Development & Characterization of Fluorescently Tagged Nanocellulose for Nanotoxicological Studies

The rapid adoption of nanocellulose-based engineered nanomaterials (CNM) by many industries generates environmental health and safety (EHS) concerns. This work presents the development of fluorescently tagged CNM which can be used to study their interactions with biological systems. Specifically, cellulose nano-fibrils and cellulose nano-crystals with covalently attached fluorescein isothiocyanate (FITC) molecules on their surface were synthesized. The fluorescence of the FITC-tagged materials was assessed along with potential FITC detachment under pH conditions encountered in the human gastrointestinal tract, in intracellular compartments, and in cell culture media. Finally, the potential cytotoxicity due to the presence of FITC molecules on the surface of CNM was assessed using a cellular gut epithelium model. The results showed that neither FITC-CNF nor FITC-CNC were cytotoxic and that they have a comparable bioactivity to their untagged counterparts, rendering them suitable for biological studies.

Development of a standardized food model for studying the impact of food matrix effects on the gastrointestinal fate and toxicity of ingested nanomaterials

Food matrix effects impact the bioavailability and toxicity of pharmaceuticals, nutraceuticals, pesticides, and engineered nanomaterials (ENMs). However, there are currently no standardized food models to test the impact of food matrix effects using in vitro gastrointestinal models. The purpose of this study was to establish a standardized food model (SFM) for evaluating the toxicity and fate of ingested ENMs and then to assess its efficacy by examining the impact of food matrix effects on the toxicity of TiO2 nanoparticles. The formulation of the SFM was based on the average composition of the US diet: 3.4% protein (sodium caseinate); 4.6% sugar (sucrose); 5.2% digestible carbohydrates (modified corn starch); 0.7% dietary fiber (pectin); 3.4% fat (corn oil); and, 0.5% minerals (sodium chloride). The SFM consisted of an oil-in-water emulsion suitable for use in both wet and dried forms. The dried form was produced by spray drying the emulsion to improve its handling and extend its shelf-life. The particle size (D32 = 135 nm), surface charge (-37.8 mV), viscosity, color (L*, a,* b* = 82.1, -2.5, 1.3), and microstructure of the wet SFM were characterized. The hydration properties, flowability (repose angle ≈ 27.9°; slide angle ≈ 28.2°), and moisture sorption isotherms of the dry SFM were comparable to commercial food powders. The potential gastrointestinal fate of the SFM was determined using a simulated gastrointestinal tract, including mouth, stomach, and small intestine steps. Conversion of the SFM into a powdered form did not impact its gastrointestinal fate. A nanotoxicology case study with TiO2 nanoparticles exposed to a tri-culture epithelial cell model showed that food matrix effects reduced ENM cytotoxicity more than 5-fold. The SFM developed in the current study could facilitate studies of the impact of food matrix effects on the gastrointestinal fate and toxicity of various types of food NPs.

Effectiveness of Early Hematopoietic Stem Cell Transplantation in Preventing Neurocognitive Decline in Mucopolysaccharidosis Type II: A Case Series

The early progressive form of the X-linked disorder, Hunter syndrome or mucopolysaccharidosis type II (MPS II) (OMIM #309900), is characterized by cognitive decline, and pulmonary and cardiac complications that often cause death before 20 years of age. Deficiency of the lysosomal enzyme, iduronate-2-sulfatase (EC 3.1.6.13) results in deposition of the glycosaminoglycans, dermatan, and heparan sulfate in various tissues. In recent years, enzyme replacement therapy (ERT) has become the mainstay of treatment, but is expensive and ineffective in arresting cognitive decline. Hematopoietic stem cell transplantation (HSCT) also provides enzyme replacement, and may be effective in stabilizing neurocognitive function if initiated early, though data are limited. We present a case series of four patients who demonstrated neurocognitive stabilization with early HSCT. HSCT is a potentially underutilized treatment strategy for select groups of MPS II patients.

