This is a descriptive longitudinal pilot study aimed at investigating the individual variation in milk osmolality, within and between cows, both diurnally and over one lactation. Milk samples from 21 Swedish Holstein (n = 9) and Swedish Red Breed (n = 12) dairy cows on one farm were collected 5–44 days after calving, then monthly for 12 months. During the first month, samples were also obtained every second hour (during the day) for 4 days. Milk samples were collected by hand milking in 10 ml tubes and analysed in a Fiske osmometer. The sample collection time was measured, and individual variation in milk osmolality was investigated within both days and months. In addition, bulk-tank milk samples (including milk from additional 230 cows) were collected at the end of each sampling day, with osmolality varying between 286 and 305 mOsm/kg among days. Individual osmolality ranged from 279 to 317 mOsm/kg, and there were significant variations in the mean milk osmolality between cows (2% variation). The individual osmolality varied significantly within days (up to 8%) and over months (up to a 13% variation). Swedish Red Breed cows had higher (1%, P = 0.02) osmolality (301 ± 1 mOsm/kg) than Swedish Holstein cows (299 ± 1 mOsm/kg). The observed differences range from 1% to 9% with variations between breeds being the smallest and those between months/lactation stages and individuals being the largest. It is concluded that there are variations in milk osmolality between individuals, days and breeds that exceed what can be interpreted as thirst-stimulating (+1–2%). Since the variation among clinically healthy animals and over time is considerable, there is potentially a challenge to the practical use of milk osmolality as an indicator of hydration state to be of practical use. Further studies are needed to understand the variations in milk osmolality when cows are water deprived.

This study is a prospective observational study to systematically compare the effects of intermittent tube feeding and thickened feeding on dehydration status, thirst degree and quality of life in patients with dysphagia after stroke. A total of forty-eight patients with dysphagia after stroke were selected and divided into intermittent tube feeding group (twenty-four cases) and thickened feeding group (twenty-four cases). The grouping was based on the nutritional intake mode after clinical decision-making. Participants were selected from the Affiliated Brain Hospital of Nanjing Medical University and the First Affiliated Hospital of Nanjing Medical University. All enrolled patients received conventional treatment and nursing measures and were treated for 2 weeks. The dehydration status was evaluated by plasma osmotic pressure. The degree of thirst is evaluated by the Numerical Rate Scale. Total protein and Hb are used to assess nutritional status; The Functional Oral Intake Scale (FOIS) assesses swallowing function. The Swallowing Quality of Life Scale (SWAL-QOL) was used to assess the quality of life. After 2 weeks of treatment, the improvement in dehydration and thirst in intermittent tube feeding group was better than that in thickened feeding group (P < 0·05). The FOIS and SWAL-QOL scores of both groups of patients improved compared with those before treatment (P < 0·05). Intermittent tube feeding can improve the dehydration status of patients with dysphagia after stroke, relieve thirst and enhance swallowing function and quality of life. The study may provide a more comprehensive basis for the selection of clinical nutritional support plans.

Dehydration, assessed by urine and blood evaluation, is a risk factor for chronic kidney disease (CKD). The association between water deficit, as determined by a dietary assessment, and CKD prevalence is unclear. Therefore, this study aimed to clarify this association among adults in the USA. This cross-sectional study included the data of 9332 participants aged 18 years or older from the 2009–2012 National Health and Nutrition Examination Survey. Water turnover was calculated using an equation developed by the International Doubly Labelled Water Database Group. Total water intake was assessed by 24-h dietary recall on ≥ 1 d. Water deficit was defined as the ratio of water intake to water turnover. CKD was defined as an estimated glomerular filtration rate < 60 ml/min/1·73 m2, calculated by the 2021 CKD Epidemiology formula. OR for CKD prevalence were calculated using multivariate logistic regression and restricted cubic spline models. The mean daily water intake, turnover and deficit were 2799 ml, 3290 ml and –15 %, respectively. CKD prevalence was 6·3 %. After adjusting for lifestyle and urine and serum osmolality, the fourth water deficit quartile was inversely associated with CKD prevalence when compared with the first quartile (OR, 0·71; 95 % CI, 0·51, 0·98). In the spline analysis, the water deficit at which the OR for CKD prevalence plateaued was approximately –30 % to 0 %. Water deficit had an L-shaped association with CKD prevalence independent of urine and serum osmolality, highlighting the importance of assessing water intake relative to dietary needs. These findings may assist the development of water requirements.

