Factors of Force Potentiation Induced by Stretch-Shortening Cycle in Plantarflexors

Muscle force is potentiated by countermovement; this phenomenon is called stretch-shortening cycle (SSC) effect. In this study, we examined the factors strongly related to SSC effect in vivo, focusing on tendon elongation, preactivation, and residual force enhancement. Twelve healthy men participated in this study. Ankle joint angle was passively moved by a dynamometer, with a range of motion from 15° dorsiflexion (DF) to 15° plantarflexion (PF). Muscle contraction was evoked by electrical stimulation, with stimulation timing adjusted to elicit three types of contraction: (1) concentric contraction without preliminary contraction (CON), (2) concentric contraction after preliminary eccentric contraction (ECC), and (3) concentric contraction after preliminary isometric contraction (ISO). Joint torque was recorded at DF5°, PF0°, and PF5°, respectively. SSC effect was calculated as the ratio of joint torque obtained in ECC or ISO with respect to that obtained in CON at the aforementioned three joint angles. SSC effect was prominent in the first half of movement in both ECC (DF5°, 329.3 ± 101.2%; PF0°, 159.2 ± 29.4%; PF5°, 125.5 ± 20.8%) and ISO (DF5°, 276.4 ± 87.0%; PF0°, 134.5 ± 24.5%; PF5°, 106.8 ± 18.0%) conditions. SSC effect was significantly larger in ECC than in ISO at all joint angles (P < 0.001). Even without preliminary eccentric contraction (i.e., ISO condition), SSC effect was clearly large, indicating that a significant part of SSC effect is derived from preactivation. However, the active lengthening-induced force potentiation mechanism (residual force enhancement) also contributes to SSC effect.     

Giga-Pixel Lensfree Holographic Microscopy and Tomography Using Color Image Sensors

We report Giga-pixel lensfree holographic microscopy and tomography using color sensor-arrays such as CMOS imagers that exhibit Bayer color filter patterns. Without physically removing these color filters coated on the sensor chip, we synthesize pixel super-resolved lensfree holograms, which are then reconstructed to achieve ∼350 nm lateral resolution, corresponding to a numerical aperture of ∼0.8, across a field-of-view of ∼20.5 mm². This constitutes a digital image with ∼0.7 Billion effective pixels in both amplitude and phase channels (i.e., ∼1.4 Giga-pixels total). Furthermore, by changing the illumination angle (e.g., ±50°) and scanning a partially-coherent light source across two orthogonal axes, super-resolved images of the same specimen from different viewing angles are created, which are then digitally combined to synthesize tomographic images of the object. Using this dual-axis lensfree tomographic imager running on a color sensor-chip, we achieve a 3D spatial resolution of ∼0.35 µm×0.35 µm×∼2 µm, in x, y and z, respectively, creating an effective voxel size of ∼0.03 µm³ across a sample volume of ∼5 mm³, which is equivalent to >150 Billion voxels. We demonstrate the proof-of-concept of this lensfree optical tomographic microscopy platform on a color CMOS image sensor by creating tomograms of micro-particles as well as a wild-type C. elegans nematode.     

Closed-Cell Stent-Assisted Coiling of Intracranial Aneurysms: Evaluation of Changes in Vascular Geometry Using Digital Subtraction Angiography

