Self-oscillating polymeric refrigerator with high energy efficiency.

Electrocaloric1,2 and electrostrictive3,4 effects concurrently exist in dielectric materials. Combining these two effects could achieve the lightweight, compact localized thermal management that is promised by electrocaloric refrigeration5. Despite a handful of numerical models and schematic presentations6,7, current electrocaloric refrigerators still rely on external accessories to drive the working bodies8-10 and hence result in a low device-level cooling power density and coefficient of performance (COP). Here we report an electrocaloric thin-film device that uses the electro-thermomechanical synergy provided by polymeric ferroelectrics. Under one-time a.c. electric stimulation, the device is thermally and mechanically cycled by the working body itself, resulting in an external-driver-free, self-cycling, soft refrigerator. The prototype offers a directly measured cooling power density of 6.5 W g-1 and a peak COP exceeding 58 under a zero temperature span. Being merely a 30-µm-thick polymer film, the device achieved a COP close to 24 under a 4 K temperature span in an open ambient environment (32% thermodynamic efficiency). Compared with passive cooling, the thin-film refrigerator could immediately induce an additional 17.5 K temperature drop against an electronic chip. The soft, polymeric refrigerator can sense, actuate and pump heat to provide automatic localized thermal management.

Induction of Siglec-G by RNA viruses inhibits the innate immune response by promoting RIG-I degradation.

RIG-I is a critical RNA virus sensor that serves to initiate antiviral innate immunity. However, posttranslational regulation of RIG-I signaling remains to be fully understood. We report here that RNA viruses, but not DNA viruses or bacteria, specifically upregulate lectin family member Siglecg expression in macrophages by RIG-I- or NF-κB-dependent mechanisms. Siglec-G-induced recruitment of SHP2 and the E3 ubiquitin ligase c-Cbl to RIG-I leads to RIG-I degradation via K48-linked ubiquitination at Lys813 by c-Cbl. By increasing type I interferon production, targeted inactivation of Siglecg protects mice against lethal RNA virus infection. Taken together, our data reveal a negative feedback loop of RIG-I signaling and identify a Siglec-G-mediated immune evasion pathway exploited by RNA viruses with implication in antiviral applications. These findings also provide insights into the functions and crosstalk of Siglec-G, a known adaptive response regulator, in innate immunity.

Regulation of candidalysin underlies Candida albicans persistence in intravascular catheters by modulating NETosis.

Candida albicans is a leading cause of intravascular catheter-related infections. The capacity for biofilm formation has been proposed to contribute to the persistence of this fungal pathogen on catheter surfaces. While efforts have been devoted to identifying microbial factors that modulate C. albicans biofilm formation in vitro, our understanding of the host factors that may shape C. albicans persistence in intravascular catheters is lacking. Here, we used multiphoton microscopy to characterize biofilms in intravascular catheters removed from candidiasis patients. We demonstrated that, NETosis, a type of neutrophil cell death with antimicrobial activity, was implicated in the interaction of immune cells with C. albicans in the catheters. The catheter isolates exhibited reduced filamentation and candidalysin gene expression, specifically in the total parenteral nutrition culture environment. Furthermore, we showed that the ablation of candidalysin expression in C. albicans reduced NETosis and conferred resistance to neutrophil-mediated fungal biofilm elimination. Our findings illustrate the role of neutrophil NETosis in modulating C. albicans biofilm persistence in an intravascular catheter, highlighting that C. albicans can benefit from reduced virulence expression to promote its persistence in an intravascular catheter.

USP39 Regulates NF-κB-Mediated Inflammatory Responses through Deubiquitinating K48-Linked IκBα.