Differences were found in the differential thermal analysis curves and in the temperatures of new-phase development between allophanes of high (1.91–1.99) and low (1.47–1.53) SiO2/Al2O3 ratios. The endothermic peak due to continuous dehydration and dehydroxylation was at higher temperatures (153°-185°C) for allophanes with high SiO2/Al2O3 ratios and at lower temperatures (148°–165°C) for those with low SiO2/Al2O3 ratios. The temperature of the exothermic peak was lower and the height affected more by the exchangeable cation content for allophanes with high ratios than for those with low ratios. New phases did not develop in allophanes having high Si02/Al2O3 ratios even after they were heated to 1000°C, above the temperature of the exothermic peak. In contrast, a symptomatic development of new phases was noted in allophanes with low SiO2/Al2O3 ratios at 900°C, below the temperature of the exothermic peak. The effect of SiO2/Al2O3 ratio in the thermal behavior of allophane strongly suggests that differences in the structure are closely associated with the chemical composition of this material.

The structure and hydration status of attapulgite clay after heating at elevated temperatures and the stability of parathion on these clays was studied. Using infrared spectroscopy and scanning electron microscopy it was found that the bound water was lost in two steps, at 250° and 450° with the first step being largely reversible. At 650°C the structure began to dissolve releasing significant amounts of Mg, and a decrease in aggregate porosity was noted. At 850°C an amorphous phase was formed bearing little resemblance to the original attapulgite. Parathion was stable on all of the preheated clays when kept at 25°C for 190 days. The reactions of parathion on the preheated clays was studied at 110°C Hydrolysis of parathion was found to be minimal. Isomerization was the main reaction occurring on the Ca-attapulgite, whereas on an organo-clay no isomerization was observed. A mechanism for the isomerization reaction is proposed which entails a distortion of the phosphate moiety of the pesticide by the oxygen of the ligand water resulting in the conformational changes necessary for the isomerization to take place. On the organo-clay such a conformation was not possible; hence no isomerization occurred.

The hydrated form of tubular halloysite [halloysite (10 Å)] was observed by a conventional electron microscope equipped with an environmental cell (E.C.), by which the “natural” form was revealed without dehydration of the interlayer water. This study mainly reports the selected area electron diffraction (SAED) analysis of the halloysite (10 Å) and its morphological changes by dehydration. The SAED pattern showed halloysite (10 Å) has two-layer periodicity in a monoclinic structure with the unit cell parameters of a = 5.14 Å, b = 8.90 Å, c = 20.7 Å, β = 99.7°, in space group Cc, and almost the same structure as the dehydrated form of halloysite [halloysite (7 Å)]. This means that the dehydration of the interlayer water did not greatly change or affect the structure of halloysite (10 Å). Accompanying the dehydration of the interlayer water, there appeared along the halloysite tube axis clear stripes that were about 50–100 Å in width. The diameters of the tubular particles also increased about 10%. From the results of various experiments, such as a focussing series, observation of the surface structure by the replica method, observation of end-views of the tubular particles, and others, these two phenomena were explained as follows: Halloysite crystals have “domains” along the c-axis direction, the thicknesses of the “domains” vary ca. 50–100 Å. They are tightly connected with each other when the halloysite is hydrated, but are separated from each other by the dehydration of the interlayer water, whereupon the stripes come into existence along the tube axis. Taking these considerations into account, a model of dehydration is proposed. Moreover, a new method of calculating the β-angle is proposed in the Appendix.

Dimensional changes in kaolinite pellets as a function of temperature show two sharp shrinkage “steps,” at about 450–550°C and 900–980°C, which are roughly comparable in magnitude. Isothermal heat-soaking tests confirm that the rates for both are kinetically controlled. Water vapor inhibits shrinkage at low temperature but promotes shrinkage at high temperature. Both the former reaction, related to dehydroxylation, and the latter reaction, related to “mullitization,” take place at temperatures well below those observed in DTA, TG, and other measurements, indicating that bond-breaking is a necessary prelude to transitions at higher temperatures.

Bonding energy changes, as measured by X-ray fluorescence shifts, were used in interpreting the phenomena involved. The relative absence of bonding energy changes in the aluminum until the range 950–1100°C, and the presence of such changes in the silicon, suggest that high-temperature energy release is probably related to segregation or crystallization of silica, rather than of an aluminum-containing phase. Caution must be used in interpreting bonding energy changes, and in distinguishing kinetic and thermodynamic contributions to dynamic phenomena.

