Rod Shape Research Articles

Characterization of Green synthesised Iron nanoparticles and application of synthesised Iron nanoparticles as an effective catalyst for the removal of Carcinogenic metals in aqueous solution

The heavy metals such as chromium (Cr), lead (Pb) and cadmium (Cd) are considered as serious toxicants and act as carcinogenic agents that cause serious cancers to humans. The use of these heavy metals drastically increased in various industrial applications and subsequently increased the risk of contamination of these heavy metals in soil, water etc. To minimize the negative effects of these heavy metals, there is a need to reduce these heavy metals concentrations in environment samples. Hence this study focused to fabricate iron nanoparticles using Diospyros chloroxylon (Roxb.) for the removal of carcinogenic metals in water. The crystal structure, size and morphology of the nanoaprticles were evaluated and it was found that the particles were of rod shape with smooth surface and rhombohedral phase structure with an average particle size of 24 nm that contains 71.91 % of elemental iron. The heavy metal sorption experiments was conducted using selected concentration of heavy metal solution at various pH ranges, time and agitation rate. The maximum adsorption removal was 95.36 %, 98.42 % and 92.80 % within 120 min equilibrium time for Cr, Pb and Cd respectively suggesting that the nanoparticles possess high adsorption efficiency. The adsorption process follows pseudo-first order reaction kinetics with correlation coefficient of 0.978, 0.994 and 0.994 with rate constant (K) of 0.140, 0.280 and 0.108 respectively for Cr, Pb and Cd. The results suggest that the synthesized iron nanoparticles were biocompatible, stable and reusable that can be effectively utilized as promising agents for the removal of carcinogenic heavy metals in polluted water.

Biogenic Synthesis of Different forms of Bio-caped Silver Nanoparticles using Microcystis sp. and its Antimicrobial Activity

Background: Nanobiotechnology is a cutting-edge field that is revolutionizing the way we produce and utilize nanoparticles. With bacteria becoming increasingly resistant to traditional antibiotics, researchers are exploring new ways to synthesize antimicrobials. Objective:: The aim of this study was to investigate the biosynthesis of different forms of silver nanoparticles using different biological methods from Microcystis sp. to be used as an antimicrobial agent. Methods: We employed the direct strain powder method, ethanolic extract pellets, and ethanolic extract. Then a combination of analytical techniques was used to characterize the properties of nanoproperties. Finally, we evaluated the antimicrobial activity of the AgNPs against a panel of bacteria and fungi. Results: AgNPs were found in various forms, such as cubic, spherical, and rod shapes. UV-Vis detected a peak at 420 nm, and SEM identified the AgNPs with bio-capped layers ranging from 40-130 nm. The antibacterial test revealed that the pellet method produced the most effective AgNPs, specifically against Gram-positive bacteria such as Staphylococcus sp. with a clear zone of 32 mm, while the larger cubic AgNPs produced by the powder method were less effective as antibacterial agents. Conclusion: This study demonstrates that AgNPs can be produced using Microcysts sp. as a reducing and capping agent; furthermore, they are produced in different shapes as cubic, spherical, and rod shapes. Besides that, cubic nanoparticles are more effective in killing germs than spherical ones. The results of this study will help to improve our understanding of the mechanisms of AgNPs biosynthesis and pave the way for the development of new and more effective antimicrobial agents.

The morphological spicules of Acaudina sp. (sea cucumber) from Delta Wulan waters, Demak, Central of Java, Indonesia

This research aims to study the morphological spicules of sea cucumber Acaudina sp. This species is belong to Class Holothuroidea, Order Molpadida, and Family Caudinidae. Samples Acaudina sp. were taken randomly from Delta Wulan Waters, Demak Regency, Central of Java. The sample was preserved by alcohol 70%. NaOCl solution was used for bleaching the samples. According to the result research, most of body part (anterior, posterior, dorsal and ventral) have rod shape, irregular rod shape, straight rod shape, and dumbbell curved.

