Culture-free, highly sensitive, quantitative detection of bacteria from minimally processed samples using fluorescence imaging by smartphone

Publication date: 30 June 2018
Source:Biosensors and Bioelectronics, Volume 109
Author(s): Sajal Shrivastava, Won-Il Lee, Nae-Eung Lee
A critical unmet need in the diagnosis of bacterial infections, which remain a major cause of human morbidity and mortality, is the detection of scarce bacterial pathogens in a variety of samples in a rapid and quantitative manner. Herein, we demonstrate smartphone-based detection of Staphylococcus aureus in a culture-free, rapid, quantitative manner from minimally processed liquid samples using aptamer-functionalized fluorescent magnetic nanoparticles. The tagged S. aureus cells were magnetically captured in a detection cassette, and then fluorescence was imaged using a smartphone camera with a light-emitting diode as the excitation source. Our results showed quantitative detection capability with a minimum detectable concentration as low as 10 cfu/ml by counting individual bacteria cells, efficiently capturing S. aureus cells directly from a peanut milk sample within 10 min. When the selectivity of detection was investigated using samples spiked with other pathogenic bacteria, no significant non-specific detection occurred. Furthermore, strains of S. aureus from various origins showed comparable results, ensuring that the approach can be widely adopted. Therefore, the quantitative fluorescence imaging platform on a smartphone could allow on-site detection of bacteria, providing great potential assistance during major infectious disease outbreaks in remote and resource-limited settings.

Graphical abstract

http://ift.tt/2Ii5hP1

Sorption of selected pharmaceuticals by a river sediment: role and mechanisms of sediment or Aldrich humic substances

Abstract

Sorption of pharmaceuticals onto sediments is frequently related to organic matter content. Thus, the present work aimed to compare the effect of humic substances (HS) extracted from a river sediment versus Aldrich (HS) on the sorption of selected pharmaceuticals onto this river sediment. The results exhibited no "unique" effect of the presence of HS from the same origin. Thus, the sediment HS increased the sorption of sulfamethoxazole (SMX), diclofenac (DCF), and trimethoprim (TMP), but reduced the sorption of atenolol (ATN). The presence of Aldrich HS increased the sorption of TMP and ATN and decreased the sorption of SMX and DCF. Fluorescence quenching measurements revealed that these effects cannot be explained only by the presence of pharmaceutical HS associations. The use of several sorption models suggested that the sorption of SMX, DCF, and ATN involves multilayer mechanisms. Furthermore, it was pointed out that the presence of HS does not change the sorption mechanisms although it was observed interaction between HS and the sediment. Indeed, the sediment HS sorbs onto the sediment whereas the Aldrich HS tends to mobilize organic compounds from the sediment to the solution.

http://ift.tt/2p7pTAr

Modes of selenium occurrence and LCD modeling of selenite desorption/adsorption in soils around the selenium-rich core, Ziyang County, China

Abstract

Studying the modes of selenium occurrence in high-Se soils and its behaviors can improve understanding and evaluating its cycling, flux, and balance in geo-ecosystems and its influence on health. In this paper, using a modified sequential chemical extraction technique, seven operationally defined selenium fractions and Se valence distribution were determined about five soils in which paddy was planted (W1, W2, W3, W4, W5) and five soils in which maize was planted (H1, H2, H3, H4, H5) around the selenium-rich core, Ziyang County, Shaanxi Province, China. The results show that selenium fractions in the soils mainly include sulfide/selenide and base-soluble Se, and ligand-exchangeable Se is also high for five soils in which paddy was planted. For water-soluble Se, Se (IV) is main Se valence and almost no Se (VI) was determined about five soils in which paddy was planted, while almost 1:1 of Se (IV) and Se (VI) coexist about five soils in which maize was planted. For exchangeable Se, similar results were found. For the first time, two typical high-Se soils (W1 soil and H1 soil) were chosen to measure the pH-dependent solid-solution distribution of selenite in the pH range 3–9, and the results were explained using LCD (ligand and charge distribution) adsorption modeling. The desorbed selenite concentrations from the two soils are in general underestimated by the model due to a comparable binding affinity of phosphate and selenite on goethite and much lower amount of total selenite than total reactively adsorbed phosphate. The pH dependency of adsorption of selenite added to the soil can be successfully described with the LCD model for W1 soil. Whereas considering the influence of Al-oxides, by lowering selenite adsorption affinity constant K of Se adsorption on goethite by 16 times, the LCD model can describe the adsorption much better. The results can help to understand selenium cycling, flux, and balance in typical high-Se soils.

