Free Water Content Research Articles

Hydration characteristics and mechanism analysis of β-calcium sulfate hemihydrate based on low-field NMR

Free water plays a crucial role in the hydration process of β-calcium sulfate hemihydrate (β-HH) based plaster. To further understand the hydration mechanism of β-HH, this study monitored water consumption and pore structure evolution of plaster prepared by different water/β-HH (W/H) ratios using low-field NMR. The hydration characteristics were jointly analyzed using X-ray diffraction (XRD), thermogravimetric (TG), and isothermal calorimetry. In addition, the pore structure of the plaster was characterized by BET and MIP. Results indicated that during early hydration (0–10 min), free water migrated from macropores to micropores in β-HH samples. The specific surface area and free water content of β-HH based plaster decreased during rapid hydration period. It is also found that increasing the W/H ratio accelerated free water consumption but resulted in larger pore diameter. Furthermore, signal intensity and transverse relaxation time were found to be exponentially related (y = Ae(-x/B) + y0) to the CaSO4∙2H2O crystal content, hydration degree, and heat release. These correlations suggest that low-field NMR correlated well with other measurements and could be viable method to characterize the plaster hydration process.

Fabrication and evaluation of novel amphiphilic star block copolymers for increasing free water content in lignite to make coal water slurries

In order to reduce the apparent viscosity of lignite coal water slurries (CWSs) and improve its static stability, a series of three-arm amphiphilic block copolymers have been prepared through RAFT polymerization by using poly(ethylene glycol) methyl ether acrylate (PEGMA) and sodium 4-vinylbenzenesulfonate (SSNa) as hydrophilic monomers and styrene (St) as hydrophobic monomer. The chemical structure of the copolymers has been investigated, and the impact of relative molecular weight, hydrophilic/hydrophobic ratio, and ionic group content on the pulping performance of three-arm amphiphilic block copolymers has been examined. The lignite coal water slurries (CWSs) prepared from the block copolymer tri-P(St50-s-SSNa50)10K-b-PPEGMA10K exhibit a remarkably low apparent viscosity of 395 mPa·s and excellent static stability when the coal content is at 55 wt% and dispersant content is at 0.5 wt%. Moreover, these CWSs can achieve a maximum pulping concentration of up to 59 wt%. Additionally, the thermogravimetric test reveals insights into the water occurrence in CWSs, indicating that higher levels of free water content correspond to lower apparent viscosities. Suitable hydrophobicity facilitates the removal of internal water from lignite by dispersants, disrupting its flocculation structure and promoting CWSs formation. Meanwhile, the presence of ionic groups enhances the static stability of the resulting CWSs. Furthermore, the adsorption behavior of the three-arm amphiphilic block copolymer dispersant in lignite has been analyzed through XPS testing to elucidate its dispersion mechanism. The use of three-arm amphiphilic block copolymers in preparing lignite CWSs results in lower apparent viscosity and improved static stability, attributed to the amphiphilic and steric hindrance effects of dispersants. This not only expands the application range of lignite CWSs but also highlights the significant potential of this type of dispersant.

Effect of nanocellulose on early hydration and microstructure of cement paste under low and high water-cement ratios

The early hydration and microstructure of cement paste with nanocellulose (CNC) at low and high water-cement ratios (0.3 and 0.5) was investigated coupled with isothermal calorimetry (IC), scanning electron microscopy (SEM), and X-ray diffraction (XRD). IC results showed that at both water-cement ratios, CNC prolonged the ending time of the induction period and acceleration period and reduced the main exothermic peak to inhibit early hydration. The inhibition effect became more significant with the increase of CNC dosage. XRD results showed that CNC inhibited the formation of ettringite and portlandite, and SEM images also confirmed that CNC delayed the formation and deposition of early hydration products. Interestingly, the inhibition effects of CNC on early hydration exotherms and hydration products at low and high water-cement ratios were different. At a water-cement ratio of 0.3, CNC inhibited the cumulative hydration heat of cement paste until 120 h. In the presence of CNC, porous microstructures were formed later, and the appearance of needle-like CSH gels was also delayed. At a water-cement ratio of 0.5, the inhibition effect of CNC gradually disappeared with increasing hydration time. After 24 h of hydrating, the needle-like CSH gels appeared first in CNC-cement paste, and the early-formed structure was also denser than pure cement paste. Additionally, the different influence reasons of CNC on early hydration under high and low water-cement ratios were explained from the perspective of charge adsorption and free water content.