Preparation of amine-incorporated hydroxyapatite through a single-step hydrothermal reaction

We report on the preparation of an amine-incorporated hydroxyapatite (NH2-HAP) by applying o-phosphorylethanolamine (PEA) as a phosphate source. By changing the ratio of PEA to normal phosphate source, three samples of NH2-HAPs having different contents of amine are synthesized. The TEM analysis confirmed that NH2-HAP exhibits elongated rod shape which is similar to the hexagonal rod of pure hydroxyapatite (HAP). As the concentration of PEA increases, the average size of NH2-HAP along (001) direction decreases approximately from 55.4(±10.39) to 31.2(±8.3) nm. The XRD patterns of NH2-HAPs are well matched with typical HAP patterns. Line broadening of XRD peaks in NH2-HAP seems to originate from low crystallinity and smaller size compared to pure HAP. Primary amine group on the surface of NH2-HAP is confirmed by both surface elemental analysis (XPS) and the ninhydrin test. The nitrogen content of NH2-HAP surface is approximately 0.6 ∼ 1.1 at.% based on XPS experiment.

Physicochemical Characterization of Acid-Treated Nanocrystal Cellulose and Amorphous Cellulose from Bamboo Sawdust

ABSTRACT The major by-product of bambooworking (i.e. making items from bamboo) is bamboo sawdust, which is a waste product from bambooworking operations and can cause human health hazards. Specifically, this experimental research investigates the effects of acid treatment methods on the physicochemical characteristics of nanocellulose fibers from bamboo sawdust. The experimental acid treatment methods are sulfuric acid hydrolysis for bamboo fiber nanocrystal cellulose (BBF-NCC) and sulfuric acid dissolution for bamboo fiber amorphous cellulose (BBF-AC). The physicochemical properties of nanocellulose from bamboo sawdust include the crystalline structure, morphology, and colloidal stability. The experimental results indicate that BBF-NCC possesses a higher crystallinity index (89.5%), in comparison with 35.4% for BBF-AC. The BBF-NCC is of rod shape with 10 nm in diameter and 50–100 nm in length, while BBF-AC coalesces into clusters of varying sizes. In addition, BBF-NCC possesses higher colloidal stability than BBF-AC, as indicated by a zeta potential of −30.93 mV for BBF-NCC, compared with −19.73 mV for BBF-AC. Essentially, this research is the first to experimentally convert bamboo sawdust into cellulose nanofibers as an eco-friendly and economically viable solution to the waste problem from the bamboomaking industry. Moreover, BBF-NCC and BBF-AC could potentially be adopted as a reinforcing agent in biocomposites or as a carrying agent in multiple applications.

Fabrication of SnO2 micron-rods embedding in 3D composite of graphene oxide@MWNTs as high-performance anode for lithium-ion batteries

Tin dioxide-based anode materials have attracted extensive attention in lithium-ion batteries due to their high specific capacity. However, the low intrinsic conductivity and volume expansion of commercial SnO2, as well as the aggregation due to snation result in electrodes that are highly susceptible to crush during the cycling process. Here, SnO2@GO@MWNTs complex consisting of rod-like SnO2 with micron-size uniformly embedded in the multi-walled carbon nanotubes (MWNTs) and multilayer graphene oxide (GO) was constructed via a simple ultrasonic mixing method, and was employed as the anode materials of lithium-ion batteries. This composite electrode showed excellent cycling performance, exhibiting a high reversible capacity of 1242.6 mAh·g−1 after 280 cycles (at 200 mA·g−1), and excellent rate performance at current densities of 1000 mA·g−1 and 2000 mA·g−1, with high specific capacity of 770.5 mAh·g−1 and 640.1 mAh·g−1, respectively. The excellent electrochemical performance was attributed to the fact that the framework structure formed by GO and MWNTs effectively mitigates the volume expansion of rod-shaped SnO2 while improving its electrical conductivity, and the micron-sized rods shape alleviates the aggregation of particles due to the partial tinisation of SnO2.

Experimental study on the effect of different shear reinforcement shapes and arrangement on 3D crack propagation and shear failure mechanism in RC beams

Surface crack patterns have been considered to determine the shear failure behavior of RC beams but the effect of three-dimensional crack propagation on shear crack development and shear strength of RC beams is still debatable. In this study, a three-dimensional crack evaluation was carried out to investigate the shear failure mechanism of RC beams with different shapes and arrangement of shear reinforcement (close shape shear reinforcement, rod shape reinforcement with mechanical anchorage, combination of close shape reinforcement and rod shape reinforcement, rod shape reinforcement and transverse distribution rebar) using three-point loading test by keeping the amount of shear reinforcement same in all beams. The load displacement relationships, 3D crack maps, stirrup strain and concrete strain relationships with displacement and shear resistance components were discussed in detail and these information’s are useful for designing and shear strengthening of existing beams. It was clarified that a clear difference in three-dimensional cracking pattern, shear resistance components of concrete and shear reinforcement contribution was observed in RC beams. This was due to the shear reinforcement shapes and arrangement of rod shape reinforcement, which influenced the shear strength of RC beams.

