Hairy Surface Research Articles

Youngiahangii (Asteraceae, Crepidinae), a new species from Hubei, China.

Youngiahangii T.Deng, D.G.Zhang, Qun Liu & Z.M.Li, sp. nov., a new species of Asteraceae, is described and illustrated. It was collected in Wufeng County, Hubei Province, Eastern Central China. Youngiahangii is morphologically most similar to Y.rubida, but can be easily distinguished from the latter by capitula with 8–10 florets and the hairy leaf surface. Phylogenetic analyses, based on the internal transcribed spacers (ITS) and one chloroplast marker (rps16), showed that Y.hangii and Y.rubida were sister species with good support. The results of both phylogenetic analysis and the morphological data support the specific rank of Y.hangii.

Dust Capturing Capacity of Woody Plants in Clean Air Zones throughout Taiwan

To exploit the ability of vegetation to capture particulate matter (dust) from the air and improve air quality, 546 clean air zones (CAZs) consisting of various types of urban green space have been established in Taiwan. This study systematically assessed the pollutant filtering efficiency of tree species planted in these green spaces. This research aims to provide quantitative data on individual trees’ dust retention functions for future green space planning in urban areas. Field surveys were conducted in 98 CAZs throughout Taiwan. The vegetation composition of approximately 14,000 woody trees, consisting of 210 species, was surveyed. The vegetation surveyed showed that the dominant species in many CAZs in southern Taiwan were introduced species. The dust capturing capacity of the tree species was found to be positively correlated with leaf size. However, the amount of dust retention was affected mainly by the surface structure and morphological characteristics of the leaves, such as a rough, hairy surface. Among the tree species, Spathodea campanulata, Pterocarpus indicus, and Delonix regia exhibited the best dust capture and retention capacity in southern Taiwan, and Ficus macrocarpa, Alstonia scholaris, and Melia azedarach were the most desirable dust retention species. The results suggest that native evergreen species are suitable for dust retention in urban green spaces.

Hairy-Layer Friction Reduction Mechanism in the Honeybee Abdomen.

Abdominal sections of honeybees undergo numerous reciprocating motions during their lifetime. However, the overlapped contact areas adjacent to the abdominal sections have a shallow wear extent, a physical mechanism that remains obscure to date. Therefore, this study explored a biofrictional reduction model based on a solid surface texture and the hairy surface of the honeybee abdomen. We collected honeybee samples and observed their abdomens using a camera (Zeiss Stemi 508). Subsequently, we sliced these samples using a microtome and detected their microscopic friction. The exterior surface of the honeybee abdomen was not smooth but was distributed with a dense microvilli structure, which played a vital role in adjusting the friction reduction characteristics between the abdominal sections. When the adjacent abdominal sections moved relatively to each other, their upper and lower surfaces were not in direct rigid contact. Briefly, this study shows that the microscale hair arrays on the surface of the posterior abdominal segment can significantly reduce real contact area and friction, which considerably decreases wear or abrasion. The friction reduction mechanism alleviates the abrasion during the relative bending movement and saves a large amount of energy, which is essential for the honeybees' daily activities. This microtexture compliance friction reduction characteristic could be used to fabricate hierarchical surfaces for long-lasting friction reduction mechanisms, which increase the life of soft devices, including soft actuators and hinges.

Robust Performance of Spider Viscid Silk on Hairy and Smooth Insect Substrates.

Spider viscid silk adheres to insects in orb webs and is a "smart-adhesive" that quickly changes droplet size, viscosity, and adhesiveness in response to atmospheric humidity. Different species of spiders "tune" water uptake to match the humidity of their foraging environments, achieving a similar "universal" viscosity that optimizes tradeoffs in spreading versus cohesive bulk energy needed to enhance adhesion. Too much water lowers viscosity so that the glue spreads well, but cohesive failure occurs easily, generating poor adhesion. However, the optimal viscosity model of adhesion is based on experiments using smooth glass. Here we test the hypothesis that a less viscous, "over-lubricated" glue, which shows poor adhesion on smooth glass, will be stickier on hairy insects because of its greater ability to spread across three-dimensional rough surfaces. We ran adhesion tests of the furrow spider (Larinioides cornutus [Clerck 1757]) viscid silk on honey bee (Apis mellifera) thorax, with and without hairs, in either high or medium humidity. Our results show that "over-lubricated" glue increases adhesion on hairy surfaces, performing equally as well as an optimally viscous glue.

