Comparative analysis of mandible morphology in four ant species with different foraging and nesting habits

Mandibles of ants can be considered as one of the most vital tools for the survival and success of their colonies since these are extensively utilised for defence, nest maintenance and foraging activities. We hypothesised that mandibular design is strongly dependent on the respective ecological niche and foraging habit of an ant species. In the present study, we compared the external morphology and zinc content in the mandibles of four species of ants by using scanning electron microscopy and energy dispersive X-ray spectroscopy. The ant mandible morphology varied significantly in accordance with their species-specific foraging and nesting strategies. The sickle-shaped mandibles of the strongly predaceous, Oecophylla smaragdina worker ants were characterised by a large number of pointed teeth which would be of immense utility for subduing the prey, while the shovel-shaped, highly sclerotized mandibles of Cataglyphis longipedem ants appear to be adaptations for the solitary scavenging habit and nest maintenance in arid habitats. The large-sized mandibles of Camponotus compressus ants and the stout mandibles of the predatory, Tetraponera rufonigra forager ants, have apparently evolved for collection of sugary secretions by the former and for the solitary foraging and arboreal nesting habit of the latter. The mandibular zinc content was highest in T. rufonigra ants and the lowest in the mandibles of the sugar-loving Cm. compressus ants. The diversity in the arrangement of bristles and the type of mandibular concavities, have also evolved accordingly. Thus, this study might prove to be instrumental in evaluating the various physical mechanisms involved in the evolution of insect mandibles for their defined function.

Charging Processes in Low Vacuum Scanning Electron Microscopy

Microscopy and Microanalysis ◽

10.1017/s1431927604040656 ◽

2004 ◽

Vol 10 (6) ◽

pp. 711-720 ◽

Cited By ~ 11

Author(s):

Bradley L. Thiel ◽

Milos Toth ◽

John P. Craven

Keyword(s):

Electron Microscopy ◽

Electric Fields ◽

Charge Trapping ◽

Operating Conditions ◽

X Ray ◽

Physical Mechanisms ◽

Charge Field ◽

Ion Recombination ◽

A framework is presented for understanding charging processes in low vacuum scanning electron microscopy. We consider the effects of electric fields generated above and below the specimen surface and their effects on various processes taking place in the system. These processes include the formation of an ionic space charge, field-enhanced electron emission, charge trapping and dissipation, and electron–ion recombination. The physical mechanisms behind each of these processes are discussed, as are the microscope operating conditions under which each process is most effective. Readily observable effects on gas gain curves, secondary electron images, and X-ray spectra are discussed.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100055448 ◽

1982 ◽

Vol 40 ◽

pp. 520-521

Author(s):

Ann Chidester Van Orden ◽

John L. Chidester ◽

Anna C. Fraker ◽

Pei Sung

Keyword(s):

Electron Microscopy ◽

Corrosion Behavior ◽

Anodic Polarization ◽

Saline Solution ◽

Saturated Calomel Electrode ◽

Physiological Saline ◽

X Ray ◽

Physiological Saline Solution ◽

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111550 ◽

1984 ◽

Vol 42 ◽

pp. 288-289

Author(s):

Vicki L. Baliga ◽

Mary Ellen Counts

Keyword(s):

Electron Microscopy ◽

Calcium Oxalate ◽

Growth And Development ◽

Polarized Light ◽

Calcium Oxalate Crystals ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Use of SEM, X-ray analysis and TEM to localize Fe3+ reduction in roots

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104029 ◽

1988 ◽

Vol 46 ◽

pp. 392-393 ◽

Cited By ~ 3

Author(s):

William P. Wergin ◽

P. F. Bell ◽

Rufus L. Chaney

Keyword(s):