Nitric Oxide Dependent Degradation of Polyethylene Glycol-Modified Single-Walled Carbon Nanotubes: Implications for Intra-Articular Delivery

Polyethylene glycol (PEG)-modified carbon nanotubes have been successfully employed for intra-articular delivery in mice without systemic or local toxicity. However, the fate of the delivery system itself remains to be understood. In this study 2 kDa PEG-modified single-walled carbon nanotubes (PNTs) are synthesized, and trafficking and degradation following intra-articular injection into the knee-joint of healthy mice are studied. Using confocal Raman microspectroscopy, PNTs can be imaged in the knee-joint and are found to either egress from the synovial cavity or undergo biodegradation over a period of 3 weeks. Raman analysis discloses that PNTs are oxidatively degraded mainly in the chondrocyte-rich cartilage and meniscus regions while PNTs can also be detected in the synovial membrane regions, where macrophages can be found. Furthermore, using murine chondrocyte (ATDC-5) and macrophage (RAW264.7) cell lines, biodegradation of PNTs in activated, nitric oxide (NO)-producing chondrocytes, which is blocked upon pharmacological inhibition of inducible nitric oxide synthase (iNOS), can be shown. Biodegradation of PNTs in macrophages is also noted, but after a longer period of incubation. Finally, cell-free degradation of PNTs upon incubation with the peroxynitrite-generating compound, SIN-1 is demonstrated. The present study paves the way for the use of PNTs as delivery systems in the treatment of diseases of the joint.

Graphene oxide is degraded by neutrophils and the degradation products are non-genotoxic

Neutrophils were previously shown to digest oxidized carbon nanotubes through a myeloperoxidase (MPO)-dependent mechanism, and graphene oxide (GO) was found to undergo degradation when incubated with purified MPO, but there are no studies to date showing degradation of GO by neutrophils. Here we produced endotoxin-free GO by a modified Hummers' method and asked whether primary human neutrophils stimulated to produce neutrophil extracellular traps or activated to undergo degranulation are capable of digesting GO. Biodegradation was assessed using a range of techniques including Raman spectroscopy, transmission electron microscopy, atomic force microscopy, and mass spectrometry. GO sheets of differing lateral dimensions were effectively degraded by neutrophils. As the degradation products could have toxicological implications, we also evaluated the impact of degraded GO on the bronchial epithelial cell line BEAS-2B. MPO-degraded GO was found to be non-cytotoxic and did not elicit any DNA damage. Taken together, these studies have shown that neutrophils can digest GO and that the biodegraded GO is non-toxic for human lung cells.

Involvement of NK Cells against Tumors and Parasites

Host resistance against pathogens depends on a complex interplay of innate and adaptive immune mechanisms. Acting as an early line of defence, the immune system includes activation of neutrophils, tissue macrophages, monocytes, dendritic cells, eosinophils and natural killer (NK) cells. NK cells are lymphoid cells that can be activated without previous stimulation and are therefore like macrophages in the first line of defence against tumor cells and a diverse range of pathogens. NK cells mediate significant activity and produce high levels of proinflammatory cytokines in response to infection. Their cytotoxicity production is induced principally by monocyte-, macrophage- and dendritic cell-derived cytokines, but their activation is also believed to be cytokine-mediated. Recognition of infection by NK cells is accomplished by numerous activating and inhibitory receptors on the NK cells’ surface that selectively trigger the cytolytic activity in a major histocompability complex-independent manner. NK cells have trypanocidal activity of fibroblast cells and mediate direct destruction of extracellular epimastigote and trypomastigote forms of T. cruzi and T. lewisi in vitro; moreover, they kill plasmodia-infected erythrocytes directly through cell-cell interaction. This review provides a more detailed analysis of how NK cells recognize and respond to parasites and how they mediate cytotoxicity against tumor cells. Also the unique role of NK cells in innate immunity to infection and the relationship between parasites and carcinogenesis are discussed.