BackgroundStent-assisted coil embolization (SACE) plays an important role in the treatment of intracranial aneurysms. The purpose of this study was to investigate geometrical changes caused by closed-cell design stents in bifurcation and sidewall aneurysms.Methods31 patients with 34 aneurysms underwent SACE with closed-cell design stents. Inflow angle α, determined by aneurysm neck and afferent vessel, and angle between afferent and efferent vessel close to (δ₁), respectively, more remote from the aneurysm neck (δ₂) were graphically determined in 2D angiography projections.ResultsStent assisted coiling resulted in a significant increase of all three angles from a mean value (±SEM) of α = 119° (±6.5°) pretreatment to 130° (±6.6°) posttreatment (P ≤ .001), δ₁ = 129° (±6.4°) to 139° (±6.1°), (P ≤ .001) and δ₂ = 115° (±8.4°) to 126° (±7.5°), (P ≤ .01). Angular change of δ₁ in AcomA aneurysms was significant greater compared to sidewall aneurysms (26°±4.9° versus 8°± 2.3°, P ≤ .05). The initial angle of δ₁ and δ₂ revealed a significantly inverse relationship to the angle increase (δ₁: r = -0.41, P ≤ .05 and δ₂: r = -0.47, P ≤ .01). Moreover, angle δ₁ was significantly higher in unruptured compared to ruptured aneurysms (135°±7.1° versus 103°±10.8°, P ≤ .05).ConclusionStent deployment modulates the geometry of the aneurysm-vessel complex, which may lead to favorable hemodynamic changes more similar to unruptured than to ruptured aneurysms. Our findings also suggest that the more acute-angled aneurysm-vessel anatomy, the larger the angular change. Further studies are needed to investigate whether these changes improve the clinical outcome.     

Decadal Changes in the World's Coastal Latitudinal Temperature Gradients

Most of the world''s living marine resources inhabit coastal environments, where average thermal conditions change predictably with latitude. These coastal latitudinal temperature gradients (CLTG) coincide with important ecological clines,e.g., in marine species diversity or adaptive genetic variations, but how tightly thermal and ecological gradients are linked remains unclear. A first step is to consistently characterize the world''s CLTGs. We extracted coastal cells from a global 1°×1° dataset of weekly sea surface temperatures (SST, 1982–2012) to quantify spatial and temporal variability of the world''s 11 major CLTGs. Gradient strength, i.e., the slope of the linear mean-SST/latitude relationship, varied 3-fold between the steepest (North-American Atlantic and Asian Pacific gradients: −0.91°C and −0.68°C lat⁻¹, respectively) and weakest CLTGs (African Indian Ocean and the South- and North-American Pacific gradients: −0.28, −0.29, −0.32°C lat⁻¹, respectively). Analyzing CLTG strength by year revealed that seven gradients have weakened by 3–10% over the past three decades due to increased warming at high compared to low latitudes. Almost the entire South-American Pacific gradient (6–47°S), however, has considerably cooled over the study period (−0.3 to −1.7°C, 31 years), and the substantial weakening of the North-American Atlantic gradient (−10%) was due to warming at high latitudes (42–60°N, +0.8 to +1.6°C,31 years) and significant mid-latitude cooling (Florida to Cape Hatteras 26–35°N, −0.5 to −2.2°C, 31 years). Average SST trends rarely resulted from uniform shifts throughout the year; instead individual seasonal warming or cooling patterns elicited the observed changes in annual means. This is consistent with our finding of increased seasonality (i.e., summer-winter SST amplitude) in three quarters of all coastal cells (331 of 433). Our study highlights the regionally variable footprint of global climate change, while emphasizing ecological implications of changing CLTGs, which are likely driving observed spatial and temporal clines in coastal marine life.     

Quaternary structure of bovine α-crystallin: influence of temperature

The tertiary and quaternary structure of α-crystallin is still a matter of controversy. We have characterized the native α-crystallin quaternary structure by isolating it at the in vivo temperature and solvent conditions. It can be represented by a distribution of expanded particles with a weight average molar mass of 550 000 g/mol. On decreasing (to 4°C) or increasing (up to 50°C) the temperature, the size distribution increases to larger particles. Only at lower temperatures (4°C), a stable population of particles is obtained with weight average molar mass of 700 000 g/mol. In all conditions, α-crystallin behaves as a very expanded particle with a maximum hydrodynamic volume of 3.15 ml/g. The transitions in quaternary structure are rather slow: it takes several hours to evolve from a population of aggregates, characteristic for given solvent conditions, to another distribution in size and quaternary structure on changing the environment. The quaternary structure of α-crystallin is an uncharacteristic parameter of the particle: a broad distribution of values can be obtained on changing the environment. Any realistic model should include this property. Our studies favor an open loose structure, where peptides can be added or removed without drastic changes of secondary and tertiary structure of the peptides.     

