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Changing ratios of stable carbon (δ13C) and nitrogen (δ15N) isotopes in consumer tissues reflect foraging patterns over time and can be used to inform studies on historically vulnerable populations. Northern fur seals (NFS; Callorhinus ursinus) at San Miguel Island (SMI), California, have been severely impacted by climate events such as El Niño and remain susceptible to future environmental disturbances, necessitating the need to further understand their foraging ecology. We analyzed sequential δ13C and δ15N values along single NFS whiskers sampled from five pups and five unrelated post-parturient females at SMI and reconstructed temporally aligned stable isotope profiles for each whisker. Pup profiles consistently showed increases in postnatal δ13C and δ15N values that likely stem from pup consumption of maternal milk and changes in maternal foraging locations after parturition. Adult female profiles indicated predominantly heterogeneous foraging strategies and minimal foraging outside the Southern California Bight. These findings provide initial characterizations of longitudinal, stable isotope-derived foraging data for NFS from SMI and offer insight into the inference of otariid foraging ecology with sequential δ13C and δ15N values. [ABSTRACT FROM AUTHOR]

The test conditions under which whiskers generated from galvanized steel sheets were investigated. Then, it was found that whiskers are generated when a temperature cycle that satisfies certain conditions is given. Based on the results, we estimated the correlation between heat stress and market stress in the test, and devised a method to determine an appropriate test period from the market temperature data. [ABSTRACT FROM AUTHOR]

Magnetoresistance of GaAs whiskers with concentrations in the vicinity to metal-insulator transition (MIT) 1017–1018 cm−3 were studied at low temperatures and high magnetic fields (up to 14 T). The whiskers were doped with Te during the growth. The whisker diameter ranges from 10 to 40 μm. Temperature dependence of the whisker resistance have shown metallic and semiconductor character in the proximity to MIT from various sides of the transition. Depending on doping level the character of the whisker magnetoresistance changes from linear positive to quadratic negative. The magnetoresistance of metallic whiskers is explained in terms of weak antilocalization (WAL) model. The specimens with semiconductor character of conductance revealed negative magnetoresistance, magnitude of which rises due to moving away from MIT and reach 15% for the whiskers with concentration 1017 cm−3. The possible reasons of the negative magnetoresistance are discussed. The effect observed is attributed to weak localization (WL) of charge carriers in the region of hopping conductance for the whiskers in the vicinity to MIT. A high negative magnetoresistance (NMR) for the whiskers of low dopant concentration is connected with subsurface conductance in the disordered upper layers of the whiskers due to their core-shell structure. [ABSTRACT FROM AUTHOR]

The mechanical recycling of discarded plastic products as resources for environmental preservation has recently gained research attention. In this context, it is necessary to use waste materials for fiber-reinforced thermoplastics (FRTP). Glass and carbon fibers are often damaged by shear and compression during melt-forming processes. To achieve a sustainable society, it is necessary for thermal recycling to produce minimal to no residue and for mechanical recycling to maintain the length of fibers used in FRTP to preserve their performance as a reinforcing agent. Aramid fibers (AFs) do not shorten during the melt-molding process, and their composites have excellent impact strength. On the other hand, plastics reinforced with glass or carbon fibers are reported to have a superior strength and modulus of elasticity compared to aramid fibers. This study investigates the dispersion of a carbon nanofiber (CNF), a whisker, as the third component in aramid-fiber-reinforced polypropylene (PP/AF). The results and discussion sections demonstrate how the dispersion of CNF in PP/AF can enhance the mechanical properties of injection-molded products without compromising their impact resistance. The proposed composition will have excellent material recyclability and initial mechanical properties compared to glass-fiber-reinforced thermoplastics. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Minerals & Processing / Huagong Kuangwu yu Jiagong is the property of Industrial Minerals & Processing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Refractories / Naihuo Cailiao is the property of Naihuo Cailia (Refractories) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ceramic membranes with high porosity and excellent separation efficiency are necessary for the efficient treatment of large‐scale wastewaters. However, the conventional ceramic membranes are usually prepared by particles‐packing, which inhibits the advances of separation efficiency because of the low porosity and connectivity. Here, a fibrous ceramic membrane with mullite whiskers‐interlocked structure was prepared by gas‐solid reaction. The effects of aluminum fluoride (AlF3) on the formation and growth of mullite whiskers, and then the permeability and selectivity of the ceramic membranes were investigated. With the increase of AlF3 contents, the mullite phase evolved from needle‐like, rod‐like to flake‐like structure, thus the catalyst accelerated the growth of mullite whiskers in the diameter direction. For the ceramic membrane sintered at 1400°C, the porosity increased from 58% to 76% while the average pore sizes increased from 0.65 to 3.93 μm because of the whisker‐constructed structures. For the ceramic membrane sintered at 1450°C, the emulsion flux increased stably from 295 L/(m2·h) to 992 L/(m2·h) with the increase of trans‐membrane pressure, and the oil rejection exceeded 98%. Thus, this study provides a feasible strategy for the preparation of ceramic membranes with high porosity and excellent separation performances. [ABSTRACT FROM AUTHOR]

The orientation of hydroxyapatite whiskers ( HAw ) is one of key to design and develop bioactive ceramics for bone regeneraction. Guided behavior based on the construction of magnetic anisotropy. In this study, magnetic nanoparticles Fe3O4 were loaded onto the surface of HAw by hydrothermal method, and magnetic HAw composites with excellent magnetic response characteristics were successfully prepared. The physicochemical properties and biological properties of magnetized HAw were systematically studied, and its orientation behavior in weak magnetic field was explored. The results show that ferric oxide ( Fe3 O4) nanoparticles are successfully loaded onto the surface of HAw, and the magnetized HAw has superparamagnetism and good magnetic response at room temperature, which can be manupulated by conventional permanent magnets. The alignment direction applied by the external magnetic field is effectively fixed by combining the magnetic field-induced grouting molding technology. The results of CCK-8 experiment show that magnetized HAw has no cytotoxicity. [ABSTRACT FROM AUTHOR]

