Tubular Structures Research Articles

Self-sacrificing MOF-74 to amorphous CoMoS4 hollow tube with nanosheet surface for high stability supercapacitors

Designing high-performance electrodes and elucidating their energy storage mechanisms are crucial for supercapacitors. In this study, an in situ conversion method is firstly employed to transform CoCH (Co(CO3)0.5(OH)·0.11 H2O) into Co-MOF-74 nanorods, which serves as a self-sacrificial template. Subsequently, the amorphous CoMoS4 hollow tube arrays with self-assembled nanosheet surfaces are obtained through MoO42- etching and S2- exchange. Benefiting from the nanosheets-coated hollow tubular structure and amorphous characteristics, CoMoS4 exhibits a high areal capacitance of 7.01 F·cm−2 at 2 mA·cm−2 and 91.81 % retention after 5000 cycles. When further assembled into a hybrid supercapacitor, the CoMoS4//AC device exhibits excellent performance with the energy density of 0.684 mWh·cm−2 at 1.876 mW·cm−2 and 91.39 % retention after 10000 cycles. Furthermore, the mechanism study reveals that Mo- and S-doped amorphous CoOOH is a genuine energy storage material. This work provides valuable insights into the preparation of amorphous materials using the self-sacrificial template transformation method and the understand of their energy storage mechanisms.

Modification of selectively acid-etched halloysite by mucoadhesive chitosan derivatives: New bionanocomposites with improved functional properties

In this study, the modification of selectively acid-etched halloysite (eHal) by low molecular weight chitosan (LChi) and its methacrylated derivative (MeLChi) is investigated to form new bionanocomposites with improved functional properties. The formation of nanocomposites was confirmed by various instrumental techniques (ζ-potential measurements, SEM, FT-IR, DSC, XRD and 1H NMR). Both nanocomposites exhibited improved functional properties while preserving the tubular structure of halloysite. The cytotoxic activity of eHal and eHal-polycation nanocomposites against normal human lung fibroblasts (MRC5) was determined using MTT assay. The results showed good biocompatibility of the prepared nanocomposites, with a cell survival rate of more than 90 %. The mucoadhesive properties of eHal and the corresponding chitosan nanocomposites were investigated in vitro. Primarily, ζ-potential measurements revealed electrostatic interactions between the eHal-polycation nanocomposites and mucin. The absorption study showed that the eHal-MeLChi nanocomposites could adsorb a greater amount of mucin (≈82 %) than the eHal-LChi nanocomposites (≈72 %) and eHal (≈58 %) after 8 h of incubation. Furthermore, the compacts of the tested samples were prepared by direct compression, and the detachment force against the mucin compact was measured using a texture analyzer. A significantly higher detachment force of the eHal-MeLChi nanocomposite compact (1.59 ± 0.07 N) from the mucin compact was determined compared to the eHal-LChi (1.35 ± 0.08 N) and eHal (0.98 ± 0.08 N) samples, demonstrating their improved mucoadhesive potential. In summary, this study demonstrates that functionalization of eHal with MeLChi may be a useful approach for the preparation of nanocomposites as potential carriers for mucoadhesive dosage forms.

Machine Learning Augmentation of the Failure Assessment Diagram Methodology for Enhanced Tubular Structures Integrity Evaluation

Failure assessment diagrams (FADs) are essential engineering tools for evaluating the structural integrity of components. However, their widespread application can be limited by complexity and computational expense. This study presents a novel machine learning-based approach to streamline FAD analysis, offering accuracy and efficiency while overcoming these limitations. The approach integrates numerical contour integral-based FADs with artificial neural networks (ANNs). To ensure reliable material modeling for the Finite Element Analysis (FEA) used to generate J-integral based FADs that train the ANNs, careful experimental and numerical procedures were employed. This involved uniaxial tensile tests, an iterative method for obtaining precise true stress–strain curves, and a Ramberg–Osgood material model for accurate material behavior representation. The ANNs themselves not only analyze large datasets to generate precise FAD envelopes but also predict limit loads and the Φ parameter, incorporating the effect of residual stress on the FAD methodology. To verify and test the proposed method, hypothetical fitness-for-service assessment cases were conducted, incorporating experimental residual stress measurements from split-ring tests on P110 and L80 pipes. These assessments were compared to both traditional FAD methods and computationally intensive FEA-based FADs. Results demonstrate a closer agreement with FEA-based calculations than traditional methods provided in engineering standards. Ultimately, this work provides a rather innovative and adaptable approach for structural integrity evaluations and critical engineering assessments through the proposal of an ANN enhanced FAD approach, simplifying these calculations while maintaining high fidelity.