Micromonospora veneta sp. nov., an endophytic actinobacterium with potential for nitrogen fixation and for bioremediation

Strain CAP181T, an endophytic actinobacterium, was isolated from a surface sterilized root sample of a native pine tree, Flinders University, Adelaide, South Australia. Chemotaxonomic data including cell wall components, major fatty acids, and major menaquinones confirmed the affiliation of strain CAP181T to the genus Micromonospora. This strain was Gram stain positive with well-developed substrate mycelia to forma single spore with hairy surface. The phylogenetic tree showed that M. coerulea NBRC 13504T is the closest phylogenetic neighbour, sharing 99.2% 16S rRNA gene similarity and the next closest neighbor is M. chaiyaphumensis DSM 45246T (98.7%). Genome mining of this strain revealed genes encoding to enzymes relating to nitrogen fixation and bioremediation. Based on genotypic and phenotypic studies including DNA-DNA hybridization data, strain CAP181T was different from any of the closely related species with valid names. The name proposed for the new species is Micromonospora veneta sp. nov. The type strain is CAP181T (= DSM 109713T = NRRL B-65535T).

A Morphable Ionic Electrode Based on Thermogel for Non-Invasive Hairy Plant Electrophysiology.

Plant electrophysiology lays the foundation for smart plant interrogation and intervention. However, plant trichomes with hair-like morphologies present topographical features that challenge stable and high-fidelity non-invasive electrophysiology, due to the inadequate dynamic shape adaptability of conventional electrodes. Here, this issue is overcome using a morphable ionic electrode based on a thermogel, which gradually transforms from a viscous liquid to a viscoelastic gel. This transformation enables the morphable electrode to lock into the abrupt hairy surface irregularities and establish a conformal and adhesive interface. It achieves down to one tenth of the impedance and 4-5 times the adhesive strengths of conventional hydrogel electrodes on hairy leaves. As a result of the improved electrical and mechanical robustness, the morphable electrode can record more than one order of magnitude higher signal-to-noise ratio on hairy plants and maintains high-fidelity recording despite plant movements, achieving superior performance to conventional hydrogel electrodes. The reported morphable electrode is a promising tool for hairy plant electrophysiology and may be applied to diversely textured plants for advanced sensing and modulation.

Echinops sahyadricus sp. nov. (Asteraceae: Cardueae), from the northern Western Ghats, Maharashtra, India

The new species Echinops sahyadricus is discovered and described from northern Western Ghats, India. It is endemic to the Maharashtra state and probably restricted to few high mountain peaks in Western Maharashtra. The new species is distinguished from the related E. echinatus by adaxially glabrous to sparsely elgandular hairy leaf surfaces, larger non‐cornigerous synflorescences up to 9 cm in diameter and numerous (19–24) glabrous phyllaries up to 27 mm long. An identification key to all Indian taxa of Echinops, illustration and colour plates are provided.

Identifying Counterfeit Cigarettes Using Environmental Pollen Analysis: An Improved Procedure.

Traditional pollen preparation techniques provide clear residues for pollen identification; however, such methods are time-consuming, requiring repeated centrifugation, heating, and digestion with high-concentration hazardous chemicals. Tobacco leaves can effectively trap environmental pollen due to hairy surface and terpene-rich exudates. A new tobacco sample processing method was developed by using different extraction chemistry with surfactant. Marlboro Gold cigarettes were employed as model samples for method development. Parameters critical for pollen extraction, which include number of cigarette sticks used, extraction solution, and extraction temperature, were optimized. By using 1% dishwashing detergent to treat three cigarettes at room temperature, the improved method was able to recover sufficient pollen for microscopic analysis in three repeated centrifuge-washing steps and omit hazardous chemicals involved in traditional methods. We focused on the pollen of common ragweed (Ambrosia artemisiifolia), a plant native to North America, as an indicator to differentiate genuine and counterfeit U.S. brand cigarettes. Results from analyzing randomly purchased genuine (authenticated by forensic examination) and known counterfeit Marlboro Gold provided by law enforcement revealed that a significant amount (39%) of Ambrosia were consistently present in all genuine samples, while counterfeit contained none or only trace count. Similar results were found in other counterfeit U.S. brand cigarettes (all seized in the U.S.) involved in this study as well. Lack of Ambrosia in cigarette strongly indicates the product was not originated in the United States.