TIME-TEMPERATURE RELATIONS IN THE INCUBATION OF THE WHITEFISH,COREGONUS CLUPEAFORMIS (MITCHILL)

1. Whitefish eggs incubated in aerated lake water at controlled tempera tures of 0°, 0.5°, 2°, 4°, 6°, 8°, 10°, and 12°C., failed to hatch at either 0° or 12°C. 0.6 per cent hatched alive at 10°C., 72.67 per cent hatched alive at 0.5°C., and an intermediate proportion hatched at intermediate temperatures. 2. The percentage of abnormal embryos which developed to the hatching stage varied directly with temperature between 4° and 12°, all embryos being abnormal at 12°C.; but none were abnormal at either 0.5°, or 2°C. Normal development predominated from 0.5 to 6°C. The highest proportion of embryos to hatch alive was 72.67 per cent at 0.5°C., which is, hence, the optimum temperature. 3. Total incubation time ranged from 29.6 days at 10°C. to 141 days at 0.5°C. 4. The time (T) required to attain any given stage of development is expressed in equations See PDF for Equation where temperature, t, is a negative exponent of the constant, A, whose value differs above or below 6°C., a critical temperature. Values of A above 6° fluctuate about 1.13; those of A below 6° fluctuate about 1.19 as a mean. 5. Applying Arrhenius'' equation µ values for the total incubation period are 27,500 below 6° and 27,100 above it. 6. The relative magnitude of A values of the exponential equation and µ values of Arrhenius'' equation show corresponding changes from one developmental period to another. 7. When plotted, thermal increments show cyclic variations, with maxima during periods of cleavage and of organogenesis. These may indicate the interaction of two separate sets of embryonic processes, which give a maximal response to temperature differences during these two separate periods. 8. Above 6°, µ values during the hatching process are distinct from those of developmental stages and are regarded as being due to the action of hatching enzymes.     

The sodium, potassium and chloride of cerebral tissues: maintenance, change on stimulation and subsequent recovery

1. Cerebral tissues were prepared for incubation by cutting them from the brain rapidly and in situ, and the calcium concentration in the incubating medium was altered from the customary 2·8mm to 0·75mm. This provided incubated cerebral cortex with fluid and ion content more closely resembling that of the brain in vivo than hitherto obtained. 2. From a systematic difference in size between inulin spaces of slices with one and those with two cut surfaces, it was estimated that cutting directly affected a layer 0·02mm. thick. On the basis of the volume of this layer, it was calculated that the portion of the tissue not affected by cutting had an inulin space of 258 μl./g. initial wt., and during the process of preparation and incubation had gained 30μequiv. of sodium and 17 μequiv. of chloride/g. and had lost 14 μequiv. of potassium/g. 3. Several aspects of the ion content of the incubated tissue were compatible with the observed membrane potential of −60mv between cellular and extracellular phases. 4. In response to electrical stimulation, sodium of the non-inulin space increased from 28 to 57 μequiv./g., potassium decreased from 68 to 48 μequiv./g. and chloride increased from 16 to 22 μequiv./g. in the non-inulin space. These changes were complete in about 6min., and thereafter the concentrations remained steady during continued stimulation. Initial rates of change were 460 μequiv./g./hr. for sodium and 480 μequiv./g./hr. for potassium. 5. After stimulation was stopped the ionic composition of the tissue returned completely to its pre-stimulation state within 10min. Initial rates for extrusion of sodium and gain of potassium were 160 and 230 μequiv./g./hr. respectively.     