Effects of different drying methods on quality and water distribution of Lycium barbarum

AbstractAlthough Lycium barbarum is a valuable medicinal food, it is unfortunately not easy to store due to its high moisture content. In order to maximize the preservation of the medicinal value of L. barbarum, drying is increasingly used for its storage. Motivated by the need to better understand and improve the drying of L. barbarum, in this study, the VFD (vacuum freeze drying) and HD (hot air drying) are employed as drying processes, and the rehydration ratio, drying time, specific energy consumption, sensory characteristics, moisture ratio, energy consumption, moisture mobility, and amino acids and flavonoids content of dried L. barbarum are comprehensively analyzed. The results show that, after VFD, L. barbarum has lower hardness (71.53 ± 1.68), higher rehydration ratio (1.31 ± 0.02), larger volume, plump, round and smooth surface, and similar color to the fresh L. barbarum. At the same time, compared with the sample after HD, the moisture ratio of L. barbarum after VFD is lower (1.4 ± 0.1), and its content of free water is almost negligible (2.2%). In addition, the amino acids and flavonoids content of L. barbarum after VFD are closer to those of the fresh product (133.7 μmol/g, 5.69 mg/g). Based on the analysis of the drying effect on the physical and chemical properties of L. barbarum, we conclude that VFD is a promising processing technology. However, HD proves to greatly reduce the specific energy consumption and drying time when raising the temperature appropriately, whereas VFD could not achieve the same result by increasing the heating rate of VFD.Practical applicationsIn this paper, based on the mechanism of different drying methods, the quality of L. barbarum products after drying was compared, and the water distribution in the drying process was analyzed. It is found that using VFD technology to dry L. barbarum can improve the production efficiency of L. barbarum industry and the quality of L. barbarum products. Meanwhile, the research results can provide reference for the optimization of VFD system and the scientific formulation of process parameters.

Effects of Potassium Bicarbonate on Gel, Antioxidant and Water Distribution of Reduced-Phosphate Silver Carp Surimi Batter under Cold Storage.

The changes in storage loss, water distribution status, gel characteristics, thiobarbituric acid reactive substances (TBARSs), total volatile basic nitrogen, and total plate count of cooked reduced-phosphate silver carp surimi batter during cold storage at 4 °C were investigated. The storage loss, content of free water, pH, hardness, TBARSs, total volatile basic nitrogen value, and total plate count of all cooked silver carp surimi batters significantly increased (p < 0.05) with an increase in cold storage time. Meanwhile, the content of immobilized water, whiteness, springiness, and cohesiveness significantly decreased (p < 0.05). At the same cold storage time, the sample of cooked reduced-phosphate silver carp surimi batter had lower water mobility, darker color, and better texture characteristics than the cooked silver carp surimi batter without potassium bicarbonate; however, the values of TBARSs, total volatile basic nitrogen, and total plate count were not significantly different (p > 0.05). This meant that there was no difference between potassium bicarbonate and sodium tripolyphosphate in antioxidant and antibacterial activity during the cold storage of silver carp surimi batter. To summarize, the use of potassium bicarbonate instead of sodium tripolyphosphate could produce cooked reduced-phosphate silver carp surimi batter with better water-holding capacity and gel characteristics during cold storage.

