A case study on occupational exposure assessment and characterization of particles in a printing shop in China.

Printers can release numerous particles to contaminate indoor environments and pose health risks. Clarifying the exposure level and physicochemical properties of printer-emitted particles (PEPs) will help to evaluate the health risks of printer operator. In our study, the particles concentration in the printing shop was monitored in real time for a long time (12 h/day, total 6 days), and the PEPs were collected to characterize their physicochemical properties including shape, size and compositions. The result showed that the concentration of PEPs is closely related to the printing workload and the highest particle mass concentration of PM10 and PM2.5 was 212.73 µg m-3 and 91.48 µg m-3, respectively. The concentration of PM1 in the printing shop was in the range of 11.88-80.59 µg m-3 for mass value, and 174.83-1348.84 P cm-3 for count value which changed with the printing volume. The particle sizes of PEPs were less than 900 nm, 47.99% of PEPs was less than 200 nm, and 14.21% of the particles were at the nanoscale. PEPs contained 68.92% organic carbon (OC), 5.31% elemental carbon (EC), 3.17% metal elements, and 22.60% other inorganic additives, which contained more OC and metal elements than toners. Total polycyclic aromatic hydrocarbons (PAHs) levels were 18.95 ng/mg in toner and 120.70 ng/mg in PEPs. The carcinogenic risk of PAHs in PEPs was 1.40 × 10-7. These findings suggested future studies should pay more attention to the health effects of printing workers exposed to nanoparticles.

Recent progress of 4D printing in cancer therapeutics studies.

Cancer is a critical cause of global human death. Not only are complex approaches to cancer prognosis, accurate diagnosis, and efficient therapeutics concerned, but post-treatments like postsurgical or chemotherapeutical effects are also followed up. The four-dimensional (4D) printing technique has gained attention for its potential applications in cancer therapeutics. It is the next generation of the three-dimensional (3D) printing technique, which facilitates the advanced fabrication of dynamic constructs like programmable shapes, controllable locomotion, and on-demand functions. As is well-known, it is still in the initial stage of cancer applications and requires the insight study of 4D printing. Herein, we present the first effort to report on 4D printing technology in cancer therapeutics. This review will illustrate the mechanisms used to induce the dynamic constructs of 4D printing in cancer management. The recent potential applications of 4D printing in cancer therapeutics will be further detailed, and future perspectives and conclusions will finally be proposed.

Microfluidic Lab-on-a-Chip for Studies of Cell Migration under Spatial Confinement.

Understanding cell migration is a key step in unraveling many physiological phenomena and predicting several pathologies, such as cancer metastasis. In particular, confinement has been proven to be a key factor in the cellular migration strategy choice. As our insight in the field improves, new tools are needed in order to empower biologists' analysis capabilities. In this framework, microfluidic devices have been used to engineer the mechanical and spatial stimuli and to investigate cellular migration response in a more controlled way. In this work, we will review the existing technologies employed in the realization of microfluidic cellular migration assays, namely the soft lithography of PDMS and hydrogels and femtosecond laser micromachining. We will give an overview of the state of the art of these devices, focusing on the different geometrical configurations that have been exploited to study specific aspects of cellular migration. Our scope is to highlight the advantages and possibilities given by each approach and to envisage the future developments in in vitro migration studies under spatial confinement in microfluidic devices.

Synthesis of End-Cap Enabled Self-Immolative Photoresists For Extreme Ultraviolet Lithography.

Conventional chemically amplified resists (CARs) rely on the usage of photoacid generators to serve as the source of chemical amplification. However, acid diffusion inevitably accompanies CARs and has led to the resolution, line edge roughness, and sensitivity (RLS) trade-off, which is the most challenging technical problem for modern photoresists. Herein, we take advantage of the self-immolative property of polyphthalaldehyde (PPA) derivatives to create end-cap enabled chain scissionable resists for extreme ultraviolet (EUV) lithography. The feasibility of this strategy was demonstrated under UV photodegradation experiments. The dose-to-clear (DTC) under EUV radiation was 90 mJ/cm2 for the most promising resist, representing more than a 100-fold improvement over previous PPA resists. Density functional theory (DFT) calculations were conducted to understand the structural origin of end-cap EUV sensitivity.

Treatment of real printing and packaging wastewater by combination of coagulation with Fenton and photo-Fenton processes.

