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Microbial Ecology on Solar Panels in Berkeley, CA, United States
摘要： Solar panels can be found practically all over the world and represent a standard surface that can be colonized by microbial communities that are resistant to harsh environmental conditions, including high irradiation, temperature fluctuations and desiccation. These properties make them not only ideal sources of stress-resistant bacteria, but also standard devices to study the microbial communities and their colonization process from different areas of Earth. We report here a comprehensive description of the microbial communities associated with solar panels in Berkeley, CA, United States. Cultivable bacteria were isolated to characterize their adhesive capabilities, and UV- and desiccation-resistance properties. Furthermore, a parallel culture-independent metagenomic and metabolomic approach has allowed us to gain insight on the taxonomic and functional nature of these communities. Metagenomic analysis was performed using the Illumina HiSeq2500 sequencing platform, revealing that bacterial population of the Berkeley solar panels is composed mainly of Actinobacteria, Bacteroidetes and Proteobacteria, as well as lower amounts of Deinococcus-Thermus and Firmicutes. Furthermore, a clear predominance of Hymenobacter sp. was also observed. A functional analysis revealed that pathways involved in the persistence of microbes on solar panels (i.e., stress response, capsule development, and metabolite repair) and genes assigned to carotenoid biosynthesis were common to all metagenomes. On the other hand, genes involved in photosynthetic pathways and general autotrophic subsystems were rare, suggesting that these pathways are not critical for persistence on solar panels. Metabolomics was performed using a liquid chromatography tandem mass spectrometry (LC-MS/MS) approach. When comparing the metabolome of the solar panels from Berkeley and from Valencia (Spain), a very similar composition in polar metabolites could be observed, although some metabolites appeared to be differentially represented (for example, trigonelline, pantolactone and 5-valerolactone were more abundant in the samples from Valencia than in the ones from Berkeley). Furthermore, triglyceride metabolites were highly abundant in all the solar panel samples, and both locations displayed similar profiles. The comparison of the taxonomic profile of the Californian solar panels with those previously described in Spain revealed striking similarities, highlighting the central role of both selective pressures and the ubiquity of microbial populations in the colonization and establishment of microbial communities.
关键词： microbiome,stress-resistant bacteria,solar panels,metabolomics,metagenomics
更新于2025-09-19 17:15:36
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Strain-Independent Temperature Measurements with Surface-Glued Polarization-Maintaining Fiber Bragg Grating Sensor Elements
摘要： A novel technique for strain and temperature decoupling with surface-glued fiber Bragg gratings (FBGs) is presented and applied for strain-independent temperature measurements in a temperature range between ?30 °C and 110 °C with uncertainties below 4 °C over the entire measurement range. The influence of temperature-dependent glue-induced transversal forces on the fiber sensor could be eliminated with a sensor element consisting of two FBGs in identical polarization-maintaining fibers that were spliced perpendicular to each other. After aligning and gluing the sensor element with its optical axes parallel and perpendicular to the specimen, the averaged Bragg wavelength shifts of both FBGs were proven to be independent of the glue's influence and therefore independent of any change in the material characteristics of the glue, such as aging or creeping behavior. For the first time, this methodology enables temperature measurements with surface-attached bare FBGs independently of arbitrary longitudinal and glue-induced strains. This is of great value for all applications that rely on a fully glued sensor design, e.g., in applications with high electromagnetic fields, on rotating parts, or in vacuum for space applications.
关键词： surface-attached Fiber Bragg gratings,multi-parameter measurements,glue-induced stress,fiber optic temperature sensing
更新于2025-09-19 17:15:36
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Evolution of Mechanically Formed Bow Due to Surface Waviness and Residual Stress difference on Sapphire (0001) Substrate
摘要： Single crystalline sapphire is one of the most widely used wafers for modern high-technology electronic and optical devices owing to the well-established mass production, own physical properties with high thermal, mechanical, and chemical stability, and lattice constants suitable for growth of highly crystalline films. When single crystalline wafers are used as substrates, the curvature of the wafer surface usually called bow is inevitable. Since bow can degrade the quality of deposited film by defects generation or undesirable strain at the interface, to reduce the bow and surface roughness, procedures such as lapping, annealing, and polishing are followed after wafer slicing. Although single crystalline sapphire has sufficiently high hardness for the device applications, surface waviness after abrasion and residual stress within wafer can induce bow. In this study, we revealed the mechanism of bow evolution using high-resolution X-ray diffraction and Raman spectroscopy following each wafering steps. We found that bow in single crystalline sapphire wafer is mainly determined by the irregularly abraded surface after wafer slicing at earlier wafering process. This kind of bow is significantly reduced after lapping and annealing procedure. However, additional surface polishing can inflict stress on the surface and increase bow due to residual stress difference between the polishing surface and the opposite surface. While bow can be effectively reduced by further polishing on the opposite surface, the surface lattice remains still strained.