Slippery and magnetically responsive micropillared surfaces for manipulation of droplets and beads

Stimuli-responsive surfaces are of practical importance for applications ranging from enhanced mixing of reagents in lab-on-a-chip systems until probing cellular traction forces. Non-destructive reversible bending of cilia-inspired magnetic pillars can be used for controlled transportation of non-magnetic objects and bio-inspired sensing. Magnetic actuation of micropillars suspended in liquids allows controlled mixing, propelling, and stirring of fluids as well as droplet manipulation, which are important for various applications including generation of cell spheroids and droplet coalescence in microfluidic systems. In order to expand their practical applications, fabrication processes capable of rapid prototyping have to be developed. Inspired by biological cilia and their functionalities, actuating hairy surfaces are herein fabricated and implemented to manipulate both microbeads and droplets. The artificial cilia are based on microscale magnetic pillar arrays made of flexible polydimethylsiloxane functionalized with magnetic microparticles. The arrays are fabricated by a new method using patterned molds that relies on cryogenic separation to produce transparent cilia-inspired arrays without requiring manual interference to clean the templates during the process. Magnetic actuation of the pillar arrays is demonstrated in isopropanol and silicone oil. Filling with oil yields magnetically responsive slippery lubricated surfaces allowing directional motion of droplets by repetitive bending and recovery of the flexible magnetic pillars. The achieved structures allow manipulation of microbeads and droplets which is uncommon even at the sub-mm scale; directional motion is demonstrated for 250 μm–550 μm sized droplets. Droplet transportation is facilitated by extremely low hysteresis and a high degree of omnidirectional bending of the pillar array.

Asymmetric modification of cellulose nanocrystals with PAMAM dendrimers for the preparation of pH-responsive hairy surfaces

In this work, we present a straightforward method to attach a globular dendrimer at the reducing end of cellulose nanocrystals obtained from tunicates (t-CNC). We investigated the first four generations of poly(amidoamine) dendrimers (PAMAMs G0 to G3) to obtain hybrid t-CNCs. The aggregation behavior of hybrid t-CNCs was studied by dynamic light scattering (DLS) and scanning transmission electron microscopy (STEM); and interactions of these asymmetric nanoparticles with gold surface were elucidated using quartz crystal microbalance with dissipation (QCM-D) and surface plasmon resonance (SPR). Hybrid t-CNCs formed hairy layers onto gold surface combining the properties of rigid rod-like nanocrystals with globular and flexible PAMAM dendrimers. Moreover, the presence of amino groups provided pH-responsive properties to hybrid t-CNCs, and QCM-D results revealed reversible swelling/deswelling behavior. Thereby, we achieved to synthesize tree-shaped functional bio-based materials that adsorbed on gold and formed pH-responsive hairy surfaces.

Effect of hairy surface on heat production and thermal insulation on the building

AbstractIn the extreme wind and cold weather conditions, animals have developed incredible protection techniques in order to achieve the regulation of body thermal insulation. While birds fluff their feathers to reduce heat loss, some animals take advantage of the other varying unique structures of the skin. In this study, inspired by birds, the effect of hairy surfaces like hedgehog skin on thermal insulation and also heat production at the low‐speed wind on the building wall surface was investigated numerically by using the finite element method. For this, a portion of the wall surface was covered with rigid barbs to increase friction on the wall, and for the comparison, a part of the surface was left smooth without any coating. Menter's shear stress transport (SST) turbulence model by algebraic multigrid solver was used for the modeling of wind motion and heat transfer equations by direct solver PARDISO was used to simulate heat transfer in the solid and fluid environment. According to the numerical calculation, the wind speed slows down along the rough surface, high‐pressure zone on the surface (a thick no‐slip boundary region) was created and a part of wind energy was converted to extra heat and especially the convective heat loss due to the movement of the wind on the surface was reduced, and finally, the building was insulated further by creating a stagnant air layer in the barbs.

The bubble problem of the plasma facing material: A finite element study

The damage of first wall material in fusion reactor due to the bubbles caused by plasma has been studied by introducing a relation between the von Mises equivalent stress and the temperature field. The locations and shapes of the bubbles and the synergetic effect between the different bubbles under steady operational conditions have been studied using the finite elements method. Under transient heat loads, plastic deformations have been found to occur, and are significantly enhanced by the presence of the bubbles. The calculated concentration locations of von Mises equivalent stress are well consistent with the observed crack positions of the tungsten surface in many test experiments. Our simulations show that the damage of the bubbles is not severe enough to lead to catastrophic failure of the tungsten armor; however, it can cause local and gradual detachment of tungsten surface, which provides a reasonable explanation for the observed pits and rough or hairy surface morphology etc. Considering the transient heat loads, the lower bound of the security thickness of the tungsten tile is estimated to be greater than 2 mm.

