Increases of Chamber Height and Base Diameter Have Contrasting Effects on Grazing Rate of Two Cladoceran Species: Implications for Microcosm Studies

<div><p>Aquatic microcosm studies often increase either chamber height or base diameter (to increase water volume) to test spatial ecology theories such as “scale” effects on ecological processes, but it is unclear whether the increase of chamber height or base diameter have the same effect on the processes, i.e., whether the effect of the shape of three-dimensional spaces is significant. We orthogonally manipulated chamber height and base diameter and determined swimming activity, average swimming velocity and grazing rates of the cladocerans <i>Daphnia magna</i> and <i>Moina micrura</i> (on two algae <i>Scenedesmus quadricauda</i> and <i>Chlorella vulgaris</i>; leading to four aquatic algae-cladoceran systems in total) under different microcosm conditions. Across all the four aquatic systems, increasing chamber height at a given base diameter significantly decreased the duration and velocity of horizontal swimming, and it tended to increase the duration but decrease the velocity of vertical swimming. These collectively led to decreases in both average swimming velocity and grazing rate of the cladocerans in the tall chambers (at a given base diameter), in accordance with the positive relationship between average swimming velocity and grazing rate. In contrast, an increase of base diameter at a given chamber height showed contrasting effects on the above parameters. Consistently, at a given chamber volume increasing ratio of chamber height to base diameter decreased the average swimming velocity and grazing rate across all the aquatic systems. In general, increasing chamber depth and base diameter may exert contrasting effects on zooplankton behavior and thus phytoplankton-zooplankton interactions. We suggest that spatial shape plays an important role in determining ecological process and thus should be considered in a theoretical framework of spatial ecology and also the physical setting of aquatic microcosm experiments.</p></div

Illustration of the experimental design showing five different chamber treatments.

<p>The experiment included four algae-grazer systems including <i>Scenedesmus quadricauda</i>-<i>Daphnia magna</i>, <i>S</i>. <i>quadricauda</i>-<i>Moina micrura</i>, <i>Chlorella vulgaris</i>-<i>D</i>. <i>magna</i>, and <i>C</i>. <i>vulgaris</i>-<i>M</i>. <i>micrura</i> system, and each system was subject to five treatments incorporating chamber height and base diameter as treatment factors. SL: short height and large diameter; SM: short height and medium diameter; MM: medium height and medium diameter; TM: tall height and medium diameter; TS: tall height and small diameter.</p

Average swimming velocity (means ± s. d, n = 6) of grazer species in different plankton systems under three levels of chamber height and three levels of base diameter.

<p>(A) <i>Daphnia magna</i> fed with <i>Scenedesmus quadricauda</i>, (B) <i>Moina micrura</i>fed with <i>S</i>. <i>quadricauda</i>, (C) <i>D</i>. <i>magna</i> fed with <i>Chlorella vulgaris</i>, (D) <i>M</i>. <i>micrura</i> fed with <i>C</i>. <i>vulgaris</i>. Different lowercase letters indicate significant chamber height effect among treatments at a given base diameter. Different upper case letters indicate significant chamber shape effect at a given chamber volume. “*” indicates a significant difference between two treatments at a given chamber height.</p

Formation of Layer-by-Layer Assembled Titanate Nanotubes Filled Coating on Flexible Polyurethane Foam with Improved Flame Retardant and Smoke Suppression Properties

A fire blocking coating made from chitosan, titanate nanotubes and alginate was deposited on a flexible polyurethane (FPU) foam surface by a layer-by-layer assembly technique in an effort to reduce its flammability. First, titanate nanotubes were prepared by a hydrothermal method. And then the coating growth was carried out by alternately submerging FPU foams into chitosan solution, titanate nanotubes suspension and alginate solution. The mass gain of coating on the surface of FPU foams showed dependency on the concentration of titanate nanotubes suspension and the trilayers’s number. Scanning electron microscopy indicated that titanate nanotubes were distributed well on the entire surface of FPU foam and showed a randomly oriented and entangled network structure. The cone calorimeter result indicated that the coated FPU foams showed reduction in the peak heat release rate (peak HRR), peak smoke production rate (peak SPR), total smoke release (TSR) and peak carbon monoxide (CO) production compared with those of the control FPU foam. Especially for the FPU foam with only 5.65 wt % mass gain, great reduction in peak HRR (70.2%), peak SPR (62.8%), TSR (40.9%) and peak CO production (63.5%) could be observed. Such a significant improvement in flame retardancy and the smoke suppression property for FPU foam could be attributed to the protective effect of titanate nanotubes network structure formed, including insulating barrier effect and adsorption effect

Algal density of <i>Scenedesmus quadricauda</i> and <i>Chlorella vulgaris</i> (control treatment), and the grazing rate of <i>Daphnia magna</i> and <i>Moina micrura</i> on these two algae.

