Kaolinite is often a cause of deformation in soft-rock tunnel engineering, leading to safety problems. The mechanism of the deformation is closely related to the interaction between kaolinite and water molecules. Because kaolinite has multiple defects, the effects of Mg, Ca, and Fe(II) doping on the atomic structure of the kaolinite (001) surface, and the subsequent adsorption and penetration of H2O into the interlayer, were studied systematically using density-functional theory. The results showed that for the Mg-, Ca-, and Fe(II)-doped kaolinites (001), the surface relaxation around the doping layer changed from contraction to expansion, due to the redistribution of electrons. The adsorption energies of the H2O monomer on Mg-, Ca-, and Fe(II)-doped kaolinites (001) were less than on undoped kaolinite (001). The results further revealed that the H2O molecule can also adsorb on the hollow site on the second-layer O surface of the Mg-, Ca-, and Fe(II)-doped kaolinites (001). For the undoped kaolinite, however, the H2O molecule adsorbs on the surface only. The energetic barriers for penetration of H2O from the adsorption site on the surface to the adsorption site on the O surface of Mg-, Ca-, and Fe(II)-doped kaolinites were also calculated: 1.18 eV, 1.07 eV, and 1.41 eV, respectively. The results imply that the influences of Mg, Ca, and Fe(II) doping on kaolinite allow the adsorbed water molecules to penetrate from the on-surface adsorption site to the O-surface site.

The TanDEM-X DEM is a valuable data source for estimating glacier mass balance. However, the accuracy of TanDEM-X elevation over glaciers can be affected by microwave penetration and phase decorrelation. To investigate the bias of TanDEM-X DEMs of glaciers on the Tibetan Plateau, these DEMs were subtracted from SPOT-6 DEMs obtained around the same time at two study sites. The average bias over the studied glacier areas in West Kunlun (175.0 km2) was 2.106 ± 0.012 m in April 2014, and it was 1.523 ± 0.011 m in Geladandong (228.8 km2) in October 2013. By combining backscatter coefficients and interferometric coherence maps, we found surface decorrelation and baseline decorrelation can cause obvious bias in addition to microwave penetration. If the optical/laser data and winter TanDEM-X data were used as new and historic elevation sources for mass-balance measurements over an arbitrary observation period of 10 years, the glacier mass loss rates in West Kunlun and Geladandong would be potentially underestimated by 0.218 ± 0.016 and 0.158 ± 0.011 m w.e. a−1, respectively. The impact is therefore significant, and users should carefully treat the bias of TanDEM-X DEMs when retrieving a geodetic glacier mass balance.

Research was conducted to determine foliar absorption of 14C-clethodim and its polar degradation products with five adjuvants and to compare the relative herbicidal activity of clethodim and its polar degradation products. Differential 14C-clethodim and 14C-polar degradation products absorption occurred among the five adjuvants. Adjuvants that mediated rapid foliar absorption of clethodim did not always mediate rapid foliar uptake of polar degradation products. Herbicidal activity of clethodim exceeded activity of polar degradation products regardless of time of day of application or whether adjuvant was used. Inclusion of adjuvant was required for herbicidal activity of polar degradation products. Clethodim activity declined when applied at 0800 h EDT compared to applications at 2000 h EDT. To maximize herbicidal activity of clethodim, adjuvants should be selected that mediate rapid foliar absorption of both clethodim and the polar degradation products of clethodim and that minimize photodegradation of clethodim.