Animals interact with their environment through mechanically active, mobile sensors. The efficient use of these sensory organs implies the ability to track their position; otherwise, perceptual stability or prehension would be profoundly impeded. The nervous system may keep track of the position of a sensorimotor organ via two complementary feedback mechanisms--peripheral reafference (external, sensory feedback) and efference copy (internal feedback). Yet, the potential contributions of these mechanisms remain largely unexplored. By training male rats to place one of their vibrissae within a predetermined angular range without contact, a task that depends on knowledge of vibrissa position relative to their face, we found that peripheral reafference is not required. The presence of motor cortex is not required either, except in the absence of peripheral reafference to maintain motor stability. Finally, the red nucleus, which receives descending inputs from motor cortex and cerebellum and projects to facial motoneurons, is critically involved in the execution of the vibrissa positioning task. All told, our results point toward the existence of an internal model that requires either peripheral reafference or motor cortex to optimally drive voluntary motion. [ABSTRACT FROM AUTHOR]

We studied how the ratio of precursor titanium and boron powders influenced the combustion temperature and combustion velocity in the high-temperature self-propagating synthesis (SHS) mode, and the microstructure, phase composition, and mechanophysical properties of rods fabricated by SHS extrusion. The subject matters of the study were materials for which the as-batch phase compositions of products were TiB–(20–40) wt % Ti. The formation of boron solid solution in titanium was considered. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and mechanical measurements implied the texture of the prepared materials (TiB whiskers were aligned in the direction in which the external pressure was applied). In all of the composites studied, the conductivity was close to the conductivity of undoped titanium; the electrical resistance increased slightly in response to increasing boron weight fraction. The three-point bending strength of the material increased by a factor of 1.7 at most as the weight fraction of boron solid solution in titanium increased from 20 to 40 wt %. [ABSTRACT FROM AUTHOR]

The development of flexible and wearable devices is mainly required for tactile sensing; as such devices can adapt to complicated nonuniform surfaces, they can be applied to the human body. Nevertheless, it remains necessary to simultaneously achieve small-scale, portable, and stable developments in such devices. Thus, this work aims at fabricating a novel, lightweight, ultra-flexible, and fiber-shaped coaxial structure with a diameter of 0.51 mm using polydimethylsiloxane/graphene/nylon material, based on piezoresistive and triboelectric principles. The piezoresistive-based robotic-hand-controlled sensor thus realized exhibits a response time of 120 ms and a fast recovery time of 55 ms. Further, the piezoresistive-based sensors effectively feature whisker/joystick-guided behaviors and also sense the human finger contact. Owing to the triboelectric-based self-powered nanogenerator behavior, the resulting sensor can convert mechanical motion into electrical energy, without adversely affecting human organs. Moreover, this triboelectric-based human finger sensor can be operated under different bending modes at specific angles. Notably, this multifunctional sensor is cost-effective and suitable for various applications, including robotic-hand-controlled operations in medical surgery, whisker/joystick motions in lightweight drone technology, and navigation with high-sensitivity components. [ABSTRACT FROM AUTHOR]

The direct parametrisation method for invariant manifolds is used for model order reduction of forced-damped mechanical structures subjected to geometric nonlinearities. Nonlinear mappings are introduced, allowing one to pass from the degrees of freedom of the finite-element model to the normal coordinates. Arbitrary orders of expansions are considered for the unknown mappings and the reduced dynamics, which are then solved sequentially through the homological equations for both autonomous and time-dependent terms. It is emphasised that the two problems share a similar structure, which can be used for an efficient implementation of the non-autonomous added terms. Special emphasis is also put on the new resonance conditions arising due to the presence of the external forcing frequencies, which allow predicting phenomena such as parametric excitation and isolas formation. The method is then applied to structures of academic and industrial interest. First, the large amplitude vibrations of a forced-damped cantilever beam are studied. This example highlights that high-order non-autonomous terms are compulsory to correctly estimate the maximum vibration amplitude experienced by the structure. The birth of isolated solutions is also illustrated on this example. The cantilever is then used to show how quadratic coupling creates conditions for the excitation of the parametric instability, and that this feature is correctly embedded in the reduction process. A shallow arch excited with multi-modal forcing is then studied to detail different forcing effects. Finally, the approach is validated on a structure of industrial relevance, i.e. a comb-driven micro-electro-mechanical resonator. The accuracy and computational performance reported suggest that the proposed methodology can accurately predict the nonlinear dynamic response of a large class of nonlinear vibratory systems. [ABSTRACT FROM AUTHOR]

To realize the resource utilization of coal gangue, mullite whisker in-situ reinforced cordierite-mullite porous ceramics were synthesized using kaolin powder, coal gangue powder, talc powder, and aluminum hydroxide powder as main raw materials. Effects of the coal gangue addition (0,9%, 17%, 26% and 33%, by mass) and the AlF3 addition (0,1.5%, 2.0%, 2.5% and 3.0%, by mass) on the phase composition, the microstructure and the properties of the porous ceramics were studied. The results show that (1) the main mineral compositions of the samples are cordierite and mullite with the coal gangue addition≤= 17% and the AlF3 addition ≤2.5%; (2) raising the coal gangue addition obviously increases the bulk density and the cold compressive strength, but it is unfavorable to maintain the apparent porosity; raising the AlF3 addition reduces the bulk density and the cold compressive strength, but increases the apparent porosity; (3) with the increase of the coal gangue and the AlF3 additions, mullite whiskers have increased diameter and length to diameter ratio, showing square column-like or needle-like shapes; (4) added with 17% coal gangue and 2.5% AlF3, the porous ceramic fired at 1 350 °C for 2 h has the bulk density of 1.86 g ⋅ cm-3, the apparent porosity of 31.0% and the cold compressive strength of 27.8 MPa; the needle-like mullite whiskers in the porous ceramic form an interlocking structure and they have an average diameter of 0.5 µm and the length to diameter ratio >20. [ABSTRACT FROM AUTHOR]

Alzheimer's disease is the most frequent form of dementia in elderly people. The triple transgenic (3xTg‐AD) mouse model of Alzheimer's Disease is important in biomedical research as these mice develop both neuropathological and behavioural phenotypes. However, their behavioural phenotype is variable, with findings depending on the specific task, as well as the age and sex of the mice. Whisker movements show motor, sensory and cognitive deficits in mouse models of neurodegenerative disease. Therefore, we examined whisker movements in 3, 12.5 and 17‐month‐old female 3xTg‐AD mice and their B6129S/F2 wildtype controls. Mice were filmed using a high‐speed video camera (500 fps) in an open arena during a novel object exploration task. Genotype and age differences were found in mice exploring the arena prior to object contact. Prior to whisker contact, the 3‐month‐old 3xTg‐AD mice had smaller whisker angles compared with the wildtype controls, suggesting an early motor phenotype in these mice. Pre‐contact mean angular position at 3 months and whisking amplitude at 17 months of age differed between the 3xTg‐AD and wildtype mice. During object contact 3xTg‐AD mice did not reduce whisker spread as frequently as the wildtype mice at 12.5 and 17 months, which may suggest sensory or attentional deficits. We show that whisker movements are a powerful behavioural measurement tool for capturing behavioural deficits in mouse models that show complex phenotypes, such as the 3xTg‐AD mouse model. [ABSTRACT FROM AUTHOR]