DIRECT COUNTING AND SIZING OF MITOCHONDRIA IN SOLUTION

Resistive particle counting has been developed for the accurate sizing and counting of mitochondria in solution. The normal detection limit with a 30 µ aperture is 0.48 µ diameter, or 0.056 µ³ particle volume The mean volume of rat liver mitochondria was 0.42 µ³ or 0.93 µ in diameter. The average value for numbers of particles per milligram of mitochondrial protein was 4.3 x 10³, and per gram of rat liver was about 11 x 10¹⁰. These values compare satisfactorily with those derived by light microscopy and electron microscopy. The mean volume for mitochondria from rat heart was 0 60 µ³ and from rat kidney cortex, 0.23 µ³. These values agree within 15% of those determined by electron microscopy of whole tissue. Mitochondrial fragility and contaminating subcellular organelles were shown to have little influence on the experimentally determined size distributions The technique may be applied to rapid swelling studies, as well as to estimations of the number and size of mitochondria from animals under different conditions such as liver regeneration and hormonal, pathological, or drug-induced states Mitochondrial DNA, RNA, cytochrome c-oxidase, cytochrome (a ÷ a₃), and iron were nearly constant per particle over large differences in particle size. Such data may be particularly valuable for biogenesis studies and support the hypothesis that the net amount per particle of certain mitochondrial constituents remains constant during mitochondrial growth and enlargement     

Effect of Wrist Angle on Median Nerve Appearance at the Proximal Carpal Tunnel

This study investigated the effects of wrist angle, sex, and handedness on the changes in the median nerve cross-sectional area (MNCSA) and median nerve diameters, namely longitudinal diameter (D1) and vertical diameter (D2). Ultrasound examination was conducted to examine the median nerve at the proximal carpal tunnel in both dominant and nondominant hands of men (n = 27) and women (n = 26). A total of seven wrist angles were examined: neutral; 15°, 30°, and 45° extension; and 15°, 30°, and 45° flexion. Our results indicated sexual dimorphism and bilateral asymmetry of MNCSA, D1 and D2 measurements. MNCSA was significantly reduced when the wrist angle changed from neutral to flexion or extension positions. At flexion positions, D1 was significantly smaller than that at neutral. In contrast, at extension positions, D2 was significantly smaller than that at neutral. In conclusion, this study showed that MNCSA decreased as the wrist angle changed from neutral to flexion or extension positions in both dominant and nondominant hands of both sexes, whereas deformation of the median nerve differed between wrist flexion and extension.     

Chemical Profiling of Jatropha Tissues under Different Torrefaction Conditions: Application to Biomass Waste Recovery

Gradual depletion of the world petroleum reserves and the impact of environmental pollution highlight the importance of developing alternative energy resources such as plant biomass. To address these issues, intensive research has focused on the plant Jatropha curcas, which serves as a rich source of biodiesel because of its high seed oil content. However, producing biodiesel from Jatropha generates large amounts of biomass waste that are difficult to use. Therefore, the objective of our research was to analyze the effects of different conditions of torrefaction on Jatropha biomass. Six different types of Jatropha tissues (seed coat, kernel, stem, xylem, bark, and leaf) were torrefied at four different temperature conditions (200°C, 250°C, 300°C, and 350°C), and changes in the metabolite composition of the torrefied products were determined by Fourier transform-infrared spectroscopy and nuclear magnetic resonance analyses. Cellulose was gradually converted to oligosaccharides in the temperature range of 200°C–300°C and completely degraded at 350°C. Hemicellulose residues showed different degradation patterns depending on the tissue, whereas glucuronoxylan efficiently decomposed between 300°C and 350°C. Heat-induced depolymerization of starch to maltodextrin started between 200°C and 250°C, and oligomer sugar structure degradation occurred at higher temperatures. Lignin degraded at each temperature, e.g., syringyl (S) degraded at lower temperatures than guaiacyl (G). Finally, the toxic compound phorbol ester degraded gradually starting at 235°C and efficiently just below 300°C. These results suggest that torrefaction is a feasible treatment for further processing of residual biomass to biorefinery stock or fertilizer.     

