Elevated Growth Temperatures Research Articles

Lettuce Genotype-Dependent Effects of Temperature on Escherichia coli O157:H7 Persistence and Plant Head Growth

Lettuce has been commonly associated with the contamination of human pathogens, such as Escherichia coli O157:H7 (hereafter O157:H7), which has resulted in serious foodborne illnesses. Contamination events may happen throughout the farm-to-fork chain, when O157:H7 colonizes edible tissues and closely interacts with the plant. Environmental conditions have a significant impact on many plant–microbe interactions; however, it is currently unknown whether temperature affects O157:H7 colonization of the lettuce phyllosphere. In this study, we investigated the relationship between elevated growth temperatures, O157:H7 persistence, and lettuce head growth using 25 lettuce genotypes. Plants were grown under optimal or elevated temperatures for 3.5 weeks before being inoculated with O157:H7. The bacterial population size in the phyllosphere and lettuce head area was estimated at 0- and 10-days postinoculation (DPI) to assess bacterial persistence and head growth during contamination. We found that growing temperature can have a positive, negative, or no effect on O157:H7 persistence depending on the lettuce genotype. Furthermore, temperature had a greater effect on head area size than the presence of O157:H7. The results suggested that the combination of plant genotype and temperature level is an important factor for O157:H7 colonization of lettuce and the possibility to combine desirable food safety traits with heat tolerance into the lettuce germplasm.

Involvement of Escherichia coli YbeX/CorC in ribosomal metabolism.

YbeX of Escherichia coli, a member of the CorC protein family, is encoded in the same operon with ribosome-associated proteins YbeY and YbeZ. Here, we report the involvement of YbeX in ribosomal metabolism. The ΔybeX cells accumulate distinct 16S rRNA degradation intermediates in the 30S particles and the 70S ribosomes. E. coli lacking ybeX has a lengthened lag phase upon outgrowth from the stationary phase. This growth phenotype is heterogeneous at the individual cell level and especially prominent under low extracellular magnesium levels. The ΔybeX strain is sensitive to elevated growth temperatures and to several ribosome-targeting antibiotics that have in common the ability to induce the cold shock response in E. coli. Although generally milder, the phenotypes of the ΔybeX mutant overlap with those caused by ybeY deletion. A genetic screen revealed partial compensation of the ΔybeX growth phenotype by the overexpression of YbeY. These findings indicate an interconnectedness among the ybeZYX operon genes, highlighting their roles in ribosomal assembly and/or degradation.

Antioxidant Responses and Phytochemical Accumulation in Raphanus Species Sprouts through Elicitors and Predictive Models under High Temperature Stress.

Crop production is being impacted by higher temperatures, which can decrease food yield and pose a threat to human nutrition. In the current study, edible and wild radish sprouts were exposed to elevated growth temperatures along with the exogenous application of various elicitors to activate defense mechanisms. Developmental traits, oxidative damage, glucosinolate and anthocyanin content, and antioxidant capacity were evaluated alongside the development of a predictive model. A combination of four elicitors (citric acid, methyl jasmonate-MeJa, chitosan, and K2SO4) and high temperatures were applied. The accumulation of bioactives was significantly enhanced through the application of two elicitors, K2SO4 and methyl jasmonate (MeJa). The combination of high temperature with MeJa prominently activated oxidative mechanisms. Consequently, an artificial neural network was developed to predict the behavior of MeJa and temperature, providing a valuable projection of plant growth responses. This study demonstrates that the use of elicitors and predictive analytics serves as an effective tool to investigate responses and enhance the nutritional value of Raphanus species sprouts under future conditions of increased temperature.

Genomic Insights into Moderately Thermophilic Methanotrophs of the Genus Methylocaldum.

Considering the increasing interest in understanding the biotic component of methane removal from our atmosphere, it becomes essential to study the physiological characteristics and genomic potential of methanotroph isolates, especially their traits allowing them to adapt to elevated growth temperatures. The genetic signatures of Methylocaldum species have been detected in many terrestrial and aquatic ecosystems. A small set of representatives of this genus has been isolated and maintained in culture. The genus is commonly described as moderately thermophilic, with the growth optimum reaching 50 °C for some strains. Here, we present a comparative analysis of genomes of three Methylocaldum strains-two terrestrial M. szegediense strains (O-12 and Norfolk) and one marine strain, Methylocaldum marinum (S8). The examination of the core genome inventory of this genus uncovers significant redundancy in primary metabolic pathways, including the machinery for methane oxidation (numerous copies of pmo genes) and methanol oxidation (duplications of mxaF, xoxF1-5 genes), three pathways for one-carbon (C1) assimilation, and two methods of carbon storage (glycogen and polyhydroxyalkanoates). We also investigate the genetics of melanin production pathways as a key feature of the genus.