Immune systems play a critical role in the regulation of bone formation and homeostasis, which arouses a growing interest in the development of biomaterials that can modulate both immune response and osteogenesis. In this study, biphasic calcium phosphate (BCP) ceramics were modified with different whiskered surface, and their effects on macrophage polarization and functional status were investigated. The results showed that compared to BCP-W ceramics with long and solid whiskers, BCP-HW ceramics with short and hollow whiskers surface were conducive to protein adsorption and macrophage elongation. Furthermore, BCP-HW ceramics down-regulated the expression of M1 macrophage markers (II1β, Tnfα, and iNos), promoted the expression of M2 macrophage markers (Il10 and Arg) and growth factors (Tgfβl and Bmp2), which might be attributed to the differential integrin expression regulated by different whisker structures. The conditioned medium derived from the supernatant of macrophage/whiskered ceramic co-culture was further used to culture MC3T3-E1 pre-osteoblasts to evaluate the effects of whiskered ceramic-mediated macrophage secretion on osteogenesis in vitro. Compared with BCP-W ones, the secretion pattern induced by BCP-HW ceramics could promote the expression of bone markers in pre-osteoblasts, which might due to the activation of intracellular signaling cascades like BMP/Smad and TGF-β/Smad signaling pathways. A murine intramuscular implantation model suggested that after implantation for 1, 2, and 3 weeks, BCP-HW ceramics drove the switch of macrophages to ARG+ wound-healing M2 phenotype, while BCP-W ceramics increased the proportion of iNOS+ M1 inflammatory macrophages. At 2 months, only BCP-HW could induce ectopic bone formation. Taken together, these results indicated that BCP ceramics with hollow whiskers were capable of creating a proper inflammatory microenvironment to induce bone formation. These whiskered BCP ceramics with good osteo-immunomodulatory capacity hold promise in serving as bone grafts to achieve desired bone repair and regeneration. [ABSTRACT FROM AUTHOR]

Hexagonal boron nitride (h-BN) is a novel non-metallic material which is newly discovered in the field of photocatalysis due to its high surface area, excellent optical features and high electrical conductivity. Herein, hexagonal boron nitride whiskers were fabricated by using the polymeric precursor method and, the photocatalytic degradation performance was measured towards tetracycline antibiotic under visible-light-illumination. The morphological, physical, and optical features of the catalyst were identified by several characterization analyses. The characteristic peaks associated with the hexagonal phase of boron nitride were determined and high crystallinity of h-BN was confirmed by X-ray diffraction analysis. The characteristic B-N absorption peaks were detected in the Fourier transfer infrared spectrum. Brunauer- Emmet-Teller specific surface area of the boron nitride catalyst was calculated as 1019 m2/g which was relatively high, supplying abundant active regions to interact with the target pollutant. In photocatalytic degradation experiments, 91.9% of tetracycline decomposition was achieved within 180 min with a catalyst dosage of 0.2 g/L and initial concentration of 10 mg/L. The outstanding catalytic activity of the h-BN catalyst was attributed to the high surface area and negatively charged groups on the surface which captured the photo-induced holes and inhibited the recombination rate of charge carriers. These findings highlight the potential application of h-BN in the field of photocatalytic processes. [ABSTRACT FROM AUTHOR]

Metal—organic framework-derived materials have attracted significant attention in the applications of functional materials. In this work, the rod-like nickel-based metal—organic frameworks were first synthesized and subsequently employed as the hard templates and nickel sources to prepare the whisker-shaped nickel phyllosilicate using a facile hydrothermal technology. Then, the nickel phyllosilicate whiskers were evaluated to enhance the mechanical, thermal, flammable, and tribological properties of epoxy resin. The results show that adequate nickel phyllosilicate whiskers can disperse well in the matrix, improving the tensile strength and elastic modulus by 13.6% and 56.4%, respectively. Although the addition of nickel phyllosilicate whiskers could not obtain any UL-94 ratings, it enhanced the difficulty in burning the resulted epoxy resin nanocomposites and considerably enhanced thermal stabilities. Additionally, it was demonstrated that such nickel phyllosilicate whiskers preferred to improve the wear resistance instead of the antifriction feature. Moreover, the wear rate of epoxy resin nanocomposites was reduced significantly by 80% for pure epoxy resin by adding 1 phr whiskers. The as-prepared nickel phyllosilicate whiskers proved to be promising reinforcements in preparing of high-performance epoxy resin nanocomposites. [ABSTRACT FROM AUTHOR]

Atypical sensory processing is common in autism, but how neural coding is disrupted in sensory cortex is unclear. We evaluate whisker touch coding in L2/3 of somatosensory cortex (S1) in Cntnap2 −/− mice, which have reduced inhibition. This classically predicts excess pyramidal cell spiking, but this remains controversial, and other deficits may dominate. We find that c-fos expression is elevated in S1 of Cntnap2 −/− mice under spontaneous activity conditions but is comparable to that of control mice after whisker stimulation, suggesting normal sensory-evoked spike rates. GCaMP8m imaging from L2/3 pyramidal cells shows no excess whisker responsiveness, but it does show multiple signs of degraded somatotopic coding. This includes broadened whisker-tuning curves, a blurred whisker map, and blunted whisker point representations. These disruptions are greater in noisy than in sparse sensory conditions. Tuning instability across days is also substantially elevated in Cntnap2 −/− . Thus, Cntnap2 −/− mice show no excess sensory-evoked activity, but a degraded and unstable tactile code in S1. [Display omitted] • Characterizes sensory coding in S1 cortex in the Cntnap2 −/− mouse model of autism • Broad tuning and blurred, unstable maps, but no excess sensory-evoked spiking • Reduced inhibition is associated with degraded, unstable sensory coding in Cntnap2 −/− mice Wang and Feldman characterize tactile coding abnormalities in whisker S1 cortex in the Cntnap2 −/− mouse model of autism. These mice show multiple signs of degraded sensory coding, including blurred maps and unstable tuning, but not excess spiking. Impaired discriminative coding may be a common feature of the sensory cortex in autism. [ABSTRACT FROM AUTHOR]