Studies on the origin of bacterial viruses. V. The effect of temperature on the terramycin-resistant and phage-producing cells of Bacillus megatherium cultures

The growth rates, the mutation frequency rate constants of the terramycin-resistant cells, the burst size of the phage-producing cells, and the ratio of phage to cells all have a temperature coefficient of about 2 from 20 to 35° (µ = 9 x 10³ calories), with a maximum at 40°. The mutation frequency rate constant (or time rate constant) of the phage-producing cells increases from 20 to 45° with a temperature coefficient of about 3 (µ = 2 to 3 x 10⁴ cal.). The change in the values for the growth rate, mutation rate, and cell volume occurs in less than 1 hour, after the temperature is changed. The value for the burst size of phage-producing cells changes for 3 to 4 hours. Prolonged growth of megatherium 899 at 48 to 50° results in the production of C + S phage, in place of T. Returning the culture to 25° results in the production of small T phage.     

Digital Inline Holographic Microscopy (DIHM) of Weakly-scattering Subjects

Weakly-scattering objects, such as small colloidal particles and most biological cells, are frequently encountered in microscopy. Indeed, a range of techniques have been developed to better visualize these phase objects; phase contrast and DIC are among the most popular methods for enhancing contrast. However, recording position and shape in the out-of-imaging-plane direction remains challenging. This report introduces a simple experimental method to accurately determine the location and geometry of objects in three dimensions, using digital inline holographic microscopy (DIHM). Broadly speaking, the accessible sample volume is defined by the camera sensor size in the lateral direction, and the illumination coherence in the axial direction. Typical sample volumes range from 200 µm x 200 µm x 200 µm using LED illumination, to 5 mm x 5 mm x 5 mm or larger using laser illumination. This illumination light is configured so that plane waves are incident on the sample. Objects in the sample volume then scatter light, which interferes with the unscattered light to form interference patterns perpendicular to the illumination direction. This image (the hologram) contains the depth information required for three-dimensional reconstruction, and can be captured on a standard imaging device such as a CMOS or CCD camera. The Rayleigh-Sommerfeld back propagation method is employed to numerically refocus microscope images, and a simple imaging heuristic based on the Gouy phase anomaly is used to identify scattering objects within the reconstructed volume. This simple but robust method results in an unambiguous, model-free measurement of the location and shape of objects in microscopic samples.     

Spectral characterization of hydroxyapatite extracted from Black Sumatra and Fighting cock bone samples: A comparative analysis

At present, chicken business is occupying a major portion in the market and huge amount of bone wastes are dumped into the open places lead in environmental pollution. In this analysis, natural hydroxyapatite was extracted by thermal calcination process at different temperature ranges from 700 °C, 900 °C and 1100 °C and compared its spectral characteristics. The crystalline nature, functional groups and morphological characteristics of hydroxyapatite obtained from both bone samples were studied using XRD, FTIR and SEM analysis. The crystallite size, lattice parameters, specific surface area, volume and degree of crystallinity were measured using XRD data. The mean grain size of Black Sumatra and Fighting Cock bone hydroxyapatite was 62.67 nm and 31.34 nm respectively. The FTIR spectrum showed major peaks at 634.58 cm⁻¹ and 470.63 cm⁻¹, 1413.82 cm⁻¹ and 1460 cm⁻¹ indicates the presence of carbonate group and phosphate groups in both samples. The SEM micrograph confirmed the existence of maximum pores in matrix of fighting cock bone than Black Sumatra bone sample. Thus, the comparative analysis concluded that nano-sized hydroxyapetite obtained from bone wastes of fighting cock can be utilized as a low-cost biomaterial for the production of various implant coating materials and substitute for ceramics in bones and dentistry applications.     