IκBα is a critical protein that inhibits NF-κB nuclear translocation and impairs NF-κB-mediated signaling. The abundance of IκBα determines the activation and restoration of the inflammatory response. However, posttranslational regulation of IκBα remains to be fully understood. In this study, we identified ubiquitin-specific protease 39 (USP39) as a negative regulator in the NF-κB inflammatory response by stabilizing basal IκBα. The expression of USP39 in macrophages was reduced under LPS-induced inflammation. Knockdown or knockout of USP39 in macrophages significantly increased the expression and secretion of proinflammatory cytokines upon exposure to LPS or Escherichia coli, whereas reexpression of exogenous USP39 in USP39-deficient macrophages rescued the effect. Moreover, USP39-defective mice were more sensitive to LPS or E. coli-induced systemic sepsis. Mechanistically, USP39 interacted with and stabilized IκBα by reducing K48-linked polyubiquination of IκBα. Taken together, to our knowledge, our study for the first time revealed the inhibitory function of USP39 in the NF-κB inflammatory response, providing a previously unknown mechanism for control of inflammatory cytokine induction in the cellular anti-inflammatory response.

CAT-DTI: cross-attention and Transformer network with domain adaptation for drug-target interaction prediction.

Accurate and efficient prediction of drug-target interaction (DTI) is critical to advance drug development and reduce the cost of drug discovery. Recently, the employment of deep learning methods has enhanced DTI prediction precision and efficacy, but it still encounters several challenges. The first challenge lies in the efficient learning of drug and protein feature representations alongside their interaction features to enhance DTI prediction. Another important challenge is to improve the generalization capability of the DTI model within real-world scenarios. To address these challenges, we propose CAT-DTI, a model based on cross-attention and Transformer, possessing domain adaptation capability. CAT-DTI effectively captures the drug-target interactions while adapting to out-of-distribution data. Specifically, we use a convolution neural network combined with a Transformer to encode the distance relationship between amino acids within protein sequences and employ a cross-attention module to capture the drug-target interaction features. Generalization to new DTI prediction scenarios is achieved by leveraging a conditional domain adversarial network, aligning DTI representations under diverse distributions. Experimental results within in-domain and cross-domain scenarios demonstrate that CAT-DTI model overall improves DTI prediction performance compared with previous methods.

Estimated glucose disposal rate for predicting cardiovascular events and mortality in patients with non-diabetic chronic kidney disease: a prospective cohort study.

BACKGROUND: Evidence suggests that insulin resistance (IR) is an autonomous risk factor for cardiovascular disease (CVD). Nevertheless, the association between estimated glucose disposal rate (eGDR), a novel indicator of IR, and incident CVD and mortality in chronic kidney disease (CKD) patients without diabetes remains uncertain. METHODS: The study included 19,906 participants from the UK Biobank who had an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73m2 or a urinary albumin-to-creatinine ratio (UACR) ≥ 30 mg/g and no history of CVD and diabetes. Individuals were divided into three categories based on tertiles of eGDR. The outcome was a composite CVD (coronary heart disease (CHD) and stroke) and mortality (all-cause, non-accidental, and cardiovascular mortality). Furthermore, a cohort of 1,600 individuals from the US National Health and Nutrition Examination Survey (NHANES) was applied to validate the association between eGDR and mortality. The Cox proportional hazards regression models were used to examine the association between eGDR and event outcomes. RESULTS: During a follow-up of around 12 years, 2,860 CVD, 2,249 CHD, 783 stroke, 2,431 all-cause, 2,326 non-accidental and 492 cardiovascular deaths were recorded from UK Biobank. Higher eGDR level was not only associated with lower risk of CVD (hazard ratio [HR] 0.641, 95% confidence interval [CI] 0.559-0.734), CHD (HR 0.607, 95% CI 0.520-0.709), stroke (HR 0.748, 95% CI 0.579-0.966), but also related to reduced risk of all-cause (HR 0.803, 95% CI 0.698-0.923), non-accidental (HR 0.787, 95% CI 0.682-0.908), and cardiovascular mortality (HR 0.592, 95% CI 0.423-0.829). Validation analyses from NHANES yielded consistent relationship on mortality. CONCLUSIONS: In these two large cohorts of CKD patients without DM, a higher eGDR level was associated with a decreased risk of CVD and mortality.

