Search Results (1,800)

Poly(β-L-malic acid) (PMLA) is a water-soluble, biodegradable aliphatic polyester whose pendant carboxyl groups support chemical functionalization for biomedical, packaging, and materials applications. Microbial fermentation can use pure sugars and biomass-derived carbon sources under mild conditions, but industrial translation remains constrained by feedstock cost and variability, strain performance, oxygen and pH control, pretreatment-derived inhibitors, and downstream recovery. This review therefore focuses on the fermentative production of PMLA from refined and renewable carbon sources, the microorganisms and metabolic routes involved, and the process variables that govern titer, yield, productivity, molecular weight, and purification. Agricultural and forestry feedstocks are compared according to their actual carbohydrate class and processing requirements. Bamboo shoot shell hydrolysate is treated as an emerging case study rather than an established production platform: one accepted shake-flask study directly demonstrated PMLA production by Aureobasidium pullulans NRRL Y-2311-1, but controlled bioreactor validation, reproducibility, techno-economic analysis, and application-specific product qualification remain to be further investigated. The review also examines autohydrolysis, low-molecular-weight PMLA for biomedical use, furan inhibition, membrane and ion-exchange purification, and the limits of current economic comparisons. This evidence-based framing identifies where bamboo-processing residues may contribute to renewable PMLA production while distinguishing laboratory feasibility from industrial readiness. Full article

β-Nicotinamide mononucleotide (NMN) is an important intermediate in nicotinamide adenine dinucleotide (NAD⁺) metabolism and has attracted increasing interest as a bioactive compound and biomanufacturing product. In this study, Pseudomonas putida KT2440 was engineered for NMN production using a “block–enhance–transport” strategy. Deletion of nicB impaired nicotinic acid degradation and resulted in the accumulation of 66.2 μM nicotinic acid in cell extracts, whereas additional deletion of the putative NMN-consuming genes pncC and ushA did not lead to detectable NMN accumulation. Coexpression of endogenous pncB and engineered Francisella tularensis nadE* enabled low-level NMN formation through a Preiss–Handler pathway-based route. By contrast, overexpression of endogenous nadA, nadB, and nadC strengthened precursor supply through the NAD⁺ de novo biosynthetic pathway and resulted in approximately 0.17 mM NMN in cell extracts. Chromosomal integration of an engineered Salmonella enterica pnuC* transporter cassette was associated with pronounced extracellular NMN accumulation. Additional overexpression of genes involved in downstream NAD⁺ metabolism or phosphoribosyl pyrophosphate supply did not considerably improve production, possibly because of metabolic competition or expression burden. The best-performing strain, LW10, produced 1.28 mM extracellular NMN, corresponding to approximately 0.43 g/L, after 96 h of shake-flask cultivation in basal salt medium containing glucose and L-aspartate. These results suggest the feasibility of NMN biosynthesis in engineered P. putida KT2440 and highlight the importance of balancing precursor supply, competing reactions, and product transport. Thus, P. putida KT2440 represents an alternative chassis for further pathway balancing and process optimization toward fermentative NMN production. Full article

Macroscopic and microscopic aggregation patterns of reconstituted poly-L-lactic acid (PLLA) products may vary with product formulation, diluent, preparation protocol, and time. This descriptive in vitro pilot study compared two commercial formulations, StiCol Volume (150 mg PLLA reconstituted to 9 mL) and StiCol Soft (50 mg PLLA reconstituted to 6 mL), under 11 diluent conditions and 2 composite preparation protocols: roller mixing for 30 min and manual shaking for 3 min followed by 3 h of hydration. One preparation was evaluated for each formulation–diluent–protocol combination. Gross appearance was documented immediately and at 15, 30, 45, and 60 min and 24 h; microscopy was performed at ×40 and ×100 from 15 min onward. Two evaluators applied an ordinal visual aggregation scale, and the findings were analyzed descriptively. In the observed preparations, the StiCol Soft formulation generally showed lower aggregation grades than StiCol Volume; however, the products differed in nominal PLLA concentration, particle size, and excipient composition, so this pattern cannot be attributed to concentration alone. SWFI-based conditions tended to show fewer microscopic clusters than NSS-based conditions. The roller/30 min protocol also tended to show lower grades than the manual/3 h protocol, although mixing mode and hydration duration were inseparable. Macroscopic upper-layer accumulation was interpreted as vertical phase separation with creaming/flotation-like behavior rather than sedimentation. These exploratory findings generate hypotheses for replicated studies incorporating standardized sampling, redispersibility, particle size, rheological, and injectability testing; they do not establish an administration window or improved clinical safety. Full article