Tracking urban human activity from mobile phone calling patterns

Timings of human activities are marked by circadian clocks which in turn are entrained to different environmental signals. In an urban environment the presence of artificial lighting and various social cues tend to disrupt the natural entrainment with the sunlight. However, it is not completely understood to what extent this is the case. Here we exploit the large-scale data analysis techniques to study the mobile phone calling activity of people in large cities to infer the dynamics of urban daily rhythms. From the calling patterns of about 1,000,000 users spread over different cities but lying inside the same time-zone, we show that the onset and termination of the calling activity synchronizes with the east-west progression of the sun. We also find that the onset and termination of the calling activity of users follows a yearly dynamics, varying across seasons, and that its timings are entrained to solar midnight. Furthermore, we show that the average mid-sleep time of people living in urban areas depends on the age and gender of each cohort as a result of biological and social factors.

Refractive index profilometry using the total internally reflected light field

A full-field polarization-based technique is presented for quantitative evaluation of the spatial distribution of the refractive index in macro and micro samples. The sample is mounted on a glass-air interface of a prism, illuminated by a linearly polarized collimated light beam, and two intensity frames are digitally recorded with specific orientations of an analyzer. The pair of intensity data frames captured with this simple setup is combined through an algorithm specially developed for the purpose, to yield the phase difference between the transverse electric and transverse magnetic components of the total internally reflected light field. The phase difference is then related to the refractive index of the sample. Experimental results for refractive index variations in a laser-etched glass plate and red blood corpuscles are presented. One of the salient features of the proposed technique is that the depth of measurement is dependent on the penetration depth of the sample's evanescent field, which is typically of the order of a few hundred nanometers, thereby facilitating refractive index measurements along a thin section of the sample.

Safe limit of arsenic in soil in relation to dietary exposure of arsenicosis patients from Malda district, West Bengal- A case study

Safe limit of arsenic in soil in relation to dietary exposure of arsenicosis patients was established in Malda district of West Bengal. Out of 182 participants examined, 80 (43.9%) participants showed clinical features of arsenicosis, characterized by arsenical skin lesion (pigmentation and keratosis), while 102 participants did not have any such lesion (control). Experimental results of the twenty eight soils (own field) of the participants showed the mean Olsen extractable and total arsenic concentration of 0.206 and 6.70mgkg^-1, respectively. Arsenic concentration in rice grain ranged from 2.00 to 1260μgkg^-1 with the mean value of 146μgkg^-1. The hazard quotient (HQ) for intake of As by human through consumption of rice varied from 0.03 to 3.52. HQ exceeds 1.0 for drinking water and rice grain grown in the study area in many cases. As high as 77.6% variation in As content in rice grain could be explained by the solubility-free ion activity model. Toxic limit of extractable As in soil for rice in relation to soil properties and human health hazard, associated with consumption of rice grain by human, was established. For example, the permissible limit of Olsen extractable As in soil would be 0.43mgkg^-1 for rice cultivation, if soil pH and organic carbon content were 7.5% and 0.50%, respectively. However, the critical limit of Olsen extractable As in soil would be 0.54mgkg^-1, if soil pH and organic carbon were 8.5% and 0.75%, respectively. The conceptual framework of fixing the toxic limit of arsenic in soils with respect to soil properties and human health under modeling-framework was established.

Seasonal and geographical impact on human resting periods

We study the influence of seasonally and geographically related daily dynamics of daylight and ambient temperature on human resting or sleeping patterns using mobile phone data of a large number of individuals. We observe two daily inactivity periods in the people's aggregated mobile phone calling patterns and infer these to represent the resting times of the population. We find that the nocturnal resting period is strongly influenced by the length of daylight, and that its seasonal variation depends on the latitude, such that for people living in two different cities separated by eight latitudinal degrees, the difference in the resting periods of people between the summer and winter in southern cities is almost twice that in the northern cities. We also observe that the duration of the afternoon resting period is influenced by the temperature, and that there is a threshold from which this influence sets in. Finally, we observe that the yearly dynamics of the afternoon and nocturnal resting periods appear to be counterbalancing each other. This also lends support to the notion that the total daily resting time of people is more or less conserved across the year.

