A literature review of the effect of heat on the physical-chemical properties of calcium silicate-based sealers

INTRODUCTION

Recently, calcium silicate-based sealers (CSSs) have gained popularity in endodontic practice due to their biocompatibility and antimicrobial properties. They are considered viable alternatives to epoxy resin-based sealers. With the increased use of CSSs and warm vertical compaction techniques in root canal treatment, evaluating the impact of heat on CSSs properties is essential, therefore this review aimed to present a qualitative synthesis of available in vitro studies assessing the impact of heat on the physical-chemical properties of CSSs.

METHODS

Following the PRISMA 2020 guidelines, a systematic advanced electronic search was performed in Scoups, Embase, Medline (via PubMed), Web of Science, and Cochrane databases in November 2023 and updated in April 2024. In vitro studies that evaluated the physical-chemical properties of CSSs were eligible. PRILE 2021 guidelines were used for the assessment of the risk of bias included studies.

RESULTS

The search identified a total of 6421 preliminary results and 10 studies were included for qualitative assessment. 11 different physiochemical properties were assessed by the included studies. Setting time and flow were the most evaluated property among the studies. A qualitative synthesis of the evidence on each property is presented.

CONCLUSIONS

Based on the in vitro studies assessed in the present systematic review, results reveal that exposing CSSs to heat can accelerate their setting time, reduce their flow, and increase their film thickness. Concerns persist regarding solubility, viscosity, radiopacity, dimensional change, microhardness, porosity, and compressive strength; requiring further research. Certain CSSs, like MTA Fillapex and Endosequence BC sealer HiFlow, show minimal changes under heat, making them potential candidates for warm filling techniques.

Protein sequence comparison based on representation on a finite dimensional unit hypercube

Numerous techniques are used to compare protein sequences based on the values of the physiochemical properties of amino acids. In this work, a single physical/chemical property value based non-binary representation of protein sequences is obtained on a 20 × 20-dimensional unit hypercube. The represented vector expressed in the matrix form is taken as the descriptor. The generalized NTV metric, which is an extension of the NTV metric used for polynucleotide space is taken as a distance measure. Based on this distance measure, a distance matrix is obtained for protein sequence comparison. Using this distance matrix, phylogenetic trees are drawn by using Molecular Evolutionary Genetics Analysis 11 (MEGA11) software applying the neighbor-joining method. Data sets used in this current work are 9-ND4, 9-ND5, 9-ND6, 24 TF-LF proteins, 27 different viruses and 127 proteins from the protein kinase C (PKC) family. Two sets of phylogenetic trees are obtained - one based on property value of polarity and the other based on property value of molecular weight. They are found to be exactly the same. Similar results also hold for other single property value based representation. The present trees are individually tested for efficiency based on the criterion of rationalized perception and computational time. The results of the present method are compared with those obtained earlier by other methods on the same protein sequences using assessment criteria of Symmetric distance (SD), Correlation coefficient, and Rationalized perception. In all the cases, the present results are found to be better than the results of other methods under comparison.Communicated by Ramaswamy H. Sarma.

Using enzyme activities as an indicator of soil fertility in grassland - an academic dilemma

Grasslands play an important role in conserving natural biodiversity and providing ecosystem functions and services for societies. Soil fertility is an important property in grassland, and the monitoring of soil fertility can provide crucial information to optimize ecosystem productivity and sustainability. Testing various soil physiochemical properties related to fertility usually relies on traditional measures, such as destructive sampling, pre-test treatments, labor-intensive procedures, and costly laboratory measurements, which are often difficult to perform. However, soil enzyme activity reflecting the intensity of soil biochemical reactions is a reliable indicator of soil properties and thus enzyme assays could be an efficient alternative to evaluate soil fertility. Here, we review the latest research on the features and functions of enzymes catalyzing the biochemical processes that convert organic materials to available plant nutrients, increase soil carbon and nutrient cycling, and enhance microbial activities to improve soil fertility. We focus on the complex relationships among soil enzyme activities and functions, microbial biomass, physiochemical properties, and soil/crop management practices. We highlight the biochemistry of enzymes and the rationale for using enzyme activities to indicate soil fertility. Finally, we discuss the limits and disadvantages of the potential new molecular tool and provide suggestions to improve the reliability and feasibility of the proposed alternative.

