AN APPARATUS FOR DETERMINING THE EFFECTS OF TEMPERATURE AND HUMIDITY ON GERMINATION OF FUNGOUS SPORES

1955 ◽  
Vol 33 (4) ◽  
pp. 289-292 ◽  
Author(s):  
Mary P. Hart ◽  
Donald M. MacLeod

An apparatus is described by which fungous spores can be uniformly distributed on microscope slides. A procedure is outlined whereby Petri dishes can be converted into airtight humidity chambers, the humidity of which can be readily checked. It was found that above 94% relative humidity maximum germination among Beauveria bassiana spores occurs at 28 °C.

2020 ◽  
Author(s):  
Lei Qin ◽  
Qiang Sun ◽  
Jiani Shao ◽  
Yang Chen ◽  
Xiaomei Zhang ◽  
...  

Abstract Background: The effects of temperature and humidity on the epidemic growth of coronavirus disease 2019 (COVID-19)remains unclear.Methods: Daily scatter plots between the epidemic growth rate (GR) and average temperature (AT) or average relative humidity (ARH) were presented with curve fitting through the “loess” method. The heterogeneity across days and provinces were calculated to assess the necessity of using a longitudinal model. Fixed effect models with polynomial terms were developed to quantify the relationship between variations in the GR and AT or ARH.Results: An increased AT dramatically reduced the GR when the AT was lower than −5°C, the GR was moderately reduced when the AT ranged from −5°C to 15°C, and the GR increased when the AT exceeded 15°C. An increasedARH increased theGR when the ARH was lower than 72% and reduced theGR when the ARH exceeded 72%.Conclusions: High temperatures and low humidity may reduce the GR of the COVID-19 epidemic. The temperature and humidity curves were not linearly associated with the COVID-19 GR.


2014 ◽  
Vol 633 ◽  
pp. 3-6 ◽  
Author(s):  
Xiang Yun Lu ◽  
Lan Chen ◽  
Rui Lin Heng ◽  
Yun Zhang Cheng ◽  
Umezuruike Linus Opara

Powder flowability is one of the most important properties affecting the filling and delivering processes of dry powder inhalations. When the powder is exposed to different environmental (temperature, relative humidity (RH)) conditions, the interaction between particulates would influence the flowability of powders. Blends of 83% coarse lactose (D50=126μm) and 17% fine lactose (D50= 7μm) were prepared at three different mixing environments and the effects of temperature and humidity on powder flowability were investigated. Results indicated that mixing under relatively higher temperature and lower RH environmental conditions improved the flowability of lactose blends.


Author(s):  
Mohammad H. Hasan ◽  
Hassen M. Ouakad ◽  
Fadi Alsaleem

In this paper, we present a comprehensive model to simulate the behavior of a general MEMS arch resonator under various thermal conditions. The model takes into account the changes in the microbeam’s parameters, air properties and the internal stresses due to temperature and humidity. The continuous, flexible, initially curved microbeam was excited linearly and nonlinearly around both its first and third modal natural frequencies. It was found that the mutual effects of temperature and humidity on air viscosity is amplified over four times when the microbeam is operated in the nonlinear regime. Furthermore, results showed that the relative humidity influence is more severe at higher values of the temperature. Finally, the microbeam’s frequency shift due to change in humidity increases when operating the microbeam at its third natural frequency compared to first natural frequency.


Author(s):  
Pingchuan Li ◽  
Xianguo Tuo ◽  
Mingzhe Liu ◽  
Jun Ren ◽  
Qibiao Wang ◽  
...  

This paper reported the experimental results of ion current under different temperatures and relative humidity using long range alpha detector (LRAD). An approximation relation between the measuring values, temperatures and relative humidity has been obtained using the linear multiple regression method. The experimental results have shown that the measuring values decrease with the increase of temperature and humidity. The influence of humidity on results outweighs that of temperatures. And both temperature and humidity are obviously negative correlated with measured values. Further experiments will be performed to confirm the coupling effects of temperature and humidity and reported later.


1976 ◽  
Vol 56 (3) ◽  
pp. 517-523 ◽  
Author(s):  
M. KHOSH-KHUI ◽  
A. BASSIRI ◽  
M. NIKNEJAD

Pollen of six species of genus Rosa was stored under partial vacuum at 0 and 25 C and 10, 30, 50, 70 and 90% relative humidity. Data obtained showed significant interaction between temperature and humidity. The best conditions for pollen storage at 0 C were 50 and 70% relative humidity, while at 25 C, the best humidity was 30 and 50%, respectively. Most species reached the highest percentage of viable pollen in 2–3 wk of storage. It was concluded that for short periods of pollen storage, 25 C was more suitable than 0 C for rose pollen. Differences among responses of Rosa pollen grains to storage environment are discussed.


2014 ◽  
Vol 70 (12) ◽  
pp. 3167-3176 ◽  
Author(s):  
Yuri Gerelli ◽  
Alexis de Ghellinck ◽  
Juliette Jouhet ◽  
Valérie Laux ◽  
Michael Haertlein ◽  
...  

Neutron scattering studies on mimetic biomembranes are currently limited by the low availability of deuterated unsaturated lipid species. In the present work, results from the first neutron diffraction experiments on fully deuterated lipid extracts from the yeastPichia pastorisare presented. The structural features of these fully deuterated lipid stacks are compared with those of their hydrogenous analogues and with other similar synthetic systems. The influence of temperature and humidity on the samples has been investigated by means of small momentum-transfer neutron diffraction. All of the lipid extracts investigated self-assemble into multi-lamellar stacks having different structural periodicities; the stacking distances are affected by temperature and humidity without altering the basic underlying arrangement. At high relative humidity the deuterated and hydrogenous samples are similar in their multi-lamellar arrangement, being characterized by two main periodicities of ∼75 and ∼110 Å reflecting the presence of a large number of polar phospholipid molecules. Larger differences are found at lower relative humidity, where hydrogenous lipids are characterized by a larger single lamellar structure than that observed in the deuterated samples. In both cases the heterogeneity in composition is reflected in a wide structural complexity. The different behaviour upon dehydration can be related to compositional differences in the molecular composition of the two samples, which is attributed to metabolic effects related to the use of perdeuterated growth media.


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