cefotaxime, < 0.25 µgml-1 for norfloxacin, < 10 µgml-1 for cephaloridine, < 10 µgml-1 for cephalexin, and < 50 µgml-1 for kanamycin. Antibiotic resistance among N. gonorrhoeae isolates from Tucumán, Argentina, appeared to be primarily limited to penicillin and tetracycline, which has been a general use against gonorrhoeae in Tucumán since 1960. Periodic monitoring of the underlying susceptibility profiles of the N. gonorrhoeae strains prevalent in areas of frequent transmission may provide clues regarding treatment options and emerging of drug resistance

Magnetic nanoparticles coated with anacardic acid derived from cashew nut shell liquid

Magnetic nanoparticles functionalized with biomolecules have received special attention due to their various biomedical applications, such as drug delivery and magnetic hyperthermia treatment for cancer. In this study, we present the synthesis and characterization of new nanoparticles coated with anacardic acid derived from cashew nut shell liquid. The results showed that Fe3O4 nanoparticles coated with anacardic acid (AA-MAG) have superparamagnetic behavior and the magnetization is almost equal when compared with the pure Fe3O4. This coating provides stability by preventing the aggregation nanoparticles without losing its magnetization potential. The AA-MAG demonstrates excellent and fast magneto-temperature response which can be used as high-performance hyperthermia agents

Late Mesozoic magmatism from the Daye region, eastern China: U-Pb ages, petrogenesis, and geodynamic implications

Late Mesozoic dioritic and quartz dioritic plutons are widespread in the Daye region, eastern Yangtze craton, eastern China. Detailed geochronological, geochemical, and Sr–Nd isotopic studies have been undertaken for most of these plutons, in an attempt to provide a comprehensive understanding in the age, genesis and geodynamical control of the extensive magmatism. SHRIMP and LA-ICP-MS zircon U–Pb dating indicate that the plutons were emplaced in the range of latest Jurassic (ca. 152 Ma) to early Cretaceous (ca. 132 Ma), which was followed by dyke emplacement between 127 and 121 Ma and volcanism during the 130–113 Ma interval. Both diorites and quartz diorites are sodic, metaluminous, high-K calc-alkaline, and characterized by strongly fractionated, sub-parallel REE patterns without obvious Eu anomalies. The rocks are enriched in highly incompatible elements and large ion lithophile elements, but depleted in high field strength elements. Samples of diorite and quartz diorite have similar Sr–Nd isotopic compositions that are consistent with the early Cretaceous basalts and mafic intrusions throughout the eastern Yangtze craton. The geochemical and isotopic data, together with results of geochemical modeling, indicate an enriched mantle source for the plutonic rocks. The quartz diorites have geochemical signatures resembling adakites, such as high Al2O3 (15–19 wt.%), Sr (630–2,080 ppm), Na2O (>3.5 wt.%), negative Nb–Ta anomalies, low Y (7–19 ppm), Yb (0.5–1.8 ppm), Sc (5–15 ppm), and resultant high Sr/Y (45–200) and La/Yb (31–63) ratios. Genesis of the adakitic quartz diorites is best explained in terms of low-pressure intracrustal fractional crystallization of cumulates consisting of hornblende, plagioclase, K-feldspar, magnetite, and apatite from mantle-derived dioritic magmas. Mantle-derived magmatism broadly coeval with that of the Daye region also is widespread in other regions of the eastern Yangtze craton, reflecting large-scale melting of the lithospheric mantle during the Late Mesozoic. The large-scale magmatism was most likely driven by lithospheric extension associated with thinning of lithospheric mantle beneath the eastern China continent

Origin of the Tongshankou porphyry-skarn Cu-Mo deposit, eastern Yangtze craton, Eastern China: geochronological, geochemical, and Sr-Nd-Hf isotopic constraints.

The Tongshankou Cu–Mo deposit, located in the westernmost Daye district of the Late Mesozoic Metallogenic Belt along the Middle-Lower reaches of the Yangtze River, eastern China, consists mainly of porphyry and skarn ores hosted in the Tongshankou granodiorite and along the contact with the Lower Triassic marine carbonates, respectively. Sensitive high-resolution ion microprobe zircon U–Pb dating constrains the crystallization of the granodiorite at 140.6 ± 2.4 Ma (1σ). Six molybdenite samples from the porphyry ores yield Re–Os isochron age of 143.8 ± 2.6 Ma (2σ), while a phlogopite sample from the skarn ores yields an 40Ar/39Ar plateau age of 143.0 ± 0.3 Ma and an isochron age of 143.8 ± 0.8 Ma (2σ), indicating an earliest Cretaceous mineralization event. The Tongshankou granodiorite has geochemical features resembling slab-derived adakites, such as high Sr (740–1,300 ppm) and enrichment in light rare earth elements (REE), low Sc