An electrolyte-rich nano-organic cathode constructs an ultra-high voltage Zinc-ion battery

To realize green and sustainable energy storage systems, it is urgent to propose emerging strategies to construct and understand the relationship between electrode materials and electrolytes. Based on the strategy of storing the electrolyte in an organic cathode, we prepare a Zn2+-doped polyaniline (PAZ) nano-organic cathode with a re-doping method, which possesses high crystallinity in the (010) plane and high conductivity compared with conventional H+-doped polyaniline (PA). The resultant Zn//PAZ battery exhibits outstanding electrochemical performance for 3000 cycles at an ultra-high voltage of 2.4 V, attributed to the enhancement of electrolyte concentration and reduction of free water stemming from the dedoping of PAZ. A hybrid charge storage mechanism including Zn2+ and multi-anions insertion/extraction is also demonstrated for the Zn//PAZ batteries during the charge/discharge process. To further expand the practical applications of the strategy, we manufacture an electrolyte-free Zn//PAZ battery, which achieves acceptable performance for 400 cycles. This research provides insight into the relationship between the electrolyte and re-doped polyaniline organic cathode and opens a new avenue for emerging Zinc batteries.

Exploring the interaction between Lycium barbarum polysaccharide and gelatin: Insights into gelation behaviors, water mobility, and structural changes

Gelatin-polysaccharide interactions have garnered significant attention in recent years due to their profound effects on the properties (rheology and structure) of various food products. This study investigates the interaction between Lycium barbarum polysaccharide (LBP) and gelatin, focusing on the impact of different concentrations LBP (0–2.0%, w/v) on gelation behavior, water mobility, and gelatin structure. The results show that the addition of LBP initially increases and then decreases the gel strength and hardness of the gelatin. Incorporating LBP into gelatin leads to decreased brightness, gelling temperature (Tg), gelation rate (kgel), immobile water content, and residue, while increasing the redness, yellowness, bound and free water content, and thermal stability. Fourier transform infrared spectroscopy (FTIR), x-ray diffractometer (XRD), cryogenic scanning electron microscopy (Cryo-SEM), and atomic force microscopy (AFM) analyses provide evidence for the existence of hydrogen bonds, electrostatic interactions, and ionic bond interactions between LBP and gelatin, in addition to covalent bonds formed through the Maillard reaction. Moreover, LBP induces changes in the structure of gelatin, including alterations in secondary structure, crystalline structure, and microstructure. AFM observations further indicate that LBP promotes the formation of gelatin aggregates. These findings present promising avenues for the application of LBP-gelatin composite gels as novel materials in the food industries.

Bimodal Gating Mechanism in Hybrid Thin-Film Transistors Based on Dynamically Reconfigurable Nanoscale Biopolymer Interfaces.

In recent years, increased control over naturally-derived structural protein formulations and their self-assembly has enabled the application of high-resolution manufacturing techniques to silk-based materials, leading to bioactive interfaces with unprecedented miniaturized formats and functionalities. We present here a hybrid biopolymer-semiconductor device obtained by integrating nanoscale silk layers in a well-established class of inorganic field-effect transistors (silk-FETs). The devices offer two distinct modes of operation - either traditional field-effect or electrolyte-gated - enabled by the precisely controlled thickness, morphology and biochemistry of the integrated silk layers. The different operational modes are selectively accessed by dynamically modulating the free-water content within the nanoscale protein layer from the vapor phase. The utility of these hybrid devices is illustrated in a highly sensitive and ultrafast breath sensor, highlighting the opportunities offered by the integration of nanoscale biomaterial interfaces in conjunction with traditional semiconductor devices, enabling functional outcomes at the intersection between the worlds of microelectronics and biology. This article is protected by copyright. All rights reserved.

Strategies for solving hydrogen precipitation problems in aqueous zinc ion batteries

Aqueous zinc ion batteries have revealed many problems while solving the safety problems of conventional batteries, among which the narrow electrochemical stability window of water causes the battery to be prone to hydrogen precipitation reactions. In this paper, we summarize two strategies to solve the problem. From the electrolyte side, firstly, we use a mixture of salt-in-water electrolyte to lower the starting potential of hydrogen precipitation reaction, so that the hydrogen precipitation reaction can be inhibited. The second strategy is to use intermolecular forces to configure a high concentration electrolyte to change the presence of ions in the solution, thus reducing the free water content and the activity of water to inhibit the hydrogen precipitation reaction.