Startified thermal degradation in blue InGaN quantum well structures: P-GaN growth temperature and its influence on quantum well optical properties

Thermal degradation in blue InGaN multi-quantum well (MQW) structures induced by varying high p-GaN growth temperature and the subsequent influence on the optical properties of MQW are investigated. The results indicate that higher p-GaN growth temperatures improve p-GaN layer contact quality, but may lead to an optical property degradation of InGaN MQWs. A stratified thermal degradation mechanism is observed. The degradation primarily affects the upper quantum barrier layers and results in indium desorption and re-evaporation, where elevated p-GaN growth temperatures may induce more indium segregation and decomposition than in lower layers of MQW. In extreme conditions, such as 1060℃, indium atoms in lower layers escape, causing partial lattice structure corruption and severe degradation in MQW structure, which is also more distinctive in the upper layers.

Role of interdiffusion on the magnetism of ultrathin LaMnO3 films

We present a detailed study of the magnetic, spectroscopic and structural properties of ultrathin LaMnO3 films deposited on SrTiO3(001) substrates by oxide molecular beam epitaxy. We find that the as-grown LaMnO3 films are slightly reduced and present a significant magnetic moment, while annealing to 600 °C fully oxidizes and enhances its magnetic properties. From synchrotron x-ray photoemission spectromicroscopy, we find the presence of Sr, Ca and Si in the LaMnO3 film that diffuse from the SrTiO3 substrate; these impurities act as hole dopants, and can explain the presence of ferromagnetism in LaMnO3. This work highlights the importance of cation mobility at the elevated growth temperature in modifying the magnetic properties of ultrathin LaMnO3 films.

Archaea membranes in response to extreme acidic environments

Bipolar tetraether lipids (BTL), such as glycerol dialkyl calditol tetraether (GDNT) and glycerol dialkyl glycerol tetraether (GDGT), are the dominating lipid species in thermoacidophiles that inhabit at pH ≤ 4 and temperatures ≥65°C. BTL containing archaea membranes respond to environmental pH changes by varying the number of cyclopentane rings in the isoprenoids, the amount of GDNT relative to GDGT, the ratio of tetraethers to diethers, and the level of glycosylation in polar headgroups. These structural and compositional adjustments can alter the hydrogen bond networks in the membrane polar headgroup regions and the packing tightness and rigidity in the membrane hydrophobic core. It is likely that these changes in non-covalent interactions among archaea lipids are made to retain low membrane volume fluctuations and their low sensitivity to temperature, as illustrated in the case of liposomes made of the polar lipid fraction E (PLFE) of Sulfolobus acidocaldarius. As such, a low passive proton permeability and a near neutral intracellular pH can be maintained, and, as a result, optimal activities of soluble and membrane-bound proteins in thermoacidophiles can be retained in acidic growth conditions at elevated growth temperatures.

Transcriptional regulation of oil synthesis and fatty acid desaturation in olive fruit under elevated growth temperature

AbstractAmbient temperature during olive fruit growth modulates oil content and fatty acid composition. However, the mechanisms behind their regulation are not completely understood. In this work, the transcriptional regulation of oil synthesis and fatty acid desaturation were evaluated by manipulating air temperature in the field. Three‐year‐old trees of cultivars ‘Arbequina’ and ‘Coratina’ were placed in open‐top chambers (OTC) where control or elevated air temperatures were applied early in the oil accumulation phase, and fruits were sampled after 10 or 36 days of exposure. Upon elevated temperature, the oil content in ‘Coratina’ mesocarp tissue decreased less than in ‘Arbequina’ compared to their respective controls. However, the oleic acid content of ‘Coratina’ was more sensitive to temperature. The cultivar‐dependent responses were mainly explained by differential gene expression. In ‘Arbequina’, the downregulation of genes involved in triacylglycerol biosynthesis (OeDGAT1‐2, OeDGAT2, OePDAT1‐1, and OePDAT1‐2), upon elevated temperature explains the decrease in oil content, whereas the downregulation of the fatty acid desaturases genes (OeSAD1, OeSAD3, OeFAD2‐1, OeFAD2‐2, and OeFAD2‐5) decreased the oleic/linoleic ratio. In contrast, in ‘Coratina’, OePDAT1‐2 downregulation explains the fluctuation in oil content, but the increased expression of three members of the OeFAD2 gene family was responsible for the oleic/linoleic ratio. This knowledge contributes to developing an integrated strategy for olive production under high temperatures, and the analysis of the expression of key genes could be used as a selection criterion in genetic improvement programs for the adaptation of olive cultivars to global warming.