The pretreated desulfurization gypsum was used as raw material, the sulfuric acid was used to adjust the pH value of the reaction solution, and the desulfurization gypsum whiskers were prepared by hydrothermal method to realize green production. Through the recycling of filtrate with or without reagent compensation, the effect of cycle number of filtrate on the quality of whiskers, pH value of solution and concentration of Na+ was studied. The results show that, with the increase of cycle number of filtrate, the pH value of filtrate gradually increases, but the concentration of Na+ decreases and its loss is from 27. 3% to 34. 6% in the condition of no reagent compensation. When H2 SO4 and NaCl are used to compensate the reaction solution, the effect of cycle number of filtrate on the concentration of Ca2 + is slight before and after reaction. However, the cycle number of filtrate has an obviously effect on the crystal morphology, aspect ratio and quality of whiskers. When the cycle number of filtrate is less than 5, the quality of prepared whiskers is relatively good. [ABSTRACT FROM AUTHOR]

The addition of CaF2@SiO2 and SiC whiskers to ceramic tools can improve their flexural strength and fracture toughness, reduce surface damage, and improve their cutting performance. The cutting experiments showed that under the same cutting conditions, the surface roughness of the workpiece processed with the Al2O3/TiC/SiC/CaF2@SiO2 (ATSC10) tool was significantly lower than that of the workpiece processed with the Al2O3/TiC/ SiC (ATS) tool. Additionally, the main cutting force and cutting temperature when cutting with the ATSC10 tool were lower by 30 and 31.7%, respectively. These results were attributed to the precipitation of CaF2 from the nanocoated particles during cutting and the formation of a uniform and continuous lubricating film on the surface of the tool. The wear on the front surface of the ATS tool was mainly adhesive, and that on the back tool surface was mainly abrasive. For ATSC10, the main forms of wear on the tool front surface were adhesive and abrasive, whereas the main form of wear on the tool back surface was abrasive with slight adhesive wear. The addition of nano-coated particles and whiskers improved the mechanical properties of the cutting tool while maintaining good cutting performance. [ABSTRACT FROM AUTHOR]

Neural activity exhibits oscillations, bursts, and resonance, enhancing responsiveness at preferential frequencies. For example, theta-frequency bursting and resonance in granule cells facilitate synaptic transmission and plasticity mechanisms at the input stage of the cerebellar cortex. However, whether theta-frequency bursting of Purkinje cells is involved in generating rhythmic behavior has remained neglected. We recorded and optogenetically modulated the simple and complex spike activity of Purkinje cells while monitoring whisker movements with a high-speed camera of awake, head-fixed mice. During spontaneous whisking, both simple spike activity and whisker movement exhibit peaks within the theta band. Eliciting either simple or complex spikes at frequencies ranging from 0.5 to 28 Hz, we found that 8 Hz is the preferred frequency around which the largest movement is induced. Interestingly, oscillatory whisker movements at 8 Hz were also generated when simple spike bursting was induced at 2 and 4 Hz, but never via climbing fiber stimulation. These results indicate that 8 Hz is the resonant frequency at which the cerebellar-whisker circuitry produces rhythmic whisking. [ABSTRACT FROM AUTHOR]

The darkness of the deep ocean limits the vision of diving predators, except when prey emit bioluminescence. It is hypothesized that deep-diving seals rely on highly developed whiskers to locate their prey. However, if and how seals use their whiskers while foraging in natural conditions remains unknown. We used animal-borne tags to show that free-ranging elephant seals use their whiskers for hydrodynamic prey sensing. Small, cheek-mounted video loggers documented seals actively protracting their whiskers in front of their mouths with rhythmic whisker movement, like terrestrial mammals exploring their environment. Seals focused their sensing effort at deep foraging depths, performing prolonged whisker protraction to detect, pursue, and capture prey. Feedingevent recorders with light sensors demonstrated that bioluminescence contributed to only about 20% of overall foraging success, confirming that whiskers play the primary role in sensing prey. Accordingly, visual prey detection complemented and enhanced prey capture. The whiskers' role highlights an evolutionary alternative to echolocation for adapting to the extreme dark of the deep ocean environment, revealing how sensory abilities shape foraging niche segregation in deep-diving mammals. Mammals typically have mobile facial whiskers, and our study reveals the significant function of whiskers in the natural foraging behavior of a marine predator. We demonstrate the importance of fieldbased sensory studies incorporating multimodality to better understand how multiple sensory systems are complementary in shaping the foraging success of predators. [ABSTRACT FROM AUTHOR]

The whiskers of rodents are a key sensory organ that provides critical tactile information for animal navigation and object exploration throughout life. Previous work has explored the developmental sensory-driven activation of the primary sensory cortex processing whisker information (wS1), also called barrel cortex. This body of work has shown that the barrel cortex is already activated by sensory stimuli during the first postnatal week. However, it is currently unknown when over the course of development these stimuli begin being processed by higher-order cortical areas, such as secondary whisker somatosensory area (wS2). Here we investigate the developmental engagement of wS2 by whisker stimuli and the emergence of corticocortical communication from wS1 to wS2. Using in vivo wide-field imaging and multielectrode recordings in control and conditional KO mice of either sex with thalamocortical innervation defects, we find that wS1 and wS2 are able to process bottom-up information coming from the thalamus from birth. We also identify that it is only at the end of the first postnatal week that wS1 begins to provide functional excitation into wS2, switching to more inhibitory actions after the second postnatal week. Therefore, we have uncovered a developmental window when information transfer between wS1 and wS2 reaches mature function. [ABSTRACT FROM AUTHOR]

While cells within barrel cortex respond primarily to deflections of their principal whisker (PW), they also exhibit responses to non-principal, or adjacent, whiskers (AWs), albeit responses with diminished amplitudes and longer latencies. The origin of multiwhisker receptive fields of barrel cells remains a point of controversy within the experimental literature, with three contending possibilities: (i) barrel cells inherit their AW responses from the AW responses of thalamocortical (TC) cells within their aligned barreloid; (ii) the axons of TC cells within a barreloid ramify to innervate multiple barrels, rather than only terminating within their aligned barrel; (iii) lateral intracortical transmission between barrels conveys AW responsivity to barrel cells. In this work, we develop a detailed, biologically plausible model of multiple barrels in order to examine possibility (iii); in order to isolate the dynamics that possibility (iii) entails, we incorporate lateral connections between barrels while assuming that TC cells respond only to their PW and that TC cell axons are confined to their home barrel. We show that our model is capable of capturing a broad swath of experimental observations on multiwhisker receptive field dynamics within barrels, and we compare and contrast the dynamics of this model with model dynamics from prior work in which employ a similar general modeling strategy to examine possibility (i). [ABSTRACT FROM AUTHOR]

