Optimize Initial Freezing Time of Transbronchial Cryobiopsy for the Diagnosis of Interstitial Lung Disease: A Prospective Randomized Parallel Group Study

<b><i>Background:</i></b> Transbronchial cryobiopsy (TBCB) is increasingly being identified as a potential alternative for the diagnosis of interstitial lung disease (ILD). The specimen size of TBCB is positively related to the freezing time. However, the proper initial freezing time for the clinical application of TBCB in ILD remains unknown. <b><i>Methods:</i></b> A prospective randomized parallel group study was employed to investigate ILD patients with unclear diagnosis, who were admitted to the First Affiliated Hospital of Guangzhou Medical University from May 2019 to October 2020 and required TBCB. All patients were randomly divided into 4 groups according to the different freezing times of TBCB: 3 s, 4 s, 5 s, and 6 s groups. All operations were performed under intravenous anesthesia with endotracheal intubation, 60–65 bar pressure of freezing gas source, and 1.9-mm cryoprobe. Compare differences among groups in specimen size, complications, pathological diagnosis efficiency, and multidisciplinary discussion (MDD) diagnostic efficiency. <b><i>Results:</i></b> A total of 100 patients were recruited and randomly assigned into 4 groups (<i>n</i> = 25 each group). The specimen sizes of TBCB in ILD were positively correlated with the freezing time (<i>r</i> = 0.639, <i>p</i> &#x3c; 0.05). None of the patients experienced Grade 3 severe bleeding. Pneumothorax occurred in 1 patient in the 4 s, 5 s, and 6 s groups, respectively. The diagnostic yield of MDD in the 3 s, 4 s, 5 s, and 6 s groups were 64%, 88%, 88%, and 96%, respectively (<i>p</i> &#x3c; 0.05), but showing no significant differences among 4 s, 5 s, and 6 s groups. <b><i>Conclusions:</i></b> The specimen size and diagnostic efficiency of TBCB in ILD increased with a longer freezing time. When the freezing gas pressure is 60–65 bar, we recommended 4 s as the initial freezing time of TBCB, and this time is associated with high diagnostic efficiency and low incidence of complications.

The seasonal cycle and break-up of landfast sea ice along the northwest coast of Kotelny Island, East Siberian Sea

Arctic landfast sea ice (LFSI) represents an important quasi-stationary coastal zone. Its evolution is determined by the regional climate and bathymetry. This study investigated the seasonal cycle and interannual variations of LFSI along the northwest coast of Kotelny Island. Initial freezing, rapid ice formation, stable and decay stages were identified in the seasonal cycle based on application of the visual inspection approach (VIA) to MODIS/Envisat imagery and results from a thermodynamic snow/ice model. The modeled annual maximum ice thickness in 1995–2014 was 2.02 ± 0.12 m showing a trend of −0.13 m decade−1. Shortened ice season length (−22 d decade−1) from model results associated with substantial spring (2.3°C decade−1) and fall (1.9°C decade−1) warming. LFSI break-up resulted from combined fracturing and melting, and the local spatiotemporal patterns of break-up were associated with the irregular bathymetry. Melting dominated the LFSI break-up in the nearshore sheltered area, and the ice thickness decreased to an average of 0.50 m before the LFSI disappeared. For the LFSI adjacent to drift ice, fracturing was the dominant process and the average ice thickness was 1.56 m at the occurrence of the fracturing. The LFSI stages detected by VIA were supported by the model results.

A Mathematical Modeling of Freezing Process in the Batch Production of Ice Cream

This study deals with the mathematical modeling of crystallization kinetics occurring during batch production of the ice cream. The temperature decrease was recorded in-situ through a computerized wireless system. A robust pattern-recognition algorithm of the experimental cooling curves was developed to determine the initial freezing point. The theoretical freezing point was used to calibrate the whole time-temperature profile. Finally, a modified Gompertz’s function was used to describe the main steps of crystallization kinetics. Derivative analysis of the Gompertz’s function allowed to determine the time-temperature physical markers of dynamic nucleation, ice crystal growth and air whipping. Composition and freezing properties were used as input variables in multivariate analysis to classification purposes of the ice cream mixtures as a function of their ability to produce high-quality ice cream. The numerical analysis of the whole cooling curve was used to build predictive models of the ice cream quality indices.

Soil stabilisation for DNA metabarcoding of plants and fungi. Implications for sampling at remote locations or via third-parties

Storage of soil samples prior to metagenomic analysis presents a problem. If field sites are remote or if samples are collected by third parties, transport to analytical laboratories may take several days or even weeks. The bulk of such samples and requirement for later homogenisation precludes the convenient use of a stabilisation buffer, so samples are usually cooled or frozen during transit. There has been limited testing of the most appropriate storage methods for later study of soil organisms by eDNA approaches. Here we tested a range of storage methods on two contrasting soils, comparing these methods to the control of freezing at -80 °C, followed by freeze-drying. To our knowledge, this is the first study to examine the effect of storage conditions on eukaryote DNA in soil, including both viable organisms (fungi) and DNA contained within dying/dead tissues (plants). For fungi, the best storage regimes (closest to the control) were storage at 4 °C (for up to 14 d) or active air-drying at room temperature. The worst treatments involved initial freezing, followed by thawing which led to significant later spoilage. The key spoilage organisms were identified as Metarhizium carneum and Mortierella spp., with a general increase in saprotrophic fungi and reduced abundances of mycorrhizal/biotrophic fungi. Plant data showed a similar pattern, but with greater variability in community structure, especially in the freeze-thaw treatments, probably due to stochastic variation in substrates for fungal decomposition, algal proliferation and some seed germination. In the absence of freeze drying facilities, samples should be shipped refrigerated, but not frozen if there is any risk of thawing.