Radiographic and ultrasonographic appearance of pyometra with unilateral uterine torsion in a domestic shorthair cat.

An 8-year-old female domestic shorthair, presenting for a 3-day history of lethargy and hyporexia, was obtunded, dehydrated, tachypneic, and had abdominal distension on physical exam with no vaginal discharge or pyrexia. Abdominal radiographs revealed a large, ovoid soft tissue mass and a tortuous, tubular soft tissue structure in the abdomen. Abdominal ultrasound revealed a severely fluid-distended uterus with a left uterine torsion, which was demonstrated by a "whirl sign." Emergency ovariohysterectomy surgically confirmed a 360° torsion of the left uterine horn with a fluid-distended right uterine horn. Histopathology confirmed a diagnosis of pyometra, and the cat recovered uneventfully.

Advanced Kidney Models In Vitro Using the Established Cell Line Renal Proximal Tubular Epithelial/Telomerase Reverse Transcriptase1 for Nephrotoxicity Assays.

Nephrotoxicity stands as one of the most limiting effects in the development and validation of new drugs. The kidney, among the organs evaluated in toxicity assessments, has a higher susceptibility, with nephrotoxic potential frequently evading detection until late in clinical trials. Traditional cell culture, which has been widely used for decades, does not recapitulate the structure and complexity of the native tissue, which can affect cell function, and the response to cytotoxins does not resemble what occurs in the kidney. In the current study, we aimed to address these challenges by creating in vitro kidney models that faithfully biomimic the dynamics of the renal proximal tubule, using the well-established RPTEC/TERT1 cell line. For doing so, two models were developed, one recreating tubule-like structures (2.5D model) and the other using microfluidic technology (kidney-on-a-chip). The 2.5D model allowed tubular structures to be generated in the absence of hydrogels, and the kidney-on-a-chip model allowed shear stress to be applied to the cell culture, which is a physiological stimulus in the renal tissue. After characterization of both models, different nephrotoxic compounds such as cisplatin, tacrolimus, and daunorubicin were used to study cell responses after treatment. The developed models in our study could be a valuable tool for pre-clinical nephrotoxic testing of drugs and new compounds.

The Design and Fabrication of Engineered Tubular Tissue Constructs Enabled by Electrohydrodynamic Fabrication Techniques: A Review

AbstractElectrohydrodynamic processes have emerged as promising methods for fabricating polymetric fiber‐based artificial tubular tissues. Existing review articles focus on the biological applications and processing materials associated with electrohydrodynamic processes in artificial tubular constructs, while overlooking the design and fabrication of these constructs. To address this gap, this review article emphasizes the design and fabrication of tubular tissue constructs enabled by employing electrohydrodynamic processes. This article begins by presenting an overview of two electrohydrodynamic processes: solution electrospinning (SE) and melt electrowriting (MEW). It then delves into the control of the fiber diameter enabled by SE and MEW, offering insights into the manipulation of processing parameters to achieve desired fiber diameters. Additionally, the review highlights cutting‐edge strategies for electrohydrodynamic processes to create tubular structures with customized microarchitectures. This includes fiber alignment control for SE and pore morphology design for MEW. Moreover, the review covers the creation of customized macroscale tubular geometries through collector geometry design. Lastly, a comprehensive survey is presented for designing multiphasic tubular structures specifically for electrohydrodynamic techniques or in tandem with other techniques. The objective of this review is to offer a thorough understanding of the design considerations and potential applications of tubular structures fabricated by electrohydrodynamic processes.