Mechanism of DNA flexibility enhancement by HMGB proteins

The mechanism by which sequence non-specific DNA-binding proteins enhance DNA flexibility is studied by examining complexes of double-stranded DNA with the high mobility group type B proteins HMGB2 (Box A) and HMGB1 (Box A+B) using atomic force microscopy. DNA end-to-end distances and local DNA bend angle distributions are analyzed for protein complexes deposited on a mica surface. For HMGB2 (Box A) binding we find a mean induced DNA bend angle of 78°, with a standard error of 1.3° and a SD of 23°, while HMGB1 (Box A+B) binding gives a mean bend angle of 67°, with a standard error of 1.3° and a SD of 21°. These results are consistent with analysis of the observed global persistence length changes derived from end-to-end distance measurements, and with results of DNA-stretching experiments. The moderately broad distributions of bend angles induced by both proteins are inconsistent with either a static kink model, or a purely flexible hinge model for DNA distortion by protein binding. Therefore, the mechanism by which HMGB proteins enhance the flexibility of DNA must differ from that of the Escherichia coli HU protein, which in previous studies showed a flat angle distribution consistent with a flexible hinge model.     

Variation in Plasma Calcium with Induced Changes in Plasma Specific Gravity,Total Protein,and Albumin

The relationship of plasma calcium levels to changes in plasma specific gravity, total protein, and albumin induced by venous stasis was investigated. Factors were derived for adjusting calcium results to offset the effects of variation in protein concentration and thus to make them of increased discriminatory value to the clinician. The validity of an existing specific gravity correction has been substantiated, but a more exact adjustment of 0·23 mg/100 ml of calcium for every 0·001 change in specific gravity is proposed. We recommend for automated laboratories that the factor based on albumin be used: 0·09 mg/100 ml of calcium should be subtracted from the total calcium value for every increase of 0·1 g in albumin above 4·6 g/100 ml, and a corresponding addition should be made for values of albumin below 4·6 g/100 ml.Using a calcium specific electrode, it has been shown that the ionized calcium concentration does not alter with prolonged venous stasis.     

The Transmembrane Helices of Beef Heart Cytochrome Oxidase

The locations of the transmembrane helices in the 12 subunits of beef heart cytochrome oxidase were predicted with a modified form of the von Heijne-Blomberg hydrophobicity scale. Based on ~20 residues per transmembrane helix, about 480 of the estimated 660 helical residues (36.8% of 1,793 total residues) are expected to be in transmembrane helices that have their axes tilted by a small angle α from the normal to the plane of the membrane. This angle is calculated to be ~30°, based on the observed overall tilt angle θ of 39° obtained from circular dichroism (CD) measurements on multilamellar films, or about 25°, based on the observed tilt angle θ of 36° obtained from the infrared linear dichroism of films. For 21 residues per transmembrane helix, the calculated values of α become 32° and 28°, respectively, depending upon the value of θ used. Thus, a transmembrane helical tilt angle of ~30° accounts for the predicted transmembrane stretches in cytochrome oxidase if 20-21 residues are sufficient to span the membrane. Additional helical residues in the lipid head region may deviate by a larger angle from the normal to the plane of the membrane in cytochrome oxidase.     

Simultaneous Processing of Information on Multiple Errors in Visuomotor Learning

The proper association between planned and executed movements is crucial for motor learning because the discrepancies between them drive such learning. Our study explored how this association was determined when a single action caused the movements of multiple visual objects. Participants reached toward a target by moving a cursor, which represented the right hand’s position. Once every five to six normal trials, we interleaved either of two kinds of visual perturbation trials: rotation of the cursor by a certain amount (±15°, ±30°, and ±45°) around the starting position (single-cursor condition) or rotation of two cursors by different angles (+15° and −45°, 0° and 30°, etc.) that were presented simultaneously (double-cursor condition). We evaluated the aftereffects of each condition in the subsequent trial. The error sensitivity (ratio of the aftereffect to the imposed visual rotation) in the single-cursor trials decayed with the amount of rotation, indicating that the motor learning system relied to a greater extent on smaller errors. In the double-cursor trials, we obtained a coefficient that represented the degree to which each of the visual rotations contributed to the aftereffects based on the assumption that the observed aftereffects were a result of the weighted summation of the influences of the imposed visual rotations. The decaying pattern according to the amount of rotation was maintained in the coefficient of each imposed visual rotation in the double-cursor trials, but the value was reduced to approximately 40% of the corresponding error sensitivity in the single-cursor trials. We also found a further reduction of the coefficients when three distinct cursors were presented (e.g., −15°, 15°, and 30°). These results indicated that the motor learning system utilized multiple sources of visual error information simultaneously to correct subsequent movement and that a certain averaging mechanism might be at work in the utilization process.     

