3,229 research outputs found
DiaquaÂbisÂ(5-carbÂoxy-2-propyl-1H-imidazole-4-carboxylÂato-Îş2 N 3,O 4)cadmium(II) 3.5-hydrate
In the title complex, [Cd(C8H9N2O4)2(H2O)2]¡3.5H2O, the CdII is coordinated by two water molÂecules and N,O-chelated by two 5-carbÂoxy-2-propyl-1H-imidazole-4-carboxylÂate anions in a distorted octaÂhedral geometry. The two imidazole rings are oriented to each other with a dihedral angle of 75.1â
(2)°. Strong OâHâŻO hydrogen bonds between protonated and deprotonated carboxylÂate groups occur in the molÂecular structure. In the crystal structure extensive OâHâŻO and NâHâŻO hydrogen bonds help to stabilize the three-dimensional supraÂmolecular framework. The propyl groups of anions are disordered over two sites with refined occupancies of 0.768â
(6):0.232â
(6) and 0.642â
(8):0.358â
(8)
Axon fasciculation in the developing olfactory nerve
Olfactory sensory neuron (OSN) axons exit the olfactory epithelium (OE) and extend toward the olfactory bulb (OB) where they coalesce into glomeruli. Each OSN expresses only 1 of approximately 1,200 odor receptors (ORs). OSNs expressing the same OR are distributed in restricted zones of the OE. However, within a zone, the OSNs expressing a specific OR are not contiguous - distribution appears stochastic. Upon reaching the OB the OSN axons expressing the same OR reproducibly coalesce into two to three glomeruli. While ORs appear necessary for appropriate convergence of axons, a variety of adhesion associated molecules and activity-dependent mechanisms are also implicated. Recent data suggest pre-target OSN axon sorting may influence glomerular convergence. Here, using regional and OR-specific markers, we addressed the spatio-temporal properties associated with the onset of homotypic fasciculation in embryonic mice and assessed the degree to which subpopulations of axons remain segregated as they extend toward the nascent OB. We show that immediately upon crossing the basal lamina, axons uniformly turn sharply, usually at an approximately 90° angle toward the OB. Molecularly defined subpopulations of axons show evidence of spatial segregation within the nascent nerve by embryonic day 12, within 48 hours of the first OSN axons crossing the basal lamina, but at least 72 hours before synapse formation in the developing OB. Homotypic fasciculation of OSN axons expressing the same OR appears to be a hierarchical process. While regional segregation occurs in the mesenchyme, the final convergence of OR-specific subpopulations does not occur until the axons reach the inner nerve layer of the OB
Recommended from our members
Functional odor classification through a medicinal chemistry approach
Crucial for any hypothesis about odor coding is the classification and prediction of sensory qualities in chemical compounds. The relationship between perceptual quality and molecular structure has occupied olfactory scientists throughout the 20th century, but details of the mechanism remain elusive. Odor molecules are typically organic compounds of low molecular weight that may be aliphatic or aromatic, may be saturated or unsaturated, and may have diverse functional polar groups. However, many molecules conforming to these characteristics are odorless. One approach recently used to solve this problem was to apply machine learning strategies to a large set of odors and human classifiers in an attempt to find common and unique chemical features that would predict a chemicalâs odor. We use an alternative method that relies more on the biological responses of olfactory sensory neurons and then applies the principles of medicinal chemistry, a technique widely used in drug discovery. We demonstrate the effectiveness of this strategy through a classification for esters, an important odorant for the creation of flavor in wine. Our findings indicate that computational approaches that do not account for biological responses will be plagued by both false positives and false negatives and fail to provide meaningful mechanistic data. However, the two approaches used in tandem could resolve many of the paradoxes in odor perception
Multiple images storage and frequency conversion in a cold atomic ensemble
The strong demand for quantum memory, a key building block of quantum
network, has inspired new methodologies and led to experimental progress for
quantum storage. The use of quantum memory for spatial multimode or image
storage could dramatically increase the channel bit-rate. Furthermore, quantum
memory that can store multiple optical modes would lead to higher efficiencies
in quantum communication and computation. Here, by using resonant tripod
electromagnetically induced transparency in a cold atomic ensemble, we
experimentally demonstrate multiple probes storage in frequency domain, where
two probe fields have discrete wavelengths and different spatial information.
In addition, by using different read-light, we realize frequency conversion of
retrieved images with high efficiency. Besides, our method could be used to
create a superposition of the images by realizing the function of a
beamsplitter. All advantages make our method useful in many fields including
quantum information, detection, imaging, sensing and even astrophysical
observation.Comment: Frequency-multiplexed image storage,high efficiency storage and
conversion for an imag
- âŚ