Evaluation of the effectiveness of surgical treatment using sonographic diagnostics with pyometra in dogs

The relevance of this study lies in the necessity to evaluate the effectiveness of surgical treatment for pyometra in dogs, employing sonographic diagnosis. Pyometra, a common uterine infection in female dogs, can lead to life-threatening complications such as sepsis and kidney damage if left untreated. Ultrasound imaging, a non-invasive and effective diagnostic tool, plays a crucial role in the early detection of pyometra and can identify potential post-operative complications following ovariohysterectomy. This study aimed to identify the ultrasound characteristics of the abdominal cavity in dogs affected by pyometra and to compare the postoperative ultrasound features of the abdominal cavity following ovariohysterectomy over time in a group of animals with and without complications. The primary research method involved a sequential and targeted ultrasound examination of the abdominal cavity in dogs diagnosed with pyometra. Subsequent ultrasound examinations were performed during ovariohysterectomy and at 1, 5, and 10 days postoperatively. It was established that the pathologically altered uterus on ultrasound often exhibited characteristics of an enlarged, distended tubular structure with anechoic or hypoechoic content. Ultrasound examination of affected dogs also demonstrated diagnostic effectiveness in cases of visualising intrauterine fluid, even when the uterine size was within normal limits. The use of ultrasound diagnostics allowed for the timely detection of pyometra at early stages, significantly improving the effectiveness of subsequent treatment. Ovariohysterectomy proved to be the most effective treatment method for dogs with pyometra, promoting the normalisation of vital functions as early as 2-3 days post-surgery, which reduced the risk of recurrence. Dynamic ultrasound examination of the abdominal cavity after surgery ensured timely adjustment of treatment measures and improved prognosis for patients. The established facts have practical significance for veterinarians, which will contribute to improving the quality of pyometra diagnosis in dogs, the effectiveness of their treatment, and reducing mortality

Cryo-electron tomography elucidates annular intraluminal configurations in Caenorhabditis elegans microtubules.

Microtubules serve as integral components in cellular operations such as cell division, intracellular trafficking, and cellular architecture. Composed of tubulin protein subunits, these hollow tubular structures have been increasingly elucidated through advanced cryo-electron microscopy (Cryo-EM), which has unveiled the presence of microtubule inner proteins (MIPs) within the microtubular lumen. In the present investigation, we employ a synergistic approach incorporating high-pressure freezing, cryo-focused ion beam milling, and Cryo-electron tomography (Cryo-ET) to interrogate the in situ architecture of microtubules in Caenorhabditis elegans larvae. Our Cryo-ET assessments across neuronal cilia and diverse tissue types consistently demonstrate the formation of annular configurations within the microtubular lumen. In concert with recently characterized MIPs, our in situ observations within a living organism corroborate the hypothesis that intricate luminal assemblages exist within microtubule scaffolds. These findings necessitate further exploration into the molecular constituents and functional ramifications of these internal microtubular configurations in both cellular physiology and pathophysiology.

The Horizons of Medical Mineralogy: Structure-Bioactivity Relationship and Biomedical Applications of Halloysite Nanoclay.

Medical mineralogy explores the interactions between natural minerals and living organisms such as cells, tissues, and organs and develops therapeutic and diagnostic applications in drug delivery, medical devices, and healthcare materials. Many minerals (especially clays) have been recognized for pharmacological activities and therapeutic potential. Halloysite clay (Chinese medicine name: Chishizhi), manifested as one-dimensional aluminum silicate nanotubes (halloysite nanotubes, HNTs), has gained applications in hemostasis, wound repair, gastrointestinal diseases, tissue engineering, detection and sensing, cosmetics, and daily chemicals formulations. Various biomedical applications of HNTs are derived from hollow tubular structures, high mechanical strength, good biocompatibility, bioactivity, and unique surface characteristics. This natural nanomaterial is safe, abundantly available, and may be processed with environmentally safe green chemistry methods. This review describes the structure and physicochemical properties of HNTs relative to bioactivity. We discuss surface area, porosity and surface defects, hydrophilicity, heterogeneity and charge of external and internal surfaces, as well as biosafety. The paper provides comprehensive guidance for the development of this tubule nanoclay and its advanced biomedical applications for clinical diagnosis and therapy.