Background/Objectives: Inflammatory bowel disease (IBD) may require topical rectal treatment for distal colonic inflammation. Rectal foams or rectal enemas can reach deeper bowel sections but are complex to administer, especially for pediatric patients with IBD. Furthermore, it is a challenge to visualize this administration process in a structured manner. We aimed to design a rectal demonstration model to enable the visualization of rectal foam administration and to assess the clinical risk potentially associated with detectable errors. Methods: A rectal demonstration model was developed, handling errors were defined, and their clinical risk was rated. The model was tested for rectal foam administration by 19 adolescent patients (aged 12–18 years). Results: A total of 12 observable administration steps, including their clinical risk, were defined by an expert panel of physicians and pharmacists. Seven handling errors were rated with a high clinical risk, such as “Not shaking the spray can at all before administration”. In demonstrations by adolescent patients, a median of three (Q25/Q75; 2/4.5; min/max 1/7) handling errors were identified. The most frequent error was releasing the pump dome too quickly after pushing down (11/19, 58%). At least one error with high clinical risk (score: 5–6) was identified in 15/19 (79%) of patients’ administrations. Conclusions: The developed demonstration model facilitates the visualization of handling errors in rectal foam administration that would otherwise not be accessible in routine care. A high rate of clinically relevant handling errors was identified in adolescents. Prospectively, the model can be used to practice rectal foam administration and address patient handling errors to increase patient safety. Full article

This study presents a performance-based forensic investigation of the Tanada wall, a geosynthetic reinforced soil wall with a full-height rigid facing that experienced strong shaking during the 1995 Hyogoken Nambu earthquake in Japan. The analytical framework integrates a compiled soil stress–displacement dataset, limit equilibrium constraints, displacement-based back analysis, reconstruction of the displacement (Δ_3h)–seismic inertial coefficient (k_h) curve, and systematic parameter sensitivity evaluation. The displacement-based seismic resistance curves developed using representative soil parameters show that the Tanada wall maintains strong seismic resistance up to HPGA ≈ 0.7–0.8 g, with displacement trends that remain physically consistent across three logarithmic cycles. Sensitivity analyses demonstrate that only three parameters—the soil stiffness number K, peak friction angle φ_peak, and the initial pullout stiffness number K_t—produce variations of approximately ±0.8–1.5 × 10⁻³ m in the final displacement Δ_3h. All remaining soil, reinforcement, and facing parameters contribute only minor variations on the order of a few 10⁻⁴ m. These findings show that the force-equilibrium-based finite displacement method (FFDM), supported by laboratory evidence and displacement-based inference, provides a rigorous and physically grounded methodology for forensic evaluation of reinforced soil structures. Full article

To simulate the fracture behavior of members during structural collapse, this paper proposes a member fracture simulation algorithm that integrates the plastic hinge model with a ductile fracture damage model within the member discrete element method (MDEM) framework. The coupling is achieved by computing stresses at the four most unfavorable edge points of the contact section and using the minimum fracture strain as the section-level failure criterion. The algorithm is validated against a cantilever beam fracture example, yielding results in good agreement with reference data under two yield stress conditions. The fracture algorithm is then embedded as a self-contained module into an adaptively coupled DEM/FEM algorithm and applied to simulate the shaking table collapse test of a single-layer spherical reticulated shell. The simulation predicts structural collapse at a peak ground acceleration (PGA) of 2268 gal—consistent with the experimental value—with 126 members fractured at collapse onset, and reproduces the observed fracture sequence in which first-ring diagonal members near the supports fail progressively from the bottom upward. The proposed framework provides a computationally robust and practically deployable tool for collapse analysis of large-span reticulated structures, with direct implications for progressive-collapse prevention in seismic design and post-event structural forensic investigation of collapse mechanisms. Full article