Ag Incorporated MoO3 Thin Films and Fabrication of Ag/MoO3/p-Si Structured Photodiode

MoO3 have been widely investigated for their applications ranging from electronics to energy storage. Orthorhombic structured MoO3 thin films were prepared on a glass substrate. The Ag doped materials to add the MoO3 in different concentrations (1%, 3%, 5%) at Wt% with MoO3 precursor and synthesis was done using the spray pyrolysis method. X-ray diffraction revealed the incorporation of Ag in the MoO3 orthorhombic structure. FE-SEM images showed more dispersive and rod shapes than Agi-doped MoO3 and pure MoO3 respectively. The jet nebulizer spray pyrolysis technique for fabrication of n-Ag: MoO3/p-Si photodiodes makes it suitable for good response photo-detecting applications.

Comparative genomics hints at dispensability of multiple essential genes in two Escherichia coli L-form strains.

Despite the critical role of bacterial cell walls in maintaining cell shapes, certain environmental stressors can induce the transition of many bacterial species into a wall-deficient state called L-form. Long-term induced Escherichia coli L-forms lose their rod shape and usually hold significant mutations that affect cell division and growth. Besides this, the genetic background of L-form bacteria is still poorly understood. In the present study, the genomes of two stable L-form strains of E. coli (NC-7 and LWF+) were sequenced and their gene mutation status was determined and compared with their parental strains. Comparative genomic analysis between two L-forms reveals both unique adaptions and common mutated genes, many of which belong to essential gene categories not involved in cell wall biosynthesis, indicating that L-form genetic adaptation impacts crucial metabolic pathways. Missense variants from L-forms and Lenski's long-term evolution experiment (LTEE) were analyzed in parallel using an optimized DeepSequence pipeline to investigate predicted mutation effects (α) on protein functions. We report that the two L-form strains analyzed display a frequency of 6-10% (0% for LTEE) in mutated essential genes where the missense variants have substantial impact on protein functions (α<0.5). This indicates the emergence of different survival strategies in L-forms through changes in essential genes during adaptions to cell wall deficiency. Collectively, our results shed light on the detailed genetic background of two E. coli L-forms and pave the way for further investigations of the gene functions in L-form bacterial models.

Tailoring the Size and Shape of ZnO Nanoparticles for Enhanced Performance of OLED Device.

We synthesized zinc oxide nanoparticles (ZnO NPs) by meticulously controlling both temperature and reaction times, allowing us to fine-tune their crystalline properties, morphology, and particle dimensions. This analysis confirmed the existence of a mixture of rod and sphere shapes (ZnO-I), including rod-shaped NPs with an average size of 14.8 nm × 5.2 nm and spherical NPs with an average diameter of 5.27 nm. We subsequently incorporated these synthesized ZnO NPs into organic light-emitting diode (OLED) devices for red, green, and blue colors, utilizing them as the electron injection layer through a solution-based process. The green OLED device using ZnO-I exhibited a promising current efficiency of 4.02 cd/A and an external quantum efficiency of 1.47%.

Room-temperature SnO2-based sensor with Pd-nanoparticles for real-time detection of CO dissolved gas in transformer oil

SnO2 and Pd nanoparticles (NPs) were synthesized by hydrothermal method and sol-gel, respectively. A paste formed by tin dioxide NP and PVDF was deposited as thick film on alumina substrates through screen printing method and decorated with Pd on surface. The morphology and structure of the samples were investigated by Scanning Electronic Microscopy (SEM), X-Ray Diffraction (XRD) and Raman Spectroscopy. The SEM images show SnO2 nanoparticles with rod shapes and 10–15 nm of diameter size and Pd spherical nanograins with 15–35 nm of diameter. XRD analysis identifies rutile structure for SnO2 powder and cubic structure for Pd NP. To investigate the gas sensing property of the SnO2:Pd nanostructured composite, the electrodes were immersed in an insulating mineral oil, in a closed system where different gas concentration of monoxide carbon (CO) were injected into the headspace and then dissolved into oil, according to Ostwald coefficient. All measurements were carried out at room temperature using a concentration range from 50 to 500 ppm (in headspace). The electric characterization showed that our SnO2-based sensor had change its resistance in a lower concentration of dissolved gas, ∼13.3 ppm of CO, into the mineral oil, indicating its potential use for real time monitoring of transformers.

