Agilent Technologies

About: Agilent Technologies is a company organization based out in Santa Clara, California, United States. It is known for research contribution in the topics: Signal & Mass spectrometry. The organization has 7398 authors who have published 11518 publications receiving 262410 citations. The organization is also known as: Agilent Technologies, Inc..

Ultrafast Rabi flopping and coherent pulse propagation in a quantum cascade laser

Abstract: Coherent Rabi flopping and coherent pulse reshaping are directly observed in an operating quantum cascade laser. The findings indicate the potential for coherent effects to be exploited in mode locking, and may stimulate new approaches for generating short pulses in quantum cascade lasers.

Locking precision male BNC connector with latch mechanism allowing cable rotation

Abstract: A precision locking BNC male connector mates without requiring twisting of the cable or multiple bends to accommodate the rotation of the BNC latch. The shell portion of the male connector that carries the adapter connector or cable clamp on one end and that is the male cylindrical shield at the other end, is free to rotate whenever the precision locking BNC male connector is not locked, whether or not it is mated with a female connector. A knurled sleeve is captive at a location along the male shell, but is free to rotate. The knurled sleeve has internal threads that engage external threads on a portion of the BNC latch. A radial friction device is in contact with both an-external surface of the BNC latch and the internal surface of the knurled sleeve. When not engaged with the bayonet pins of a female connector, rotating the knurled sleeve will rotate the BNC latch also, by virtue of the friction device, but both will, as a unit, rotate freely relative to the shell. Once the bayonet pins engage the spiral portion of the slot in the BNC latch, the friction between the sleeve and the latch is sufficient to rotate the latch all the way into the detent. At that point the latch can turn no more, and further CW rotation of the sleeve by about three-quarters of a turn causes thread driven displacement of the male shell toward the female parts by about 0.030 inches. This applies the compression that produces the locked condition. To unlock the connectors the knurled sleeve is turned in the CCW direction. The friction device does not transmit enough torque to overcome the detent, which is also temporarily maintained by an anti-jam spring, so that the shell initially stays still as the knurled sleeve rotates about it, which undoes the thread-induced displacement until no more displacement in the other direction is possible, and further rotation is transmitted to the latch, which causes it to leave its detent and traverse the spiral over the bayonet pins to where they are opposite the entrance to the groove. A simple axial tug then separates the connectors. The friction device may be a neoprene washer held between two adjacent metallic washers.

Immunodominant fragments of myelin basic protein initiate T cell-dependent pain

Abstract: The myelin sheath provides electrical insulation of mechanosensory Aβ-afferent fibers. Myelin-degrading matrix metalloproteinases (MMPs) damage the myelin sheath. The resulting electrical instability of Aβ-fibers is believed to activate the nociceptive circuitry in Aβ-fibers and initiate pain from innocuous tactile stimulation (mechanical allodynia). The precise molecular mechanisms, responsible for the development of this neuropathic pain state after nerve injury (for example, chronic constriction injury, CCI), are not well understood. Using mass spectrometry of the whole sciatic nerve proteome followed by bioinformatics analyses, we determined that the pathways, which are classified as the Infectious Disease and T-helper cell signaling, are readily activated in the nerves post-CCI. Inhibition of MMP-9/MMP-2 suppressed CCI-induced mechanical allodynia and concomitant TNF-α and IL-17A expression in nerves. MMP-9 proteolysis of myelin basic protein (MBP) generated the MBP84-104 and MBP68-86 digest peptides, which are prominent immunogenic epitopes. In agreement, the endogenous MBP69-86 epitope co-localized with MHCII and MMP-9 in Schwann cells and along the nodes of Ranvier. Administration of either the MBP84-104 or MBP68-86 peptides into the naive nerve rapidly produced robust mechanical allodynia with a concomitant increase in T cells and MHCII-reactive cell populations at the injection site. As shown by the genome-wide expression profiling, a single intraneural MBP84-104 injection stimulated the inflammatory, immune cell trafficking, and antigen presentation pathways in the injected naive nerves and the associated spinal cords. Both MBP84-104-induced mechanical allodynia and characteristic pathway activation were remarkably less prominent in the T cell-deficient athymic nude rats. These data implicate MBP as a novel mediator of pain. Furthermore, the action of MMPs expressed within 1 day post-injury is critical to the generation of tactile allodynia, neuroinflammation, and the immunodominant MBP digest peptides in nerve. These MBP peptides initiate mechanical allodynia in both a T cell-dependent and -independent manner. In the course of Wallerian degeneration, the repeated exposure of the cryptic MBP epitopes, which are normally sheltered from immunosurveillance, may induce the MBP-specific T cell clones and a self-sustaining immune reaction, which may together contribute to the transition of acute pain into a chronic neuropathic pain state.

Improved Free-Space S-Parameter Calibration

Abstract: An improved method for performing a full two-port s-parameter calibration in free-space is presented. The proposed calibration technique computes the error coefficients from measurements made on an empty fixture and a measurement made on a metal plate of known thickness. Time-domain gating was employed. This technique requires fewer and simpler standards than the existing TRL and TRM calibration techniques. Permittivity calculated from measurements, calibrated using this technique, made on a material sample appear to be superior to results published using the TRL and TRM calibration technique

Perceptual image quality: Effects of tone characteristics

Abstract: Tone mapping refers to the conversion of luminance values recorded by a digital camera or other acquisition device, to the luminance levels available from an output device, such as a monitor or a printer. Tone mapping can improve the appearance of rendered images. Although there are a variety of algorithms available, there is little information about the image tone characteristics that produce pleasing images. We devised an experiment where preferences for images with different tone characteristics were measured. The results indicate that there is a systematic relation between image tone characteristics and perceptual image quality for images containing faces. For these images, a mean face luminance level of 46-49 CIELAB L* units and a luminance standard deviation (taken over the whole image) of 18 CIELAB L* units produced the best renderings. This information is relevant for the design of tone-mapping algorithms, particularly as many images taken by digital camera users include faces.