Electron Microscopy ◽

Root Hairs ◽

Rapid Reduction ◽

X Ray ◽

Physical Evidence ◽

Transmission Electron ◽

Young Root ◽

Insoluble Precipitate ◽

Uptake And Transport ◽

In dicotyledons, Fe3+ must be reduced to Fe2+ before uptake and transport of this essential macronutrient can occur. Ambler et al demonstrated that reduction along the root could be observed by the formation of a stain, Prussian blue (PB), Fe4 [Fe(CN)6]3 n H2O (where n = 14-16). This stain, which is an insoluble precipitate, forms at the reduction site when the nutrient solution contains Fe3+ and ferricyanide. In 1972, Chaney et al proposed a model which suggested that the Fe3+ reduction site occurred outside the cell membrane; however, no physical evidence to support the model was presented at that time. A more recent study using the PB stain indicates that rapid reduction of Fe3+ occurs in a region of the root containing young root hairs. Furthermore the most pronounced activity occurs in plants that are deficient in Fe. To more precisely localize the site of Fe3+ reduction, scanning electron microscopy (SEM), x-ray analysis, and transmission electron microscopy (TEM) were utilized to examine the distribution of the PB precipitate that was induced to form in roots.

Scanning Electron Microscopy and X-Ray Analyses of Dental Tissues from a Hibernator

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100090877 ◽

1976 ◽

Vol 34 ◽

pp. 178-179

Author(s):

M. L. Zimny ◽

A. C. Haller

Keyword(s):

Electron Microscopy ◽

Body Temperature ◽

Ground Squirrel ◽

Alveolar Bone ◽

X Ray ◽

Dental Tissues ◽

Bone Minerals ◽

Apical Tooth ◽

During hibernation the ground squirrel is immobile, body temperature reduced and metabolism depressed. Hibernation has been shown to affect dental tissues varying degrees, although not much work has been done in this area. In limited studies, it has been shown that hibernation results in (1) mobilization of bone minerals; (2) deficient dentinogenesis and degeneration of alveolar bone; (3) presence of calculus and tears in the cementum; and (4) aggrevation of caries and pulpal and apical tooth abscesses. The purpose of this investigation was to study the effects of hibernation on dental tissues employing scanning electron microscopy (SEM) and related x-ray analyses.

Scanning Electron Microscopy and x-ray analysis of microparticles and early hydration effects

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100139834 ◽

1995 ◽

Vol 53 ◽

pp. 692-693

Author(s):

Yun Lu ◽

David C. Joy

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Morphological Development ◽

Early Hydration ◽

X Ray ◽

Blended Cements ◽

Powder Particles ◽

Chemical Wastes ◽

High resolution scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA) were performed to investigate microparticles in blended cements and their hydration products containing sodium-rich chemical wastes. The physical appearance of powder particles and the morphological development at different hydration stages were characterized by using high resolution SEM Hitachi S-900 and by SEM S-800 with a EDX spectrometer. Microparticles were dispersed on the sample holder and glued by 1% palomino solution. Hydrated bulk samples were dehydrated by acetone and mounted on the holder by silver paste. Both fracture surfaces and flat cutting sections of hydrating samples were prepared and examined. Some specimens were coated with an 3 nm thick Au-Pd or Cr layer to provide good conducting surfaces. For high resolution SEM S-900 observations the accelerating voltage of electrons was 1-2 KeV to protect the electron charging. Microchemical analyses were carried out by S800/EDS equipped with a LINK detector of take-off angle =40°.

Defects of Platelet Function Recognized by X-Ray Imaging and Scanning Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100119806 ◽

1985 ◽

Vol 43 ◽

pp. 610-613

Author(s):

M.G. Baldini ◽

S. Morinaga ◽

D. Minasian ◽

R. Feder ◽

D. Sayre ◽

...