A low-cost, highly efficient solid-state dye laser made of Rhodamine B dopped photopolymer host cured by mercury or halogen lamp

In this work, we designed a rod shape solid-state laser gain media (GM) that can produce amplified spontaneous emission (ASE) in the 630–670 nm region. The GM is made with Rhodamine B (RhB) dissolved in acetone mixed with commercially available rapid photopolymer (PP) resin that predominately (80 %) contains 3-nitro-9-octyl-9H-carbazole (NOCB) and solidified with mercury or halogen lamp. We used a solid-state matrix laser (SSL) rod of RhB embedded NOCB. The results showed that the photoluminescence (PL) of SSL was at approximately 630 m, and the absorption peak was at 575 nm. The concentration of the RhB in acetone was varied from 25 mg/ml to 100 mg/ml and mixed in a 1:10 ratio volume/weight (v/w). GM could be pumped transversely using 355 nm (3rd Harmonic of Nd: YAG) or 405 nm diode laser or a UV lamp. The GM was initially designed with the aim to be pumped using 532 nm since the resin solidified using UV and blue light irradiation. Supersizing, we found that after complete polymerization, optical pumping using 355 nm can be employed to produce ASE. The main advantage of using these SSL are (i) ease of manufacturing, (ii) simplicity to scale up, (iii) low cost, and (iv) 3D printer compatibility. It also has potential applications in the military, science, and medicine, especially facial rejuvenation.

PLAAT1 expression triggers fragmentation of mitochondria in an enzyme activity-dependent manner.

The phospholipase A and acyltransferase (PLAAT) family is a protein family consisting of five members (PLAAT1-5), which acts as phospholipid-metabolizing enzymes with phospholipase A1/A2 and N-acyltransferase activities. Since we previously reported that the overexpression of PLAAT3 in mammalian cells causes the specific disappearance of peroxisomes, in the present study we examined a possible effect of PLAAT1 on organelles. We prepared HEK293 cells expressing mouse PLAAT1 in a doxycycline-dependent manner and found that the overexpression of PLAAT1 resulted in the transformation of mitochondria from the original long rod shape to a round shape, as well as their fragmentation. In contrast, the overexpression of a catalytically inactive point mutant of PLAAT1 did not generate any morphological change in mitochondria, suggesting the involvement of catalytic activity. PLAAT1 expression also caused the reduction of peroxisomes, while the levels of the marker proteins for ER, Golgi apparatus and lysosomes were almost unchanged. In PLAAT1-expressing cells, the level of dynamin-related protein 1 responsible for mitochondrial fission was increased, whereas those of optic atrophy 1 and mitofusin 2, both of which are responsible for mitochondrial fusion, were reduced. These results suggest a novel role of PLAAT1 in the regulation of mitochondrial biogenesis.

Hydrothermally synthesized rod shaped Y2O3:Eu3+ as red emitter

Rod shape Y2O3:Eu3+ were synthesized by using simple hydrothermal method. Characterizations of the samples were done with X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. Increase of Eu3+ concentration in Y2O3 renders shift in Eu – O charge transfer band (CTB) to lower energy. PL emission indicates the asymmetric nature of Eu3+ surroundings. The calculated values of second order crystal field parameter corroborate the asymmetric environment of Eu3+. The improvement in the luminescence with the increase annealing temperature is realized from PL emission and decay lifetime studies. The quantum yield for Y2O3:Eu3+ (13 at.%) under 255 nm excitation is found to be 10 %.

Plasticity in the cell division processes of obligate intracellular bacteria.