http://ift.tt/2Ikd3aL

Distillers’ grains anaerobic digestion residue biochar used for ammonium sorption and its effect on ammonium leaching from an Ultisol

Abstract

The aim of this work was to explore the potential application of biochar from distillers' grains anaerobic digestion residue pyrolyzed at 700 °C (ADR-DG₇₀₀) to ammonium (NH₄⁺) adsorption from aqueous solution, as well as its effect on NH₄⁺ leaching from an Ultisol. The adsorption kinetic of NH₄⁺ on the ADR-DG₇₀₀ could be described by an Elovich model (R² = 0.995), and the combined Langmuir-Freundlich model (R² = 0.997) fitted the isotherm data better than the Langmuir, Freundlich, Redlich-Peterson, and Temkin models with a maximum adsorption of 11.41 mg N g⁻¹. The NH₄⁺ adsorption on ADR-DG₇₀₀ was mainly controlled by the cation exchange, the surface complexation with oxygen-containing functional groups of carboxyl C〓O (C▬O) and carbohydrate C▬OH, as well as the electrostatic interactions with Si▬O▬Si functional group. In addition, the ADR-DG₇₀₀ soil application reduced 2.48–20.67% of NH₄⁺-N leaching loss after nitrogen fertilizer application in an Ultisol. These results suggested that the ADR-DG₇₀₀ could be a sorbent for NH₄⁺-contaminated water as well as an inhibitor for soil NH₄⁺ leaching.

http://ift.tt/2p5DxUS

Heavy metals transfer in the olive tree and assessment of food contamination risk

Abstract

Due to constraints of fresh water for agricultural irrigation, wastewater was used for irrigation of agricultural land as alternative water resources in arid and semi-arid Tunisian regions. However, long-term irrigation may cause contamination by heavy metals in the soil as well as for crops, thus becoming a threat to humans. To understand the effect of irrigation with wastewater on the concentrations of heavy metals Cr, Cu, Mn, Zn, and Pb, in soil and plants, soil samples and plants were collected and analyzed. Results have shown that all soil samples do not exhibit extreme values. The content of heavy metals in the surface layer (0–30 cm) is much higher than that in depth. Overall, the concentrations of Mn, Pb, Cu, Cr, and Zn in soil were found to be lower than the authorized national safety limits. Moreover, the content in both parts of forage crops have not exceeded the WHO standard. For olive trees, no negative values were found in the different organs, which was also true for the extracted oil. An exception happened for the oils produced from fallen olives in direct contact with the wastewater and the soil. Therefore, to ensure food security and wastewater use for irrigation, monitoring and control of pollution is required.

Graphical abstract

Biomass production from treated wastewater without risk

http://ift.tt/2IkTCyH

Quantification of polychlorinated biphenyl contamination using human placenta as biomarker from Punjab Province, Pakistan