Energy absorption of foam-filled TPMS-based tubular lattice structures subjected to quasi-static lateral crushing

Aluminium foam and TPMS-based tubular lattice structures (T-TLS) were of interest due to their superior energy absorption capabilities and inherent lightweight characteristics. However, their synergistic functionality in a composite form remained unexplored. In pursuit of augmenting the crashworthiness characteristics, aluminum foam was filled into T-TLS to form foam-filled T-TLS. FE models were established and validated using lateral crushing experiments. Foam-filled T-TLS exhibited higher energy absorption (EA) compared to the sum of empty T-TLS and foam filler, primarily attributed to the interaction between T-TLS and foam filler. Compared to single circular filled tubes (SCFT) with the same outer sizes and mass, foam-filled T-TLS revealed markedly enhanced crashworthiness, with EA and SEA values being 3.5–3.9 times and 4.0–4.7 times that of SCFT, respectively. Subsequently, parametric investigations underscored the evident influences of relative densities of T-TLS and foam filler, tube thickness and diameter on crashworthiness of foam-filled T-TLS. Finally, a multi-objective optimization was performed to derive optimized configurations by using non-dominated sorting genetic algorithm II (NSGA-II) and radial basis function (RBF) metamodels. In comparison with the baseline designs, the optimal results demonstrated significant enhancements in crashworthiness, with SEA increasing by 173.3 to 206.6 %. The present work provided a new paradigm in the design and development of advanced energy absorbers characterized by high-efficiency energy dissipation under lateral impact scenarios.

Learning experimental data to predict fluid-elastic instability and optimize configuration of tube arrays

Fluid-elastic instability (FEI) poses a particularly significant challenge to the safety of steam generators, given its potential to cause substantial damage in short periods. The tube bundle system model is inherently complex, resulting in expensive costs for experiments and numerical simulations during the design process. In this study, a substantial volume of FEI experimental data, conducted by various scholars, was compiled to create FEI surrogate model. The accuracy and feasibility of this surrogate model were demonstrated and compared to experimental results. This work represents the pioneering reference on the optimization of tube array configurations, achieved by combining FEI deep neural network (DNN) surrogate model with genetic algorithm (GA). The design variables for optimization encompassed tube array configurations and structural parameters. The optimization objective is to achieve a tubular array structure exhibiting a higher critical velocity, Ur, enabling safe operation of the heat exchanger tube bundle across a wider range of flow rates without any FEI accident. The developed approach holds promise for data-driven FEI analysis and optimized tube bundle design, resulting in substantial time and cost savings. We publicly share all code implementations, and we believe that our efforts open a door for the surrogate-model-assisted structural optimization of tube arrays.

Tribo-induced evolution of nodular supporting structures providing high-performance solid lubricants in carbon nanotube coated films

Carbon nanotubes (CNTs) exhibit a high degree of sp2-bonded carbon and form long tubular structures that are one-dimensional and multi-walled. Pristine CNT films show poor lubrication performance when sliding against different counterparts due to their loose and porous carbon structures. However, heat treatments, particularly the 600 °C annealing process in a vacuum, have greatly improved their wear resistance. The 600 °C annealed film has a slightly high coefficient of friction (COF) than the unannealed (pristine) film but possesses significantly enhanced durability. During the 600 °C annealing treatment, numerous nodular structures appear on the surface of the steel substrate and beneath the CNT film. When the CNT film is worn out, these nodules support the periodic reciprocating counterpart and enable a lower COF to be remained for an extended lifespan. This is due to a new tribolayer that forms on both sides of the tribocouples where the tubular CNT transforms into amorphous carbon with continuous friction testing. Ultimately, the annealed CNT films and the as-formed nodules provide exceptional synergetic protection for the durable friction process.

Vinyl-bearing sp2 carbon-conjugated covalent organic framework composites for enhanced electrochemical performance in hydrogen evolution reaction and lithium–sulfur batteries

Vinyl-bearing triazine-functionalized covalent organic frameworks (COFs) have emerged as promising materials for electrocatalysis and energy storage. Guided by density functional theory calculations, a vinyl-enriched COF (VCOF-1) featuring a donor–acceptor structure was synthesized based on the Knoevenagel reaction. Moreover, the VCOF-1@Ru without pyrolysis was obtained through chemical coordination interactions between VCOF-1 and RuCl3, exhibiting enhanced electrocatalytic performance in the hydrogen evolution reaction when exposed to 0.5 M H2SO4. The results demonstrated that the protonation of VCOF-1@Ru enhanced the electrical conductivity and accelerated the generation of H2 on the catalytically active site Ru. Additionally, VCOF-1@CNT with a tubular structure was prepared by uniformly wrapping VCOF-1 onto carbon nanotubes (CNTs) and using it as a cathode for lithium–sulfur batteries by chemically and physically encapsulating S. The enhanced performance of VCOF-1@CNT was attributed to the effective suppression of lithium polysulfide migration. This suppression was achieved through several mechanisms, including the inverse vulcanization of vinyl on VCOF-1@CNT, the enhancement of material conductivity, and the interaction between N in the materials and Li ions. This study demonstrated a strategy for enhancing material performance by precisely modulating the COF structure at the molecular level.