Printing and packaging process wastewater (PPPW) with high flow rates causes severe damage to the environment due to high organic pollution (3830.0 mg O2/L of COD and 813.6 mg/L of TOC) and turbidity (9110 NTU). This study examined the efficiencies of coagulation, Fenton, and photo-Fenton procedures, and their combinations in the treatment of PPPW. The three inorganic salts (FeCl3, Al2(SO4)3, and Fe2(SO4)3) were used in a wide range of pH (2.5-10) as a coagulant, and FeCl3 was chosen as the optimum coagulant. The 71.3% of TOC removal and the decreasing of turbidity up to 5.8 NTU were obtained at 0.5 g/L FeCl3 and pH of 6.0. Then, Fenton and photo-Fenton processes were applied to the effluent of the coagulation process. The Fenton process engaged the TOC removal efficiencies up to 85.2% in the presence of 7.350 g/L iron catalysts and 36.0 mL/L H2O2. The combined coagulation and Fenton process is a promising way to decrease the COD up to 119 mg O2/L, meeting the wastewater discharge standards of COD (200 mg O2/L) in Turkey. However, adding UV sources to the Fenton process showed a little bit of engagement (only %1.4 extra removal). When evaluated for PPPW, it is seen that the usage of combined coagulation and the Fenton process is an important treatment alternative. Furthermore, Zeta potential measurements and size exclusion chromatography were used to understand the removal mechanism.

Bubble-based microrobots enable digital assembly of heterogeneous microtissue modules.

The specific spatial distribution of tissue generates a heterogeneous micromechanical environment that provides ideal conditions for diverse functions such as regeneration and angiogenesis. However, to manufacture microscale multicellular heterogeneous tissue modulesin vitroand then assemble them into specific functional units is still a challenging task. In this study, a novel method for the digital assembly of heterogeneous microtissue modules is proposed. This technique utilizes the flexibility of digital micromirror device-based optical projection lithography and the manipulability of bubble-based microrobots in a liquid environment. The results indicate that multicellular microstructures can be fabricated by increasing the inlets of the microfluidic chip. Upon altering the exposure time, the Young's modulus of the entire module and different regions of each module can be fine-tuned to mimic normal tissue. The surface morphology, mechanical properties, and internal structure of the constructed bionic peritoneum were similar to those of the real peritoneum. Overall, this work demonstrates the potential of this system to produce and control the posture of modules and simulate peritoneal metastasis using reconfigurable manipulation.

Reading digital- versus print-easy texts: a study with university students who prefer digital sources

The transition from on-paper to on-screen reading seems to make it necessary to raise some considerations, as a greater attentional efort has been claimed for print texts than digital ones. Not surprisingly, most university students prefer this digital medium. This research aims to examine reading times by contextualizing this phenomenon into two processes: namely, word recognition and reading comprehension task on paper and on screen. Thus, two diferent tasks­counterbalanced into digital and print mediums­were carried out per each participant with a preference for a digital medium: a reading comprehension task (RCT) and a lexical decision task (LDT) after reading a specifc story. Participants were slower reading print texts and no statistically signifcant diferences were found in RCT accuracy. This result suggests that the task required more cognitive resources under the print medium for those with a worse comprehension performance in reading, and a more conservative pattern in digital RCT for those with a better performance.

Fabricating and printing chemiresistors based on monolayer-capped metal nanoparticles.

Chemiresistors that are based on monolayer-capped metal nanoparticles (MCNPs) have been used in a wide variety of innovative sensing applications, including detection and monitoring of diagnostic markers in body fluids, explosive materials, environmental contaminations and food quality control. The sensing mechanism is based on reversible swelling or aggregation and/or changes in dielectric constant of the MCNPs. In this protocol, we describe a procedure for producing MCNP-based chemiresistive sensors that is reproducible from device to device and from batch to batch. The approach relies on three main steps: (i) controlled synthesis of gold MCNPs, (ii) fabrication of electrodes that are surrounded with a microbarrier ring to confine the deposited MCNP solution and (iii) a tailor-made drying process to enable evaporation of solvent residues from the MCNP sensing layer to prevent a coffee-ring effect. Application of this approach has been shown to produce devices with ±1.5% variance-a value consistent with the criterion for commercial sensors-as well as long shelf life and stability. Fabrication of chemical sensors based on dodecanethiol- or 2-ethylhexanethiol-capped MCNPs with this approach provides high sensitivity and accuracy in the detection of volatile organic compounds (e.g., octane and decane), toxic gaseous species (e.g., HCl and NH3) in air and simulated mixtures of lung and gastric cancer from exhaled breath.

Release and cytotoxicity screening of the printer emissions of a CdTe quantum dots-based fluorescent ink.