Copyright of Journal of Synthetic Crystals is the property of Journal of Synthetic Crystals Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Individual longitudinal records of diet, movement, and physiological state of endangered Tasmanian devils (Sarcophilus harrisii) are needed for effective management of wild populations, yet most traditional techniques are expensive or labor‐intensive. Stable isotope analysis of inert tissue, such as vibrissae (whiskers), provides a viable and minimally invasive solution to chronologically record the foraging ecology and habitat use of individuals. Species‐specific information on whisker growth (i.e., time‐position growth of isotopic signatures), retention time, and arrangement on the face is required before the implementation of stable isotope analysis in wild populations. Here, whiskers of six captive Tasmanian devils were internally marked with 13C‐ and 15N‐labeled glycine at three‐month intervals followed by isotopic analysis of the longest whisker to provide a time stamp for whisker growth and estimate retention time. Intradermal and extradermal lengths of wild Tasmanian devil whiskers were used to assess the arrangement and relative length of whiskers on the face. We found that whiskers can record at least nine months of an animal's ecological history and that whisker growth is not linear, the growth gradually slows down as the whisker lengthens. Our findings demonstrate that sequentially sampled whiskers have the potential to track monthly and seasonal isotopic changes of an individual animal in the wild, both within its historical range and in areas to which it has recently been introduced. Such information can be used to identify temporal shifts in habitat and prey preferences within populations and help select suitable individuals for translocations. We recommend that the longest mystacial whiskers, positioned posteriorly at the third and fourth row, should be preferentially used for stable isotope studies in this species. The timeframe represented by the root of the whisker (˜3–63 d) can be used to adjust the base of cut whiskers to the correct time period. [ABSTRACT FROM AUTHOR]

The function of the higher-order sensory thalamus remains unclear. Here, the posterior medial (POm) nucleus of the thalamus was examined by in vivo extracellular recordings in anesthetized rats across a variety of contralateral, ipsilateral, and bilateral whisker sensory patterns. We found that POm was highly sensitive to multiwhisker stimuli involving diverse spatiotemporal interactions. Accurate increases in POm activity were produced during the overlapping time between spatial signals reflecting changes in the spatiotemporal structure of sensory patterns. In addition, our results showed for first time that POm was also able to respond to tactile stimulation of ipsilateral whiskers. This finding challenges the notion that the somatosensory thalamus only computes unilateral stimuli. We found that POm also integrates signals from both whisker pads and described how this integration is generated. Our results showed that ipsilateral activity reached one POm indirectly from the other POm and demonstrated a transmission of sensory activity between both nuclei through a functional POm-POm loop formed by thalamocortical, interhemispheric, and corticothalamic projections. The implication of different cortical areas was investigated revealing that S1 plays a central role in this POm-POm loop. Accordingly, the subcortical and cortical inputs allow POm but not the ventral posteromedial thalamic nucleus (VPM) to have sensory information from both sides of the body. This finding is in agreement with the higher-order nature of POm and can be considered to functionally differentiate and classify these thalamic nuclei. A possible functional role of these higher-order thalamic patterns of integrated activity in brain function is discussed. [ABSTRACT FROM AUTHOR]

Copyright of China Plastics / Zhongguo Suliao is the property of Journal Office of CHINA PLASTICS and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aluminum nitride (AlN) usually exhibits a microstructure consisting of equiaxed grains. However, these grains do not allow for the positive control of the microstructure and mechanical properties of AlN. In this work, we attempted to control the microstructure of AlN through the addition of whiskers and investigated the relationship between the microstructure and mechanical properties. The sintered AlN showed a microstructure consisting of large, rod-like grains, which originated from the whiskers. Furthermore, the microstructure varied with the size and amount of whiskers added, and so did the flexural strength and fracture toughness. The flexural strength and fracture toughness of the whisker-added AlN samples ranged from 197 to 267 MPa and 5.4 to 6.4 MPa m1/2, respectively. In contrast, those of AlN without whiskers were 336 MPa and 3.1 MPa m1/2, respectively. [ABSTRACT FROM AUTHOR]

Cerebellar Purkinje neurons help compute absolute subsecond timing, but how their firing is affected during repetitive sensory stimulation with consistent subsecond intervals remains unaddressed. Here, we investigated how simple and complex spikes of Purkinje cells change during regular application of air puffs (3.3 Hz for ~4 min) to the whisker pad of awake, head-fixed female mice. Complex spike responses fell into two categories: those in which firing rates increased (at ~50 ms) and then fell [complex spike elevated (CxSE) cells] and those in which firing rates decreased (at ~70 ms) and then rose [complex spike reduced (CxSR) cells]. Both groups had indistinguishable rates of basal complex (~1.7 Hz) and simple (~75 Hz) spikes and initially responded to puffs with a well-timed sensory response, consisting of a short-latency (~15 ms), transient (4 ms) suppression of simple spikes. CxSE more than CxSR cells, however, also showed a longer-latency increase in simple spike rate, previously shown to reflect motor command signals. With repeated puffs, basal simple spike rates dropped greatly in CxSR but not CxSE cells; complex spike rates remained constant, but their temporal precision rose in CxSR cells and fell in CxSE cells. Also over time, transient simple spike suppression gradually disappeared in CxSE cells, suggesting habituation, but remained stable in CxSR cells, suggesting reliable transmission of sensory stimuli. During stimulus omissions, both categories of cells showed complex spike suppression with different latencies. The data indicate two modes by which Purkinje cells transmit regular repetitive stimuli, distinguishable by their climbing fiber signals. [ABSTRACT FROM AUTHOR]