Most bacteria divide through a highly conserved process called binary fission, in which there is symmetric growth of daughter cells and the synthesis of peptidoglycan at the mid-cell to enable cytokinesis. During this process, the parental cell replicates its chromosomal DNA and segregates replicated chromosomes into the daughter cells. The mechanisms that regulate binary fission have been extensively studied in several model organisms, including Eschericia coli, Bacillus subtilis, and Caulobacter crescentus. These analyses have revealed that a multi-protein complex called the divisome forms at the mid-cell to enable peptidoglycan synthesis and septation during division. In addition, rod-shaped bacteria form a multi-protein complex called the elongasome that drives sidewall peptidoglycan synthesis necessary for the maintenance of rod shape and the lengthening of the cell prior to division. In adapting to their intracellular niche, the obligate intracellular bacteria discussed here have eliminated one to several of the divisome gene products essential for binary fission in E. coli. In addition, genes that encode components of the elongasome, which were mostly lost as rod-shaped bacteria evolved into coccoid organisms, have been retained during the reductive evolutionary process that some coccoid obligate intracellular bacteria have undergone. Although the precise molecular mechanisms that regulate the division of obligate intracellular bacteria remain undefined, the studies summarized here indicate that obligate intracellular bacteria exhibit remarkable plasticity in their cell division processes.

Archaeal Tubulin-like Proteins Modify Cell Shape in Haloferax volcanii during Early Biofilm Development.

Tubulin, an extensively studied self-assembling protein, forms filaments in eukaryotic cells that affect cell shape, among other functions. The model archaeon Haloferax volcanii uses two tubulin-like proteins (FtsZ1/FtsZ2) for cell division, similar to bacteria, but has an additional six related tubulins called CetZ. One of them, CetZ1, was shown to play a role in cell shape. Typically, discoid and rod shapes are observed in planktonic growth, but under biofilm formation conditions (i.e., attached to a substratum), H. volcanii can grow filamentously. Here, we show that the deletion mutants of all eight tubulin-like genes significantly impacted morphology when cells were allowed to form a biofilm. ΔftsZ1, ΔcetZ2, and ΔcetZ4-6 created longer, less round cells than the parental and a higher percentage of filaments. ΔcetZ1 and ΔcetZ3 were significantly rounder than the parental, and ΔftsZ2 generated larger, flat, amorphic cells. The results show all tubulin homologs affect morphology at most timepoints, which therefore suggests these genes indeed have a function.

A Galerkin approach for analysing coupling effects in the piezoelectric semiconducting beams

The piezoelectric semiconductor combines the characteristics of both piezoelectric and semiconducting materials, making it highly promising for a variety of engineering applications. The present work adopts a Galerkin approach to derive a general weak form of the coupled governing equations for the analysis of piezoelectric semiconductors. The coupling effect between the strain, the electric field, and the gradients of the concentrations of holes and electrons has been considered. Piezoelectric semiconductors are often deployed in the shape of rods and beams and therefore commonly experience axial and transverse load. Thus, the Euler–Bernoulli beam theory is employed to formulate a numerical approach to analyse the coupling behaviour of such piezoelectric semiconductor beams. In order to satisfy the C1 continuity requirement of Euler–Bernoulli beam theory without introducing additional degrees of freedom, a discretisation with B-Splines is used. Non-mechanical variables, including electrical potential, holes and electrons concentrations, are decomposed into constant, linear and quadratic terms through series expansion along the thickness, which ensures compatibility with beam formulation. To validate the proposed method, an N-type piezoelectric semiconducting beam under a sinusoidal distributed load, for which an analytical solution is available, is initially examined. Subsequently, complex examples including a cantilever beam with generalised loading conditions and a beam with PN-junction are analysed to demonstrate the capabilities of the proposed method in handling more challenging scenarios.

Facile green synthesis of highly stable, water dispersible carbohydrate conjugated Ag, Au and Ag-Au biocompatible nanoparticles: Catalytic and antimicrobial activity