Mechanical ecology of fruit-insect interaction in the adult Mediterranean fruit fly Ceratitis capitata (Diptera: Tephritidae)

Fruit features represent a trade-off between dispersal and protection against frugivore insects. To prevent insect attack, plants evolved chemical and physical barriers, mainly studied in leaves, while limited knowledge is available for fruits, especially concerning mechanical barriers. We used the Mediterranean fruit fly to shed light on the mechanical ecology of insect-fruit attachment in a pest species. We tested the following hypotheses: is there any sexual dimorphism in attachment devices and attachment ability? Can the attachment ability of females of Ceratitis capitata to fruits of various host plants vary according to fruit surfaces with different morphology (smooth, hairy, waxy) or physico-chemical properties? The tarsal attachment devices were studied using Cryo-SEM and TEM. The maximum friction forces of C. capitata females on fruit surfaces of typical host plants were evaluated using a load cell force transducer. The attachment ability of both sexes on artificial surfaces was evaluated using a centrifugal force tester. Our data revealed sexual dimorphism in the size of pulvilli, which are wider in females. A higher friction force is exerted by females in comparison with males, in agreement with the need to firmly adhere to the host plant fruit during oviposition. Among the tested fruits, the stronger friction force was recorded on hairy or rough surfaces while a force reduction was recorded on waxy fruits. To unravel the mechanical ecology of insect-plant interaction between plants and species of Tephritidae can be useful to develop non-chemical methods to control these important crop pests.

Reduction of urban traffic-related particulate matter-leaf trait matters.

Particulate matter in European cities, especially in urban areas, is mainly from urban road traffic and constitutes a great threat to the health of inhabitants. Therefore, understanding of the role of common urban roadside plant plays for particulate matter (PM) reduction would have important meaning for the mitigation of urban air pollution. The leaf surface PM capturing capacity of 12 representative urban plants (five shrubs and seven trees) alongside one main street in Hanover Germany was explored in this study. Significant differences for the amount of captured PM (both PM10 and PM2.5) on the leaf surface were found between plant species. Leaves of Taxus baccata, Berberis thunbergii, Pinus nigra, and Quercus robur showed the highest capturing capacity, while leaves of Prunus laurocerasus and Carpinus betulus showed the lowest value. Leaf shape is an important factor which affects the capturing capacity of the tested plant species. Needle-leaved pants were relatively more effective than broad-leaved species. Besides, species with small leaf surface area (0-10cm2) showed a notably higher capacity than species with large leaf surface area (over 100cm2). Additionally, by the observation of leaf surface characteristics, plant species with rough and hairy leaf surface tended to be more effective than species with smooth leaf surface. More PM was found distributed on the upper leaf surface close to the midrib rather than on the surface area away from it. At last, no significant correlation was found between the leaf surface contact angle and its PM capturing capacity for the 12 tested plant species in September. In summary, leaf traits including leaf form, leaf shape, leaf surface area, leaf surface hydrophilicity and leaf surface characteristics all have notable effects on the PM capturing capacity of the roadside plant species. This study provides a scientific basis for roadside plants as an eco-friendly solution for the reduction of urban traffic-related PM and stresses the importance of leaf traits as criteria for the plant selection.

Ethnobotany of Jonggol Plants (Erechtites valerianifolia Wolf.) on Communities in Traditional Markets in Malang City and Detection of Its Chemical Compounds

The increasing number of population causes increasing food needs too. The market is one place where food needs are available. One of the plants that has economic value and can be used is jonggol (Erechtites valerianifolia Wolf.). The objective of this study is to determine the morphology, forms of use and chemical compounds found in the jonggol plant. This research was conducted on October 2017 until March 2018. The methods used in this study were preliminary surveys, market area selection, morphological observations, interviews, chemical compound detection, and data analysis. The selection of market areas was carried out in 5 sub-districts of Malang City, with each sub-district selected by one market, they are Sawojajar Market, Sukun Market, Malang Big Market, Blimbing Market, and Dinoyo Market. The results of the study show that jonggol is a herbaceous plant. Jonggol has a taproot type with a hairy and grooved stem surface. The jonggol leaves are obovate, pointed ends, tapered base with a leaf surface with adaxial and abaxial hair. The flowers are cup-shaped compound flowers and they are located at the end of the stem. The petals are modified into pappus. The crown is reddish yellow, the pistil head is brownish red, and the stamens are purple. The fruit type is achene which is brown. Jonggol has a UVs value of 3.0 meaning that it is an important species or priority species, this is due to Jonggol plants often used as vegetables. Chemical compounds found in Jonggol plants are alkaloids, flavonoids, and steroids.