Across all sensory modalities, first-stage sensory neurons are an information bottleneck: they must convey all information available for an animal to perceive and act in its environment. Our understanding of coding properties of primary sensory neurons in the auditory and visual systems has been aided by the use of increasingly complex, naturalistic stimulus sets. By comparison, encoding properties of primary somatosensory afferents are poorly understood. Here, we use the rodent whisker system to examine how tactile information is represented in primary sensory neurons of the trigeminal ganglion (Vg). Vg neurons have long been thought to segregate into functional classes associated with separate streams of information processing. However, this view is based on Vg responses to restricted stimulus sets which potentially underreport the coding capabilities of these neurons. In contrast, the current study records Vg responses to complex three-dimensional (3D) stimulation while quantifying the complete 3D whisker shape and mechanics, thereby beginning to reveal their full representational capabilities. The results show that individual Vg neurons simultaneously represent multiple mechanical features of a stimulus, do not preferentially encode principal components of the stimuli, and represent continuous and tiled variations of all available mechanical information. These results directly contrast with proposed codes in which subpopulations of Vg neurons encode select stimulus features. Instead, individual Vg neurons likely overcome the information bottleneck by encoding large regions of a complex sensory space. This proposed tiled and multidimensional representation at the Vg directly constrains the computations performed by more central neurons of the vibrissotrigeminal pathway. [ABSTRACT FROM AUTHOR]

A comparative analysis of the electrical conductivity of whisker, epitaxial film, and single crystal of tellurium was undertaken in the 77–273 K temperature range. The electrical conductivity of the film and single crystal increases monotonically up to 200 K, after which it begins to rise steeply, corresponding to the thermal excitation of intrinsic carriers. The electrical conductivity of whiskers decreases with increasing temperature to 230 K, after which it begins to increase more gradually. It is assumed that in the case of tellurium whiskers, the classical size effect takes place: the decrease in electrical conductivity is due to diffuse scattering of carriers by the lateral surface of the crystal of tellurium and is intensified with increasing temperature. The uneven, tightly-convoluted surface of developed samples is shown in images produced in a scanning electron microscope in the nanometer range. [ABSTRACT FROM AUTHOR]

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The classical view of sensory information mainly flowing into barrel cortex at layer IV, moving up for complex feature processing and lateral interactions in layers II and III, then down to layers V and VI for output and corticothalamic feedback is becoming increasingly undermined by new evidence. We review the neurophysiology of sensing and processing whisker deflections, emphasizing the general processing and organisational principles present along the entire sensory pathway--from the site of physical deflection at the whiskers to the encoding of deflections in the barrel cortex. Many of these principles support the classical view. However, we also highlight the growing number of exceptions to these general principles, which complexify the system and which investigators should be mindful of when interpreting their results. We identify gaps in the literature for experimentalists and theorists to investigate, not just to better understand whisker sensation but also to better understand sensory and cortical processing. [ABSTRACT FROM AUTHOR]

Zinc borate having the formula of 4ZnO·B2O3·H2O has been used as a fire retardant for polymers requiring high processing temperatures since it has a high dehydration temperature (around 415°C). The effects of reaction time, reaction temperature were investigated on the heterogeneous reaction between solid zinc oxide and boric acid solution. A stoichiometric amount of zinc oxide and 5.0% excess boric acid were used in experiments and the other parameters, mixing speed (1700 rpm), the solid-liquid ratio of 20%, and the amount of seed crystal (3.9% wt) were kept constant for all experiments. A 91.1% conversion was obtained at 120°C for 5 h of reaction time. Precipitated product was filtered and washed by hot water to remove the excess boric acid. Finally it was dried until reaching to a constant mass in an air circulating oven at 105°C. Powder products were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). FTIR spectrum and XRD pattern of powders are consistent with data of the zinc borate given in the literature. According to SEM analysis, whiskers are less than 1 μm in diameter and their lengths are in the range of 1–10 μm. [ABSTRACT FROM AUTHOR]

Women approximate one-third of the annual 2.8 million people in the United States who sustain traumatic brain injury (TBI). Several clinical reports support or refute that menstrual cycle-dependent fluctuations in sex hormones are associated with severity of persisting post-TBI symptoms. Previously, we reported late-onset sensory hypersensitivity to whisker stimulation that corresponded with changes in glutamate neurotransmission at 1-month following diffuse TBI in male rats. Here, we incorporated intact age-matched naturally cycling females into the experimental design while monitoring daily estrous cycle. We hypothesized that sex would not influence late-onset sensory hypersensitivity and associated in vivo amperometric extracellular recordings of glutamate neurotransmission within the behaviorally relevant thalamocortical circuit. At 28 days following midline fluid percussion injury (FPI) or sham surgery, young adult Sprague-Dawley rats were tested for hypersensitivity to whisker stimulation using the whisker nuisance task (WNT). As predicted, both male and female rats showed significantly increased sensory hypersensitivity to whisker stimulation after FPI, with females having an overall decrease in whisker nuisance scores (sex effect), but no injury and sex interaction. In males, FPI increased potassium chloride (KCl)-evoked glutamate overflow in primary somatosensory barrel cortex (S1BF) and ventral posteromedial nucleus of the thalamus (VPM), while in females the FPI effect was discernible only within the VPM. Similar to our previous report, we found the glutamate clearance parameters were not influenced by FPI, while a sex-specific effect was evident with female rats showing a lower uptake rate constant both in S1BF and VPM and longer clearance time (in S1BF) in comparison to male rats. Fluctuations in estrous cycle were evident among brain-injured females with longer diestrus (low circulating hormone) phase of the cycle over 28 days post-TBI. Together, these findings add to growing evidence indicating both similarities and differences between sexes in a chronic response to TBI. A better understanding of the influence of gonadal hormones on behavior, neurotransmission, secondary injury and repair processes after TBI is needed both clinically and translationally, with potential impact on acute treatment, rehabilitation, and symptom management. [ABSTRACT FROM AUTHOR]

The effect of graphene content (0.08, 0.16 and 0.33 wt.%) on the thermal conductivity and thermal aging performance of an Sn based composite material with 0.7 wt.% Cu and various graphene additions was investigated via X-ray diffraction (XRD), scanning electron microscope (SEM) and accelerated thermal aging test. The XRD results showed that the graphene diffraction intensity was weak (approximately 10∘) due to little content and distribution of the graphene on the surface of the composite materials. After thermal aging testing the diffraction intensity on some crystal planes of the composite materials was enhanced, proving that preferential growth occurs on the crystal plane. SEM results showed that before aging testing no whiskers were generated on the surface of the composite materials. After the accelerated thermal aging at 100∘C for 24 h, whisker growth became apparent in the composite materials. All the whiskers were located in the grains rather than on the grain boundaries of the composite materials. The highest thermal conductivity was obtained at 0.16 wt.% graphene addition (indicated as 0.16 wt.% graphene–0.7 wt.% Cu/Sn). After the accelerated thermal aging at 100∘C for 24 h, the bamboo-shaped whiskers with a low aspect ratio grew in large quantities on the surface of the 0.16 wt.% graphene–0.7 wt.% Cu/Sn composite material, while when the aging was at 100∘C for 366 h the thermal conductivity decreased from 67 W m − 1 K − 1 to 52 W m − 1 K − 1 . When the graphene addition was 0.33 wt.% (indicated as 0.33 wt.% graphene–0.7 wt.% Cu/Sn) the thermal conductivity maintains a value above 59 W m − 1 K − 1 after the accelerated thermal aging. [ABSTRACT FROM AUTHOR]