Low-Frequency Electrical Conductivity of Trabecular Bone: Insights from In Silico Modeling

Background: The electrical conductivity of trabecular bone at 100 kHz has recently been reported as a good predictor of bone volume fraction. However, quantifying its relationship with free water (or physiological solution) content and the conductivities of its constituents is still difficult. Methods: In this contribution, in silico models inspired by microCT images of trabecular bovine samples were used to build realistic geometries. The finite element method was applied to solve the electrical problem and to robustly fit the conductivity of the constituents to the literature data. The obtained effective electrical conductivity was compared with the Bruggeman three-medium mixture model using a physiological solution, bone marrow and a bone matrix. Results: The values for the physiological solution plus bone marrow (together as one material) and the bone matrix that best captured the bone volume fraction in the two-medium finite element model were σps+bm = 298.4 mS/m and σb = 21.0 mS/m, respectively. Additionally, relatively good results were obtained with the three-medium Bruggeman mixture model, with σbm= 103 mS/m, σb= 21.0 mS/m and σps= 1200 mS/m. Simple linear relationships between the proportions of constituents depending on bone volume fraction were tested. Degree of anisotropy and fractal dimension do not show detectable changes in effective conductivity. Conclusions: These results provided some useful findings for simulation purposes. First, a higher value for the electrical conductivity of bone marrow has to be used in order to obtain similar values to those of experimental published data. Second, anisotropy is not detectable with conductivity measurements for small trabecular samples (5 mm cube). Finally, the simulations presented here showed relatively good fitting of the Bruggeman mixture model, which would potentially account for the free water content and could rescale the model for whole-bone electrical simulations.

Internal stress development within wood during drying: A master curve concept and its application on drying stress evaluation

The generation of internal stress (IS) in flat-sawn and quarter-sawn rubberwood boards during drying has been investigated using an online restoring force (RF) technique, which restrained a half-split rectangular wood specimen. Particular attention was given to the longest IS reversal regime. The IS development proceeds faster in the flat-sawn specimens than that in the quarter-sawn specimens while the maximum IS magnitudes in both specimens are rather similar. By normalizing the IS reversal period, a master IS profile, the derivative of the measured RF to the IS reversal time ratio versus the IS reversal time ratio, is proposed. This master curve, exhibiting some degree of independence from wood orientation and drying temperature, shows variations correlated with the free water content in the wet zone and the dry/wet zone fractions. The process of IS reversal, unaffected by temporary unrestraint, advances as the dry zone expands inwards and ends when the wet zone disappears. Assuming mechanical equilibrium between the dry and wet zones, the IS in both zones can be estimated from the RF data. The maximum tensile IS in the dry zone, indicating a risk of surface checks, evolves at slightly lower magnitudes at higher drying temperatures and is lower in the quarter-sawn specimens. The IS relaxation in the dry zone, still largely taking place in the absence of the applied RF, highlights the main contribution of the dry/wet zone fractions, continuing to proceed without restraining, to the IS development. These findings, emphasizing the significance of dry and wet zones, should pave the way for a better understanding of the IS development within wood during drying.

Effects of glycerol content on structure and molecular motion in thermoplastic starch-based nanocomposites during long storage

Thermoplastic starch-based nanocomposites with varying glycerol content and montmorillonite as a nanofiller were studied using dynamic-mechanical analysis (DMA), X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) during one-year storage. DMA results showed that starch-rich and glycerol-rich domains were present in the samples and during storage for up to one year the content of the amorphous phase decreased and molecular mobility changed. 13C NMR and XRD measurements confirmed that ordered structures were formed during storage and its content was larger for samples with higher glycerol content and increased with the storage time. The data obtained from deconvolutions of 1H broad line NMR spectra indicate increased overall molecular mobility in the samples up to four months of storage, while after nine months the trends were opposite. Lower free water content compared to the total water content in the samples determined according to deconvoluted 1H MAS (magic-angle spinning) NMR spectra indicated that a part of water molecules was immobilized in the ordered structures.