The fluorescent properties of cadmium telluride (CdTe) containing quantum dots (QDs) have led to novel products and applications in the ink and pigment industry. The toxic effects of the emissions associated to the use of printing ink containing CdTe QDs might differ from those of conventional formulations which do not integrate nanoparticles, as CdTe QDs might be emitted. Within this work, the airborne emissions of a water-soluble fluorescent ink containing polyethylene glycol (PEG)-coated CdTe QDs of 3-5 nm diameter have been characterized and studied under controlled conditions during household inkjet printing in a scenario simulating the use phase. Subsequently, the cytotoxicological potential of atomized CdTe QDs ink in an acute exposure regimen simulating an accidental, worse-case scenario has been evaluated in vitro at the air-liquid interface (ALI) using the pulmonary cell line BEAS-2B. Endpoints screened included cell viability, oxidative stress and inflammatory effects. We have observed that CdTe QDs ink at 54.7 ng/mL decreased cell viability by 25.6 % when compared with clean air after 1h of exposure; a concentration about 65 times higher was needed to observe a similar effect in submerged conditions. However, we did not observe oxidative stress or inflammatory effects. The present study integrates the development of scenarios simulating the use phase of nano-additivated inks and the direct cell exposure for in vitro effects assessment, thus implementing a life-cycle oriented approach in the assessment of the toxicity of CdTe QDs.

Highly sensitive electrochemical aptasensor for Glypican-3 based on reduced graphene oxide-hemin nanocomposites modified on screen-printed electrode surface.

Glypican-3 (GPC3) is a highly specific tumor marker for hepatocellular carcinoma (HCC), and plays an important role in reflecting the existence, therapeutic evaluation, monitoring and prognosis of HCC. Herein, an electrochemical aptasensor was designed for GPC3 detection with the reduced graphene oxide-hemin nanocomposites (RGO-Hemin) modified on the screen-printed electrode surface as the sensing platform and GPC3 aptamer as recognize molecule. In the existence of GPC3, the aptamer can specifically bind with the target GPC3 and form GPC3-aptamer conjugations on the sensing surface, which would increase the resistance of the electron transfer on the electrode and make the decrease of electrochemical signals of Hemin in RGO-Hemin nanocomposites. The electrochemical current change was recorded by differential pulse voltammetry (DPV). Scanning electron microscopy (SEM), Raman microscope (RM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the GPC3 electrochemical aptasensor. Under the optimum conditions, the current response of the electrochemical aptasensor is linearly correlated with the concentration of GPC3 (0.001-10.0 µg/mL) with the detection limit of 2.86 ng/mL (S/N = 3) and the sensitivity of 0.134 µA/µM/cm2. In addition, the aptasensor was applied to the determination of GPC3 in spiked human plasma and the recoveries fluctuated from 102.68% to 117.29%. All these results show that the aptasensor has good specificity, sensitivity, stability and reproducibility for GPC3 detection.

Prevalence of work-related musculoskeletal disorders among Egyptian printing workers evidenced by using serum biomarkers of inflammation, oxidative stress, muscle injury, and collagen type I turnover.

OBJECTIVE: Printing workers experience a high rate of musculoskeletal disorders (MSDs). This study aims to determine the prevalence of MSDs, estimate serum biomarkers denoting musculoskeletal tissue changes, and determine some individual risk factors for MSDs among Egyptian printing workers. METHODS: Eighty-five male printing workers and 90 male administrative employees (control group) were recruited from a printing press in Giza. A validated version of the standardized Nordic questionnaire was used. Serum biomarkers of inflammation (interleukin (IL)-1α, IL-1ß, IL-6, tumor necrosis factor (TNF)-α, and C-reactive protein (CRP)), cell stress or injury (malondialdehyde (MDA) and creatine kinase skeletal muscle (CK-MM)), and collagen metabolism (collagen-I carboxy-terminal propeptide (PICP) and type-I collagen cross-linked C-telopeptide (CTx)) were measured for all participants. RESULTS: This study showed a significant (p < 0.001) prevalence of the musculoskeletal symptoms (76.5%) and significant (p < 0.001) elevation in the levels of all measured biomarkers among the printing workers (means ± SD: IL-1α = 1.55 ± 0.9, IL-1ß = 1.53 ± 0.87, IL-6 = 1.55 ± 0.85, TNF-α = 4.9 ± 2.25, CRP = 6.78 ± 3.07, MDA = 3.41 ± 1.29, CK-MM = 132.47 ± 69.01, PICP = 103.48 ± 36.44, and CTx = 0.47 ± 0.16) when compared with their controls (prevalence: 34.4%; means ± SD: IL-1α = 0.88 ± 0.61, IL-1ß = 0.96 ± 0.72, IL-6 = 1.03 ± 0.75, TNF-α = 2.56 ± 1.99, CRP = 2.36 ± 1.1, MDA = 0.85 ± 0.21, CK-MM = 53.48 ± 33.05, PICP = 56.49 ± 9.05, and CTx = 0.31 ± 0.06). Also, significant (p < 0.001) positive strong associations were observed between age, body mass index (BMI), and the duration of employment with all measured biomarkers, where all correlation coefficients were >0.7. CONCLUSION: Printing workers suffer a high prevalence of work-related MSDs that might be related to some individual factors (age, BMI, and duration of employment). Consequently, preventive ergonomic interventions should be applied. Further studies should be done to elucidate the link between tissue changes and detected biomarkers to follow the initiation and progression of MSDs and study the effectiveness of curative interventions.