Cytotoxicity screening and cytokine profiling of nineteen nanomaterials enables hazard ranking and grouping based on inflammogenic potential

Engineered nanomaterials (ENMs) are being produced for an increasing number of applications. Therefore, it is important to assess and categorize ENMs on the basis of their hazard potential. The immune system is the foremost defence against foreign bodies. Here we performed cytokine profiling of a panel of nineteen representative ENMs procured from the Joint Research Centre (JRC) and commercial sources. Physicochemical characterization was performed using dynamic light scattering. The ENMs were all shown to be endotoxin content free. The human macrophage-differentiated THP.1 cell line was employed for cytotoxicity screening and based on the calculated IC₅₀ values, the multi-walled carbon nanotubes (MWCNTs), ZnO, Ag and SiO₂ NMs were found to be the most cytotoxic while single-walled carbon nanotubes (SWCNTs), TiO₂, BaSO₄ and CeO₂ NMs, as well as the nanocellulose materials, were non-cytotoxic (at doses up to 100 µg/mL). Multiplex profiling of cytokine and chemokine secretion indicated that the TiO₂, SiO₂, BaSO₄, CeO₂ and nanocellulose materials induced potent inflammatory responses at sub-cytotoxic doses. Hierarchical clustering of cytokine responses coupled with pathway analysis demonstrated that the panel of ENMs could be segregated into two distinct groups characterized by activation and deactivation, respectively, of PPAR (peroxisome proliferator-activated receptor)/LXR (liver X receptor/retinoid X receptor) nuclear receptor pathways (NRPs). Furthermore, using rosiglitazone, a selective PPAR-γ agonist, we could show that PPAR-γ played an important role in the activation of inflammatory responses in cells exposed to TiO₂ and SiO₂ NMs. These studies show that ENMs of diverse chemical compositions can be grouped according to their inflammatory potential.

Absence makes the heart grow fonder: social compensation when failure to interact risks weakening a relationship

Social networks require active relationship maintenance if they are to be kept at a constant level of emotional closeness. For primates, including humans, failure to interact leads inexorably to a decline in relationship quality, and a consequent loss of the benefits that derive from individual relationships. As a result, many social species compensate for weakened relationships by investing more heavily in them. Here we study how humans behave in similar situations, using data from mobile call detail records from a European country. For the less frequent contacts between pairs of communicating individuals we observe a logarithmic dependence of the duration of the succeeding call on the time gap with the previous call. We find that such behaviour is likely when the individuals in these dyadic pairs have the same gender and are in the same age bracket as well as being geographically distant. Our results indicate that these pairs deliberately invest more time in communication so as to reinforce their social bonding and prevent their relationships decaying when these are threatened by lack of interaction.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1140/epjds/s13688-016-0097-x) contains supplementary material.

Communication with Family and Friends across the Life Course

Each stage of the human life course is characterised by a distinctive pattern of social relations. We study how the intensity and importance of the closest social contacts vary across the life course, using a large database of mobile communication from a European country. We first determine the most likely social relationship type from these mobile phone records by relating the age and gender of the caller and recipient to the frequency, length, and direction of calls. We then show how communication patterns between parents and children, romantic partner, and friends vary across the six main stages of the adult family life course. Young adulthood is dominated by a gradual shift of call activity from parents to close friends, and then to a romantic partner, culminating in the period of early family formation during which the focus is on the romantic partner. During middle adulthood call patterns suggest a high dependence on the parents of the ego, who, presumably often provide alloparental care, while at this stage female same-gender friendship also peaks. During post-reproductive adulthood, individuals and especially women balance close social contacts among three generations. The age of grandparenthood brings the children entering adulthood and family formation into the focus, and is associated with a realignment of close social contacts especially among women, while the old age is dominated by dependence on their children.