Unveiling the dielectric property change of concrete during hardening process by ground penetrating radar with the antenna frequency of 1.6 GHz and 2.6 GHz

With the extensively application of electronics at information age, the dielectric property of concrete is one of the worthiest study topics for enhancing the development of smart infrastructure and enabling efficient non-destructive testing and monitoring of concrete structures. In this work, concrete samples with the water-to-cement (w/c) ratios of 0.4 and 0.5 were prepared and cured in saturated lime water, by curing compound and directly exposed in air. The dielectric properties of concrete samples during hardening process were investigated by a ground penetrating radar (GPR) system with the frequency of 1.6 GHz and 2.6 GHz. Moreover, the compressive strength and free water content were determined to interpretate the dielectric property change of concrete. The pore structure of concrete was examined by mercury intrusion porosimetry (MIP) method to reveal its influence on dielectric property change. The hydration kinetics of concrete was measured by thermogravimetric analysis (TGA) to understand the underlying mechanism of dielectric property change. The research findings from this work have the potential to be used for non-destructively assessing the quality and uniformity of concrete hydration in field.

Effects of organic carbon and clay contents on structure‐related properties of arable soils with high clay content

AbstractUnderstanding of factors governing soil structural features is necessary for managing key processes affecting crop productivity and environmental impacts of agriculture, for example, soil water balance, aeration, and root penetration. Organic matter is known to act as a major binding agent in soil aggregation and thus constitutes a central pillar in soil structure formation. However, knowledge of the structural role of organic matter or carbon (OC) in soils highly rich in clay‐sized particles (&lt;0.002 mm) is limited. In this study, the effects of clay and OC contents on aggregate stability, water holding capacity, near‐saturated hydraulic conductivity, total porosity, and pore size distribution were assessed in cultivated fields with high clay content located in private crop production farms in southern Finland. Significant positive correlations were found between OC content and proportion of water stable aggregates and specific pore sizes from the range of 30 μm up to 1 mm diameter determined by image analysis. Porosities on a smaller size range derived from water retention measurements likewise showed a positive correlation with OC in &lt;0.2 μm sizes. On the range of 0.2–1 μm, a negative relationship was observed, which induced a negative effect of OC on soil plant available water reserves. In line with the positive correlation between OC and larger soil pores, free water, representing the amount of water that can be drained by gravity, exhibited a positive relationship with OC suggesting that OC content can enhance aeration of soils with high clay content. Compared to OC, clay content tended to have an adverse effect on soil structural properties. Clay correlated negatively with pores larger than 30 μm, free water content, and extrapolated field saturated hydraulic conductivity. Further, our imaging results showed how saturated hydraulic conductivity was controlled by pore morphology, and there was a power law relationship between the conductivity and critical pore diameter. in agreement with the percolation theory. Overall, the structural impacts and hydrological implications of OC and clay in heavy clay soils vary by pore size ranges and their emergent practical impacts are thus not straightforward.

Comprehensive study on the hydration kinetics, mechanical properties and autogenous shrinkage of cement pastes during steam curing

Steam curing is a crucial stage for the strength development of steam-cured concrete. This study comprehensively investigated the hydration kinetics, mechanical properties, and autogenous shrinkage (AS) of cement pastes during steam curing. A hydration-dependent analytical method was proposed to analyze the mechanisms governing the development of mechanical properties and AS of steam-cured cement pastes (SCPs). Results revealed that in this investigated curing regimes, the peak hydration rate of SCPs was approximately 7 times higher than that of standard-cured pastes (NCPs). SCPs exhibited faster time-dependent mechanical property development but slower hydration-dependent mechanical property development than NCPs. This difference was primarily attributed to variations in initial structure establishment and free water content. Moreover, an elevated curing temperature reduced the growth rate of hydration-dependent AS due to large capillary pores and low surface tension, which suggested that AS should not be considered as a cause of heat damage to SCPs.