Soil stabilisatizion for DNA metabarcoding of plants and fungi. Implications for sampling at remote locations or via third-parties

Storage of soil samples prior to metagenomic analysis presents a problem. If field sites are remote or if samples are collected by third parties, transport to analytical laboratories may take several days or even weeks. The bulk of such samples and requirement for later homogenisation precludes the convenient use of a stabilisation buffer, so samples are usually cooled or frozen during transit. There has been limited testing of the most appropriate storage methods for later study of soil organisms by eDNA approaches. Here we tested a range of storage methods on two contrasting soils, comparing these methods to the control of freezing at −80°C followed by freeze-drying. To our knowledge this is the first study to examine the effect of storage conditions on eukaryote DNA in soil, including both viable organisms (fungi) and DNA contained within dying/dead tissues (plants). For fungi, the best storage regimes (closest to the control) were storage a 4°C (for up to 14 d) or active air-drying at room temperature. The worst treatments involved initial freezing followed by thawing which led to significant later spoilage. The key spoilage organisms were identified as Metarhizium carneum and Mortierella spp., with a general increase in saprotrophic fungi and reduced abundances of mycorrhizal/biotrophic fungi. Plant data showed a similar pattern but with greater variability in community structure especially in the freeze-thaw treatments, probably due to stochastic variation in substrates for fungal decomposition, algal proliferation and some seed germination. In the absence of freeze drying facilities, samples should be shipped refrigerated but not frozen if there is any risk of thawing.

Ice Formation due to Condensation of Moist Air on Commercial Wicks

Heat pipes are valuable heat transfer devices that can be used in space; however, when exposed to the extremely low temperature of space, the working fluid can freeze. Currently, there are different methods to help mitigate freezing effects, including non-condensable gas-charged heat pipes and understanding ice formation on surfaces (e.g., typically surfaces with hydrophobic coatings). However, there is limited research about ice formation on wicks. Different wicking structures may delay freezing or mitigate freezing effects. This paper will investigate ice formation on two surfaces — commercial sintered and grooved wicks. An indoor environmental chamber was used to control ambient air temperature (i.e., 22°C) and relative humidity (i.e., 60% RH) and a Peltier cooler was used to control the surface temperature (i.e., −5°C). The resulting condensation of water onto the surface and then freezing was recorded for an hour and analyzed for the time freezing began on the surface (i.e., ice is initially visible) and the time freezing was complete on the surface. Initial results indicate that the sintered wick begins to freeze first (on average at 10.73 minutes versus 13.66 for the grooved wick) and the freezing front propagates faster (taking on average 10.83 minutes versus 12.44 minutes for the grooved wick). From the analysis, it is seen that the wicking surface structure influences the initial freezing time and the rate the freezing front propagates across the surface. These differences and the causes are investigated in this paper. These differences can, in the future, be exploited to design an optimal freeze-tolerant heat pipe and heat pipe freezing models.

Analysis of moisture and temperature fields coupling process in freezing shaft

The temperature change of frozen soil wall and the evolution characteristics of the specific heat capacity are analyzed. The frozen soil cylinders form surrounding freezing pipes at initial freezing stage, and the temperature field of frozen soil presents a non-linear decrease. With the increase of freezing time, the radius of the frozen soil cylinder increases and a frozen soil wall is enclosed. After freezing 30 days, the thickness of the frozen soil wall is obtained as 1.7 m. After freezing 250 days, the thickness of frozen soil wall increases to about 11.0 m.

Numerical simulation of the temperature fields in the shielding walls of frozen soil with multi-circle-pipe freezing in shaft sinking

In this study, the temperature fields of frozen soil wall were calculated by using numerical method, and were analyzed after the soil was actively frozen with different freezing time. The results showed that the temperature field evolved from the freezing pipes, and then formed into frozen soil cylinders. After a certain freezing duration, the cylinders of frozen soil began to connect, and frozen soil walls started to form. At initial freezing stage, the thickness of frozen soil wall was mainly determined by the freezing pipes of the inner two circles. Then, connections were found to have occurred between the inner and outer frozen soil walls. Finally, the temperature fields of the unfrozen and frozen soils reached a state of stability. The results also showed that it was feasible to use numerical method to simulate the temperature fields of frozen soil walls during shaft sinking process, and potentially provided important references for the design and construction of deep alluvium shaft.