Investigation of emission plane control in GaInN/GaN multiple-quantum shells for efficient nanowire-based LEDs.

Significant attention has been directed toward core-shell GaInN/GaN multiple-quantum shell (MQS) nanowires (NWs) in the context of high-efficiency micro light-emitting diodes (micro-LEDs). These independent three-dimensional NWs offer the advantage of reducing the impact of sidewall etching regions. Furthermore, the emitting plane on the sidewalls demonstrates either nonpolar or semipolar orientation, while the dislocation density is exceptionally low. In this study, we assessed how changes in the NW morphology are affected by GaInN/GaN superlattice (SL) structures grown at varying growth temperatures, as well as control of the emission plane via the p-GaN shell and emission sizes. The SL growth rate was enhanced at elevated growth temperatures, accompanied by the shrinkage of the (0001)-plane and expansion of the (11̄01)-plane on the NWs. The samples exhibited a higher light output when the SLs were grown at elevated temperatures compared to those grown with lower temperatures. A similar trend was observed for the samples with a gradual temperature transition during the growth. These findings indicate that the dimensions of the (0001)-plane can be controlled through SL growth, which in turn influences the emission properties of NW-LEDs. In addition, the emission properties of NW-LEDs with different growth time p-GaN shells and different emission sizes were investigated. Based on the NW-LED characteristics, it was revealed that the weak emission of the (0001)-plane was the dominant factor for the limited light output, and the most effective way to realize high efficiency devices is to suppress current injection into the apex or minimize the grown (0001)-plane region. Overall, it is one promising way to control the emission planes of NWs, which holds significant relevance for the potential application of NW-LEDs in the realm of micro-LEDs.

Controllable phase transition of two-dimensional ferromagnetic chromium telluride thin films grown by molecular beam epitaxy

Two-dimensional (2D) Cr(1+δ)Te2 materials exhibit strong magnetic ordering and high Curie temperatures, making them attractive for various applications. It is crucial to achieve controllable synthesis for their successful integration into device technologies. In this study, we present the synthesis of phase-controllable 2D Cr(1+δ)Te2 films on the Si (111) substrate via molecular beam epitaxy. The composition and phase transition of the as-grown Cr(1+δ)Te2 films are characterized by using in-situ reflection high-energy electron diffraction, scanning tunneling microscopy, ex-situ X-ray photoelectron spectroscopy, X-ray diffraction, and theoretical calculations. At low growth temperatures, by carefully adjusting the film thickness from 2 to more than 3 layers, we achieve precise control over the phase of Cr(1+δ)Te2, from CrTe2 to Cr intercalated Cr2Te3. At a relatively elevated growth temperature, it is demonstrated that the Cr(1+δ)Te2 phase is independent of the film thickness, only Cr2Te3 forms and its growth mode is thickness-dependent. These phase transitions at low growth temperatures and growth mode changes at elevated growth temperatures are attributed to interfacial effects and the phase stability of Cr(1+δ)Te2 compounds. Additionally, we utilize scanning tunneling spectroscopy and computations to gain insights into the electronic properties of Cr2Te3. The magnetic measurements reveal that the 30-nm Cr2Te3 film exhibits ferromagnetic behavior with a Curie temperature of about 180 K. Our work offers a robust method for the controllable growth of high-quality 2D Cr(1+δ)Te2 films on Si substrates, providing an ideal platform for investigating their intrinsic properties and advancing the development of 2D magnet-based spintronics devices.