Keyword(s):

Electron Microscopy ◽

Cell Biology ◽

Imaging Technique ◽

Human Platelets ◽

X Rays ◽

X Ray ◽

X Ray Imaging ◽

Complex Phenomena ◽

Contact X-ray imaging is presently developing as an important imaging technique in cell biology. Our recent studies on human platelets have demonstrated that the cytoskeleton of these cells contains photondense structures which can preferentially be imaged by soft X-ray imaging. Our present research has dealt with platelet activation, i.e., the complex phenomena which precede platelet appregation and are associated with profound changes in platelet cytoskeleton. Human platelets suspended in plasma were used. Whole cell mounts were fixed and dehydrated, then exposed to a stationary source of soft X-rays as previously described. Developed replicas and respective grids were studied by scanning electron microscopy (SEM).

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131243 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1322-1323

Author(s):

Howard S. Kaufman ◽

Keith D. Lillemoe ◽

John T. Mastovich ◽

Henry A. Pitt

Keyword(s):

Electron Microscopy ◽

Environmental Scanning Electron Microscopy ◽

Environmental Scanning ◽

X Ray Diffraction ◽

Calcium Salts ◽

Cholesterol Gallstones ◽

X Ray ◽

Ca Carbonate ◽

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

Synthesis of HTCMgFe for the degradation of indigo carmine through heterogeneous photo-Fenton treatment

MRS Advances ◽

10.1557/adv.2020.421 ◽

2020 ◽

Vol 5 (62) ◽

pp. 3273-3282

Author(s):

I. Cosme-Torres ◽

M.G. Macedo-Miranda ◽

S.M. Martinez-Gallegos ◽

J.C. González-Juárez ◽

G. Roa-Morales ◽

...

Keyword(s):

Electron Microscopy ◽

Treatment Time ◽

Uv Light ◽

Indigo Carmine ◽

Oh Radicals ◽

Absorption Bands ◽

Chromophore Group ◽

X Ray ◽

Catalytic Sites ◽

AbstractThe heterogeneous catalyst HTCMgFe was used in the degradation of the IC, through the heterogeneous photo-fenton treatment, this material in combination with H2O2 and UV light degraded the dye in 30 min at pH 3. As the amount of HTCMgFe increases the degradation it was accelerated because there are more active catalytic sites of Fe2+ on the surface of the material, which generates a greater amount of •OH radicals. The HTCMgFe was characterized by infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray energy dispersive elemental analysis (EDS). The UV-vis spectrum shows that the absorption bands belonging to the chromophore group of the IC disappear as the treatment time passes, indicating the degradation of the dye.

Photocatalytic activity of TiO2 synthesized by anodization and anodic spark deposition

MRS Advances ◽

10.1557/adv.2020.405 ◽

2020 ◽

Vol 5 (61) ◽

pp. 3141-3152

Author(s):

Alma C. Chávez-Mejía ◽

Génesis Villegas-Suárez ◽

Paloma I. Zaragoza-Sánchez ◽

Rafael Magaña-López ◽

Julio C. Morales-Mejía ◽

...

Keyword(s):

Electron Microscopy ◽

Photocatalytic Activity ◽

Surface Characteristics ◽

Amorphous Solids ◽

X Ray Diffraction ◽

X Ray ◽

Catalytic Activities ◽

Anodic Spark Oxidation ◽

Porous Surfaces ◽

AbstractSeveral photocatalysts, based on titanium dioxide, were synthesized by spark anodization techniques and anodic spark oxidation. Photocatalytic activity was determined by methylene blue oxidation and the catalytic activities of the catalysts were evaluated after 70 hours of reaction. Scanning Electron Microscopy and X Ray Diffraction analysis were used to characterize the catalysts. The photocatalyst prepared with a solution of sulfuric acid and 100 V presented the best performance in terms of oxidation of the dye (62%). The electric potential during the synthesis (10 V, low potential; 100 V, high potential) affected the surface characteristics: under low potential, catalyst presented smooth and homogeneous surfaces with spots (high TiO2 concentration) of amorphous solids; under low potential, catalyst presented porous surfaces with crystalline solids homogeneously distributed.