Potential hazardous effects of printing room PM2.5 exposure include promotion of lung inflammation and subsequent injury.

There have been few studies investigating the potential effects of indoor sources of particulate matter on human health. In this study, the effect of different concentrations of fine particulate matter (PM2.5) collected from a printing room on lung health was examined using cultured cells and a mouse model. Further, the mechanism of lung injury was examined. The results indicated that PM2.5 significantly enhanced malondialdehyde activity (P<0.05), decreased superoxide dismutase activity (P<0.05), upregulated the expression of pro­inflammatory factors including interleukin (IL)­1ß, tumor necrosis factor­, IL­6 and downregulated the expression of the inflammatory factor IL­2 (P<0.05). Western blot analysis indicated that PM2.5 significantly enhanced expression of phosphorylated (p)­ERK relative to total ERK, cyclooxygenase­2, p­anti­nuclear­factor­κB (p­NF­κB) relative to NF­κB, transforming growth factor­ß1 and Bax relative to Bcl­2 in inflammation (P<0.05), fibrosis and apoptosis signaling pathways. Furthermore, the results revealed that exposure was associated with an increased abundance of pathogens including Burkholderiales, Coriobacteriia, and Betaproteobacteria in in the lungs. In conclusion, exposure to PM2.5 from a printing room significantly increased inflammation, fibrosis, apoptosis and the abundance of pathogenic bacteria, indicating that exposure is potential threat to individuals who spend a significant amount of time in printing rooms.

Perception of the use and understanding of nutrition labels among different socioeconomic groups in Mexico: a qualitative study / Percepción del uso y comprensión del etiquetado de alimentos en diferentes grupos socioeconómicos de México: un estudio cualitativo

Abstract: Objectiv: To explore the perception of the use and comprehension of the nutrition labeling (GDA, NFT, NS) and claims in packaged foods among different socio economic-status (SES). Materials and methods: This was a qualitative study, 12 focus groups were performed in four cities of Mexico. Participants were recruited outside the supermarkets, which were selected according to SES using Basic Geostatistical Areas. The focus groups had a total of 78 participants. Results: Participants perceived several barriers to the use and understanding of the GDA; like technicalities of the terms used, and the format (small font size and percentages). Claims are mistrusted in general. Participants from the high SES believed that the claims are just a marketing strategy. Conclusion: This study shows the consumers' difficulties to understand the current nutrition labeling system regardless SES. These data might call attention in order to implement a simpler nutrition labeling system that is understood regardless of SES.

Resumen: Objetivo: Explorar la percepción sobre el uso y la comprensión del etiquetado de alimentos (GDA, NFT, NS) y sobre las declaraciones de alimentos empaquetados entre diferentes niveles socioeconómicos (NSE). Material y métodos: Estudio cualitativo en el que se formaron 12 grupos focales en cuatro ciudades de México. Los participantes fueron reclutados afuera de supermercados y fueron seleccionados por nivel socioeconómico, a partir de Áreas Geoestadísticas Básicas. El número total de participantes fue 78. Resultados: Los participantes percibieron barreras para el uso y comprensión del GDA como términos técnicos utilizados, fuente pequeña y porcentajes numéricos. Se reportó desconfianza hacia las declaraciones en alimentos empaquetados. Los participantes del NSE alto perciben que las declaraciones son estrategia de marketing. Conclusión: Este estudio muestra las dificultades para entender el etiquetado de alimentos actual entre diferentes NSE. Estos datos enfatizan la necesidad de implementar un etiquetado que sea comprendido entre NSE.

Nanocomposites of poly(l-methionine), carbon nanotube-graphene complexes and Au nanoparticles on screen printed carbon electrodes for electrochemical analyses of dopamine and uric acid in human urine solutions.