Increasing Water Temperature Triggers Dominance of Small Freshwater Plankton

Climate change scenarios predict that lake water temperatures will increase up to 4°C and rainfall events will become more intense and frequent by the end of this century. Concurrently, supply of humic substances from terrestrial runoff is expected to increase, resulting in darker watercolor (“brownification”) of aquatic ecosystems. Using a multi-seasonal, low trophic state mesocosm experiment, we investigated how higher water temperature and brownification affect plankton community composition, phenology, and functioning. We tested the hypothesis that higher water temperature (+3°C) and brownification will, a) cause plankton community composition to shift toward small sized phytoplankton and cyanobacteria, and, b) extend the length of the growing season entailing higher phytoplankton production later in the season. We demonstrate that the 3°C increase of water temperature favored the growth of heterotrophic bacteria and small sized autotrophic picophytoplankton cells with significantly higher primary production during warmer fall periods. However, 3X darker water (effect of brownification) caused no significant changes in the plankton community composition or functioning relative to control conditions. Our findings reveal that increased temperature change plankton community structure by favoring smaller sized species proliferation (autotrophic phytoplankton and small size cladocerans), and increase primary productivity and community turnover. Finally, results of this multi-seasonal experiment suggest that warming by 3°C in aquatic ecosystems of low trophic state may cause planktonic food web functioning to become more dominated by fast growing, r-trait species (i.e., small sizes and rapid development).     

The specific heat of red cells,with special reference to the paracrystalline rat red cell

The specific heat of the rat red cell, kept in cold sodium citrate, changes in the neighborhood of 6°C., the temperature near which the cell passes from its paracrystalline state to a state of greater disorder. The change in the specific heat is from 0.74 with a standard deviation of ±0.022 (paracrystalline state) to 0.87 with a standard deviation of ±0.021 (normal state). Although it has been looked for, no evidence of a change in specific heat has been found, between 1°C. and 15°C., in the case of the human red cell or of the fresh rat red cell in saline or plasma.     

Heading for New Shores: Projecting Marine Distribution Ranges of Selected Larger Foraminifera

The distribution of modern symbiont-bearing larger foraminifera is confined to tropical and subtropical shallow water marine habitats and a narrow range of environmental variables (e.g. temperature). Most of today''s taxa are restricted to tropical and subtropical regions (between 30°N and 30°S) and their minimum temperature limits are governed by the 14 to 20°C isotherms. However, during times of extensive global warming (e.g., the Eocene and Miocene), larger foraminifera have been found as far north as 50°N (North America and Central Europe) as well as towards 47°S in New Zealand. During the last century, sea surface temperatures have been rising significantly. This trend is expected to continue and climate change scenarios for 2050 suggest a further increase by 1 to 3°C. We applied Species Distribution Models to assess potential distribution range changes of three taxa of larger foraminifera under current and future climate. The studied foraminifera include Archaias angulatus, Calcarina spp., and Amphistegina spp., and represent taxa with regional, superregional and global distribution patterns. Under present environmental conditions, Amphistegina spp. shows the largest potential distribution, apparently due to its temperature tolerance. Both Archaias angulatus and Calcarina spp. display potential distributions that cover currently uninhabited regions. Under climate conditions expected for the year 2050, all taxa should display latitudinal range expansions between 1 to 2.5 degrees both north- and southward. The modeled range projections suggest that some larger foraminifera may colonize biogeographic regions that so far seemed unsuitable. Archaias angulatus and Calcarina spp. also show an increase in habitat suitability within their native occurrence ranges, suggesting that their tolerance for maximum temperatures has yet not been fully exploited and that they benefit from ocean warming. Our findings suggest an increased role of larger foraminifera as carbonate producers and reef framework builders in future oceans.