Pentagonal noble metal crystals, with a five-fold-twinned (FFT) structure that exhibits prominent noncrystallographic symmetry, have been the focus of research in the past several decades due to their promising applications in various fields such as chemical and biological sensors, electronics and optoelectronics. A great deal of previous experimental studies and theoretical analyses suggested that such an FFT structure could only exist in the nanoscale crystals, because of the lateral restriction in growth, or in microscale crystals with re-entrant grooves that can effectively release the internal strain. In this study, we synthesized the microscale single-crystalline and multi-twinned Ag crystals with various morphologies, using physical vapor deposition (PVD). FFT Ag microwhiskers with diameters up to 10 μ m were produced, but without re-entrant grooves on their side surfaces. Our findings suggest that FFT whiskers can be formed without the use of any surface-capping agents or without necessitating restriction in lateral growth. This further suggests that the current understanding of the surface passivation or the strain-restriction formation of five-fold-twined micro- and nanowhiskers needs improvement. [ABSTRACT FROM AUTHOR]

The broad range of possibilities for optimizing the design and electrical parameters of crystals of Schottky diodes, manufactured according to the mesa–substrate and mesa–mesa planar technologies with anode terminals in the form of an air bridge with a whisker, along with the use of higher quality compact models, make it possible to efficiently exploit the physical potential of Schottky contacts when designing monolithic integrated circuits according to diode technologies, increase their reliability, and overcome the significant lag of semiconductor electronics behind optoelectronics in the terahertz (THz) frequency range. [ABSTRACT FROM AUTHOR]

The relationships between the reinforcing index (RI: the product of volume fraction and length-to-diameter ratio of fibers) and rheological parameters (hysteresis loop area, yield stress, plastic viscosity, flow spread, and flow rate) of a single type of fiber-reinforced cementitious composites (SgFRCCs) and hybrid fiber-reinforced cementitious composites (HyFRCCs) with steel, polyvinyl alcohol (PVA) fibers, and calcium carbonate (CaCO3) whiskers, were systematically studied for the first time. After shearing action, short whiskers between cement particles prevented the cement particles from coming close to each other, leading to more irreversible broken structures in the entire rheological test process, which means higher hysteresis loop areas than those of longer fibers. The new hybrid fiber system decreased the yield stress and plastic viscosity to a certain extent, as a result of the "grading effect" of hybrid fibers and whiskers. Based on the theoretical framework of random loose packing, the critical RI values for single PVA fibers and hybrid fibers were approximately 1.0 and 2.0, respectively, which supports this theoretical framework and the effect of critical RI values in fiber-reinforced mortar. The influence of the RI on the characteristics of fresh HyFRCCs can be quantified well into a multivariate linear relationship. Moreover, these findings can be used to optimize fiber mixtures in practical project applications. [ABSTRACT FROM AUTHOR]

Based on previous research, hydrogen has an enhancing effect on the kinetics of the Si-O-C system [1-3]. In this study silicon carbide (SiC) formation, from a reaction between SiO(g) and carbon, were investigated in a hydrogen atmosphere, an argon atmosphere, and an argon atmosphere containing 10% methane, at temperatures between 1495°C and 1695°C. The SiO(g) was generated from pellets comprised of a 2:1 ratio of silica (SiO2) and SiC. The SiO(g) generation was monitored through analysis of the CO(g) content of the off-gas, the results indicated that the hydrogen atmosphere had an enhancing effect on SiO(g) generation through this reaction. Samples were retrieved from various locations within the set-up: the crucible, the reaction chamber roof, and from the condensation chamber. The reaction products were imaged in SEM using secondary electrons. SiC was found growing throughout the reaction chamber, when using an argon atmosphere, a layer of SiC was found covering the graphite parts, whereas utilising a hydrogen atmosphere, or argon with 10% methane, the SiC would instead grow as whiskers. Thermal decomposition of methane is expected to be a challenge in this temperature range [4]. [ABSTRACT FROM AUTHOR]

Rats can be trained to associate relative spatial locations of objects with the spatial location of rewards. Here we ask whether rats can localize static silent objects with other body parts in the dark, and if so with what resolution. We addressed these questions in trained rats, whose interactions with the objects were tracked at high-resolution before and after whisker trimming. We found that rats can use other body parts, such as trunk and ears, to localize objects. Localization resolution with non-whisking body parts (henceforth, 'body') was poorer than that obtained with whiskers, even when left with a single whisker at each side. Part of the superiority of whiskers was obtained via the use of multiple contacts. Transfer from whisker to body localization occurred within one session, provided that body contacts with the objects occurred before whisker trimming, or in the next session otherwise. This transfer occurred whether temporal cues were used for discrimination or when discrimination was based on spatial cues alone. Rats' decision in each trial was based on the sensory cues acquired in that trial and on decisions and reward locations in previous trials. When sensory cues were acquired by body contacts, rat decisions relied more on the reward location in previous trials. Overall, the results suggest that rats can generalize the idea of relative object location across different body parts, while preferring to rely on whiskers-based localization, which occurs earlier and conveys higher resolution. [ABSTRACT FROM AUTHOR]

Rats can be trained to associate relative spatial locations of objects with the spatial location of rewards. Here we ask whether rats can localize static silent objects with other body parts in the dark, and if so with what resolution. We addressed these questions in trained rats, whose interactions with the objects were tracked at high-resolution before and after whisker trimming. We found that rats can use other body parts, such as trunk and ears, to localize objects. Localization resolution with non-whisking body parts (henceforth, 'body') was poorer than that obtained with whiskers, even when left with a single whisker at each side. Part of the superiority of whiskers was obtained via the use of multiple contacts. Transfer from whisker to body localization occurred within one session, provided that body contacts with the objects occurred before whisker trimming, or in the next session otherwise. This transfer occurred whether temporal cues were used for discrimination or when discrimination was based on spatial cues alone. Rats' decision in each trial was based on the sensory cues acquired in that trial and on decisions and reward locations in previous trials. When sensory cues were acquired by body contacts, rat decisions relied more on the reward location in previous trials. Overall, the results suggest that rats can generalize the idea of relative object location across different body parts, while preferring to rely on whiskers-based localization, which occurs earlier and conveys higher resolution. [ABSTRACT FROM AUTHOR]