Effect of growth temperature of NH3-MBE grown GaN-on-Si layers on donor concentration and leakage currents

The effect of growth temperature on the buffer leakage currents of GaN-on-Si layers grown by the NH3-MBE technique within the technologically acceptable temperature range (750 °C-850 °C) has been investigated. It is shown that the lowest leakage currents are exhibited by GaN layers grown at elevated growth temperature (growth temperature 825 °C, buffer leakage current 1 mA/mm at electric field strength 41 kV/cm). The photoluminescence technique was used to study the defects in GaN layers grown at different growth temperatures and to estimate the number of neutral donors in GaN-on-Si layers. A correlation between leakage currents, structural perfection and donor concentration in GaN-on-Si layers was established. It was found that the reduced growth temperature can lead to the formation of inversion domains in GaN-on-Si layers grown by the NH3-MBE technique.

Hardness and Mechanical Properties of Wurtzite B–C–N Compounds

Diamond, cubic BN (c-BN), and cubic B–C–N compounds, i.e., c-BCXN, are well-known ultrahard materials. While cubic phases of these materials are relatively stable and have been widely studied, recent experimental and theoretical studies have reported evidence that indentation hardness can be significantly enhanced in wurtzite phases of BN (w-BN) and diamond, i.e., lonsdaleite. However, the mechanical properties and hardness of wurtzite B–C–N compounds have been less explored. In this study, we systemically investigated wurtzite B–C–N compounds (w-BCXN), such as wurtzite BCN (w-BCN), BC2N (w-BC2N), and BC4N (w-BC4N), and compared their properties with those of c- and w-BN, diamond, and lonsdaleite. Although w-BCXN shows relatively high formation energies compared with the others, configurational entropy can assist the compounds to be stabilized at elevated growth temperatures (over 2700 K). In addition, w-BCXN exhibits a relatively superior hardness, which increases with the C ratio. Our results provide a basic understanding of w-BCXN as a possible family of superhard materials.

Thermal optimum of photosynthesis is controlled by stomatal conductance and does not acclimate across an urban thermal gradient in six subtropical tree species.

Modelling the response of plants to climate change is limited by our incomplete understanding of the component processes of photosynthesis and their temperature responses within and among species. For ≥20 individuals, each of six common subtropical tree species occurring across steep urban thermal gradients in Miami, Florida,USA, we determined rates of net photosynthesis (Anet ), maximum RuBP carboxylation, maximum RuBP regenerationand stomatal conductance, and modelled the optimum temperature (Topt ) and process rate of each parameter to address two questions: (1) Do the Topt of Anet (ToptA ) and the maximum Anet (Aopt ) of subtropical trees reflect acclimation to elevated growth temperatures? And (2) What limits Anet in subtropical trees? Against expectations, we did not find significant acclimation of ToptA , Aopt or the Topt of any of the underlying photosynthetic parameters to growth temperature in any of the focal species. Model selection for the single best predictor of Anet both across leaf temperatures and at ToptA revealed that the Anet of most trees was best predicted by stomatal conductance. Our findings are in accord with those of previous studies, especially in the tropics, that have identified stomatal conductance to be the most important factor limiting Anet , rather than biochemical thermal responses.

Brassica napus Roots Use Different Strategies to Respond to Warm Temperatures.

Elevated growth temperatures are negatively affecting crop productivity by increasing yield losses. The modulation of root traits associated with improved response to rising temperatures is a promising approach to generate new varieties better suited to face the environmental constraints caused by climate change. In this study, we identified several Brassica napus root traits altered in response to warm ambient temperatures. Different combinations of changes in specific root traits result in an extended and deeper root system. This overall root growth expansion facilitates root response by maximizing root-soil surface interaction and increasing roots' ability to explore extended soil areas. We associated these traits with coordinated cellular events, including changes in cell division and elongation rates that drive root growth increases triggered by warm temperatures. Comparative transcriptomic analysis revealed the main genetic determinants of these root system architecture (RSA) changes and uncovered the necessity of a tight regulation of the heat-shock stress response to adjusting root growth to warm temperatures. Our work provides a phenotypic, cellular, and genetic framework of root response to warming temperatures that will help to harness root response mechanisms for crop yield improvement under the future climatic scenario.

Engineering the Performance and Stability of Molybdenum Disulfide for Heavy Metal Removal.

