A Paradigm for the study of insect-ciliate Relationships: Tetrahymena sialidos sp. nov. (Hymenostomatida: Tetrahymenidae), Parasite of Larval Sialis Lutaria (Linn.) (Megaloptera: Sialidae)

A new species of hymenostome ciliate, Tetrahymena sialidos sp.nov., is described and proposed as a model for studies upon insect-ciliate interactions. This ciliate occurs as a parasite in the haemocoel of larval Sialis lutaria (Megaloptera) and exhibits field and laboratory characteristics favourable for two particular areas of study, the regulation of invertebrate populations by parasites and insect immunity to parasitic infections. The prevalence of T. sialidos infection in S. lutaria from a small lake in mid-Wales has been monitored during a four-year period. Each summer, early in the first of their two-year aquatic development, 40-70% of S. lutaria larvae become infected. Death of infected larvae due to parasite proliferation is inevitable but does not occur until 11-12 months after infection, when the mean intensity has reached 55000 ciliates per infected host. Ciliates escaping from moribund or dead host larvae undergo a distinct morphological transformation followed by a period of synchronous conjugation. Death of infected host larvae and release of ciliates coincides with the appearance of a new generation of host larvae in which the prevalence of infection rises rapidly. The possible significance of this substantial and persistent regulatory influence upon host population dynamics is discussed in relation to current ideas of parasite regulation of invertebrate populations. Sialis lutaria is not able normally to mount a successful host response against T. sialidos infections. A laboratory thermalshock technique is described by means of which parasitic ciliates may be killed in situ without incurring physical damage to the host. Infected larvae subjected to thermalshock at 39 °C for 1 h subsequently encapsulate and melanize the dead ciliates. The use of this technique is discussed in relation to recognition of non-self in insects and survival strategies of parasites infecting insects.

1986 ◽  
Vol 64 (8) ◽  
pp. 1696-1700 ◽  
Author(s):  
Eric Gilbert ◽  
Bruno Vincent ◽  
Luc Roseberry

Experiments in a natural environment on the Gastropod Bithynia tentaculata showed that adult density and available food have significant effects on the growth of smaller adults and newborns. Mean length of the new generation at the end of the experiment incresed as adult densities decreased from the initial value and as food abundance increased. The only case of interaction between these two factors can be explained by an increase in the number of young brought about by the addition of food when density was low and by the influence of the density of these young on their growth. Different combinations of density and food can produce the various types of length–frequency histograms observed in a natural environment and during the past 8 years in the St. Lawrence River. There was no significant correlation between these two factors and the adult mortality rate, but density did have a significant effect on the mean number of young per adult.[Journal translation]


Author(s):  
Kranti Singh ◽  
Surajpal Verma ◽  
Shyam Prasad ◽  
Indu Bala

Ciprofloxacin hydrochloride loaded Eudragit RS100 nanoparticles were prepared by using w/o/w emulsification (multiple emulsification) solvent evaporation followed by drying of nanoparticles at 50°C. The nanoparticles were further incorporated into the pH-triggered in situ gel forming system which was prepared using Carbopol 940 in combination with HPMC as viscosifying agent. The developed nanoparticles was evaluated for particle size, zeta potential value and loading efficiency; nanoparticle incorporated in situ gelling system was evaluated for pH, clarity, gelling strength, rheological studies, in-vitro release studies and ex-vivo precorneal permeation studies. The nanopaticle showed the mean particle size varying between 263.5nm - 325.9 nm with the mean zeta potential value of -5.91 mV to -8.13 mV and drug loading capacity varied individually between 72.50% to 98.70% w/w. The formulation was clear with no suspended particles, showed good gelling properties. The gelling was quick and remained for longer time period. The developed formulation was therapeutically efficacious, stable and non-irritant. It provided the sustained release of drug over a period of 8-10 hours.


2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Chunming Huang ◽  
Wei Li ◽  
Shaodong Zhang ◽  
Gang Chen ◽  
Kaiming Huang ◽  
...  

AbstractThe eastward- and westward-traveling 10-day waves with zonal wavenumbers up to 6 from surface to the middle mesosphere during the recent 12 years from 2007 to 2018 are deduced from MERRA-2 data. On the basis of climatology study, the westward-propagating wave with zonal wave number 1 (W1) and eastward-propagating waves with zonal wave numbers 1 (E1) and 2 (E2) are identified as the dominant traveling ones. They are all active at mid- and high-latitudes above the troposphere and display notable month-to-month variations. The W1 and E2 waves are strong in the NH from December to March and in the SH from June to October, respectively, while the E1 wave is active in the SH from August to October and also in the NH from December to February. Further case study on E1 and E2 waves shows that their latitude–altitude structures are dependent on the transmission condition of the background atmosphere. The presence of these two waves in the stratosphere and mesosphere might have originated from the downward-propagating wave excited in the mesosphere by the mean flow instability, the upward-propagating wave from the troposphere, and/or in situ excited wave in the stratosphere. The two eastward waves can exert strong zonal forcing on the mean flow in the stratosphere and mesosphere in specific periods. Compared with E2 wave, the dramatic forcing from the E1 waves is located in the poleward regions.