Experiments were conducted to determine 14C absorption, translocation, and metabolism by pitted morningglory (Ipomoea lacunosa L. # IPOLA) and ivyleaf morningglory [Ipomoea hederacea (L.) Jacq. # IPOHE] foliarly treated with 14C-acifluorfen [5-(2-chloro-4-(trifluoromethyl)phenoxy)-2-nitrobenzoic acid] or 14C-lactofen [(±)-2-ethoxy-1-methyl-2-oxoethyl-5-(2-chloro-4-(trifluoromethyl)phenoxy)-2-dinitrobenzoate]. Seventy-one to 84% of applied 14 C-acifluorfen was recovered in leaf water wash of ivyleaf morningglory compared to 32 to 46% from pitted morningglory. Sixty-four percent of applied 14C-lactofen was recovered in leaf water wash 96 h after treatment in both morningglory species. Thirty-five to 37% more 14C from applied 14C-acifluorfen was found in pitted morningglory treated leaves than ivyleaf morningglory treated leaves. Less than 28% of applied 14C-lactofen was extracted from treated leaves of either morningglory species. Translocation and metabolism of 14C-acifluorfen and 14C-lactofen were minimal in both morningglory species.

Retention, absorption, translocation, and volatility of foliarly applied diclofop-methyl {methyl 2-[4-(2,4-dichlorophenoxy) phenoxy] propanoate} were compared in barnyardgrass [Echinochloa crus-galli (L.) Beauv.], a susceptible grass; proso millet (Panicum miliaceum L.), a moderately susceptible grass; longspine sandbur [Cenchrus longispinus (Hack.) Fern.], a tolerant grass; and soybean [Glycine max (L.) Merr. ‘Hark’] and cucumber (Cucumis sativus L. ‘Green Star’), both tolerant broadleaf plants. On a jug/plant basis, the order of diclofop-methyl spray retention was cucumber > soybean > proso millet > longspine sandbur = barnyardgrass. On a μg/mg dry weight basis, proso millet retained 3 to 10 times more diclofop-methyl than all other species. One day after treatment (DAT), absorption of 14C-diclofopmethyl was 14 to 18% less in longspine sandbur than in the other species, 3 DAT absorption in cucumber was 8 to 14% greater than in the other species, and 5 DAT absorption in soybean was 3 to 12% less than in other species. Translocation of 14C-diclofop-methyl did not differ among species, with 98% of the applied radioactivity located in the treated leaf. An average of 11% of radioactivity applied to the surface of intact, living plants and excised, dried leaves of cucumber, soybean, and barnyardgrass, as well as glass cover slips, was lost by evaporation. None of the parameters measured showed differences large enough to be implicated as primary selectivity mechanisms.

A mathematical model describing the behavior of 14C-haloxyfop {2-[4-[(3-chloro-5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid} and its methyl and ethoxyethyl esters on yellow foxtail [Seteria glauca (L.) Beauv. #3 SETLU] has been developed to evaluate volatility, penetration, ester transformation, metabolism, and transport of the chemical in the plant system. The effects of crop oil concentrate, temperature, structure of the molecule, and the addition of bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] to the application solution on the kinetic rate constants have been studied. Crop oil concentrate was found to dramatically increase penetration at an optimal level of approximately 0.3% (v/v). Significant increases in rate constants were observed at higher temperatures. Esters were rapidly converted to the acid in the plant with conversion of the ethoxyethyl ester being approximately twice as fast as the methyl ester. Subsequent metabolism of the acid proceeded at a moderate rate which was independent of the original ester form of the molecule. All kinetic processes were described by first-order rate constants with the exception of transport which appeared to slow a few hours after application even though acid levels in the plant were high. When bentazon was applied in combination with haloxyfop-methyl, penetration of the ester was somewhat inhibited, while transport of radioactivity associated with the molecule to other plant parts was dramatically reduced.