关键词： HR-XRD,Machining process,Residual stress,Sapphire,Bow,Raman spectroscopy
更新于2025-09-19 17:15:36
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Bias-stress effects in diF-TES-ADT field-effect transistors
摘要： A systematic analysis of the bias-stress effects in solution-processed organic field-effect transistors is reported. Difluoro 5,11-bis(triethylsilylethynyl) anthradithiophene, a high-performance molecular semiconductor, forms a charge-transport channel and is coupled with injection contacts made of Au, Ag, or Cu. The electrode metal is found to not only greatly affect the switching performances but also drive the response of transistors to the extended applications of gate voltage. The observations are put into the framework of contact-limited transistor model, which holistically assesses the material, geometry, and stress-related contributions.
关键词： Bias stress,Device physics,Contact resistance,DiF-TES-ADT,Organic field-effect transistors
更新于2025-09-19 17:15:36
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Comparative physiological and proteomic analysis of Arabidopsis thaliana revealed differential wound stress responses following the exposure to different LED light sources
摘要： A comparative proteomic analysis was carried out to investigate the effects of various Light Emitting Diode (LED) light qualities (wavelengths), including red LED (R), blue LED (B), red (70%) + blue (30%) LED (RB), and white LED (W), on the wounding response in Arabidopsis thaliana. The majority of differentially expressed proteins were unique to each light condition. The highest (54%) and the lowest (22%) changes in total protein expression were observed in plants exposed to RB and B light, respectively. In wounded plants exposed to red + blue LED (RB) light, expression of antioxidant enzymes and a number of proteins related to dark reaction of photosynthesis decreased while the abundance of several proteins involved in the resistance to pathogen and lignin biosynthesis increased. Under blue LED (B) light, plants responded to wounding mainly through cell wall modification, biosynthesis of lignin and over expression of glutathione peroxidase. The results also indicated enhanced antioxidative capacity in response to wounding under red LED (R) light as compared to the other LED light conditions. The analyses of hormone metabolism suggested an increase in gibberellic acid (GA), abscisic acid (ABA) and salicylic acid (SA) signaling in the red + blue LED (RB), an enhancement in ethylene biosynthesis in the red LED (R), and increased jasmonic acid (JA) and brassinosteroid (BR) biosynthesis in the white LED (W) light conditions in response to wounding. Consistent with proteomic results related to JA metabolism, the highest concentration of methyl jasmonate (MeJA) was detected in white LED exposed plants. Late induction of JA biosynthesis-associated genes (AOC and AOS) in response to wounding was observed in all LED conditions, with the highest intensity in W light exposed plants. Collectively, we conclude that although white LED (W) light induces JA signaling pathway, red + blue LED (RB) light condition provides a better capability to recover from wound stress in A. thaliana. The results of H2O2 detection between different LED exposed plants showed different amounts of hydrogen peroxide production in response to wounding suggesting the possible signaling role of ROS in light-induced wound responses.
关键词： Abiotic stress,Pathogen resistance,Biotic stress,Wounding,Proteomics,LED
更新于2025-09-19 17:13:59
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Optimization of the optical fiber with triple sector stress elements
摘要： The stress distribution characteristics of the optical ?ber with triple sector stress elements are studied in detail. The relationship between the stress oscillation amplitude of the optical ?ber and the structural parameters is analyzed. The structural parameters include the distance from the stress element center to the core center and the stress element area. The results show that the stress oscillation amplitude of the optical ?ber with triple sector stress elements will increase rapidly if the stress element is close to the core while the stress element area is ?xed. When the distance from the stress element center to the core center is ?xed, the stress oscillation amplitude increases linearly with the increase of the stress element area under the premise of selecting the optimum stress element expanded angle. Based on the drawn conclusion, the optical ?ber with triple sector stress elements is optimized. The maximum stress oscillation amplitude and the optical ?ber structure with optimal stress distribution are determined to improve the coupling e?ciency of the optical ?ber and better realize the circular polarization state stable transmission.
关键词： Optimization,Stress distribution characteristics,Stress oscillation amplitude
更新于2025-09-19 17:13:59
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Re: Erbium:YAG Laser Treatment of Female Stress Urinary Incontinence: Midterm Data
摘要： The role of intravaginal laser therapy for the treatment of women with a clinical and urodynamic diagnosis of stress urinary incontinence (SUI) or mixed urinary incontinence was the focus of the recent study by Kuszka and colleagues. To evaluate subjective and objective outcomes of Er:YAG therapy with SMOOTH mode technology, the authors enrolled 59 women, of whom 32 had grade I (54%), 16 had grade II (27%), and 11 had grade III SUI (19%). Using validated questionnaires (ICIQ-UI SF, PISQ 12) and 1-h pad weight at baseline, after two, four, and five laser sessions, and at 6-mo and 2-yr follow-up, the authors found that intravaginal laser therapy led to cure/improvement for grades I and II but not for severe SUI. At least three laser sessions at intervals of 1 mo are required to obtain better results from laser therapy. Outcomes at the 6-mo and 2-yr follow-up visits were similar, indicating that laser treatment is suitable and does not need to be repeated within 2 yr.