Effects of Cherry (Prunus cerasus L.) Powder Addition on the Physicochemical Properties and Oxidation Stability of Jiangsu-Type Sausage during Refrigerated Storage

Effects of different levels (1%, 3% and 5%) of cherry powder on the physiochemical properties and antioxidant activity of Jiangsu-type sausages were investigated at 4 °C for 30 days. The results show that the sensory evaluation values and physicochemical properties of the sausages had no significant differences compared to the control group when cherry powder addition was 1%, and the alcohols, aldehydes and esters were increased after the addition of cherry powder improved the flavor of sausages. However, higher concentration of cherry powder (3% and 5%) exerted adverse influences on sensory evaluation values and physicochemical properties of sausages compared with the control. The addition of cherry powder could better inhibit lipid and protein oxidation of sausages, and the cherry powder concentration has a positive correlation with its effect on the inhibition of lipid and protein oxidation. In addition, cherry powder could effectively control TVB-N values of sausages during chilled storage. All these results indicate that 1% cherry powder could not only guarantee the physicochemical properties of sausages, but also inhibited the oxidation of sausages during chilled storage.

[Characteristics of heavy metals and bacterial community in manure and surrounding soil of cattle farm in Xiji, Ningxia, China]

To understand the contamination status of heavy metals and bacterial community in the manure and surrounding soils of cattle farm in Ningxia, we collected cattle manure at different breeding periods (lactation, calf, growing, pre-fattening and post-fattening periods) and soil samples from the largest beef breeding area in the region by different distances, with the waste land far away as control. We measured heavy metal contents and the composition and diversity of bacterial community in manure and soil samples. The results showed that: 1) The contents of Cu, Zn, Cd, Pb and Hg in cattle manure were 33.8%-95.8% lower than the national average, while As content was 94.7% higher than the national average. During the breeding periods, the change tendencies of seven kinds of heavy metals in cattle manure were different. The contents of Cu, Cd, Hg and Cr of cattle manure in the pre-fattening period were the highest across all periods. The comprehensive pollution index of heavy metals in pre-fattening and post-fattening periods of cattle manure was highest in all periods. 2) The contents of Cu and Zn in the soils with cattle manure application were higher than control, and the content of Zn were significantly higher than surrounding soil samples. All single and comprehensive soil pollution indices of soil were safe. 3) During the breeding periods, Sequence, OTU and Chao1 index of cattle manure had no specific change. Sequence, OTU and Chao1 of soil with cattle manure application were higher than the soil around the farm. 4) The types of dominant phylum were less in the manure. The relative abundance of Firmicutes was the highest, followed by Bacteroidetes and Proteobacteria. The relative abundance of Firmicutes in the growing period was significantly lower than other breeding periods, and that of other phylum had little variation among periods. The cattle farm did not affect bacterial community in the surrounding soil. The cattle manure application didn't change the relative abundance of bacteria at the phyla level. The abundance of Gp, Gemmatimona, Lysobacte, Subdivision3_genera_incertae_sedis were significantly higher than control and surrounding soil. 5) Organic matter, pH, EC, total nitrogen, total potas-sium, Cd and As significantly affected bacterial diversity and component abundance in cattle manure. Soil pH, total phosphorus and Hg significantly influenced soil bacterial diversity and component abundance. On the whole, the effects of physicochemical properties in cattle manure and soil on bacterial community were more significant than heavy metals. Our results could provide scientific basis for selecting the variety and dosage of feed and veterinary drugs in local cattle farms, as well as the rational application of organic fertilizers.

Effects of High Intensity Ultrasound on Physiochemical and Structural Properties of Goat Milk β-Lactoglobulin

This study aimed to compare the effects of high intensity ultrasound (HIU) applied at various amplitudes (20~40%) and for different durations (1~10 min) on the physiochemical and structural properties of goat milk β-lactoglobulin. No significant change was observed in the protein electrophoretic patterns by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Deconvolution and second derivative of the Fourier transform infrared spectra (FTIR) showed that the percentage of β-sheet of goat milk β-lactoglobulin was significantly decreased while those of α-helix and random coils increased after HIU treatment The surface hydrophobicity index and intrinsic fluorescence intensity of samples was enhanced and increased with increasing HIU amplitude or time. Differential scanning calorimetry (DSC) results exhibited that HIU treatments improved the thermal stability of goat milk β-lactoglobulin. Transmission electron microscopy (TEM) of samples showed that the goat milk β-lactoglobulin microstructure had changed and it contained larger aggregates when compared with the untreated goat milk β-lactoglobulin sample. Data suggested that HIU treatments resulted in secondary and tertiary structural changes of goat milk β-lactoglobulin and improved its thermal stability.

