The beta 2-adrenergic receptor as a surrogate odorant receptor in mouse olfactory sensory neurons

In the mouse, mature olfactory sensory neurons (OSNs) express one allele of one of the similar to 1200 odorant receptor (OR) genes, which encode G-protein coupled receptors (GPCRs). Axons of OSNs that express the same OR coalesce into homogeneous glomeruli at conserved positions in the olfactory bulb. ORs are involved in OR gene choice and OSN axonal wiring, but the mechanisms remain poorly understood. One approach is to substitute an OR genetically with another GPCR, and to determine in which aspects this GPCR can serve as a surrogate OR under experimental conditions. Here, we characterize a novel gene-targeted mouse strain in which the mouse beta 2-adrenergic receptor (beta 2AR) is coexpressed with tauGFP in OSNs that choose the OR locus M71 for expression (beta 2AR -> M71-GFP). By crossing these mice with beta 2AR -> M71-lacZ gene-targeted mice, we find that differentially tagged beta 2AR -> M71 alleles are expressed monoallelically. The OR coding sequence is thus not required for monoallelic expression - the expression of one of the two alleles of a given OR gene in an OSN. We detect strong (beta 2AR immunoreactivity in dendritic cilia of (beta 2AR -> M71-GFP OSNs. These OSNs respond to the beta 2AR agonist isoproterenol in a dose-dependent manner. Axons of beta 2AR -> M71-GFP OSNs coalesce into homogeneous glomeruli, and beta 2AR immunoreactivity is detectable within these glomeruli. We do not find evidence for expression of endogenous beta 2AR in OSNs of wild-type mice, also not in M71-expressing OSNs, and we do not observe overt differences in the olfactory system of beta 2AR and beta 1AR knockout mice. Our findings corroborate the experimental value of the beta 2AR as a surrogate OR, including for the study of the mechanisms of monoallelic expression. (C) 2013 Elsevier Inc All rights reserved

SIGIFSDP: A Service Id Guided Intelligent Forwarding Service Discovery Protocol in Pervasive Computing Environments

Service discovery constructs a bridge between the service providers and the service consumers, and is a key point in pervasive computing environments. In group-based service discovery protocols, selective forwarding service requests only based on the service group maybe lead to unnecessary forwarding, which produces large packet redundancy. This paper proposes an efficient service discovery protocol: SIGIFSDP (Service Id Guided Intelligent Forwarding Service Discovery Protocol). In SIGIFSDP, based on GSD, SIGIF (Service Id Guided Intelligent Forwarding) is introduced to select the exact forwarding nodes based on the service id. Theoretical analysis and simulation results using GloMosim verify that SIGIFSDP can save the response time, reduce the service request packets, and improve the efficiency of service discovery

Increased extreme precipitation in Chinese deserts from 1960 to 2018

Extreme precipitation over drylands, especially deserts, has been often observed. The precipitation changes in Chinese deserts have been rarely studied. Here, we use a daily grid precipitation dataset generated via weather station data (0.25° horizontal grid spacing) to investigate the spatial and temporal changes in extreme precipitation in Chinese deserts. The extreme precipitation based on the changes in the total precipitation (PRCPTOT) and the annual‐maximum daily precipitation (Rx1day) in the Chinese desert exhibits markedly increasing trends and presents a spatial distribution of wetting in the western deserts and drying in the eastern deserts. The increase in extreme precipitation could minimize wind erosion and intensify dune stabilization in the western Chinese deserts

Persistent organic pollutants in ocean sediments from the North Pacific to the Arctic Ocean

Concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OC pesticides), and polybrominated diphenyl ethers (PBDEs) are reported in surficial sediments sampled along cruise transects from the Bering Sea to the central Arctic Ocean. OCs and PCBs all had significantly higher concentrations in the relatively shallow water (500 m) of the Bering Sea and Arctic Ocean (e.g., Canada Basin ΣPCB 149 ± 102 pg g−1 dw). Concentrations were similar to, or slightly lower than, studies from the 1990s, indicating a lack of a declining trend. PBDEs (excluding BDE-209) displayed very low concentrations (e.g., range of median values, 3.5–6.6 pg/g dw). In the shelf areas, the sediments comprised similar proportions of silt and clay, whereas the deep basin sediments were dominated by clay, with a lower total organic carbon (TOC) content. While significant positive correlations were observed between persistent organic pollutant (POP) concentrations and TOC (Pearson correlation, r = 0.66–0.75, p <0.05), the lack of strong correlations, combined with differing chemical profiles between the sediments and technical formulations (and/or marine surface waters), indicate substantial chemical processing during transfer to the benthic environment. Marked differences in sedimentation rates between the shallow and deeper water regions are apparent (the ∼5 cm-depth grab samples collected here representing ∼100 years of accumulation for the shelf sediments and ∼1000 years for the deeper ocean regions), which may bias any comparisons. Nonetheless, the sediments of the shallower coastal arctic seas appear to serve as significant repositories for POPs deposited from surface waters

A classification-based method to estimate event-related potentials from single trial EEG