2014 ◽  
Vol 27 (5) ◽  
pp. 1945-1957 ◽  
Author(s):  
John M. Lyman ◽  
Gregory C. Johnson

Abstract Ocean heat content anomalies are analyzed from 1950 to 2011 in five distinct depth layers (0–100, 100–300, 300–700, 700–900, and 900–1800 m). These layers correspond to historic increases in common maximum sampling depths of ocean temperature measurements with time, as different instruments—mechanical bathythermograph (MBT), shallow expendable bathythermograph (XBT), deep XBT, early sometimes shallower Argo profiling floats, and recent Argo floats capable of worldwide sampling to 2000 m—have come into widespread use. This vertical separation of maps allows computation of annual ocean heat content anomalies and their sampling uncertainties back to 1950 while taking account of in situ sampling advances and changing sampling patterns. The 0–100-m layer is measured over 50% of the globe annually starting in 1956, the 100–300-m layer starting in 1967, the 300–700-m layer starting in 1983, and the deepest two layers considered here starting in 2003 and 2004, during the implementation of Argo. Furthermore, global ocean heat uptake estimates since 1950 depend strongly on assumptions made concerning changes in undersampled or unsampled ocean regions. If unsampled areas are assumed to have zero anomalies and are included in the global integrals, the choice of climatological reference from which anomalies are estimated can strongly influence the global integral values and their trend: the sparser the sampling and the bigger the mean difference between climatological and actual values, the larger the influence.


2008 ◽  
Vol 88 (4) ◽  
pp. 711-719 ◽  
Author(s):  
Kenton J Hart ◽  
Brian G Rossnagel ◽  
Peiqiang Yu

The objective of this study was to compare the most widely grown barley cultivar in Canada, AC Metcalfe, a malting type barley, with five feed cultivars. Barley cultivars were grown at one location during 3 consecutive years and barley samples were milled to pass through a 1-mm screen and analysed to determine nutritive value. Additional samples were passed through a roller mill with a gap set at 1.12 mm and incubated ruminally for 0, 2, 4, 8, 12, 24, and 48 h in 3 dry Holstein cows fitted with rumen cannulae. The rate and extent of rumen digestion were estimated. AC Metcalfe had a higher (P < 0.001) concentration of NDF, and lower (P < 0.05) concentrations of non structural carbohydrates, starch, ADF, total digestible nutrients, and fermentable cell wall carbohydrates compared with the mean of the feed cultivars. The malting cultivar had a higher (P < 0.001) soluble DM fraction, lower (P < 0.05) CP and starch degradation rates, and a lower (P < 0.001) ruminally degradable starch concentration compared with the mean of the five feed cultivars. The results demonstrate that there are only small differences in terms of chemical composition and in situ degradation kinetics between the malting cultivar AC Metcalfe and the five feed cultivars of barley reported here. Key words: Barley, energy, protein, ruminants


2010 ◽  
Vol 105-106 ◽  
pp. 179-183 ◽  
Author(s):  
De Gui Zhu ◽  
Hong Liang Sun ◽  
Yu Shu Wang ◽  
Liang Hui Wang

Fully dense samples of TiB2-TiCX and TiB2-TiCX/15SiC ceramic composites were fabricated by in-situ synthesis under hot isostatic pressing from TiH2, B4C and SiC powders. Their oxidized behaviors at different temperatures were tested. Optical micrograph studies and thermo-gravimetric analyses show that the highest effective temperature of oxidation resistance is 700°C for TiB2-TiCX, and 1100°C for TiB2-TiCX/15SiC. The weight gain of TiB2-TiCX/15SiC below 1100°C is quite low, and it rises up suddenly when the temperature reaches 1200°C. Thus, the highest effective temperature of oxidation resistance is 1100°C for TiB2-TiCX/15SiC. The oxidation dynamic curves of TiB2-TiCX/15SiC ceramics accord with the parabola’s law. The activation energy of TiB2-TiCx/15SiC (189.87kJ.mol-1) is higher than that of TiB2-TiCx (96.44kJ.mol-1). In the oxidation process of TiB2-TiCx/15SiC, TiB2 reacts with oxygen and generates TiO2 and B2O3 at first. A layer of whole homogeneous oxide film cannot be formed, in the mean time, the oxidation of TiC begins. When temperature goes up to 1000°C, TiC phase is totally oxidized. SiC is oxidized to SiO2 at about 900°C, Meanwhile, TiO2 forms denser film than B2O3, which grows and covers the surface of the material, and gives better property of oxidation resistance.