Optical design and fabrication of a multi-channel imaging spectrometer for combustion flame monitoring.

We design and construct a broadband integrated multi-channel imaging spectrometer (MCIS) from visible light to near-infrared. This system can directly obtain spectral images that conform to the consistent visual habits of the human eyes through a single exposure of the detector. The genetic algorithm is used to calculate system parameters to minimize pixel waste between spectral channels, achieving nearly 100% utilization of detector pixels. The field stop suppresses stray light in the system. This device is used for imaging an optical-resolution target, an object, and a furnace to verify the basic principles of the system. The results indicate that the system can effectively utilize detectors to monitor high-temperature objects in the visible to near-infrared wavelength range.

Keplerate-Type Polyoxometalates-Based Triboelectric Nanogenerator for Higher Performance via the Morphology Modulation of Blackberry Structure.

The tribe-material is the key factor affecting the performance of triboelectric nanogenerators (TENGs). Inorganic materials have higher heat resistance and stability than widely used organic materials. However, the weaker tribe-property limits the application of TENGs. Modulating surface roughness by changing particle shape and size is a simple way to increase performance for TENGs. Polyoxometalates (POMs) have unrivalled structural diversity and can self-assemble to form different nanostructures. In this study, we propose [{(NH4)42[Mo72 VIMo60 VO372(CH3COO)30 (H2O)72] ⋅ ca.300H2O ⋅ ca.CH3COONH4)}-Mo132] and [{Na8K14(VO)2[{(MoVI) (Mo5 VIO21)(H2O)3]}10{(MoVI)Mo5 VIO21(H2O)3 (SO4)}2{VIVO(H2O)20} {VIVO}10({KSO4}5)2] ⋅ 150H2O)}-Mo72V30] with blackberry structure which are cured and prepared into film by spin-coating technique, are used as positive tribe-materials for the first time in the field of TENGs. Keplerate-type POMs can form blackberry structures with higher dispersibility and flexibility, which can be used to control surface roughness by regulating the size of particles. The discovery proves that the particle size influences the surface roughness, which adjusts the output of TENGs. According to our findings, Mo132-h-TENG generates an output voltage of 29.3 V, an output charge of 8 Nc, which is 2-3 folds higher than Mo132-TENG, and a maximum power density of 6.25 mW ⋅ m-2 at 300 MΩ. Our research provides that altering the dimensional size can be an available way to raise the output of TENGs.

Different wavelengths of LED irradiation promote secondary metabolite production in Pycnoporus sanguineus for antioxidant and immunomodulatory applications.

Pycnoporus sanguineus is a fungus of the phylum Basidiomycota that has many applications in traditional medicine, modern pharmaceuticals, and agricultural industries. Light plays an essential role in the metabolism, growth, and development of fungi. This study evaluated the mycelial growth and antioxidant and anti-inflammatory activities in P. sanguineus fermentation broth (PFB) cultured under different wavelengths of LED irradiation or in the dark. Compared to the dark cultures, the dry weight of mycelia in red- and yellow-light cultures decreased by 37 and 35% and the yields of pigments increased by 30.92 ± 2.18 mg and 31.75 ± 3.06 mg, respectively. Compared with the dark culture, the DPPH free radical scavenging ability, ABTS+ free radical scavenging capacity, and reducing power of yellow-light cultures increased significantly, and their total phenolic content peaked at 180.0 ± 8.34 µg/mL. However, the reducing power in blue-light cultures was significantly reduced, though the total phenol content did not vary with that of dark cultures. In LPS- and IFN-γ-stimulated RAW 264.7 cells, nitrite release was significantly reduced in the red and yellow light-irradiated PFB compared with the dark culture. In the dark, yellow-, and green-light cultures, TNF-α production in the inflamed RAW 264.7 cells was inhibited by 62, 46, and 14%, respectively. With red-, blue-, and white-light irradiation, TNF-α production was significantly enhanced. Based on these results, we propose that by adjusting the wavelength of the light source during culture, one can effectively modulate the growth, development, and metabolism of P. sanguineus.