Highly stable carbohydrate conjugated silver, gold and bimetallic silver-gold alloy biocompatible and nearly monodisperse nanoparticles (NPs) have been synthesized through bio-reduction of aqueous solution of corresponding metal salt precursors mediated by aqueous extracts of a high altitude lichen, Lobaria retigera. The biomolecule accountable for the reduction, stabilization and capping of the metal nanoparticles is identified to be carbohydrates. The as-synthesized carbohydrate conjugated nanoparticles have excellent dispersibilty in water, phosphate, phosphate-buffered saline, and serum media. The resulting nanoparticles were completely stable for several months in water. The nanoparticles were characterized using UV–visible spectroscopy, TEM, EDX, FT-IR, powder XRD, DLS and CV study. Though mostly spherical in shapes, occasionally truncated triangular and rod shapes were also noted. The average particle sizes of Ag, Au and Ag-Au alloy nanoparticles as determined from TEM analysis are 14.5 nm, 11.7 nm and 16.3 nm, respectively. Cyclic voltammetry pointed to a relatively high electrode potential barrier for the synthesized nanomaterials. The prepared Ag, Au and Ag-Au alloy nanoparticles served as efficient catalysts for the degradation of hazardous pollutant dye, methyl orange (MO) with rate constat of 0.1496 min−1, 0.1049 min−1, and 0.1882 min−1. The bimetallic Ag-Au nanoparticles exhibited the most accelerated reduction with 90.6% degradation efficiency. The reduction kinetics for the reactions followed a pseudo-first order, kAu < kAg< kAu-Ag. The Ag and Ag-Au alloy NPs showed pronounced antimicrobial activity towards selected bacterial strains while AuNPs lacked any such activity.

The effect of MgNPs synthesized by using green method on the produc-tion and proliferation of Capisum annuum callus culture In Vitro

Nanotechnology, consider as one of the newest important methods towards improve the production of callus using plant tissue culture. The objective of the current work was to create a unique callus induction methodology. and proliferation from Capisum annum in vitro. Therefor different concentrations of Mg nanoparticles were used which synthesized using green method. For callus inducement, young foliage, and stem from the sterile germinated seedlings using Sodium hypochlorite (NaOCL) 6% for 10 min were used as explants. They were cultivated in MS media supported by several combinations of kinetin and 2, 4- Dichlorophenoxyacetic. The maximum percentage responsive reached 100% from leaf explants at 2, 4-D 1.5 mg/L and Kin 1.0 mg/L. While 2, 4-D 1.5 mg/L and Kin 0.5 mg/L achieved the highest fresh weight for callus proliferation. The best MgNPs concentration for callus inducement and proliferation of capsicum leaves and stem explants was MS media supported with 1.0 and 0.3 ml/L respectively. While the highest proliferation mean value for callus was recorded at the concentration of 6.0 ml/L MgNPs in MS medium reached 6.1 gm. AFM photographs prove that MgNPs were in nanometer size and had the spheres and the rods shape. The average grain size of the MgNPs was 23.8 to 38.24 nm.

Architecture of vibrissae in eight rodent species of Ctenohystrica (Rodentia): A comparative SEM study

Our study was conducted within the framework of comparative functional morphology of mammalian skin (Sokolov 1982) and “Trichomorphology” (Hausmann 1930; 1944; Teerink 1991) focusing in particular on specialized tactile organs such as whiskers (vibrissae). The architecture of vibrissae was studied for the first time using SEM in the relict rodent Laonastes aenigmamus and in some other representatives of the clade Ctenohystrica (Rodentia): Ctenodactylus gundi, Pectinator spekei, Proechimys guyannensis, Echimys sp., Trichomys apereoides, Chinchilla lanigera, and Octodon degus with the aim to identify the specific characters for each species. The vibrissal architecture is specific and polymorphic: the rod shape and structure of the medulla show differences between species of different genera and differ from those of guard hairs and spines of the same species. In L. aenigmamus, the vibrissal medulla is peculiar in its internal structure, which, together with the structure of guard hairs in this species, confirms its phylogenetically distinct position within Ctenohystrica. For the compared species, the complex medulla is with variously arranged systems of keratinized septa and different degrees of development of air spaces between them (ranging from unstructured and irregular to uni- or biserial ladder-like, cellated or pyramidal). The vibrissae have a non-specialized cuticle serving mostly for protection during tactile contacts, which distinguishes it from the diverse and multifunctional cuticle of guard hairs, spines, and quills. The tactile function of vibrissae is corroborated by the presence of scuff marks, scratches and even cuticle loss at the tip and on the ventral side of the rod, a thickened dense cortex and a poorly developed medullar layer but diverse its internal architecture, which provides only a very limited thermal protection, unlike that of the hair pelage. The SEM study of vibrissal architecture is a promising line of research, because a better knowledge of vibrissae may contribute to the biology and biomimetics.