Marine crustaceans with hairy appendages: Role of hydrodynamic boundary layers in sensing and feeding

Decapod crustaceans have appendages with an array of rigid hairs covered in chemo-receptors, used to sense and track food. Crustaceans directly influence the flow behavior by changing the speed of flow past the hairy surface, thereby manipulating the Reynolds number (Re). Hairs act either as a rake - diverting flow around the hair array, or as a sieve - filtering flow through the hairs. In our experiments, we uncover a third transitional phase: deflection - where the flow partially penetrates the hair array and is deflected laterally. We develop a reduced order model that predicts the flow phase based on the depth of the boundary layer on a single hair. This model with no fitting parameters agrees very well with our experimental data. Additionally, our model agrees well with measurements of both chemo-sensing and suspension-feeding crustaceans, and can be generalized for many different geometries.

Corrsin lecture on hairy hydrodynamics

Simple models for hairy surfaces interacting with flows are derived, and used to extract optimization and design principles in idealized contexts. Reconfiguration, in which flow couples to the hairs geometric configuration, is investigated along with drainage of thin films through beds of hairs.

PHARMACOGNOSTICAL AND PHYTOCHEMICAL STANDARDIZATION OF PHYSALIS MINIMA L. LEAF

Objective: To evaluate the pharmacognostical and phytochemical parameters of Physalis minima leaf.
 Methods: The leaf of Physalis minima was examined for macroscopical, microscopical, physicochemical parameters and fluorescence analysis. Extracts obtained from the leaf was analyzed for phytochemical screening and estimation of total tannin, phenolic and flavonoid content following the standard procedure available in the literature.
 Results: Morphologically, the leaf was found to be ovate in shape, 5 to 8 cm long and up to 3 cm width with dentate margin, asymmetrical base, hairy surface, reticulate veins on each side of midrib, green in colour, characteristic odour and slight bitter in taste. Microscopic study has shown the important diagnostic characters of Solanaceae family which is characterized by presence of dorsiventral leaf with anomocytic stomata, grandular or uniseriate trichomes and cluster crystal of calcium oxalate. Physicochemical parameters like foreign organic matter (0.78%), loss on drying (8.23%), total ash (11.4%), acid insoluble ash (2.2%), water-soluble ash (6.1%), sulphated ash (2.4%) alcohol soluble extractive (10.4%), water-soluble extractive (9.5%), ether soluble extractive (1.8%) foaming index (below 100), swelling index (1), volatile oil and heavy metal content were quantified. Phytochemical analysis of different extracts of Physalis minima leaf has shown the presence of phytoconstituents viz. alkaloids, steroids, tannin, flavonoids, protein. Quantification of phytoconstituents was also reported like phenols (10.59±0.65 mg/gm equivalent to tannic acid), tannin (8.24±0.27 mg/gm equivalent to tannic acid) and flavonoids (87.17±0.87 mg/gm equivalent to rutin) respectively.
 Conclusion: This present study was provided the qualitative and quantitative standard of Physalis minima will help to prevent the possible steps of adulteration with other species of the same genus.

A common representation of fingers and toes

There are many similarities and differences between the human hands and feet. On a psychological level, there is some evidence from clinical disorders and studies of tactile localisation in healthy adults for deep functional connections between the hands and feet. One form these connections may take is in common high-level mental representations of the hands and feet. Previous studies have shown that there are systematic, but distinct patterns of confusion found between both the fingers and toes. Further, there are clear individual differences between people in the exact patterns of mislocalisations. Here, we investigated whether these idiosyncratic differences in tactile localisation are shared between the fingers and toes, which may indicate a shared high-level representation. We obtained confusion matrices showing the pattern of mislocalisation on the hairy skin surfaces of both the fingers and toes. Using a decoding approach, we show that idiosyncratic differences in individuals' pattern of confusions are shared across the fingers and toes, despite different overall patterns of confusions. These results suggest that there is a common representation of the fingers and toes.

Drop impact on hairy surfaces

A study of the impact of liquid drops on millimeter-scale hairy surfaces finds that the behavior of the impacting drops depends on the amount of kinetic energy dissipated through the hairs via a balance of inertia, viscosity, and surface tension.