Polyoxometalate-Modified g-C3N4 Composites with High Work Function for Triboelectric Nanogenerators.

Designing friction materials with high electron storage capacity, high work function, low cost, and high stability is an important method to improve the output performance of a triboelectric nanogenerator (TENG). Here, we report two kinds of friction materials based on Keggin-type polyoxometalates (POMs)-modified graphite carbon nitride (g-C3N4), namely, g-C3N4@PMo12 and g-C3N4@PW12, and form TENG with commercial indium tin oxide/poly(ethylene terephthalate) (ITO/PET) electrodes. The performance test shows that the g-C3N4@PMo12 TENG device exhibits a high output voltage of about 78 V, a current of about 657 nA, and a transfer charge of about 15 nC, which is more than 3 times higher than that of unmodified TENG. This performance improvement is attributed to the fact that POM loaded on the surface of g-C3N4 can be used as a shallow electron trap to increase the electron storage capacity through electron interaction and to increase the charge density on the surface of the material by increasing the work function of the composite. This work not only broadens the choices of TENG friction materials but also offers a practical means of enhancing TENG's output performance.

Photosynthetic System Based on a Polyoxometalate-Based Dehydrated Metal-Organic Framework for Nitrogen Fixation.

In nature, biological nitrogen fixation is accomplished through the π-back-bonding mechanism of nitrogenase, which poses significant challenges for mimic artificial systems, thanks to the activation barrier associated with the N≡N bond. Consequently, this motivates us to develop efficient and reusable photocatalysts for artificial nitrogen fixation under mild conditions. We employ a charge-assisted self-assembly process toward encapsulating one polyoxometalate (POM) within a dehydrated Zr-based metal-organic framework (d-UiO-66) exhibiting nitrogen photofixation activities, thereby constructing an enzyme-mimicking photocatalyst. The dehydration of d-UiO-66 is favorable for facilitating nitrogen chemisorption and activation via the unpaired d-orbital electron at the [Zr6O6] cluster. The incorporation of POM guests enhanced the charge separation in the composites, thereby facilitating the transfer of photoexcited electrons into the π* antibonding orbital of chemisorbed N2 for efficient nitrogen fixation. Simultaneously, the catalytic efficiency of SiW9Fe3@d-UiO-66 is enhanced by 9.0 times compared to that of d-UiO-66. Moreover, SiW9Fe3@d-UiO-66 exhibits an apparent quantum efficiency (AQE) of 0.254% at 550 nm. The tactics of "working-in-tandem" achieved by POMs and d-UiO-66 are extremely vital for enhancing artificial ammonia synthesis. This study presents a paradigm for the development of an efficient artificial catalyst for nitrogen photofixation, aiming to mimic the process of biological nitrogen fixation.

2D Atomic-Molecular Heterojunctions toward Brainoid Applications.

Brainoid computing using 2D atomic crystals and their heterostructures, by emulating the human brain's remarkable efficiency and minimal energy consumption in information processing, poses a formidable solution to the energy-efficiency and processing speed constraints inherent in the von Neumann architecture. However, conventional 2D material based heterostructures employed in brainoid devices are beset with limitations, performance uniformity, fabrication intricacies, and weak interfacial adhesion, which restrain their broader application. The introduction of novel 2D atomic-molecular heterojunctions (2DAMH), achieved through covalent functionalization of 2D materials with functional molecules, ushers in a new era for brain-like devices by providing both stability and tunability of functionalities. This review chiefly delves into the electronic attributes of 2DAMH derived from the synergy of polymer materials with 2D materials, emphasizing the most recent advancements in their utilization within memristive devices, particularly their potential in replicating the functionality of biological synapses. Despite ongoing challenges pertaining to precision in modification, scalability in production, and the refinement of underlying theories, the proliferation of innovative research is actively pursuing solutions. These endeavors illuminate the vast potential for incorporating 2DAMH within brain-inspired intelligent systems, highlighting the prospect of achieving a more efficient and energy-conserving computing paradigm.