Physiochemical properties of short-term frying oil for chicken wing and its oxidative stability in an oil-in-water emulsion

In this study, the physiochemical properties of corn oil and its oxidative stability in an O/W emulsion were studied following short-term (120 min) deep-frying of chicken wing. The results showed that the levels of polyunsaturated fatty acids in corn oil decreased after frying. Furthermore, total polar compound content in frying oil was significantly increased to 11.3%. Fourier transform infrared spectra (FTIR) indicated that hydrolysis and oxidation reactions involving triglycerides occurred after frying. Additionally, the increased a* and b* values demonstrated that deep-frying greatly enhanced the intensity of the red and yellow colors of corn oil. Frying reduced the oxidative stability of corn oil in an O/W emulsion as determined by the peroxide value and acid value. These findings indicated that short-term deep-frying of chicken wing deteriorated the quality of corn oil and decreased its oxidative stability in an O/W emulsion. Consumers should consider the potential hazards of food containing short-term deep-frying oil.

Curdlan enhances the structure of myosin gel model

The aim of this work was to investigate the gelation mechanism of curdlan on surimi using a myosin gel model. Experimental results showed that with increased levels of curdlan, the water-holding capacity, gel strength, and storage modulus of a myosin gel first increased and then decreased. The optimum level of curdlan was found to be 1%. Moreover, myosin-curdlan mixed gel showed decreased water liquidity based on the results of low-field nuclear magnetic resonance. The enhanced physicochemical properties of myosin-curdlan mixed gel were attributed to the strengthened hydrogen bonding and to the uniform and compact network structure shown by Fourier-transform infrared spectroscopy and scanning electron microscopy. The results of this study suggest that curdlan has the potential to be used in surimi-based seafood products to enhance the gel structure.

Utilization of konjac glucomannan as a fat replacer in low-fat and skimmed yogurt

Konjac glucomannan (KGM) has been reported to be beneficial to human health, as well as having potential functional properties as a fat replacer in dairy products. In this study, 0.5% KGM solution was added to prepare low-fat (LFKGM) and skimmed (SKKGM) yogurts, and their physicochemical properties were compared with those of full-fat yogurt control (FFC), low-fat yogurt control (LFC), and skimmed yogurt control (SKC). Properties and composition were determined and the microscopic structures of all yogurts were observed during storage at 4°C for 21d. Generally, addition of KGM to yogurts had no significant effect on composition, pH, and titratable acidity at each storage day. The LFKGM and SKKGM had higher whiteness, greenness, and yellowness hues compared with those of the LFC and SKC. The proteolysis of LFKGM and SKKGM was similar to that of FFC, whereas it was lower than in LFC and SKC after 14d of storage. Addition of KGM had no positive effects on the water-holding capacity, but led to a decrease in syneresis and spontaneous whey separation in LFKGM and SKKGM compared with those of LFC and SKC. The spontaneous whey separation of LFKGM was similar to that of FFC. Presence of KGM in skimmed yogurt affected textural characteristics, while having little effect on texture of low-fat yogurt. Additionally, LFKGM and SKKGM showed stronger and more stable gel structures than those of FFC, LFC, and SKC. Overall, no substantial changes were found in the characteristics for each yogurt during storage, except for pH and gel structures. Results indicated that KGM may be a good fat replacer to develop reduced-fat yogurts with desired characteristics.

Molecular and chemical investigations and comparisons of biomaterials for ocular surface regeneration

This study investigated and compared the ultrastructural and chemical properties of representative biomaterials for ocular surface regeneration: a human amniotic membrane (AM) in a basal plate, a human AM in reflected chorion, a preserved AM, and a human corneo-scleral tissue. Assessments of the morphological differences in the extracellular matrices were evaluated by hematoxylin-eosin, Masson's trichrome (for total collagen), and picrosirius-red (for newly synthesized collagen) staining. Assessments of the changes in the molecular structures and chemical compositions of the biomaterials for ocular surface regeneration were evaluated by Raman spectroscopy. A placental AM (52 %) was a dense and thick collagenous structure compared to a reflected AM (23 %). The spectroscopy did not obtain any structural information for a preserved AM. The cornea group (100 %, control) and sclera group (104 %) showed the collagen lamellae and interfibrillar spacing, and a slight inflammatory reaction with more fibrous and granulomatous tissues. There was a formation of newly synthesized collagen in a placental AM, while there were few collagen components in a reflected AM. Human AM tissues showed consistent Raman spectra and the characteristic collagen bands, similar to the corneal and scleral tissues. Therefore, these findings suggest that human placental AM and reflected AM are structurally suitable for scleral and corneal surface regeneration, respectively, while human placental or preserved AM and reflected AM are molecularly and chemically suitable for corneal and scleral surface regeneration, respectively.