Biogenic synthesis of silver nanoparticles using Funaria hygrometrica Hedw. and their effects on the growth of Zea mays seedlings.

The biogenic synthesis of silver nanoparticles (AgNPs) is an important step in developing eco-friendly and environmentally stable tools for ameliorating crop growth. In the current study, AgNPs were synthesized using Funaria hygrometrica and characterized using ultraviolet (UV) spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). The UV spectrum showed an absorption peak at 450 nm. SEM revealed an irregular and spherical morphology, FTIR spectroscopy indicated the presence of various functional groups, while XRD displayed peaks at 45.24°, 38.17°, 44.34°, 64.54°, and 57.48° 2θ. The effects of the F. hygrometrica-mediated AgNPs on maize growth and germination were assessed at 0, 100, 300, and 500 ppm. The germination percentage and relative germination rate were increased to 95% ± 1.83% and 100% ± 2.48% at 100 ppm of synthesized AgNPs and then declined at 300 and 500 ppm. The length, fresh weight, and dry matter of the root, shoot, and seedlings were highest at 100 ppm NPs. The plant height, root length, and dry matter stress tolerance indices were also the highest (112.3%, 118.7%, and 138.20% compared with the control) at 100 ppm AgNPs. Moreover, the growth of three maize varieties, that is, NR-429, NR-449, and Borlog, were assessed at 0, 20, 40, and 60 ppm F. hygrometrica-AgNPs. The results indicated the highest root and shoot length at 20 ppm AgNPs. In conclusion, seed priming with AgNPs enhances the growth and germination of maize and can ameliorate crop production globally. RESEARCH HIGHLIGHTS: Funaria hygrometrica Hedw.-mediated AgNPs were synthesized and characterized. Biogenic AgNPs influenced the growth and germination of maize seedlings. All growth parameters were highest at 100 ppm synthesized NPs.

Profile of verteporfin and its potential for the treatment of central serous chorioretinopathy.

Central serous chorioretinopathy (CSCR) is an idiopathic disorder characterized by serous retinal detachments associated with focal leakage on fluorescein angiography and pigment epithelial detachments. While the majority of cases improve spontaneously over several months, a significant subset of patients advance to a chronic recurrent form of the disease with diffuse pigment epitheliopathy, foveal atrophy, scarring, and permanent visual loss. Photodynamic therapy (PDT) with verteporfn has been extensively studied as a potential therapeutic option for chronic cases. Multiple prospective interventional studies have demonstrated the efficacy of PDT for CSCR with significant functional and anatomic improvements achieved. Refinement of the PDT protocol has subsequently been performed in an effort to minimize adverse effects. Anti-vascular endothelial growth factor (anti-VEGF) agents, such as bevacizumab, have been utilized in the treatment of CSCR. Recent advances in imaging and functional testing have shed further light on possible pathophysiologic mechanisms of disease and post treatment changes induced by PDT. While the body of evidence supports PDT as an efficacious and relatively safe treatment for CSCR, further evaluation of the long-term efficacy and safety of PDT, as well as protocol improvements are required.

Functional anatomy of the extraocular muscles during vergence.

Magnetic resonance imaging (MRI) now enables precise visualisation of the mechanical state of the living human orbit, enabling inferences about the effects of mechanical factors on ocular kinematics. We used 3-dimensional (3D) magnetic search coil recordings and MRI to investigate the mechanical state of the orbit during vergence in humans. Horizontal convergence of 23 degrees from a remote to a near target aligned on one eye was geometrically ideal, and was associated with lens thickening and extorsion of the rectus pulley array of the aligned eye with superior oblique muscle relaxation and inferior oblique muscle contraction. There was no rectus muscle co-contraction. Subjective fusion through a 1 degree vertical prism caused a clockwise (CW) torsion in both eyes, as well as variable vertical and horizontal vergences that seldom corresponded to prism amount or direction. MRI under these conditions did not show consistent torsion of the rectus pulley array, but a complex pattern of changes in rectus extraocular muscle (EOM) crossections, consistent with co-contraction. Binocular fusion during vergence is accomplished by complex, 3D eye rotations seldom achieving binocular retinal correspondence. Vergence eye movements are sometimes associated with changes in rectus EOM pulling directions, and may sometimes be associated with co-contraction. Thus, extraretinal information about eye position would appear necessary to interpret binocular correspondence, and to avoid diplopia.

Mutations in a human ROBO gene disrupt hindbrain axon pathway crossing and morphogenesis.

The mechanisms controlling axon guidance are of fundamental importance in understanding brain development. Growing corticospinal and somatosensory axons cross the midline in the medulla to reach their targets and thus form the basis of contralateral motor control and sensory input. The motor and sensory projections appeared uncrossed in patients with horizontal gaze palsy with progressive scoliosis (HGPPS). In patients affected with HGPPS, we identified mutations in the ROBO3 gene, which shares homology with roundabout genes important in axon guidance in developing Drosophila, zebrafish, and mouse. Like its murine homolog Rig1/Robo3, but unlike other Robo proteins, ROBO3 is required for hindbrain axon midline crossing.

Demonstration of systematic variation in human intraorbital optic nerve size by quantitative magnetic resonance imaging and histology.

PURPOSE: To use magnetic resonance imaging (MRI) to measure the diameter along the course of the intraorbital optic nerve in living subjects and cadaveric specimens, and to validate measurements histologically in the same specimens. METHODS: Measurements of the intraorbital optic nerve were made in 23 living human subjects and in three formalin-fixed orbits using high-resolution, surface coil MRI in the coronal plane. Fixed orbits were then serially sectioned in the same plane, and stained by Masson's trichrome for digital morphometry of nerve diameter and densitometry of connective tissue constituents. RESULTS: In cadaveric specimens, MRI and histologic measurements of optic nerve dimensions were in close quantitative agreement, showing significant decrease in the average optic nerve diameter along its retrobulbar course. This finding was confirmed by MRI in living subjects, with average optic nerve diameter declining from 3.99 +/- 0.04 mm (SEM) just posterior to the globe, to 3.50 +/- 0.04 mm at 10 mm further to the posterior (P < 0.0001). Color densitometry demonstrated a consistent cross-sectional area of nervous tissue, but decreasing amounts of collagen posteriorly. CONCLUSIONS: There is a significant decrease in normal optic nerve diameter along its length in normal subjects, reflecting reduction in connective tissue. High-resolution MRI is a valid and sensitive method of detecting subtle changes in retrobulbar optic nerve size and can be useful in the investigation of structural optic nerve lesions. Optic nerve diameters must be measured, however, at similar distances posterior to the globe to allow meaningful comparisons.