National Natural Science Foundation of China [30670669]; National Basic Research Program of China [2007CB947703]; Natural Science Foundation of Fujian Province [2011J01344]; Science and Technology Development Foundation of Fuzhou University [2009-XQ-25]A novel method based on machine learning is developed to estimate event-related potentials from single trial electroencephalography. This paper builds a basic framework using classification and an optimization model based on this framework for estimating event-related potentials. Then the SingleTrialEM algorithm is derived by introducing a logistic regression model, which could be obtained by training before SingleTrialEM is used, to instantiate the optimization model. The simulation tests demonstrate that the proposed method is correct and solid. The advantage of this method is verified by the comparison between this method and the Woody filter in simulation tests. Also, the cognitive test results are consistent with the conclusions of cognitive science

Characteristics and variations of the picophytoplankton community in the Arctic Ocean

Picophytoplankton are responsible for much of the carbon fixation process in the Arctic Ocean, and they play an important role in active microbial food webs. The climate of the Arctic Ocean has changed in recent years, and picophytoplankton, as the most vulnerable part of the high-latitude pelagic ecosystem, have been the focus of an increasing number of scientific studies. This paper reviews and summarizes research on the characteristics of picophytoplankton in the Arctic Ocean, including their abundance, biomass, spatial distribution, seasonal variation, community structure, and factors influencing their growth. The impact of climate change on the Arctic Ocean picophytoplankton community is discussed, and future research directions are considered

An Olfactory Cilia Pattern in the Mammalian Nose Ensures High Sensitivity to Odors

SummaryIn many sensory organs, specialized receptors are strategically arranged to enhance detection sensitivity and acuity. It is unclear whether the olfactory system utilizes a similar organizational scheme to facilitate odor detection. Curiously, olfactory sensory neurons (OSNs) in the mouse nose are differentially stimulated depending on the cell location. We therefore asked whether OSNs in different locations evolve unique structural and/or functional features to optimize odor detection and discrimination. Using immunohistochemistry, computational fluid dynamics modeling, and patch clamp recording, we discovered that OSNs situated in highly stimulated regions have much longer cilia and are more sensitive to odorants than those in weakly stimulated regions. Surprisingly, reduction in neuronal excitability or ablation of the olfactory G protein in OSNs does not alter the cilia length pattern, indicating that neither spontaneous nor odor-evoked activity is required for its establishment. Furthermore, the pattern is evident at birth, maintained into adulthood, and restored following pharmacologically induced degeneration of the olfactory epithelium, suggesting that it is intrinsically programmed. Intriguingly, type III adenylyl cyclase (ACIII), a key protein in olfactory signal transduction and ubiquitous marker for primary cilia, exhibits location-dependent gene expression levels, and genetic ablation of ACIII dramatically alters the cilia pattern. These findings reveal an intrinsically programmed configuration in the nose to ensure high sensitivity to odors

Numerical investigation of GHz repetition rate fundamentally mode-locked all-fiber lasers

GHz repetition rate fundamentally mode-locked lasers have attracted great interest for a variety of scientific and practical applications. A passively mode-locked laser in all-fiber format has the advantages of high stability, maintenance-free operation, super compactness, and reliability. In this paper, we present numerical investigation on passive mode-locking of all-fiber lasers operating at repetition rates of 1-20 GHz. Our calculations show that the reflectivity of the output coupler, the small signal gain of the doped fiber, the total net cavity dispersion, and the modulation depth of the saturable absorber are the key parameters for producing stable fundamentally mode-locked pulses at GHz repetition rates in very short all-fiber linear cavities. The instabilities of GHz repetition rate fundamentally mode-locked all-fiber lasers with different parameters were calculated and analyzed. Compared to a regular MHz repetition rate mode-locked all-fiber laser, the pump power range for the mode-locking of a GHz repetition rate all-fiber laser is much larger due to the several orders of magnitude lower accumulated nonlinearity in the fiber cavity The presented numerical study provides valuable guidance for the design and development of highly stable mode-locked all-fiber lasers operating at GHz repetition rates.National Science Foundation Engineering Research Center for Integrated Access Networks [EEC-0812072]; Technology Research Initiative Fund (TRIF) Photonics Initiative of the University of Arizona; National Natural Science Foundation of China (NSFC) [61575075]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Chemosensory Contributions of E-Cigarette Additives on Nicotine Use

While rates of smoking combustible cigarettes in the United States have trended down in recent years, use of electronic cigarettes (e-cigarettes) has dramatically increased, especially among adolescents. The vast majority of e-cigarette users consume “flavored” products that contain a variety of chemosensory-rich additives, and recent literature suggests that these additives have led to the current “teen vaping epidemic.” This review, covering research from both human and rodent models, provides a comprehensive overview of the sensory implications of e-cigarette additives and what is currently known about their impact on nicotine use. In doing so, we specifically address the oronasal sensory contributions of e-cigarette additives. Finally, we summarize the existing gaps in the field and highlight future directions needed to better understand the powerful influence of these additives on nicotine use