A sensitive electrochemical sensor featuring novel composites of gold and carbon nanocomplexes alongside a polymerized amino acid was developed for the determination of uric acid (UA) and dopamine (DA) concentrations in both buffer and human urine sample solutions. The sensor was fabricated by electropolymerization of l-methionine (l-Met) followed by coating of carbon nanotube-graphene complexes and electrodeposition of gold nanoparticles on a screen printed carbon electrode surface. The electrode surfaces were characterized by field emission scanning electron microscopy and energy dispersive spectroscopy, and the electrochemical properties were investigated by cyclic voltammetry and differential pulse voltammetry. Linear ranges of 0.05-3 µM and 1-35 µM with limits of detection of 0.0029 and 0.034 µM were achieved for DA and UA, respectively. In addition, the developed sensor was applied for the analysis of native UA and DA concentrations in undiluted and diluted human urine samples. The UA analysis results were compared to those obtained using high performance liquid chromatography and a fluorometric assay kit while the DA analysis results were compared to those obtained using liquid chromatography-tandem mass spectrometry.

Lithographic lecture notes. A tool of forensic medicine teaching. Observation on the lessons of Paolo Pellacani (1884-1885), forensic physician at the University of Pavia.

We focus our attention on the use of lithographed lecture notes written by professors, or more often by students, in the teaching of medicine and surgery courses, between the late 19th and early 20th centuries, a period in which, to better understand the phenomena underlying life and death, collaboration between medical professionals and natural science researchers was intense (1). In particular, we analyzed the lithographed lecture notes of Professor Paolo Pellacani at the University of Pavia for the course of legal medicine.

Proof-of-Concept for Gas-Entrapping Membranes Derived from Water-Loving SiO2/Si/SiO2 Wafers for Green Desalination.

Desalination through direct contact membrane distillation (DCMD) exploits water-repellent membranes to robustly separate counterflowing streams of hot and salty seawater from cold and pure water, thus allowing only pure water vapor to pass through. To achieve this feat, commercial DCMD membranes are derived from or coated with water-repellent perfluorocarbons such as polytetrafluoroethylene (PTFE) and polyvinylidene difluoride (PVDF). However, the use of perfluorocarbons is limiting due to their high cost, non-biodegradability, and vulnerability to harsh operational conditions. Unveiled here is a new class of membranes referred to as gas-entrapping membranes (GEMs) that can robustly entrap air upon immersion in water. GEMs achieve this function by their microstructure rather than their chemical make-up. This work demonstrates a proof-of-concept for GEMs using intrinsically wetting SiO2/Si/SiO2 wafers as the model system; the contact angle of water on SiO2 is θo ≈ 40°. Silica-GEMs had 300 µm-long cylindrical pores whose diameters at the (2 µm-long) inlet and outlet regions were significantly smaller; this geometrically discontinuous structure, with 90° turns at the inlets and outlets, is known as the "reentrant microtexture". The microfabrication protocol for silica-GEMs entails designing, photolithography, chrome sputtering, and isotropic and anisotropic etching. Despite the water loving nature of silica, water does not intrude silica-GEMs on submersion. In fact, they robustly entrap air underwater and keep it intact even after six weeks (>106 seconds). On the other hand, silica membranes with simple cylindrical pores spontaneously imbibe water (< 1 s). These findings highlight the potential of the GEMs architecture for separation processes. While the choice of SiO2/Si/SiO2 wafers for GEMs is limited to demonstrating the proof-of-concept, it is expected that the protocols and concepts presented here will advance the rational design of scalable GEMs using inexpensive common materials for desalination and beyond.

Biological monitoring of occupational exposure to dichloromethane by means of urinalysis for un-metabolized dichloromethane.

The objective of the study is to establish exposure-excretion relationship between dichlorometane (DCM) in air (DCM-A) and in urine (DCM-U) in workplace to confirm a previous report. Male workers in a screen-printing plant participated in the study. Time-weighted average DCM-A was measured by diffusive sampling followed by gas-chromatography (GC), and DCM in end-of-shift urine samples was by head-space GC. The data were subjected to regression and other statistical analyses. In practice, 30 sets of DCM-A and DCM-U values were available. The geometric mean DCM-A was 8.4 ppm and that of DCM-U (as observed) was 41.1 µg/l. The correlation coefficients (0.70-0.85) were statistically significant across the correction for urine density. Thus, the analysis for un-metabolized DCM in end-of-shift urine samples is applicable for biological monitoring of occupational exposure to DCM, in support of and in agreement with the previous report. In conclusion, biological monitoring of occupational DCM exposure is possible by use of analysis for un-metabolized DCM in end-of-shift urine.