Role of OPG/RANKL/RANK/TLR4 signaling pathway in sepsis-associated acute kidney injury.

BACKGROUND: Sepsis-associated acute kidney injury (SA-AKI) has high mortality rates. The osteoprotegerin (OPG)/receptor activator of nuclear factor-κB ligand (RANKL)/receptor activator of nuclear factor-κB (RANK)/Toll-like receptor 4 (TLR4) pathway and its potential role in SA-AKI pathogenesis remain to be fully understood. Herein, we addressed this issue using mouse models. METHODS: An SA-AKI mouse model was established using the cecal ligation and puncture method (CLP). Mice were grouped into sham, CLP model, CLP + recombinant RANKL, and CLP + anti-RANKL groups. Serum creatinine (Scr) and blood urea nitrogen (BUN) levels were measured to assess kidney function. ELISA was used to detect serum IL-1ß, TNF-α, and IL-6 levels. Real-time quantitative PCR and Western blot were used to detect the mRNA and protein expression levels of OPG, RANKL, RANK, and TLR4 in kidney tissues. HE staining was performed to evaluate the pathological changes. RESULTS: The CLP model group showed higher levels of Scr and BUN, indicating impaired kidney function in SA-AKI, compared to the sham group. Treatment with recombinant RANKL in the CLP + recombinant RANKL group reduced Scr and BUN levels, while anti-RANKL treatment in the CLP + anti-RANKL group elevated their levels. Moreover, the CLP model group had significantly increased IL-1ß, TNF-α, and IL-6 than the sham group, indicating elevated inflammation in SA-AKI. The CLP + recombinant RANKL group demonstrated decreased cytokine levels, whereas the CLP + anti-RANKL group showed an increase. Additionally, the histopathological evaluation revealed distinct kidney tissue damage in the CLP model group. Recombinant RANKL treatment reduced this damage, while anti-RANKL treatment exacerbated it. Mechanically, the mRNA and protein expression of RANKL were significantly decreased, while those of OPG, RANK, and TLR4 were significantly increased in the CLP model group and the CLP + anti-RANKL group. Interestingly, treatment with recombinant RANKL reversed these changes, as evidenced by significantly increased RANKL but decreased OPG, RANK, and TLR4. CONCLUSION: The OPG/RANKL/RANK/TLR4 pathway is involved in SA-AKI pathogenesis. Recombinant RANKL treatment attenuates the inflammatory response and kidney tissue damage in SA-AKI, possibly via regulating this pathway. This pathway shows promise as a therapeutic target for SA-AKI.

Strong In-Plane Optoelectronic Anisotropy and Polarization Sensitivity in Low-Symmetry 2D Violet Phosphorus.

Anisotropic optoelectronics based on low-symmetry two-dimensional (2D) materials hold immense potential for enabling multidimensional visual perception with improved miniaturization and integration capabilities, which has attracted extensive interest in optical communication, high-gain photoswitching circuits, and polarization imaging fields. However, the reported in-plane anisotropic photocurrent and polarized dichroic ratios are limited, hindering the achievement of high-performance anisotropic optoelectronics. In this study, we introduce novel low-symmetry violet phosphorus (VP) with a unique tubular cross-linked structure into this realm, and the corresponding anisotropic optical and optoelectronic properties are investigated both experimentally and theoretically for the first time. Remarkably, our prepared VP-based van der Waals phototransistor exhibits significant optoelectronic anisotropies with a giant in-plane anisotropic photocurrent ratio exceeding 10 and a comparable polarized dichroic ratio of 2.16, which is superior to those of most reported 2D counterparts. Our findings establish VP as an exceptional candidate for anisotropic optoelectronics, paving the way for future multifunctional applications.

Metformin attenuates PM2.5-induced oxidative stress by inhibiting the AhR/CYP1A1 pathway in proximal renal tubular epithelial cells.