The valorization of agricultural waste into high-value carbon nanomaterials offers dual benefits: it reduces pollution and provides low-cost materials for sustainable technologies. This work synthesizes graphene-like carbon from Ghars date waste via mild KOH-assisted pyrolysis at 1000 °C. The material (G-GhW1000) exhibits a sharp (002) XRD peak at 26.16° (d-spacing = 3.40 Å), a characteristic π → π* transition at 253 nm, and a high C/O ratio of 27.37. Dispersed in tap water (0.5 g/L) by simple hand shaking (without ultrasonication), it serves as a photothermal nanofluid in a modified single-slope solar still (MSS). Under outdoor conditions, the MSS produces 4.69 L·m⁻²·day⁻¹, which is 18.7% higher than a conventional still, with thermal efficiency rising from 27.2% to 30.8% (with a reproducible 19.0% enhancement in summer). Samples prepared at 800 °C and 900 °C give 4.0% and 6.4% lower yields, while the 1100 °C sample gives only 6.0% improvement, confirming 1000 °C as the optimal temperature. The superior performance at 1000 °C is attributed to the optimal balance between graphitization, deoxygenation, and structural integrity, as evidenced by XRD, FTIR, EDX and UV-Vis analyses. The enhanced performance is linked to higher water temperature (68 °C) and larger ΔT. The distilled water meets WHO standards (TDS 9.35 mg/L, >99.4% reduction) with no detectable graphene-like carbon carryover. This work demonstrates the potential of waste-derived graphene-like carbon as a low-cost additive for solar desalination, addressing water scarcity and waste management within a circular economy framework. To our knowledge, this is the first study to use Ghars date waste-derived graphene-like carbon in a solar still. Full article

Single-story unreinforced masonry rural houses along the Tanlu Earthquake Belt in Anhui Province are generally constructed without ring beams and tie columns, resulting in poor structural integrity and low seismic performance. This paper proposes a convenient single-sided High-Ductility Concrete Strip (HDCS) retrofitting method. Two 1:2 scaled test specimens, namely the unretrofitted model M1 and HDCS single-side retrofitted model M2, were fabricated for shaking table tests. Systematic analyses were carried out based on white noise sweep tests, failure modes, acceleration responses and inter-story displacement responses. The test results show that HDCS possesses excellent tensile capacity, which forms continuous confinement at wall joints and openings to boost structural stiffness and greatly restrain post-seismic stiffness degradation, as well as achieve more uniform structural deformation distribution. Under strong seismic excitations, the unretrofitted model suffers severe damage, including penetrating diagonal shear cracks and separation between gable walls and lower walls. In contrast, damage of the retrofitted model is concentrated within the HDCS overlay, realizing damage redistribution and preventing brittle failure of the main masonry. HDCS stabilizes the distribution of acceleration amplification factors and restrains wall rocking and stress concentration around openings. Although single-sided strengthening induces slight out-of-plane effects, its adverse influence is acceptable. Full article

Prestressed concrete hybrid-reinforced solid square (PCHSS) piles combine strands and rebars for improved ductility. This study presents large-scale shaking table tests (1:2 scale) on PCHSS pile–superstructure systems embedded in soft and stiff clay, subjected to four ground motions with distinct frequency contents. The experimental program systematically captured the evolution of natural frequencies, damping ratios, dynamic earth pressure distributions, bending moment profiles, curvature ductility demands, and post-test cracking patterns. Results reveal that ground stiffness governs the degradation pathway and energy dissipation mode: soft clay exhibited 37.3% frequency degradation (1.33× that in stiff clay), while stiff clay showed a 101% damping increase (>3× soft clay). Long-period ground motions generated maximum curvature ductility demands and peak bending moments 2–3 times those of short-period records under identical PGA, attributed to near-resonance coupling. Pile–soil interaction transitions from compatible deformation to progressive separation with increasing seismic intensity, with gap spacings of 40–53 mm observed in soft clay. Notably, the code-specified 4D reinforcement zone was found insufficient for soft clay foundations, where crack distributions extended to 4D–7D, warranting an extended zone up to 7D. The findings provide experimental benchmarks for numerical model calibration and offer practical guidance for extending hybrid-reinforced precast piles into moderate-to-high-seismicity regions. Full article