Abstract

The present study biomonitored the placental polychlorinated biphenyl (PCB) concentrations in women from Punjab Province, Pakistan, that provides the pioneer data for occurrence and body burden of PCBs in placental tissues from South Asian women. The ∑₃₄PCB concentrations in placental tissues were ranged from 20.2 to 115.98 ng/g lipid weight (lip. wt.), with predominance of tetra-PCB (54.67%). The levels of ∑₈DL-PCBs and ∑₆-indicator PCBs were ranged from 2.03 to 27.64 ng/g (lip. wt.) and 1.71 to 30.8 ng/g (lip. wt.), respectively. The WHO-TEQ2005 values for DL-PCBs were ranged from 1.18 × 10⁻⁵ to 0.067 ng/g (lip. wt.), with highest value evaluated for CB-126. The estimated daily intake (EDI) for DL-PCBs was ranged from 9.27 × 10⁻⁸ to 5.25 × 10⁻⁴ pg WHO-TEQ/kg body weight (bw), which was within the tolerable daily intake (TDI) values established by international organizations. The spatial distribution patterns of Σ₃₄PCB concentrations from study area have shown relative higher concentrations in samples from urban and industrial cities than rural areas, and industrial and urban releases along with e-waste handling were recognized as vital PCB sources in the environment. In order to ascertain the transplacental transfer of PCBs, the fetal growth parameters were correlated with the ∑₃₄PCB concentrations in placental tissues. The relationship between ∑₃₄PCB concentrations in placental tissues and infant's anthropometric measures through multiple linear regression showed a negative correlation of infant's body weight (R² = 0.0728), crown to heel length (R² = 0.068), head circumference (R² = 0.0342), chest circumference (R² = 0.0001), and mid arm circumference (R² = 0.0096) that noticeably highlights the inhibited fetal anthropometric development associated with maternal PCB bioaccumulation. Hence, an immediate elimination of ongoing PCB addition in the studied area has been emphasized and further investigations are suggested to appropriately manage the public and neonatal health risks in the region.

http://ift.tt/2p5DsAy

The toxicity of cadmium ion (Cd 2+ ) to phycocyanin: an in vitro spectroscopic study

Abstract

The pollution of heavy metals is a severer problem for the ecosystems in waters. The toxicity of Cd²⁺ on phycocyanin (PC) is studied in molecular level in this work. The fluorescence quenching of PC is observed by the adding Cd²⁺ from 0 to 500 × 10⁻⁷ mol L⁻¹. From the theoretical calculation and the time-resolved fluorescence decay profiles, the fluorescence quenching of PC by Cd²⁺ is found to be static. The synchronous fluorescence spectra are used to study the change in amino acid residues of PC molecules, indicating that the effect of Cd²⁺ on the Trp of PC is more significant than the Tyr. The UV-Vis absorbance of tetrapyrrole decreases from 0.26 to 0.23 cps with increasing Cd²⁺ concentration, suggesting that Cd²⁺ affects the light adsorption and the photosynthesis function of PC. The circular dichroism spectra reveal that adding Cd²⁺ also changes the secondary structure (α-helix) of PC.

http://ift.tt/2IkVisa

Dermoscopy for the detection and safe extraction of an intracutaneous foreign body Runing Title: Therapeutic Dermoscopy in detection and safe extraction

Publication date: Available online 10 March 2018
Source:Journal of the American Academy of Dermatology
Author(s): Sidharth Sonthalia, Abhijeet Kumar Jha, Feroze Kaliyadan




http://ift.tt/2FvBxfr

Fibrosing Vasculitides: A Heuristic for Investigation

Publication date: Available online 10 March 2018
Source:Journal of the American Academy of Dermatology
Author(s): Audrey Rutherford, Stephen Erickson, Emily Keimig, Heather Wickless




http://ift.tt/2oXvqdS

Inflammatory arthritis in pediatric patients with morphea

Publication date: Available online 10 March 2018
Source:Journal of the American Academy of Dermatology
Author(s): Sakeen W. Kashem, Colleen K. Correll, Richard K. Vehe, Patricia M. Hobday, Bryce A. Binstadt, Sheilagh M. Maguiness
BackgroundMorphea, or 'localized scleroderma', is an inflammatory disorder resulting in fibrosis of the skin and subcutaneous tissues. Joint contractures, arthralgias and functional compromise are recognized associations of pediatric morphea. The co-existence of inflammatory arthritis and morphea is not well-described in the literature.ObjectiveTo investigate the relationship between pediatric morphea and inflammatory arthritis with regards to cutaneous, musculoskeletal and laboratory findings and treatment regimens.MethodsA systematic retrospective chart review of 53 patients with pediatric morphea was performed and analyzed for morphea subtypes, arthritic joint involvement, serum autoantibodies and therapeutic interventions.ResultsEleven out of 53 patients had polyarthritis that involved joints unrelated to the site of the cutaneous morphea. They were mostly female and presented with either the linear or generalized subtypes of morphea. Serum levels of antinuclear antibodies were more significantly elevated in patients with arthritis. All children were treated with methotrexate in addition to other systemic and/or topical immunosuppressive agents.LimitationThis was a small, single center, retrospective study.ConclusionPediatric morphea co-existed with inflammatory arthritis in 11/53 children. Further understanding and appreciation of this relationship may direct more intensive therapy and musculoskeletal screening