The harmful effects of PM2.5 on human health, including an increased risk of chronic kidney disease (CKD), have raised a lot of attention, but the underlying mechanisms are unclear. We used the Shanghai Meteorological and Environmental Animal Exposure System (Shanghai-METAS) to simulate the inhalation of PM2.5 in the real environment and established an animal model by exposing C57BL/6 mice to filtered air (FA) and Particulate Matter (PM2.5) for 8 weeks. PM2.5 impaired the renal function of the mice, and the renal tubules underwent destructive changes. Analysis of NHANES data showed a correlation between reduced kidney function and higher blood levels of PM2.5 components, polychlorinated biphenyls (PCBs) and dioxins, which are Aryl hydrocarbon Receptor (AhR) ligands. PM2.5 exposure induced higher levels of AhR and CYP1A1 and oxidative stress as evidenced by the higher levels of ROS, MDA, and GSSG in kidneys of mice. PM2.5 exposure led to AhR overexpression and nuclear translocation in proximal renal tubular epithelial cells. Inhibition of AhR reduced CYP1A1 expression and PM2.5-increased levels of ROS, MDA and GSSG. Our study suggested metformin can mitigate PM2.5-induced oxidative stress by inhibiting the AhR/CYP1A1 pathway. These findings illuminated the role of AhR/CYP1A1 pathway in PM2.5-induced kidney injury and the protective effect of metformin on PM2.5-induced cellular damage, offering new insights for air pollution-related renal diseases.

Photochemical Ammonia Synthesis over Reduced Polyoxovanadate-Intercalated Defective ZnAl Layered Double Hydroxide Nanosheets.

The exploration of efficient and stable N2 fixation photocatalysts featuring a broad absorption spectrum and N2 fixation active sites has become specifically conspicuous. Herein, a series of reduced polyoxovanadates (POVs) were intercalated into copper-induced ZnAl layered double hydroxide (0.5%-ZnAl LDH) nanosheets with oxygen vacancies via an anion exchange strategy toward green ammonia production. The intervalence charge transfer arising from mixed-valence POV materials is responsible for its light-harvesting behavior, and the LDHs lay the foundation for the chemical adsorption and activation process of nitrogen molecules; both contributions facilitate the nitrogen photofixation performance of such composite materials. As predicted, the catalytic efficiency of V34/0.5%-ZnAl is 7.0 times higher than 0.5%-ZnAl LDH. Therefore, such an all-inorganic system exhibits an apparent quantum efficiency of 0.3137% at 500 nm. The strategy of "working in tandem" established by POV-based light-absorber species and oxygen vacancies as the sites for N2 activation is extremely vital for enhanced ammonia formation. This work opens up a versatile insight for the rational design of an efficient photo-driven nitrogen-reduction composite catalyst toward sustainable ammonia production compared to the industrial Haber-Bosch process.

A rare case of human taeniasis caused by Taenia saginata with species undetermined cysticercosis.

Taeniasis and cysticercosis, which are caused by Taenia saginata, Taenia solium and Taenia asiatica, are zoonotic parasitic infections with a significant disease burden worldwide. There is consensus amongst experts that T. saginata is a common tapeworm that causes taeniasis in humans as opposed to cysticercosis. This case study of a middle-aged Tibetan man conducted in 2021 challenges the prevailing notion that T. saginata exclusively causes taeniasis and not cysticercosis by documenting symptoms and laboratory studies related to both taeniasis and multiple cysticercosis. The patient's medical record with the symptoms of taeniasis and cysticercosis was reviewed, and the tapeworm's proglottids and cyst were identified from the patient by morphological evaluation, DNA amplification and sequencing. The patient frequently experienced severe headaches and vomiting. Both routine blood screenings and testing for antibodies against the most common parasites were normal. After anthelmintic treatment, an adult tapeworm was found in feces, and medical imaging examinations suggested multiple focal nodules in the brain and muscles of the patient. The morphological and molecular diagnosis of the proglottids revealed the Cestoda was T. saginata. Despite the challenges presented by the cyst's morphology, the molecular analysis suggested that it was most likely T. saginata. This case study suggests that T. saginata infection in humans has the potential to cause human cysticercosis. However, such a conclusion needs to be vetted by accurate genome-wide analysis in patients with T. saginata taeniasis associated with cysts. Such studies shall provide new insights into the pathogenicity of T. saginata.