Photoinduced Ordered Growth of Copper-Doped Polyaniline Nanotubes: A Method to Improve the Catalytic Activity for C-N Coupling Reactions.

Polyaniline-supported metal nanoparticles (M@PANIs) have been widely employed as catalysts for organic reactions. Traditionally, the catalytic activities of the materials can be improved by introducing functional groups onto the aniline monomers, but it may enhance the catalyst cost and reduce the production yield of the material. This work reports a new strategy for improving the catalytic activity of M@PANIs. It was found that induced by visible light in the presence of a polymeric carbon nitride catalyst and copper dopant, the oxidative polymerization of simple aniline occurred slowly and orderly to produce the copper-doped polyaniline nanotubes. The unique tubular structure protected the catalytically active Cu(I) inside and endowed even more sufficient contact of the catalytic sites with reactants so that the material exhibited excellent catalytic performances in C-N coupling reactions.

Design, infectability, and transcriptomic analysis of transregionally differentiated and scalable lung organoids derived from adult bronchial cells.

The lung is a primary target for many lethal respiratory viruses, leading to significant global mortality. Current organoid models fail to completely mimic the cellular diversity and intricate tubular and branching structures of the human lung. Lung organoids derived from adult primary cells have so far only included cells from the input cell region, proximal or distal. Existing models are expensive. They often require cells from invasive deep lung tissue biopsies. The present study aimed to address these limitations. The lung organoids obtained using an original protocol exhibited transregional differentiation and were derived from relatively more accessible primary cells from the trachea/bronchi. Immortal bronchial cell lines were also used to simplify organoid fabrication and improve its scalability. The lung organoids are formed starting from bronchial cells with fibroblasts feeder cells in an alginate hydrogel coated with base membrane zone proteins. Characterizations were performed using bulk RNA sequencing and tandem mass tags. The resulting organoids express markers of different lung regions and mimic to some extent the tubular and branching morphology of the lung. The proteomic profile of organoid from primary cells and from cell lines was found to evolve towards that of mature lung tissue. Upregulated genes were mostly related to the respiratory system, tube development, and various aspects of respiratory viral infections. Infection with SARS-CoV-2 and influenza H1N1 was successful and did not require organoid disassembly. The organoids matured within 21 days and did not require complex or expensive culture methods. Transregionally differentiated lung organoid may find applications for the study of emerging or re-emerging viral infections and fostering the development of novel in-vitro therapeutic strategies.

Carbonnanotubes: New Chemotherapeutic Drug Delivery Systems for Targeted Cancer Treatments

The complexity of the management of cancerous conditions requires innovative strategies, including the pharmacotechnical optimization of treatments. The improvement of galenic forms, or more generally of drug delivery, represents a rapidly developing area of research, particularly in oncology, in order to remedy side effects and drug resistance remains a worrying problem. Carbon nanotubes CNTs consist of thin sheets of benzene carbons coiled into a seamless tubular structure. These CNTs have remarkable size and surface properties that make them the ideal vehicle for targeted and selective drug delivery. Different in vitro and in vivo experiments have proven that these particles can be easily modified in such a way that the chemical drug can be delivered directly to the tumor site. Additionally, different types of ligands can be loaded on the surface of CNTs to improve selectivity or modulate drug release. On the other hand, advances in carbon nanotubes could well lead to a more effective understanding of biological and physicochemical processes. This will make it possible to find compounds more compatible with carbon nanotube technology and facilitate their use.

Performance and failure modes of continuous fibre-reinforced energy absorption tubes by cylindrical layered 3D printing

ABSTRACT Precisely controlling the distribution of continuous fibres on a cylindrical surface is crucial for manufacturing high-performance continuous fibre-reinforced composite (CFRC) tubular structures. Existing manufacturing processes are complex, hindering the regulation of fibre orientation and content. Therefore, this study achieved unrestricted control of 3D-printed continuous fibres in terms of content and arbitrary orientation on a cylindrical surface using a cylindrical layered path planning strategy. The study investigated the impact of different fibre orientations and printing parameters on the compressive performance and energy absorption of 3D-printed CFRC tubes under quasi-static axial compression by analysing fibre distribution and failure modes. Compared to the flat layered printing strategy, the cylindrical layered printing strategy showed significant increases in compressive strength and energy absorption, by 44.3% and 85.2%, respectively. A cusp height analysis model demonstrated that the cylindrical layered printing strategy significantly enhances forming accuracy compared to the conventional flat layered method. The CFRC lightweight energy absorption tubes fabricated with this strategy demonstrated the viability of the manufacturing process. This new manufacturing technology has significant potential for producing high-performance and high-precision CFRC energy absorption tubes, applicable in aeronautics and astronautics.