Teaser

Pediatric morphea is associated with joint contractures and arthralgia. The findings of this study support the association of inflammatory arthritis with pediatric morphea. Understanding of the relationship between morphea and arthritis in children should lead to increased musculoskeletal vigilance and appropriate systemic therapy.


http://ift.tt/2FvBr7z

Dupilumab for Hand Eczema

Publication date: Available online 10 March 2018
Source:Journal of the American Academy of Dermatology
Author(s): Matthew J. Zirwas




http://ift.tt/2oXvzOs

A Deep Learning Approach for Pose Estimation from Volumetric OCT Data

Publication date: Available online 10 March 2018
Source:Medical Image Analysis
Author(s): Nils Gessert, Matthias Schlüter, Alexander Schlaefer
Tracking the pose of instruments is a central problem in image-guided surgery. For microscopic scenarios, optical coherence tomography (OCT) is increasingly used as an imaging modality. OCT is suitable for accurate pose estimation due to its micrometer range resolution and volumetric field of view. However, OCT image processing is challenging due to speckle noise and reflection artifacts in addition to the images' 3D nature. We address pose estimation from OCT volume data with a new deep learning-based tracking framework. For this purpose, we design a new 3D convolutional neural network (CNN) architecture to directly predict the 6D pose of a small marker geometry from OCT volumes. We use a hexapod robot to automatically acquire labeled data points which we use to train 3D CNN architectures for multi-output regression. We use this setup to provide an in-depth analysis on deep learning-based pose estimation from volumes. Specifically, we demonstrate that exploiting volume information for pose estimation yields higher accuracy than relying on 2D representations with depth information. Supporting this observation, we provide quantitative and qualitative results that 3D CNNs effectively exploit the depth structure of marker objects. Regarding the deep learning aspect, we present efficient design principles for 3D CNNs, making use of insights from the 2D deep learning community. In particular, we present Inception3D as a new architecture which performs best for our application. We show that our deep learning approach reaches errors at our ground-truth label's resolution. We achieve a mean average error of 14.89 ± 9.3µm and 0.096 ± 0.072° for position and orientation learning, respectively.

Graphical abstract

http://ift.tt/2FHgLwM

In situ synthesized TiC/Mo-based composites via laser powder bed fusion

Publication date: 15 May 2018
Source:Materials & Design, Volume 146
Author(s): Weiwei Zhou, Xiaohao Sun, Keiko Kikuchi, Naoyuki Nomura, Kyosuke Yoshimi, Akira Kawasaki
A strategy utilizing carbon nanotubes (CNTs) was put forward to synthesize in situ TiC/Mo-based composites via laser powder bed fusion (laser PBF). The functionalized CNTs were dispersed with MoTiAl powders under electrostatic attraction by heteroagglomeration. During laser PBF, individual CNTs reacted with Ti elements and were completely transformed into monocrystalline TiC. Those TiC reinforcements were homogeneously dispersed and intimately contacted the matrix, giving rise to the morphological evolution of a MoTiAl matrix from the nearly columnar to fine equiaxed grains as well as improved mechanical performance. Our finding offers significant guidance for designing and producing advanced Mo-based composites in the application of heat-resistant materials.

