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Joint inversion of seismic amplitude and frequency information for fluid discrimination works as a popular approach for reservoir fluid identification. However, ignorance of the factor caused by fluid flow and the viscosity of oil and gas in current frequency-dependent inversion approaches leads to the inaccuracy of oil and gas prediction. Therefore, based on squirt flow and viscoelastic theory, a new frequency-dependent viscoelastic squirt-flow fluid factor is established, which is compared with other conventional fluid factors to verify its advantages in fluid detection. In addition, a new linearized reflectivity equation related to frequency-dependent viscoelastic squirt-flow fluid factor is derived. Finally, to verify the feasibility of the new fluid factor in predicting oil/gas, a frequency-dependent elastic impedance inversion method is introduced. Synthetic data and field data examples find that frequency-dependent viscoelastic squirt-flow fluid factor can eliminate the interference of “false bright spots” in conventional fluid factors inversion and has a higher vertical resolution, which demonstrated the effectiveness and stability of our method in fluid prediction.

SUMMARY The elastic properties of the subsurface, such as density, P-velocity and S-velocity, can be estimated in pre-stack seismic inversion. In recent research, the deep neural network is widely used in pre-stack seismic inversion for its strong non-linear fitting and feature extraction ability. However, the label data is generally inadequate due to high drilling costs and strong data-sharing barriers in the field of exploration geophysics. In order to reduce the dependence of network performance on label data and ensure the accuracy of inversion mostly, semi-supervised learning is adopted. Here, we develop a cooperative multinetworks semi-supervised pre-stack seismic inversion method. In the cooperative multinetworks inversion framework, the inversion network, mapping network, and modification network are adopted to complete the inversion task cooperatively. A forward network is constructed to automatically generate seismic data from density, P-velocity and S-velocity, which can assist the above networks to complete semi-supervised learning. Compared with some published deep learning pre-stack inversion methods, the spatio-temporal correlation of data can be fully mined, the prior geological structure and low-frequency information can be utilized effectively, and reflectivity is adopted as an intermediate output parameter to improve the robustness of the method. The experiments on the Marmousi2 model demonstrate that cooperative multinetworks semi-supervised inversion strategy is superior to conventional semi-supervised inversion methods in both inversion accuracy and antinoise performance. In addition, the susceptibility experiments of the initial model indicate that the proposed method can maintain a high inversion accuracy with little effective information in the initial model. Finally, the proposed method is successfully applied to the field data and obtains a high-resolution inversion result.

The nontraditional intrinsic fluorescence (NTIF) of polymers containing heteroatoms has gained considerable attention due to its promising applications in label-free bioimaging. Aliphatic hyperbranched polyureas (aBPUs), which have recently shown great promise in the field of nanomedicine, bear controllable urea groups distributed on the branch points and thus are potential candidate luminogens. However, their NTIF properties and how their structures influence the NTIF properties have not been illustrated yet. Here, we addressed these issues by synthesizing a series of aBPUs with different degrees of branching (DBs) or different modifications. aBPUs exhibited an obvious NTIF phenomenon and with the increase of DBs, the NTIF enhanced as well. Chemical modifications either at the branching ends or in the interior of aBPUs could affect the NTIF performances, which were highly dependent on the types of modification. Disruption of the intra-/intermolecular hydrogen-bonding interactions decreased the NTIF. In addition, poly(ethylene glycol) (PEG)-modified aBPUs could self-assemble into nanospheres, and the formation of nanoassembly led to 89% enhancement on NTIF compared with the homogeneous solution of aBPUs-PEG in dimethylformamide (DMF). Finally, aBPUs-PEG nanoassembly demonstrated a capability in realizing label-free material imaging in vitro. These results shed light on the rational design of the polymer structures to achieve desired fluorescence with unconventional luminophores.