Molybdenum disulfide (MoS2) has recently emerged as one of the most promising water nano-based adsorbent materials for heavy metal removal with the potential to provide an alternative to conventional water decontamination technologies. In this study, we demonstrate the trade-off between mercuric removal capacity and overall MoS2 adsorbent stability, both driven by MoS2 synthesis parameters. A bottom-up hydrothermal synthesis setup at various growth temperatures was employed to grow flower-like MoS2 films onto planar alumina supports. A thorough material characterization suggests that an increase in growth temperature from 150 to 210 °C results in higher MoS2 crystallinity. Interestingly, elevated growth temperatures resulted in poor mercuric removal (525 mg g-1, K = 2.2 × 10-3 h-1), yet showed enhanced chemical stability (i.e., minimal molybdenum leaching during exposure to mercury). On the other hand, low growth temperatures produce amorphous supported MoS2, exhibiting superb mercuric removal capabilities (5158 mg g-1, K = 36.1 × 10-3 h-1) but displaying poor stability, resulting in substantial byproduct molybdate leaching. Mercuric removal by crystalline MoS2 was accomplished by adsorption and electrostatic attraction-based removal mechanisms, whereas redox reactions and HgS crystallization-based removal mechanisms were more dominant when using amorphous MoS2 for mercury removal. Overall, our study provides essential insights into the delicate balance between MoS2 mercuric removal capabilities and MoS2 degradation, both related to material synthesis growth conditions. Employment of nano-enabled water treatments in general, and MoS2 for heavy metal removal in particular, requires us to better understand these important fundamental trade-off behaviors to achieve sustainable, effective, and responsible implementation of nanotechnologies in large scale systems.

Optimized molecular beam epitaxy process for lattice-matched narrow-bandgap (0.8 eV) GaInNAsSb solar junctions

High performance narrow-bandgap GaInNAsSb solar cells are instrumental for the development of lattice-matched GaAs-based solar cells with more than four junctions. To this end a comprehensive optimization process including the effects of growth temperature, As/III beam equivalent pressure ratio, and Sb flux on the performance of 0.8 eV GaInNAsSb solar cells grown by molecular beam epitaxy is reported. For this, sets of GaInNAsSb p-i-n solar cell structures with 5–6% nitrogen compositions were fabricated, while varying the key growth parameters. The quantum efficiency and current generation increased significantly when the narrow gap materials were grown at elevated growth temperatures, close to phase separation. A further improvement in the current generation was observed by employing lower As/III beam equivalent pressure ratios. The best GaInNAsSb cell exhibited about 94% peak external quantum efficiency and generated a short-circuit current of 17.7 mA/cm 2 with AM1.5D (1000 W/m 2 ) illumination at wavelengths above 900 nm without employing a back surface reflector. Our analysis indicates that the best cell is already close to being absorption limited. While the N composition should be kept as low as possible (i.e., ≲5%) to achieve high performance, increasing the Sb flux generally results in improved the material quality, i.e., leading to a slight improvement for the open-circuit voltages and fill factors. In addition, it was found that the phase separation observed at the growth temperature of 480 °C could effectively be inhibited by employing higher Sb fluxes. • Optimized MBE growth for 0.8 eV GaInNAsSb solar junctions with 5–6% N content. • High current obtained using high growth temperatures and lower As pressures. • High peak external quantum efficiency of 94% demonstrated. • Background doping level as low as 1.1 × 10 15 cm −3 for GaInNAsSb with 6% N. • Phase separation is suppressed, and power output improved by optimizing Sb flux.

Increasing the resilience of plant immunity to a warming climate

Extreme weather conditions associated with climate change affect many aspects of plant and animal life, including the response to infectious diseases. Production of salicylic acid (SA), a central plant defence hormone1–3, is particularly vulnerable to suppression by short periods of hot weather above the normal plant growth temperature range via an unknown mechanism4–7. Here we show that suppression of SA production in Arabidopsis thaliana at 28 °C is independent of PHYTOCHROME B8,9 (phyB) and EARLY FLOWERING 310 (ELF3), which regulate thermo-responsive plant growth and development. Instead, we found that formation of GUANYLATE BINDING PROTEIN-LIKE 3 (GBPL3) defence-activated biomolecular condensates11 (GDACs) was reduced at the higher growth temperature. The altered GDAC formation in vivo is linked to impaired recruitment of GBPL3 and SA-associated Mediator subunits to the promoters of CBP60g and SARD1, which encode master immune transcription factors. Unlike many other SA signalling components, including the SA receptor and biosynthetic genes, optimized CBP60g expression was sufficient to broadly restore SA production, basal immunity and effector-triggered immunity at the elevated growth temperature without significant growth trade-offs. CBP60g family transcription factors are widely conserved in plants12. These results have implications for safeguarding the plant immune system as well as understanding the concept of the plant–pathogen–environment disease triangle and the emergence of new disease epidemics in a warming climate.