Rodents are the most commonly studied model system in neuroscience, but surprisingly few studies investigate the natural sensory stimuli that rodent nervous systems evolved to interpret. Even fewer studies examine neural responses to these natural stimuli. Decades of research have investigated the rat vibrissal (whisker) system in the context of direct touch and tactile stimulation, but recent work has shown that rats also use their whiskers to help detect and localize airflow. The present study investigates the neural basis for this ability as dictated by the mechanical response of whiskers to airflow. Mechanical experiments show that a whisker’s vibration magnitude depends on airspeed and the intrinsic shape of the whisker. Surprisingly, the direction of the whisker’s vibration changes as a function of airflow speed: vibrations transition from parallel to perpendicular with respect to the airflow as airspeed increases. Recordings from primary sensory trigeminal ganglion neurons show that these neurons exhibit responses consistent with those that would be predicted from direct touch. Trigeminal neuron firing rate increases with airspeed, is modulated by the orientation of the whisker relative to the airflow, and is influenced by the whisker’s resonant frequencies. We develop a simple model to describe how a population of neurons could leverage mechanical relationships to decode both airspeed and direction. These results open new avenues for studying vibrissotactile regions of the brain in the context of evolutionarily important airflow-sensing behaviors and olfactory search. Although this study used only female rats, all results are expected to generalize to male rats. [ABSTRACT FROM AUTHOR]

Background: Nerve reconstructive surgery induces a transient loss and a prolonged and a gradual return of sensory inputs to the brain. It is unknown whether, following this massive peripheral denervation, the brain will experience a prolonged period of severe, intrinsic dysfunction. Objective: We aim to investigate the mechanisms of return of processing function in cortical neurons. Methods: We used the whisker model in rats to evaluate the functional recovery in the somatosensory cortex after a nerve reconstruction surgery. Multi-unit recording in the barrel cortex was performed in lightly anesthetized rats while their whiskers were stimulated by a whisker stimulator. Results: We observed a loss of neuronal responses to whisker stimulation 1 week after surgery, which started to recover 2 weeks after surgery. Following the surgery, only 11.8% of units had principle whiskers (PWs) returned to their original status while 17.7% had PWs different from their original status, indicating the effect of aberrant reinnervation on the whisker response map. Conclusions: Robust neuronal responses to sensory stimulation even when only sparse sensory inputs are available in the early recovery phase. During this phase, aberrant reinnervation induces disorganized whisker tuning, a finding that might be account for the hypoesthesia and paresthesia during early recovery after nerve reconstruction. [ABSTRACT FROM AUTHOR]

Recent work has quantified the geometric parameters of individual rat vibrissae (whiskers) and developed equations that describe how these parameters vary as a function of row and column position across the array. This characterization included a detailed quantification of whisker base diameter and arc length as well as the geometry of the whisker medulla. The present study now uses these equations for whisker geometry to quantify several properties of the whisker that govern its mechanical behavior. We first show that the average density of a whisker is lower in its proximal region than in its distal region. This density variation appears to be largely attributable to the presence of the whisker cuticle rather than the medulla. The density variation has very little effect on the center of mass of the whisker. We next show that the presence of the medulla decreases the deflection of the whisker under its own weight and also decreases its mass moment of inertia while sacrificing <1% stiffness at the whisker base compared with a solid whisker. Finally, we quantify two dimensionless parameters across the array. First, the deflection-to-length ratio decreases from caudal to rostral: caudal whiskers are longer but deflect more under their own weight. Second, the nondimensionalized radius of gyration is approximately constant across the array, which may simplify control of whisking by the intrinsic muscles. We anticipate that future work will exploit the mechanical properties computed in the present study to improve simulations of the mechanosensory signals associated with vibrissotactile exploratory behavior. NEW & NOTEWORTHY The mechanical signals transmitted by a whisker depend critically on its geometry. We used measurements of whisker geometry and mass to quantify the center of mass, mass moment of inertia, radius of gyration, and deflection under gravity of the whisker. We describe how variations in these quantities across the array could enhance sensing behaviors while reducing energy costs and simplifying whisking control. Most importantly, we provide derivations for these quantities for use in future simulation work. [ABSTRACT FROM AUTHOR]

Alaskan seals are found in remote and sometimes inaccessible locations, making it difficult to collect time‐series information. This study explores a novel method to examine temporal changes in diet and physiological status of ringed (Pusa hispida), spotted (Phoca largha), and harbor (Phoca vitulina) seals using cortisol concentrations and δ15N and δ13C stable isotopes (SIs) measured in serial sections of whiskers. As whiskers grow, whisker tissue is deposited sequentially making these measurements temporally aligned. Whisker cortisol presented in a distinct pattern with elevated concentrations at the root section followed by a curvilinear decline moving toward the tip of most whiskers. Comparing SIs at the root to the rest of the whiskers, δ13C values were slightly lower in ringed and harbor seal whiskers and δ15N values were slightly higher in harbor seal whiskers. The data were modeled controlling for the observed trends in cortisol concentrations and further associations between cortisol concentrations and SIs were detected in spotted and harbor seal whiskers. Additional research examining the source and stability of whisker cortisol is warranted. However, the methods presented here demonstrate that whiskers could prove valuable to gather long‐term and naturally aligned dietary and physiological information. [ABSTRACT FROM AUTHOR]

Metallic whiskers of pure lead (Pb) have been observed in the solder of several types of transistors. The conditions that lead to these whiskers were evaluated, including characterization of the whisker lengths and whisker density as a function of time and temperature. The potential cause and impact they would have on the reliability of electronics has been investigated. Based on these results, it is hypothesized that these whiskers may be caused by the relief of residual stresses that are created during the evolution of Au-In and/or Au-Pb intermetallic compounds or, possibly, by a decomposition of the AuPb3 phase. Due to their small size, the Pb whiskers that were observed were considered to not be a reliability concern, but similar or larger Pb whiskers could cause electrical failure in some applications. [ABSTRACT FROM AUTHOR]