关键词： Female Stress,Urinary Incontinence,Midterm Data,Treatment,Erbium:YAG Laser
更新于2025-09-19 17:13:59
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The model and stress analysis of self-doping SiGe/Si multi-quantum wells applied in uncooled infrared focal plane array
摘要： Silicon-germanium multi-quantum wells (MQWs) ?lm is a promising sensitive material with high temperature coe?cient of resistance (TCR). This paper focuses on solving the stress problem of uncooled infrared focal plane array caused by intrinsic stress of MQWs ?lms. First of all, the paper presents the accurate TCR model of MQWs, which is more consistent with the actual situation especially when the Fermi level enters the valence band. The energy bands distributions and each sub-band wavefunction of MQWs were calculated. The critical thickness analysis about epitaxial growth ?lm was carried out for solving intrinsic stress of MQWs ?lm, which leads to the deformation of pixel structure in the fabrication processes. The paper calculated the maximum ?lm stress in completely strain state and derived the buckling of the bolometer. Tri-layer structure was applied in support beam design for the deformation compensation. The self-doping MQWs ?lm was epitaxial growth on silicon substrate with bu?er layer to overcome the lattice slips in experiments. The bolometer was fabricated and released without visible deformation utilizing the compensation methods. The ohmic-contact problems and signals were also mentioned in the paper. The thermal conductivity and capacity were calculated by means of thermal response experiments without infrared radiation.
关键词： Multi-quantum wells,Intrinsic stress,Uncooled infrared focal plane array
更新于2025-09-19 17:13:59
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Blue laser light inhibits biofilm formation in vitro and in vivo by inducing oxidative stress
摘要： Resolution of bacterial infections is often hampered by both resistance to conventional antibiotic therapy and hiding of bacterial cells inside biofilms, warranting the development of innovative therapeutic strategies. Here, we report the efficacy of blue laser light in eradicating Pseudomonas aeruginosa cells, grown in planktonic state, agar plates and mature biofilms, both in vitro and in vivo, with minimal toxicity to mammalian cells and tissues. Results obtained using knock-out mutants point to oxidative stress as a relevant mechanism by which blue laser light exerts its anti-microbial effect. Finally, the therapeutic potential is confirmed in a mouse model of skin wound infection. Collectively, these data set blue laser phototherapy as an innovative approach to inhibit bacterial growth and biofilm formation, and thus as a realistic treatment option for superinfected wounds.
关键词： oxidative stress,Pseudomonas aeruginosa,blue laser light,antimicrobial effect,biofilm formation
更新于2025-09-19 17:13:59
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High performance nBn detectors based on InGaAsSb bulk materials for short wavelength infrared detection
摘要： Objective: To investigate whether hydrogen sulfide (H2S) counteracts formaldehyde (FA)-induced cognitive defects and whether the underlying mechanism is involved in the upregulation of hippocampal brain-derived neurotrophic factor (BDNF) expression. Methods: The cognitive function of rats was evaluated by the Morris water maze (MWM) test and the novel object recognition test. The content of superoxide dismutase (SOD) and malondialdehyde (MDA) in the hippocampus were detected by enzyme-linked immunosorbent assay (ELISA). The neuronal apoptosis in the hippocampal CA1 region was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end (TUNEL) staining. The expression of the BDNF protein was detected by Western blot and immunohistochemistry. Results: We found that sodium hydrosulfide (NaHS, a donor of H2S) significantly reversed the impairment in the function of learning and memory in the MWM test and the novel objective recognition task induced by intracerebroventricular injection of FA. We also showed that NaHS significantly reduced the level of MDA, elevated the level of SOD, and decreased the amount of TUNEL-positive neurons in the hippocampus of FA-exposed rats. Moreover, NaHS markedly increased the expression of hippocampal BDNF in FA-exposed rats. Conclusions: H2S attenuates FA-induced dysfunction of cognition and the underlying mechanism is involved in the reduction of hippocampal oxidative damage and apoptosis as well as upregulation of hippocampal BDNF.
关键词： Cognitive defect,Oxidative stress,Brain-derived neurotrophic factor,Formaldehyde,Hydrogen sulfide,Apoptosis
更新于2025-09-19 17:13:59