The effect of ammonium sulfate (AMS) on efficacy and on absorption and translocation of sethoxydim in wild oats and barley was investigated under controlled environmental conditions. Increases in efficacy in the presence of AMS were relatively small. The rate of sethoxydim required to reduce dry weight 50% was reduced from 0.08 kg a.i. ha−1, for both species, to 0.07 and 0.06 kg ha−1 for wild oats and barley, respectively, in the presence of added AMS. In short-term experiments, uptake of 14C from 14C-labeled sethoxydim 0.5 and 1 h after application was increased approximately twofold with the addition of AMS. AMS had little effect on sethoxydim absorption beyond 1 h after application. Translocation at 1 h after application was unaffected by AMS. However, translocation 12 and 24 h after application was increased with AMS. It is postulated that the translocation increase results indirectly from the increase in absorption. The observed increase in absorption with the addition of AMS is evident only when crop oil concentrate (COC) is also present In model systems, the addition of AMS enhanced sorption of sethoxydim into Isolated cuticles but had no effect on movement into excised roots.

The uptake, translocation, and metabolism of 14C-alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide] by germinating and emerged snap bean (Phaseolus vulgaris L.) seedlings were monitored under 16-h daylength (21 klux) comparing 16 C night/21 C Day and 27 C night/32 C day temperature regimes. Total uptake of 14C-alachlor by germinating snap beans was greater under the higher temperature, however, the compound was localized primarily in the roots where it was rapidly metabolized. At the lower temperature, the label was located in approximately equal amounts in all plant parts except cotyledons and significantly less of the alachlor was metabolized. Root uptake of 14C-alachlor and translocation of labeled compounds to the shoots were significantly greater under the higher temperatures. Approximately 60% of 14C-alachlor was shown to volatilize from a watchglass after 48 h at 27 C. After volatilization, uptake of 14C-alachlor occurred in adjacent snap bean plants in a closed system.

To develop an understanding of how adjuvants might enhance glyphosate [N-(phosphonomethyl)glycine] activity, absorption and translocation of a polyethoxylated tallow amine amphoteric surfactant (MON 0818) were examined in field bindweed (Convolvulus arvensis L. # CONAR). Scanning electron microscopy did not reveal any physical disruption of the epicuticular waxes from spray applications of MON 0818, an oxysorbic (20 POE) (polyoxyethylene sorbitan monolaurate) surfactant, or glyphosate. Radioactive MON 0818 absorption was rapid during the first 6 h. Maximum absorption (84%) occurred by 24 h after application. Less than 3% of the applied radioactivity was recovered from the epicuticular wax of treated leaves. Movement of radioactivity away from the treated area was limited predominantly to movement within the treated leaf. Altering light intensity or humidity in which the plants developed before treatment did not influence MON 0818 absorption.

Napropamide [2 - (α - naphthoxy) -N,N- diethylpropionamide] influx was studied using excised root segments of corn (Zea mays L.). An initial rapid influx was followed by a slower, steady influx rate. Total influx was separated into a component that eluted from the tissue (exchangeable fraction) and a nonexchangeable fraction (residual fraction). After 5 min the residual fraction was responsible for the continued influx. In further studies with root segments this fraction was nonsaturating, increased with increased temperature, and was reduced by anaerobic conditions. The exchangeable fraction was controlled by diffusional processes. The overall influx process was attributed to an initial passive diffusion supplemented with time by a binding of napropamide into the residual fraction.

Absorption and translocation of glyphosate [N-(phosphonomethyl)glycine] with and without adjuvants were examined in field bindweed (Convolvulus arvensis L. # CONAR) to develop an understanding of the influence of selected adjuvants and environment before application on glyphosate activity. Light intensity and humidity during plant development resulted in differences in 14C-glyphosate absorption. When applied in water or with an oxysorbic (20 POE) (polyoxyethylene sorbitan monolaurate) adjuvant, an average of 9% of the glyphosate was absorbed in plants grown in high light intensity, low humidity (HLLH) before treatment, compared to an average of 21% in plants grown in low light, high humidity (LLHH) before treatment, respectively. Amounts of epicuticular wax on HLLH field bindweed were almost three times as great as on LLHH leaves and may explain absorption differences. No differences in glyphosate absorption were observed between glyphosate applied with oxysorbic or no adjuvant even though the oxysorbic adjuvant effectively reduces surface tension. Absorption was increased two- to threefold with a polyethoxylated tallow amine adjuvant (MON 0818) compared to no adjuvant. Unlike absorption without adjuvant or with oxysorbic adjuvant, there were few absorption differences in plants grown in different environments before application. Absorption continued for 24 to 36 h after application regardless of adjuvant. Reductions in MON 0818 concentration and subsequent necrosis resulted in increased movement of radioactivity away from the site of application.