Water content significantly influences post-cryopreservation survival of air-desiccated oil palm (Elaeis guineensis Jacq.) zygotic embryos: A thermal and ultrastructural study

The present study outlines the influence of free water content in oil palm (Elaeis guineensis Jacq.) zygotic embryos after desiccation on survival post-cryopreservation. Aseptically isolated zygotic embryos were analysed for water content and resurgence ability after air-desiccation and freezing (in liquid nitrogen). The results indicated that the desiccated zygotic embryos with water content of below 0.24 and above 0.16 g H2O /g dry weight (dw) exhibited survival after freezing. The survival was maximum (80%) when the desiccated zygotic embryos contained 0.16 g H2O /g dw of water content. This optimal water content not only helped oil palm zygotic embryos to sustain their cellular integrity but also assisted to retain their regeneration potential following cryopreservation. On the contrary, the zygotic embryos with water content above 0.24 g H2O /g dw or below 0.16 g H2O /g dw lost their viability as well as their cellular integrity attributable to either excess water content or excessive loss of water, after desiccation and successive freezing. Differential scanning calorimetric analysis revealed characteristic sharp peak for zygotic embryos with high water content and reduced peaks with successively lower water content. Scanning electron microscopic and transmission electron micrographic studies also confirmed that there was no noteworthy distinction in morphology of epidermal layer and cellular integrity between zygotic embryos with different water content before and after desiccation as well as their successive freezing. The parallel trend was reflected in their revival also.

Effect of the superplasticizer addition time on the fresh properties of 3D printed limestone calcined clay cement (LC3) concrete

Although 3D concrete printing (3DCP) is considered one of the most significant innovations in the construction sector, its large cement consumption remains an environmental concern. In response, limestone calcined clay cements (LC³) have emerged as a promising alternative to Portland cement (PC) due to their potential for reducing environmental impact. While previous studies have shown the influence of addition timing of superplasticizer (SP) on the fresh performance of PC, its impact on LC³, particularly in the context of 3DCP, remains less understood. This study assessed the effect of the SP addition time (either directly with the mixing water or with a 10-min delay) on the rheology and printing-related properties of LC³ and PC. Rotational rheometry and 3DP-related tests were conducted over two hours, besides hydration assessment through thermogravimetric analysis (TGA). The results showed that adding SP directly to LC³ led to significantly higher yield stress (1.2–2.5 times) and viscosity (14–59 % higher) values compared to delayed SP addition within the same time frame. However, LC³ exhibited slower rates of yield stress and viscosity increase over time in contrast to PC (with Athix structuration rate approximately 92 % lower for LC³). These tendencies influenced printability performance. While direct SP addition reduced PC's open time from 100 to 30 min, it had no impact on LC³ 's open time, which remained at 80 min. TGA analysis yielded additional insights, highlighting that hydrating LC³ samples required a greater free water content to achieve the same yield stress as PC and this difference was attributed to the presence of calcined clay. These findings make contributions to the technical and scientific communities by enhancing comprehension of LC³ cement fresh behavior and solidifying 3DCP as a disruptive construction method.