Graphical abstract

http://ift.tt/2FH921P

A strategy for improving the mechanical properties of silk fiber by directly injection of ferric ions into silkworm

Publication date: 15 May 2018
Source:Materials & Design, Volume 146
Author(s): Qingsong Liu, Xin Wang, Xiaoyin Tan, Xiaoqian Xie, Yi Li, Ping Zhao, Qingyou Xia
Silk fibers produced by the silkworm, Bombyx mori, are widely used bio-materials due to their superior toughness and elongation. However, the stress and stiffness of silkworm silk are not comparable to the synthetic fiber or other natural silk such as the spider silk. How to improve the mechanical properties of silk fibers has been of great interest. In this paper, we developed a new strategy for improving the mechanical properties of silk fibers by directly injecting ferric ions (Fe³⁺) into silkworm. The Fe³⁺-injected silkworms could produce robust silk fibers with improved stress, stiffness and toughness. Secondary structural analysis indicated that Fe³⁺ promoted the conformation transition of silk from random coil or helical structure to β-sheet structure. These evidences might explain why these fibers became stronger, stiffer and tougher. Trying to unravel the molecular foundation behind this interesting phenomenon, turbidity assays and fluorescence spectroscopy were introduced. The results indicated that Fe³⁺ was able to interact with tyrosine and tryptophan residues within the silk. The crosslinking might act as the "bridge" to form the β-sheet structure, thus increasing the mechanical properties of silk fiber. These findings suggested that Fe³⁺ could be a promising target to modify the mechanical properties of silk fibers.

Graphical abstract

http://ift.tt/2tAKfrq

Collaborative behavior in α lamellae and β phase evolution and its effect on the globularization of TC17 alloy

Publication date: 15 May 2018
Source:Materials & Design, Volume 146
Author(s): Jiao Luo, Peng Ye, Wen Chao Han, Miao Quan Li
The globularization behavior of the basketweave microstructure in TC17 alloy is quantitatively analyzed during deformation and subsequent heat treatment. Collaborative behavior in the α lamellae and β phase evolution are proposed to affect globularization based on the transmission electron microscopy (TEM) and high-resolution electron backscatter diffraction (EBSD) observations as follows: (i) the interleaved α lamellae restrain the rotation of neighboring α lamellae and promote the formation of low-angle boundaries (LABs) and grooves, and then (ii) the β phase has a positive effect on facilitating the complete separation of α lamellae during deformation. During heat treatment, (iii) the formation of the LABs in the β grain interiors accelerates the appearance of necklace-like α grains, and (iv) the α lamellae promotes the break-up of β phase while the β phase has a positive effect on facilitating the complete separation of α lamellae. In other words, Collaborative behavior in α lamellae and β phase evolution promotes the globularization of TC17 alloy containing a basketweave microstructure. Except for the boundary splitting and termination migration, the mechanism of substructure rotation also participates in the globularization of TC17 alloy containing a basketweave microstructure, which is different to that of the alloys containing a colony microstructure.

Graphical abstract

http://ift.tt/2FEwBbF

Optimisation of interface formation by shear inclination: Example of aluminium-cooper hybrid produced by ECAP with back-pressure

Publication date: 15 May 2018
Source:Materials & Design, Volume 146
Author(s): Alexander E. Medvedev, Rimma Lapovok, Eric Koch, Heinz Werner Höppel, Mathias Göken
Hybrid materials present a convenient way of combining properties of more than one material in one product. However, there are problems associated with such manufacturing, particularly, in relation to the properties of the interface between components. Intermetallic compounds can potentially form in this area, whose size and composition can have a profound effect on mechanical properties of the product. In this work, we investigate the effect of temperature, mutual arrangement and hydrostatic pressure on the quality of the interface between Al and Cu parts, processed simultaneously by severe plastic deformation. We show that three intermetallic compounds - θ-Al2Cu, ζ2-Al3Cu4-δ and γ1-Al4Cu9 - form on the interface. It is shown that the formation of these phases on the interface between aluminium and copper highly depends on the combination of diffusion and recrystallization process.