A Simple Approach to Achieving Ultrasmall III-Nitride Microlight-Emitting Diodes with Red Emission.

The microdisplays for augmented reality and virtual reality require ultrasmall micro light-emitting-diodes (μLEDs) with a dimension of ≤5 μm. Furthermore, the microdisplays also need three kinds of such μLEDs each emitting red, green, and blue emission. Currently, in addition to a great challenge for achieving ultrasmall μLEDs mainly based on III-nitride semiconductors, another fundamental barrier is due to an extreme difficulty in growing III-nitride-based red LEDs. So far, there has not been any effective approach to obtain high indium content InGaN as an active region required for a red LED while maintaining high optical performance. In this paper, we have demonstrated a selective epitaxy growth approach using a template featuring microhole arrays. This allows us to not only obtain the natural formation of ultrasmall μLEDs but also achieve InGaN with enhanced indium content at an elevated growth temperature, at which it is impossible to obtain InGaN-based red LEDs on a standard planar surface. By means of this approach, we have demonstrated red μLEDs (at an emission wavelength of 642 nm) with a dimension of 2 μm, exhibiting a high luminance of 3.5 × 107 cd/m2 and a peak external quantum efficiency of 1.75% measured in a wafer form (i.e., without any packaging to enhance an extraction efficiency). In contrast, an LED grown under identical growth conditions but on a standard planar surface shows green emission at 538 nm. This highlights that our approach provides a simple solution that can address the two major challenges mentioned above.

2DEGs formed in AlN/GaN HEMT structures with AlN grown at low temperature

Integration of nitrides with other material systems has recently become of interest due to the high performance of GaN-based high-electron mobility transistors. However, the elevated growth temperatures often used to grow high quality AlN pose challenges toward metalorganic chemical vapor deposition (MOCVD) on temperature sensitive substrates such as processed wafers. In this work, the growth of AlN was conducted at temperatures below 550 °C via MOCVD using a flow-modulated epitaxy scheme, and their morphological, compositional, and electronic properties of these films were investigated. Sheet charges up to 2.1 × 1013 cm−2 and mobilities on the order of 400 cm2/V s were measured for two dimensional electron gases, which formed at the interface between the low temperature grown AlN layers and the semi-insulating GaN base layers deposited at high temperatures. Despite their low growth temperatures, nominally pure AlN barrier layers exhibited measurable unintentional gallium incorporation adjacent to the GaN interface. The result sets the stage for the integration of nitride-based electronics via epitaxy-based schemes on temperature sensitive substrates.

Rutile-phase TiO2@carbon core-shell nanowires and their photoactivation in visible light region

Titanium dioxide (TiO2) has been acknowledged as one of the efficient photocatalysts in the UV region. To extend the photo-absorption region toward visible lights, the TiO2 nanowires enclosed with carbon shells (TiO2@carbon core-shell nanowires) were synthesized by a chemical vapor deposition technique at various temperatures from 650 to 950 °C. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses revealed that TiO2 cores and carbon shells are rutile and graphitic structures, respectively. From Raman spectra, the peak intensity of the Eg mode was observed to be redshifted with elevated growth temperatures due to the increase in oxygen vacancies in the TiO2@carbon core-shell nanowires. From X-ray photoelectron spectroscopy (XPS) results, the oxygen vacancies were strongly related to the Ti3+ ions. The UV–visible spectroscopic studies show a possible decrease in photocatalytic energy from 3.1 to 2.7 eV for the TiO2@carbon core-shell nanowires, indicating that the light absorption was enhanced in the visible-light region. The optical absorbance results confirmed the presence of the mid-gap states due to the oxygen vacancies, which are responsible for the visible-light absorption. The photocatalytic activity of the TiO2@carbon core-shell nanowires studied by methylene blue (MB) dye degradation is effective under visible lights.