The dehydration reaction of kerolite was investigated using high-pressure differential thermal analysis at pressures as high as 600 bars. The peak associated with the dehydration is broad, suggesting the presence of a series of overlapping reactions ranging from the release of adsorbed water to interlayer water. The peak temperature is 136°C at 1.8 bars and increases to 516°C at 586 bars. The primary reaction represents loss of adsorbed water having a bond energy of 1.5 ± 1 kJ/mole. A small amount of water may be present as interlayer water and has a bond energy of 7.5 ± 3 kJ/mole.

The rehydration properties and behavior of interlayer cations of Ca-, Mg-, Na-, and K-saturated homoionic saponite and vermiculite heated at various temperatures were examined and their rehydration mechanisms elucidated. The most notable features of saponite were (1) except for the Mg-saturated specimen, all saponite samples rehydrated until the crystal structure was destroyed by heating; (2) the rehydration rate in air after heating decreased in the order: K+ > Na+ > Ca2+ > Mg2+; (3) the interlayer cations apparently migrated into hexagonal holes of the SiO4 network on thermal dehydration; and (4) the b-parameter expanded on thermal dehydration. The rehydration properties and behavior of interlayer cations of vermiculite were: (1) except for the K-saturated specimen, all vermiculite samples rehydrated until the crystal structure was destroyed by heating; (2) the rehydration rate in air after heating decreased in the order: Mg2+ > Ca2+ > Na+ > K+; (3) the interlayer cations apparently did not migrate into the hexagonal holes, but remained at the center of the interlayer space, even after thermal dehydration; and (4) except for the K-saturated specimen, the 6-parameters of the samples contracted on thermal dehydration. The different rehydration properties of saponite and vermiculite were apparently due to the behavior of the interlayer cations during thermal dehydration. For rehydration to occur, the interlayer cations of saponite had to migrate out of the hexagonal holes. Consequently, saponite saturated with a large cation rehydrated rapidly, whereas saponite saturated with a small cation rehydrated slowly. On the other hand, the interlayer cations of vermiculite remained in the interlayer space; therefore, the rehydration properties of vermiculite were strongly affected by the hydration energies of the interlayer cations. Furthermore, electron diffraction patterns suggested that the saponite and vermiculite consisted of random stacking and ordered stacking of adjacent 2:1 layers, respectively. The nature of the stacking of the minerals seemed to be the most important factor controlling the behavior of interlayer cations in the thermal dehydration process.

Several hydrates can be synthesized from well-crystallized kaolinites; of importance to the present work are a 10-Å hydrate (called the QS-10 hydrate), an 8.6-Å hydrate, and two kinds of partially dehydrated mixed-layer hydrates. One kind is a series of unstable materials with d(001) varying continuously between 10 and 8.6 Å, and the other kind is stable with d(001) approximately centered at 7.9 Å. The 10- and 7.9-Å phases have been observed in halloysites by many workers using X-ray powder diffraction, and the 8.6-Å phase has been seen by others in selected area electron diffraction photographs. Infrared spectra reveal additional similarities between the synthetic hydrates and both halloysite(10Å) and partially dehydrated halloysites. Because of these similarities, the synthetic hydrates can be used to develop a model for the dehydration of halloysite(10Å).

Previous work on the 10- and 8.6-Å hydrates identified two structural environments for the interlayer water. In one, the water is keyed into the ditrigonal holes of the silicate layer (hole water), and in the other, the water is more mobile (associated water). Both types are found in the QS-10 hydrate and halloysite(10Å), whereas only hole water occurs in the 8.6-Å hydrate. In the QS-10 hydrate, stronger hydrogen bonding between hole water and the clay makes the hole water more stable than the associated water. This difference in stability is responsible for a two-step dehydration process. The first step is the loss of associated water which results in a material with d(001) = 8.6 Å. This stable hydrate must be heated to temperatures near 200°C to drive off the remaining hole water. The less perfect structure of halloysite and its common curvilinear morphology reduce the difference in stability between hole and associated water molecules, so that when halloysite(10Å) dehydrates, loss of hole water and associated water overlaps, and the d-spacing goes directly to 7.2–7.9 Å.