Effect of ultrasound-assisted osmotic dehydration on the drying kinetics, water state, and physicochemical properties of microwave vacuum-dried potato slices

The effects of pre-treatments on the drying characteristics, water state, thermal properties, and bulk shrinkage of potato slices during microwave vacuum drying (MVD) were investigated. The pre-treatment included ultrasound in distilled water (USOD-0%), and ultrasound-assisted osmotic dehydration in a 60% sucrose solution (USOD-60%). Results showed that the drying time of potato slices was reduced and the drying rate was increased when USOD-0% was used as a pretreatment, whereas USOD-60% had a negative effect on the drying rate of the samples. The Weibull model was effective in predicting the water changes in potato slices during the drying process. NMR analysis revealed that the relative content of immovable water (M22) increased initially, then decreased for drying, while the transverse relaxation time (T2) and the relative content of free water (M23) decreased consistently. The DSC results indicated that the glass transition temperature (Tg) had an inverse relationship with the water content of the samples, yet had virtually no influence on the volume shrinkage. The sample volumes decreased linearly with the decrease in water content during the initial drying stages. USOD pre-treatment lessened the volume shrinkage of MVD potato slices. Static gravimetry was used to determine the moisture sorption isotherms of MVD potato slices at 30 °C within the aw range of 0.113–0.923. The GAB model accurately fitted the experimental sorption data, which showed sigmoid shape curves for the MVD samples. When aw values exceeded 0.7, the USOD-60% treatment significantly reduce the water sorption capacity of MVD potato slices, while USOD-0% treatment was observed to increase the hygroscopic properties of MVD samples. Compared with the control, USOD-0% pretreatment significantly increased the monolayer water content (X0), sorption surface area (S0), the thickness of sorbed water multilayer (tm), and density of sorbed water (Ds) values of MVD potato slices, while USOD-60% decreased these values.

Tremella Polysaccharide Has Potential to Retard Wheat Starch Gel System Retrogradation and Mechanism Research.

This study investigated the effects of adding different concentrations of TP (tremella polysaccharide) on the water distribution, rheological, thermal, microstructure, and retrogradation properties of WS (wheat starch) gels. The results showed that the starch aging increased during storage, and the addition of TP reduced the rate of change of the elastic modulus of the starch gel and delayed the short-term aging of WS. In the same storage period, the hardness value of the gel decreased and the texture became softer with the increase in the mass fraction of TP. TP increased the T0 (starting temperature) of the system and decreased the enthalpy of retrogradation (ΔHr). No new groups were formed after the retrogradation of the compound system, the hydrogen bonding force increased with the increase in polysaccharide, and the relative crystallinity and the degree of ordering of the system decreased. The addition of TP increased the content of bound water and immobile water, decreased the content of free water, and increased the gel water-holding capacity, indicating that it could effectively inhibit the long-term retrogradation of WS. The findings provide new theoretical insights for the production of starch-based foods.

Free water and iron content in the substantia nigra at different stages of Parkinson's disease

PurposeAbnormalities in free water (FW) and susceptibility values exist in the substantia nigra (SN) of patients with Parkinson’s disease (PD), but their role in characterizing the disease processes remains uncertain. This study investigated these values at various SN locations and stages of PD, and their relationship with clinical symptoms. MethodFW and quantitative susceptibility mapping (QSM) values were evaluated in the anterior and posterior SN, along with swallow-tail-sign (STS) ratings, in patients with PD (early-stage: n = 39; middle-to-advanced-stage: n = 97) and healthy controls (n = 82). The correlation between these indices and motor and non-motor symptoms, and their capability to distinguish PD from healthy controls, were also examined. ResultsIncreased FW in the anterior and posterior SN and increased QSM values in the posterior SN were observed in both early-stage and middle-to-advanced-stage PD patients (p < 0.05). However, there was no significant difference in FW, QSM values, or STS ratings among patients at different stages. FW and QSM values correlated with motor symptoms in middle-to-advanced-stage patients (p < 0.05), while STS ratings were associated with non-motor symptoms (p < 0.05). Additionally, combining FW and QSM values in the posterior SN with STS ratings in logistic regression showed better performance in distinguishing PD (area under curve = 0.931) compared to using STS ratings alone (area under curve = 0.880). ConclusionsFindings suggest elevated FW and iron content in PD at different stages, with dissociation in SN location between the two indices. Elevated signals are related to the motor symptom severity in middle-to-advanced-stage patients, and may have the potential for PD diagnosis and symptom assessment.