Graphical abstract

http://ift.tt/2tuGiVi

Scalable manufacturing of immiscible AlBi alloy by self-assembled nanoparticles

Publication date: 15 May 2018
Source:Materials & Design, Volume 146
Author(s): Chezheng Cao, Weiqing Liu, Zhiwei Liu, Jiaquan Xu, Injoo Hwang, Igor De Rosa, Xiaochun Li
Immiscible AlBi alloy, with a miscibility gap in the liquid state is not only scientifically important, but also it can offer outstanding self-lubricating properties. However, it is still difficult to control the distribution and size of minority Bi phase during cooling and solidification. Here we show that by applying a scalable molten salt assisted incorporation process, TiC nanoparticles can be incorporated in Al matrix to produce Al-TiC master nanocomposites, which can be readily used to process AlBi immiscible alloy and restrict the size of minority Bi phase. TiC nanoparticles can be self-assembled on the AlBi interface and restrict Bi phase size substantially. In addition, submicron minority Bi phase can be achieved by combining the addition of nanoparticles with high cooling rates. Mechanical properties of AlBi immiscible alloys can be further enhanced by the addition of Cu element and cold rolling.

Graphical abstract

http://ift.tt/2FFISMN

Formation and application of hierarchical calcium silicate-calcium sulfate whiskers

Publication date: 15 May 2018
Source:Materials & Design, Volume 146
Author(s): Yu-rong Yang, Qing-jie Zhang, Wei Cai, Mei-gui Yi, Lan Xiang
A facile method was designed for synthesizing hierarchical calcium silicate-calcium sulfate whiskers (H-CSW) via treatment of the calcium sulfate whiskers (CSW) in sodium silicate solution. Calcium silicate nanoparticles with a size of 70–100nm were uniformly anchored on H-CSW surfaces and the specific surface areas of the whiskers increased from 6.0m²·g⁻¹ to 29.1m²·g⁻¹. The addition of 2.0wt% of H-CSW in epoxy composite led to the increase of 10% in flexural strength, 16% in flexural modulus, 18% in storage modulus (30°C) and 8°C in glass transition temperature owing to the enhanced mechanical interlocking among H-CSW and the epoxy matrix.

Graphical abstract

http://ift.tt/2tuGhRe

Regarding “Epidemiology and risk factors for Clostridium difficile-associated diarrhea in adult inpatients in a university hospital in China: Methodologic issues”

Publication date: Available online 9 March 2018
Source:American Journal of Infection Control
Author(s): Chenjie Tang, Yi Cui, Genyan Liu




http://ift.tt/2p5sJWO

Comparison of Self-Report Versus Sensor-Based Methods for Measuring the Amount of Upper Limb Activity Outside the Clinic

Publication date: Available online 10 March 2018
Source:Archives of Physical Medicine and Rehabilitation
Author(s): Kimberly J. Waddell, Catherine E. Lang
ObjectiveTo compare self-reported with sensor-measured upper limb (UL) performance in daily life for individuals with chronic (≥6mo) UL paresis poststroke.DesignSecondary analysis of participants enrolled in a phase II randomized, parallel, dose-response UL movement trial. This analysis compared the accuracy and consistency between self-reported UL performance and sensor-measured UL performance at baseline and immediately post an 8-week intensive UL task-specific intervention.SettingOutpatient rehabilitation.ParticipantsCommunity-dwelling individuals with chronic (≥6mo) UL paresis poststroke (N=64).InterventionsNot applicable.Main Outcome MeasuresMotor Activity Log amount of use scale and the sensor-derived use ratio from wrist-worn accelerometers.ResultsThere was a high degree of variability between self-reported UL performance and the sensor-derived use ratio. Using sensor-based values as a reference, 3 distinct categories were identified: accurate reporters (reporting difference ±0.1), overreporters (difference >0.1), and underreporters (difference <−0.1). Five of 64 participants accurately self-reported UL performance at baseline and postintervention. Over half of participants (52%) switched categories from pre-to postintervention (eg, moved from underreporting preintervention to overreporting postintervention). For the consistent reporters, no participant characteristics were found to influence whether someone over- or underreported performance compared with sensor-based assessment.ConclusionsParticipants did not consistently or accurately self-report UL performance when compared with the sensor-derived use ratio. Although self-report and sensor-based assessments are moderately associated and appear similar conceptually, these results suggest self-reported UL performance is often not consistent with sensor-measured performance and the measures cannot be used interchangeably.



http://ift.tt/2GcezLv