Self-centering rocking systems redistribute seismic demand as contact conditions at structural interfaces change during excitation. Conventional peak-response measures, global-response model calibration, and system-identification summaries can obscure the transient redistribution among diaphragms, wall couplings, and restoring components. This study addresses that gap with a phase-resolved analysis of heterogeneous measurements from fourteen full-scale shake-table tests of a two-story mass-timber building with post-tensioned cross-laminated timber rocking walls. Acceleration, strain, post-tensioning-force, and wall-uplift records were aligned, screened, and placed on a common analysis grid; uplift-defined operating phases were then evaluated using normalized subsystem activity, entropy, effective participation, conditional directed predictability, and dimensional force-uplift work. Median effective participation increased from 2.7 subsystems in the closed state to approximately 5.8 during rocking. The median closed-to-rocking Jensen–Shannon divergence was 0.195, the median post-recontact recovery index was 0.813, and restoring work was 4.6–10.7% greater on the south wall line. Rocking-phase floor-diaphragm activity co-varied with south restoring work (Spearman ρ = 0.873, p < 0.001). The new scientific result is that wall uplift reorganizes the composition of measured subsystem activity rather than simply scaling a fixed response pattern. The proposed indicators therefore provide complementary, phase-conditioned targets for experimental comparison and nonlinear-model validation, while remaining distinct from equilibrium force fractions, damage indices, or unrestricted causal measures. Full article

Discrete ancillary equipment and local added masses are common in long-span steel structures, yet equal total mass can produce different dynamic responses because existing quantity-based descriptions do not encode spatial redistribution. This study establishes a mounting offset index (MODI) from mass intensity $M_I$, eccentricity $E_I$, dispersion $D_I$, and central–subcentral synergy $C_I$. Shaking-table tests on a 1:40 single-layer cylindrical reticulated-shell model examined one unloaded baseline and 44 mounted-mass layouts in the X, Y, and 45° structural orientations, yielding 135 orientation-specific cases. Same-orientation normalization produced four response ratios. All the responses differed significantly among the orientations ($p<0.001$), while the equal-mass layouts exhibited distinct MODI values and responses. In 100 repeated five-fold analyses, the four-component model achieved $Q^2=0.554\pm 0.039$ for the X-orientation time-domain peak ratio and $0.364\pm 0.052$ for its frequency-domain peak ratio; the composite MODI had no stable predictive capability. These results establish a hierarchical evaluation framework: the MODI supplies a pre-test spatial coordinate for layout comparison, the components support selected within-orientation interpretations, and the directional sensitivity index with the three-orientation envelope identifies direction-sensitive and relatively unfavorable measured-node responses. The MODI is therefore an engineering screening descriptor rather than a universal response-prediction formula. Full article

Large-amplitude water sloshing in high-filling storage tanks can generate transient roof-impact pressures that threaten structural safety and operational reliability. This study develops a simplified momentum-conservation-based model for estimating the maximum dynamic impact pressure (MDIP) in rectangular tanks. The impact load is represented by the rate of momentum change within the roof-wetted liquid region, and the model parameters are calibrated using shaking-table tests. A total of 130 sinusoidal-excitation cases covering three filling depths and multiple excitation frequencies and amplitudes were conducted. The experimental results indicate that the roof-pressure response is strongly non-sinusoidal, with short-duration impulsive peaks and pronounced cycle-to-cycle variability. In the representative cases, the MDIP occurs after the first roof-contact event and varies non-monotonically with excitation amplitude. After calibration, the model provides reasonable estimates of the measured MDIP for most test conditions. The proposed formulation is physically interpretable and computationally efficient, making it suitable for rapid preliminary estimation of sloshing-induced roof-impact pressure in high-filling rectangular water tanks. Full article