End-of-life communication strategies for healthcare professionals: A scoping review.

BACKGROUND: Timely and effective communication about end-of-life issues, including conversations about prognosis and goals of care, are extremely beneficial to terminally ill patients and their families. However, given the context, healthcare professionals may find it challenging to initiate and facilitate such conversations. Hence, it is critical to improving the available communication strategies to enhance end-of-life communication practices. AIM: To summarise the end-of-life communication strategies recommended for healthcare professionals, identify research gaps and inform future research. DESIGN: A scoping review performed in accordance with the Arksey and O'Malley framework. DATA SOURCES: A literature search was conducted between January 1990 and January 2022 using PubMed, CINAHL, Embase, PsycINFO, Web of Science, Scopus, Cochrane Library and China National Knowledge Infrastructure databases and Google, Google Scholar and ProQuest Dissertations & Theses Global. Studies that described recommended end-of-life communication strategies for healthcare professionals were included. RESULTS: Fifty-nine documents were included. Seven themes of communication strategies were found: (a) preparation; (b) exploration and assessment; (c) family involvement; (d) provision and tailoring of information; (e) empathic emotional responses; (f) reframing and revisiting the goals of care; and (g) conversation closure. CONCLUSIONS: The themes of communication strategies found in this review provide a framework to integrally promote end-of-life communication. Our results will help inform healthcare professionals, thereby promoting the development of specialised training and education on end-of-life communication.

Determination of polyamines in urine via electrospun nanofibers-based solid-phase extraction coupled with GC-MS and application to gastric cancer patients.

The simultaneous determination of polyamines and their metabolites in urine samples was achieved by gas chromatography-mass spectrometry in the selected ion monitoring mode. After conjugating with the ion-pair reagent bis-2-ethylhexylphosphate in the aqueous phase, the polyamines in the samples were extracted with polystyrene nanofiber-based packed-fiber solid-phase extraction followed by a derivatization step using pentafluoropropionyl anhydride. With optimal conditions, all analytes were separated well. For analytes of putrescine, cadaverine, N-acetylputrescine, and N-acetylcadaverine, the linearity was good in the range of 0.05-500 µmol/L (R2  ≥ 0.993). While for spermidine, spermine, acetylspermidine, N8 -acetylspermidine, and N-acetylspermine, the linearity was good in the range of 0.5-500 µmol/L (R2  ≥ 0.990). The recoveries of three spiked concentrations (0.5, 5, 300 µmol/L) were 85.6%-108.4%, and relative standard deviations for intra- and interday were in the range of 2.9%-13.4% and 4.5%-15.1%, respectively. The method was successfully applied to the analysis of urine samples of gastric cancer patients. The results showed that the levels of most polyamines and N-acetylated polyamines from the patient group were significantly higher than those from the control group. The altered concentrations of the above-mentioned metabolites suggest their role in the pathogenesis of gastric cancer, and they should be further evaluated as potential markers of gastric cancer.

High-detection-efficiency stereo microscope system based on a mobile phone.

Most stereoscopic microscopes used for industrial component detection are large and have low detection efficiencies. The use of mobile phones as imaging systems (rather than conventional sensors) in industrial fields would make industrial testing more convenient. In this study, an external stereo microscope for mobile phones is designed. The proposed system can resolve details up to 0.01 mm with an 11 mm object field of view, -6.34× angular magnification, and quantitative 3D feature measurement. The combined system proposed in this paper is suitable for the microscopic observation of industrial components, with its low cost, high detection efficiency, and short installation steps.