Firefly distribution and abundance on mangrove vegetation assemblages in Sepetang estuary, Peninsular Malaysia

Pteroptyx fireflies are commonly reported to congregate in large numbers in mangroves. Not much is known about the relationships between firefly distribution and abundance with specific mangrove vegetation assemblages. We conducted a study to investigate the vegetation assemblages that structure the distribution and abundance of Pteroptyx tener in Peninsular Malaysia. The distribution and abundance of fireflies were assessed along an 8 km stretch of mangroves in Sepetang estuary using visual assessment. Statistical analysis was carried out to test the correlation between length of display section and percentage cover of P. tener colonies and the relationship between percentage cover of fireflies with different vegetation assemblages. Five distinct vegetation assemblages were identified comprising different combination of four mangrove species. It was found that shorter display sections had higher percentage cover of P. tener colonies. In addition, vegetation assemblage which consisting of mainly Sonneratia caseolaris and Nypa fruticans was the most preferred type. The results of this study point to the necessity to consider not only a single mangrove species but the entire vegetation assemblage for firefly conservation

Remote Actuation of Magnetic Nanoparticles For Cancer Cell Selective Treatment Through Cytoskeletal Disruption

Motion of micron and sub-micron size magnetic particles in alternating magnetic fields can activate mechanosensitive cellular functions or physically destruct cancer cells. However, such effects are usually observed with relatively large magnetic particles (>250 nm) that would be difficult if at all possible to deliver to remote sites in the body to treat disease. Here we show a completely new mechanism of selective toxicity of superparamagnetic nanoparticles (SMNP) of 7 to 8 nm in diameter to cancer cells. These particles are coated by block copolymers, which facilitates their entry into the cells and clustering in the lysosomes, where they are then magneto-mechanically actuated by remotely applied alternating current (AC) magnetic fields of very low frequency (50 Hz). Such fields and treatments are safe for surrounding tissues but produce cytoskeletal disruption and subsequent death of cancer cells while leaving healthy cells intact

Design of thermosensitive polymer‐coated magnetic mesoporous silica nanocomposites with a core‐shell‐shell structure as a magnetic/temperature dual‐responsive drug delivery vehicle

A stimuli-responsive nanocomposite with a core-shell-shell structure consisting of iron oxide (Fe3O4) nanoparticles as core, mesoporous silica as middle shell, and poly(N-isopropyl acrylamide-co-acrylic acid) (P[NIPAAm-co-AAc]) as an exterior shell with thermo-responsivity properties was synthesized to be used as a magnetic/temperature responsive drug delivery system. The structure, morphology, and size of P(NIPAAm-co-AAc)-coated mesoporous silica embedded magnetite nanoparticles (P(NIPAAm-co-AAc)@mSiO2@Fe3O4) were characterized by XRD, FTIR, and TEM analyses. Also, the heating ability of mesoporous silica-coated Fe3O4 nanoparticles, and P(NIPAAm-co-AAc)@mSiO2@Fe3O4 nanocomposites was investigated under the exposure of an alternating magnetic field (AMF). The results indicated that the prepared nanocomposites could generate enough heat for hyperthermia applications. Moreover, the magnetic/temperature-responsive drug release behavior of P(NIPAAm-co-AAc)@mSiO2@Fe3O4 nanocomposites loaded with fluorouracil (5-FU) was studied under the exposure of the AMF (frequency = 120 kHz, and amplitude = 22 kA m−1), as well as two different temperatures (37°C and 45°C). The results showed that only 7.8% of the drug could be released after 20 h at 37°C (below the LCST of the copolymer). In contrast, by increasing the temperature of release medium up to 45°C (above the LCST of the copolymer), the amount of released drug was increased up to 47%. Moreover, by exposing the prepared nanocomposite to a safe AMF, a burst release of drug was observed, indicating the excellent responsivity of the carrier to an external magnetic field. These results proved that the obtained nanocomposite has a great performance to be used as a magnetic/temperature-sensitive drug carrier for advanced drug delivery applications

Sleep Disordered Breathing in Duchenne Muscular Dystrophy

This review aims to explain the inevitable imbalance between respiratory load, drive, and muscular force that occurs in the natural aging of Duchenne muscular dystrophy and that predisposes these patients to sleep disordered breathing (SDB). In DMD, SDB is characterized by oxygen desaturation, apneas, hypercapnia, and hypoventilation during sleep and ultimately develops into respiratory failure during wakefulness. It can be present in all age groups. Young patients risk obstructive apneas because of weight gain, secondary to progressive physical inactivity and prolonged corticosteroid therapy; older patients hypoventilate and desaturate because of respiratory muscle weakness, in particular the diaphragm. These conditions are further exacerbated during REM sleep, the phase of maximal muscle hypotonia during which the diaphragm has to provide most of the ventilation. Evidence is given to the daytime predictors of early symptoms of SDB, important indicators for the proper time to initiate mechanical ventilation