A study was performed on the electromagnetic response of the geological medium during the propagation of Rayleigh waves from the 2025 Kamchatka earthquakes (M8.8–7.4) at an epicentral distance of approximately 6000 km. The identities of the coseismic telluric current variations and the propagating Rayleigh wave have been revealed, with their power spectra exhibiting a pronounced quasi-line structure with dominant peaks at 0.04 Hz, 0.054 Hz, and 0.064 Hz. The high correlation of the telluric current response with the Rayleigh wave (r = 0.906, M8.8 and r = 0.83, M7.8) allowed the seismoelectric effect of the second kind to be considered the dominant mechanism for disturbance generation. Electromagnetic signals recorded by the IMS-008 induction sensor showed a lower correlation (r = 0.682), which may be attributed to the shaking of the induction sensor during the passage of the Rayleigh wave, though this does not preclude the presence of a true coseismic signal. Coseismic effects were recorded during the M7.8 and M8.8 earthquakes, but were absent during the M7.4 events. For the first time for the Northern Tien Shan region (at teleseismic distances of approximately 6000 km), key regularities in the generation of the seismoelectric effect during Rayleigh wave propagation have been identified. It is shown that the telluric current response is characterized by a threshold sensitivity to the event magnitude, with the magnitude of induced current variations strictly consistent with the intensity of the seismic wave’s dynamic impact. Utilizing telluric currents as a physical reference for the precise determination of Rayleigh wave arrival times allowed for the refinement of the Rayleigh wave group velocity (3.078–3.093 km/s), reducing calculation uncertainty to 0.5%. Full article

2,3-Butanediol (2,3-BD) is a versatile bulk chemical, serving as a high-boiling green solvent, a key monomer for polyesters and polyurethanes, and a crucial intermediate in the production of fine chemicals and cosmetics. Additionally, it is a key intermediate for pharmaceuticals and agrochemicals, supporting green chemistry. Microbial production of 2,3-BD offers a sustainable bioprocess but faces the challenge of high-concentration product inhibition. In an effort to improve 2,3-BD tolerance and production in Corynebacterium glutamicum, the engineered strain CGK4 was subjected to atmospheric and room temperature plasma (ARTP) mutagenesis, from which three superior mutant strains were isolated. Genomic and reverse engineering analyses revealed two mutations beneficial for tolerance and seven mutations beneficial for production. Among these, mutations atpG^L250P, cobT^V192V, and ctaE^L79P increased 2,3-BD titer by 18.0%, 14.5%, and 15.0%, respectively. Furthermore, we found that while certain mutations markedly enhanced stress tolerance, the highest-producing strains achieved a balanced metabolic state rather than maximal tolerance, indicating a non-linear relationship between the two traits. Finally, through mutation combination optimization, the optimal strain K4-cobT-ctaE was constructed. In shake-flask fed-batch fermentation, this strain produced 84.35 ± 3.04 g/L (2R,3R)-2,3-BD, which was 38.3% higher than that of the parental strain. Our findings provide a promising approach to addressing 2,3-BD tolerance challenges and promote the development of microbial production platforms for industrial application. Full article

Adenine base editors (ABEs) can be used to fine-tune metabolic flux by editing gene promoters. However, their targeting scope is constrained by the PAM requirement of Cas9, making it difficult to target promoter regions where NGG motifs are rare. To overcome this limitation, we fused the SpRY variant, a near-PAMless Cas9, with the highly active adenine deaminase TadA8e to construct a near-PAMless ABE. After multi-round optimization, the editor achieved A → G edit at the T7 promoter, along with a bystander C → A edit at neighboring position. The ABE was used to edit the T7 promoter in the 1,4-butanediamine-producing strain, thereby altering the promoter strength and reallocating metabolic flux into 1,4-butanediamine biosynthesis. After shake-flask fermentation, the engineered strain produced 478.8 mg/L of 1,4-butanediamine within 48 h, representing a 106% increase compared to the control. This study provides a feasible strategy for constructing near-PAMless base editors and lays a foundation for modulating metabolic pathways. Moreover, the engineered strain achieved a marked increase in 1,4-butanediamine production, demonstrating that promoter editing via ABE can effectively regulate metabolic flux and enhance the production of the target product, as well as serving as a valuable reference for the biosynthesis of other high-value-added chemicals. Full article