1998 ◽  
Vol 1998 ◽  
pp. 63-63
Author(s):  
C. Rymer ◽  
D.I. Givens

The gas production (GP) technique has been developed to assess dynamics of ruminant digestion. Relationships have been observed between a feed's GP profile and in vivo parameters such as digestibility (Khazaal et al., 1993), feed intake and growth rate (Blümmel and Ørskov, 1993), and in situ degradability (Sileshi et al., 1997). However, there are few studies which relate GP data to the in vivo pattern of rumen fermentation (in terms of the rate of pH decline 2 h post-feeding and the mean rumen pH, concentration of total VFA and molar proportion of individual VFA). The object of this experiment was to determine whether such a relationship existed between a feed's GP profile and the pattern of rumen fermentation observed in animals fed that feed.


2021 ◽  
Vol 6 (14) ◽  
pp. 56-67
Author(s):  
Arslan Say ◽  
Abdülkadir ÇAKMAK ◽  
Gökhan KESKİN ◽  
Erdinç PELİT ◽  
Yılmaz ÖZBAY

Aim: New generation anticoagulants rapidly find a wider area of use in the clinic due to the use problems of other oral anticoagulants. Anticoagulants such as Dabigatran, Rivaroxaban, and Apixaban with safer treatment intervals have been accepted in clinical practice guidelines and have taken their place as preferred drugs. In this study, we aimed to retrospectively examine the effects of three new-generation anticoagulant drugs on a group of patients. Material and Methods: In this retrospectively planned study, patients diagnosed with atrial fibrillation (n = 522) were divided into three groups according to the drugs used for treatment (Dabigatran, Rivaroxaban, and Apixaban). Routine blood values of the patients in each group were retrospectively scanned according to age, gender, time of drug initiation and presence of chronic disease. Results: According to the results obtained, it was found that the mean HCT, BUN, AST, ALT, MPV, Iron, and Ferritin were higher in patients using Apixaban than those using Dabigatran and Rivaroxaban drugs, but the age, average values of Hgb1 Hgb2, Hgb1, PLT, CrCl, Gfr and INR of the patients using Apixaban lower than those using Dabigatran and Rivaroxaban. The highest rate (22.5%) was found in the group of patients taking apixaban (n=93) when people taking the drugs were examined in terms of mortality. Conclusion: It has been observed that Rivaroxaban can be used more safely in patients with a history of acute cancer and thrombosis, patients with recurrent venous thromboembolism, and patients with high frailty, three drugs should be preferred instead of oral anticoagulants.


2015 ◽  
Vol 27 (01) ◽  
pp. 1550004 ◽  
Author(s):  
Audrey K. C. Huong ◽  
Xavier T. I. Ngu

We present the use of Extended Modified Lambert–Beer model for optical monitoring of mean blood oxygen saturation ( S m O 2) via a fitting procedure. This work focuses on the absorption characteristics of hemoglobin derivatives in the wavelength range of 520–600 nm to give the best estimates of S m O 2. The study of the feasibility of applying this analytic method to skin oximetry is via spectroscopy data collected from fingertips of four healthy volunteers both at rest and during arterial blood occlusion condition. The results revealed a decrease in the mean of mean and standard deviation of S m O 2 value of fingertips from 94.5 ± 2.19% when volunteers were at rest to 56.76 ± 5.8% during the arterial blood occlusion measurement. The larger variation in the value estimated for blood occlusion condition could be a result of differences in volunteers' physical fitness and hypertension status. These estimated S m O 2 values agreed reasonably well with the value reported in most of the previous studies. This work concluded that the proposed technique can potentially be used as a complementary technique to clinical assessment of skin grafts and burnt skin.


2018 ◽  
pp. 5-7 ◽  
Author(s):  
Vincent Podeur ◽  
Damien Merdrignac ◽  
Morgan Behrel ◽  
Kostia Roncin ◽  
Caroline Fonti ◽  
...  

A tool dedicated to assess fuel economy induced by kite propulsion has been developed. To produce reliable results, computations must be performed on a period over several years, for several routes and for several ships. In order to accurately represent the impact of meteorological trends variations on the exploitability of the kite towing concept, a time domain approach of the problem has been used. This tool is based on the weather database provided by the ECMWF. Two sailing strategies can be selected for assessing the performance of the kite system. For a given kite area, the simulation can be run either at constant speed or at constant engine power. A validation has been made, showing that predicted consumption is close from in-situ measurement. It shows an underestimation of 11.9% of the mean fuel consumption mainly due to auxiliary consumption and added resistance in waves that were not taken into account. To conclude, a case study is performed on a 2200 TEU container ship equipped with an 800m² kite on a transatlantic route between Halifax and Le Havre. Round trip simulations, performed over 5 years of navigation, show that the total economy predicted is of around 12% at a speed of 16 knots and around 6.5% at a speed of 19 knots.


Sign in / Sign up

Export Citation Format

Share Document