The influence of temperature and relative humidity on the activity of acifluorfen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid} on common cocklebur (Xanthium pensylvanicum Wallr.) and common ragweed (Ambrosia artemisiifolia L.) was studied in growth chambers. Treatment at high relative humidity (85 ± 5%) resulted in a significant increase in acifluorfen phytotoxicity and decrease in plant dry weight as compared to treatment at a lower (50 ± 5%) relative humidity (RH). Temperature (32 C day, 22 C night or 26 C day, 16 C night) was not as critical as relative humidity in influencing acifluorfen phytotoxicity. Addition of a non-ionic surfactant to the herbicide solution resulted in increased phytotoxicity. Penetration and translocation of acifluorfen in common cocklebur were increased when applications were made at high relative humidity.

The effect of moderate moisture stress on the activity of the methyl ester of diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid} applied to wild oat (Avena fatua L.) and the influence of morphological and physiological factors on the activity of the herbicide on stressed plants were investigated in growth-room experiments. Wild oat was grown in very fine sandy loam brought to a gravimetric soil moisture content (SMC) of 20% (water potential of -0.3 bars) or 10% (-6.5 bars) prior to herbicide treatment. The activity of diclofop on wild oat was slightly, but significantly, reduced when the SMC was increased from 10 to 20% immediately after spraying. Maintaining the SMC at 10% after spraying further reduced the activity of the herbicide. Wild oat plants grown at 20% SMC had 22% greater leaf area and retained 23% more herbicide than plants grown at 10% SMC. Penetration of the methyl ester of 14C-diclofop into wild oat grown at 20 or 10% SMC did not differ significantly 12, 24, or 48 h after application. Stressed and unstressed plants did not differ significantly in the metabolism of the methyl ester of 14C-diclofop. However, growth at a low SMC prior to treatment decreased the proportion of the radiolabeled herbicide recovered in the apex, third leaf, and tillers of wild oat. This may partially account for the reduced activity of this herbicide on wild oat subjected to moisture stress.

An echinostome cercaria (? Cercaria spinifera La Valette, 1855) with 37 collar spines and paraoesophageal glands has been recorded for the first time in Britain from the gastropod Planorbarius corneus. The cercariae penetrate into and encyst in planarians. Observations made on cercariae during penetration indicate that the paraoesophageal glands are used to enter the body of the planarian and that the so-called penetration glands have some other function. Gastropod molluscs may also serve as second intermediate hosts, but there is evidence to indicate that anatomically similar cercariae from different host individuals vary in their second intermediate host preferences.

The routes of penetration and the strategies of invasion of Schistosoma japonicum miracidia in the snail vector Oncomelania hupensis were observed in a histological study. In all species of the genus Schistosoma, it is usually assumed that the miracidia achieve penetration through the tegument. Our results showed that at least 57% of S. japonicum miracidia penetrated the snail by natural openings (branchial cavity, mouth and rectum). Throughout the invasion phase, the larvae were observed in all the tissues and organs with the exception of the genital gland. The spatial distribution of parasites in the snail revealed that the migration towards the visceral organs such as the kidney, heart and sinuses (which are the most usual microhabitats of the mother sporocysts of S. japonicum) appeared to take place via the circulatory system. Using natural openings as routes for penetration probably provides a selective advantage in a host–parasite system in which the target mollusc is amphibious: we presume that the miracidia inside these natural openings are protected against desiccation when the snail leaves the water, and that they can subsequently invade the tissues.