Interaction between microbiome and testicular tissue mastocytes in male infertility

Introduction. Male infertility is a complex condition with many potential causes, including hormonal imbalances, anatomical problems, genetic factors, lifestyle factors and more. But today, there is a fairly large group of infertile men with unknown causes of the disease.Objective. To analyze the taxonomic microbial diversity of testicular tissue and the urogenital tract of infertile men and to identify correlations between the microbiome and mastocytes in the testicular parenchyma.Materials & methods. The study was performed on testicular tissue samples from infertile patients with azoospermia (n = 33). All patients were divided into two groups based on the form of azoospermia: group 1 — infertile patients with non-obstructive azoospermia (NOA) (n=21); and group 2 — infertile with obstructive azoospermia (OA) patients (n=12). The bacterial diversity of testicular tissue was studied by the method of high-performance new generation sequencing (NGS). Immunohistochemical staining with anti-MCT (Anti-Mast Cell Tryptase) was used to determine the IHC expression of mastocyte markers.Results. The microbiome of patients with NOA differs markedly from the microbiome of patients with OA (p < 0.05). In group 1, representatives of the Enterobacteriaceae and Xanthomonadaceae families, the genera Finegoldia, Bifidobacterium, Porphiromonas, Prevotella, Peptoniphilus and Pseudomonas are significantly more often found. A distinctive feature of group 2 is the rare occurrence of the genus Prevotella. Histochemical analysis revealed mastocytosis in the in-between-canalicular stroma approximately in 83% of azoospermia cases. Mastocytes are found in tubule structures in 68% of cases and correlate with the microbiome of testicular tissue.Conclusions. Injuries caused by mastocytes in the stroma and tubular structures are interrelated with the taxonomic diversity of testicular tissue. Moreover, the testicles of NOA-patients have a qualitatively and quantitatively more diverse spectrum both at the level of families and genera, unlike OA-patients.

The geometry and mechanics of the Chinese finger trap

We investigate the kinematics and mechanical mechanisms of cylindrically woven straps with a plain twill pattern, which form a tubular structure known as the Chinese Finger Trap. Our findings, derived from a combination of analytical, experimental, and numerical methods, demonstrate that when subjected to axial tension, the straps within the structure undergo reconfiguration, resulting in radial contraction. The geometry of the straps influences this contraction. As the structure compacts, the linear axial force transforms into an exponential force, resulting in a catenary-like profile in woven tubes due to the axially symmetric distribution of straps. Our study of this tension-induced contraction strategy proposes a straightforward approach to manufacturing morphable structures capable of efficiently converting axial elongation into radial contraction. This technique holds potential for medical, architecture, and soft robotics applications, offering accessible and controlled engagement and disengagement capabilities.

Mechanochemical structural nanoengineering of heterooxide photocatalysts TiO<sub>2</sub>/ V<sub>2</sub>O<sub>5</sub> capable to accumulating photoinduced charges

The mechanochemical method yielding a composite photocatalyst TiO2/V2O5 of tubular morphology under localized mechanic impact on a mixture of dispersed oxides has been proposed. It has been shown that under contact loading amounting to 25–39 MPa, tubular TiO2 is growing due to bonding of hydrated oxide particles via polycondensation. In the case of a mixture of titania and vanadium oxides, the tubular structure growth is accompanied with dispersing V2O5 particles resulting in the release of free standing lamellae. The mechanochemical activation produces nanоheterojunctions TiO2/V2O5 able to ensure an effective separation of photo-induced charges and their accumulation in redox active V2O5. Employing mechanochemical activation for synthesis of a TiO2/V2O5 composite photocatalyst results in 2.5-fold enhancement of the oxidation activity induced by preliminary photocatalyst exposure.