3D bioprinting of living materials represents an interesting paradigm toward the efficacy enhancement for the biosynthesis of various functional compounds in microorganisms. Previous studies have shown the success of 3D-printed bioactive systems in the production of small molecular compounds. However, the feasibility of such a strategy in producing macromolecules and how the geometry of the 3D scaffold influences the productivity are still unknown. In this study, we printed a series of 3D gelatin-based hydrogels immobilized with fermentation bacteria that can secrete hyaluronic acid (HA), a very useful natural polysaccharide in the fields of biomedicine and tissue engineering. The 3D-printed bioreactor was capable of producing HA, and an elevated yield was obtained with the system bearing a grid structure compared to that either with a solid structure or in a scaffold-free fermentation condition. As for the grid structure, bioreactors with a 90° strut angel and a median interfilament distance displayed the highest HA yield. Our findings highlighted the significant role of 3D printing in the spatial control of microorganism-laden hydrogel structures for the enhancement of biosynthesis efficiency.

In this study, the influence of dietary compounds, including antioxidants (ethylenediaminetetraacid, ascorbic acid, catechin), chitosan and lactoferrin, on the stability of liposomes during in vitro adult and infant digestion was investigated in terms of formation of thiobarbituric acid‐reactive substances (TBARS) and free fatty acid release. Liposomes were more sensitive to degradation in adults than in infants, suggesting lower pH (1.5) and higher concentration of pancreatic enzymes (3.2 mg mL⁻¹) and bile salts (5 mg mL⁻¹) that indicated greater damage to the structure of liposomes. Compared to ethylenediaminetetraacid and ascorbic acid, catechin presented the most apparent protective effect against liposomal oxidation by scavenging free radicals. Chitosan promoted the formation of TBARS, while lactoferrin facilitated the hydrolysis rate of liposomes under both adult and infant conditions. This study provided an insight into the development of healthcare products and functional foods related to liposomes for special populations.

Protein-protein interaction in response to environmental conditions enables sophisticated biological and biotechnological processes. Aiming toward the rational design of a pH-sensitive protein-protein interaction, we engineered pH-sensitive mutants of streptococcal protein G B1, a binder to the IgG constant region. We systematically introduced histidine residues into the binding interface to cause electrostatic repulsion on the basis of a rigid body model. Exquisite pH sensitivity of this interaction was confirmed by surface plasmon resonance and affinity chromatography employing a clinically used human IgG. The pH-sensitive mechanism of the interaction was analyzed and evaluated from kinetic, thermodynamic, and structural viewpoints. Histidine-mediated electrostatic repulsion resulted in significant loss of exothermic heat of the binding that decreased the affinity only at acidic conditions, thereby improving the pH sensitivity. The reduced binding energy was partly recovered by "enthalpy-entropy compensation." Crystal structures of the designed mutants confirmed the validity of the rigid body model on which the effective electrostatic repulsion was based. Moreover, our data suggested that the entropy gain involved exclusion of water molecules solvated in a space formed by the introduced histidine and adjacent tryptophan residue. Our findings concerning the mechanism of histidine-introduced interactions will provide a guideline for the rational design of pH-sensitive protein-protein recognition.

Ozone is a major gaseous pollutant that induces crop loss. Although the physiological and morphological responses of crops to ambient ozone have been well characterized, little is known about the protein responses. We firstly investigated the protein responses in rice seedlings under ambient and elevated ozone stress by a proteome approach. Twenty proteins were differentially expressed. Expression of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) large subunit (LSU) and their 17–18 kDa fragments and RuBisCO activase were reduced by both ambient and elevated ozone. RuBisCO small subunit (SSU), large subunit fragment (37 kDa), and oxygen-evolving enhancer proteins 1 and 2 increase in expression with ambient ozone, and decreased with elevated ozone. Ambient ozone induced a slight reduction, and elevated ozone induced a significant reduction in the expression of energy metabolism proteins. Expression of the antioxidant proteins glutathione S-transferase and Mn superoxide dismutase increased upon ozone exposure, but thioredoxin peroxidase expression decreased. Three defense/stress-related proteins, pathogenesis-related (PR) class 5 protein (PR5) and two PR10 proteins OsPR10/PBZ1 and RSOsPR10, were significantly induced after 2 days exposure to elevated ozone and gradually increased during exposure period. The results not only indicate the difference in protein responses between leaves exposed to ambient and elevated ozone, but also demonstrated the highly damaging effect of elevated ozone on rice seedlings at the proteome level.