<p>(A) Algal density of <i>S</i>.<i>quadricauda</i>; (B) grazing rate of <i>D</i>. <i>magna</i> on <i>S</i>. <i>quadricauda</i>, and (C) of <i>M</i>. <i>micrura</i> on <i>Scenedesmus</i>; (D) algal density of <i>Chlorella vulgaris</i>; (E) grazing rate of <i>D</i>. <i>magna</i> on <i>C</i>. <i>vulgaris</i>, and (F) of <i>M</i>. <i>micrura</i> on <i>C</i>. <i>vulgaris</i>. Different lowercase letters indicate significant chamber height effect among treatments at a given base diameter. Different upper case letters indicate significant chamber shape effect at a given chamber volume. “*” indicates a significant difference between two treatments at a given chamber height. Data are presented as means ± s.d (n = 6).</p

Layer-by-Layer Assembly of Hypophosphorous Acid-Modified Chitosan Based Coating for Flame-Retardant Polyester–Cotton Blends

Hypophosphorous acid-modified chitosan (PCS), as a novel phosphorus-containing chitosan derivative, was first successfully synthesized and characterized by Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy. Subsequently, thin films of the ecofriendly PCS and branched polyethylenimine were deposited on polyester–cotton (PTCO) blends by the layer-by-layer assembly technique, in an effort to enhance their thermal properties and fire resistance properties. Thermogravimetric analysis, thermogravimetric analysis–Fourier transform infrared spectrometry, scanning electron microscopy, and horizontal flame test (HFT) were used to investigate the quality of the coatings as well as their fire resistance performance. The thermal and thermal oxidation stabilities at high temperature were enhanced for all coated PTCO blends. During the HFT, the afterglow phenomenon was eliminated for all coated blends, and self-extinguishing was achieved for the PCS2-20BL sample. It was found that the enhancement of the intumescent effect by the high phosphorus content in these coatings was conducive to achieving this superior performance

Quercetin and allopurinol regulate renal expression of lipid metabolism-related genes protein levels in streptozotocin (STZ)-treated rats.

<p>Representative Western blot results (A) and graphic presentation showed renal protein expression of rPPAR-α (B), rCPT1 (C), rACC2 (D), p-rACC2 (E) and rOCTN2 (F) in different groups of rats as indicated. Relative protein levels of rPPAR-α, rCPT1 and rACC2 were determined after normalization with rGAPDH. The relative renal BBMV rOCTN2 protein levels were normalized to rNa⁺-K⁺-ATPase. The data are expressed as the means ± SEM (n = 3–4). ⁺⁺<i>P</i><0.01, ⁺⁺⁺<i>P</i><0.001 <i>versus</i> normal control; *<i>P</i><0.05, **<i>P</i><0.01, ***<i>P</i><0.001 <i>versus</i> STZ control.</p

Quercetin and allopurinol inhibit renal NALP3 inflammasome activation in streptozotocin (STZ)-treated rats.

<p>Representative Western blot results (A) and graphic presentation showed renal protein expression of rNALP3 (B), rASC (C) and rCaspase-1 (D) in different groups of rats as indicated. Relative protein levels of rNALP3, rASC and rCaspase-1 were determined after normalization with rGAPDH. For rCaspase-1, the active subunit of P20 was detected. The data are expressed as the means ± SEM (n = 3–4). ⁺<i>P</i><0.05, ⁺⁺⁺<i>P</i><0.001 <i>versus</i> normal control; *<i>P</i><0.05, **<i>P</i><0.01, ***<i>P</i><0.001 <i>versus</i> STZ control. Graphic presentation of renal mRNA levels by real-time PCR analysis of rNALP3 (E), rASC (F) and rCaspase-1 (G) at 7 weeks after STZ injection in different groups of rats as indicated. The relative mRNA levels were determined after normalization with rGAPDH. The data are expressed as the means ± SEM (n = 3–4). ⁺⁺⁺<i>P</i><0.001 <i>versus</i> normal control; *<i>P</i><0.05, **<i>P</i><0.01, ***<i>P</i><0.001 <i>versus</i> STZ control. Representative Western blot results (H) and graphic presentation showed renal maturation ratio of IL-1β (I) and IL-18 (J) in different groups of rats as indicated. The data are expressed as the means ± SEM (n = 3–4). ⁺<i>P</i><0.05, ⁺⁺<i>P</i><0.01 <i>versus</i> normal control; *<i>P</i><0.05, **<i>P</i><0.01 <i>versus</i> STZ control.</p

The primers used for Real-Time PCR.

<p>The primers used for Real-Time PCR.</p

Quercetin and allopurinol restore basic characteristics of streptozotocin (STZ)-treated rats.

<p>The data are expressed as the means ± SEM (n = 8). ⁺⁺⁺<i>P</i><0.001 <i>versus</i> normal control; ^*<i>P</i><0.05, ^**<i>P</i><0.01, ^***<i>P</i><0.001 <i>versus</i> STZ control.</p