Based on an experimental field study in Japan, a model was developed to simulate dissolved nitrogen in water ponded in a paddy field. As input data, the model uses meteorological data, water balance in the field, nitrogen concentration in inlet water, and the nitrogen contribution of applied fertilizer. Five model parameters need calibration. A practical application of the model is the simulation of NH4-N and NO2+3-N concentrations in water ponded in a paddy field. The model improves our understanding of the interactions between forms of dissolved nitrogen in ponded water and can explain the complex changes in dissolved nitrogen concentrations in water ponded on a paddy field.

Variations of anions (SO42-, NO3-,NO2-, Cl- and F-),cations (K+,Na+, Ca2+, Mg2+ and \({NH}_4^+\)+) and pH values in precipitation, througfall and stemflow samples collected overa four-year period (1995–1998) in Beijing (two sitesZhongguancun and Mangshan) are presented. The annualvolume-weighted range of pH values were 6.57–7.11 inprecipitation, 5.46–6.86 in thoughfall and 5.32–6.41 instemflow. The fominant anion was \({SO}_4^{2-}\), while Ca+and NH4+ were the main cations in precipitation,throughfall and stemflow. Most of ion concentrations with precipitation, throughfall and stemflow volume showed negative correlation, except for some ones. Significant correlationvalues were also found between ions (SO42-,NO3-, Cl-, F-, Ca2+,Mg2+ andNa+) in precipitation, throughfall and stemflow indicatedthe common sources of these ions such as coal combustion,automobile emission and fertilizers application. Compared toprecipitation, there was an increased ion concentration inthroughfall or in stemflow. Changes of ion concentrations werein Quercus liatungensis Koiz. and Pinus tabulaefornisCarr. throughfall (or stemflow) because of different crown andbark qualities of tree species.

本研究では,北京郊外と東京郊外における大気汚染の実態,降水の化学組成を把握し,物質収支の差異を明らかにするために,1995年から1996年まで北京郊外の北京市林業局付属十三陵森林公園(以下十三陵と略記)と東京郊外の東京農工大学農学部波丘地付属実験実習施設(以下波丘地と略記)の2カ所の小流域で,調査を行った。この研究によって,以下のことが明らかになった。(1)1995年6月～1996年5月の降水の年間平均pH値は,十三陵で6.7,波丘地で4.7であった。pH値は北京郊外で東京郊外より高かった。(2)両地点の降水の化学組成はかなり異なり,十三陵ではSO42-濃度は平均325μeql-1で,陰イオンのおよそ70%を占め,酸性化には硫酸イオンの寄与が大きいと考えられた。波丘地で最大値を示したのはNO3-(平均46.5μeql-1)であり,全ての陰イオンの38%を占め,酸性化の原因は硝酸イオンの寄与が大きいと認められた。(3)両小流域の物質収支については,著しい差異が認められた。十三陵では,1995年6月～1996年5月の間に全ての可溶性無機物F-,Cl-,NO2--N,NO3--N,SO42--S,Na+,K+,Ca2+,Mg2+,H+,NH4+-Nの合計97.5kg ha-1 yr-1が集水域に蓄積した。波丘地では,Mg2+,Na+,F-が集水域から流出し,その他のイオンが蓄積する傾向が認められた。一方,フッ化物イオンについては著しい差異が認められた。十三陵では,フッ化物イオンの濃度および降下量は大きく,その約81%が小流域に蓄積したが,波丘地ではその濃度は小さく,インプットの約105%が流出した。フッ化物イオンは他の陰イオンに比べると著しく毒性が高いと言われており,十三陵で現在と同じレベルのフッ化物イオンが降下し続けると将来,地下水や植物に直接的な被害を与えることが考えられる。