Low-level birefringence measurement by cyclic-path polarization interferometer

A modified cyclic-path interferometer is employed for complete measurement of spatially varying birefringence. An expanded and collimated laser beam intercepted by a birefringent specimen is incident on a polarization-masked cube beam splitter, resulting in two mutually orthogonal polarization components propagating along clockwise and counterclockwise directions in the interferometer. These two wavefronts are made to interfere for four specific orientations of an analyzer. Suitable combinations of the interferograms result in determination of the direction of birefringence and its magnitude. Experimental results are presented.

Skeletal Mineralization Deficits and Impaired Biogenesis and Function of Chondrocyte-Derived Matrix Vesicles in Phospho1(-/-) and Phospho1/Pi t1 Double-Knockout Mice

We have previously shown that ablation of either the Phospho1 or Alpl gene, encoding PHOSPHO1 and tissue-nonspecific alkaline phosphatase (TNAP) respectively, lead to hyperosteoidosis, but that their chondrocyte-derived and osteoblast-derived matrix vesicles (MVs) are able to initiate mineralization. In contrast, the double ablation of Phospho1 and Alpl completely abolish initiation and progression of skeletal mineralization. We argued that MVs initiate mineralization by a dual mechanism: PHOSPHO1-mediated intravesicular generation of inorganic phosphate (Pi ) and phosphate transporter-mediated influx of Pi . To test this hypothesis, we generated mice with col2a1-driven Cre-mediated ablation of Slc20a1, hereafter referred to as Pi t1, alone or in combination with a Phospho1 gene deletion. Pi t1(col2/col2) mice did not show any major phenotypic abnormalities, whereas severe skeletal deformities were observed in the [Phospho1(-/-) ; Pi t1(col2/col2) ] double knockout mice that were more pronounced than those observed in the Phospho1(-/-) mice. Histological analysis of [Phospho1(-/-) ; Pi t1(col2/col2) ] bones showed growth plate abnormalities with a shorter hypertrophic chondrocyte zone and extensive hyperosteoidosis. The [Phospho1(-/-) ; Pi t1(col2/col2) ] skeleton displayed significant decreases in BV/TV%, trabecular number, and bone mineral density, as well as decreased stiffness, decreased strength, and increased postyield deflection compared to Phospho1(-/-) mice. Using atomic force microscopy we found that ∼80% of [Phospho1(-/-) ; Pi t1(col2/col2) ] MVs were devoid of mineral in comparison to ∼50% for the Phospho1(-/-) MVs and ∼25% for the WT and Pi t1(col2/col2) MVs. We also found a significant decrease in the number of MVs produced by both Phospho1(-/-) and [Phospho1(-/-) ; Pi t1(col2/col2) ] chondrocytes. These data support the involvement of phosphate transporter 1, hereafter referred to as Pi T-1, in the initiation of skeletal mineralization and provide compelling evidence that PHOSPHO1 function is involved in MV biogenesis. © 2016 American Society for Bone and Mineral Research.

PTEN negatively regulates mTORC2 formation and signaling in grade IV glioma via Rictor hyperphosphorylation at Thr1135 and direct the mode of action of an mTORC1/2 inhibitor

To investigate the role of PTEN (phosphatase and tensin homolog) in mammalian target of rapamycin complex 2 (mTORC2) signaling in glioblastoma multiforme (GBM), we found higher activation of mTORC2 in PTEN(mu) cells, as evidenced by enhanced phosphorylation of mTOR (Ser2481), AKT (Ser473) and glycogen synthase kinase 3 beta (GSK3β) (Ser9) as compared with PTEN(wt) cells. In addition, PTEN(wt) cells upon PTEN depletion showed mTORC2 activation. The reduced mTORC2 signaling in PTEN(wt) cells was related to higher Rictor phosphorylation at Thr1135 residue. Phosphorylation of Rictor at Thr1135 inhibited its association with mTORC and thus there was a reduction in mTORC2 complex formation. In addition, PTEN(wt) cells expressing mutated Rictor in which Thr1135 was substituted with alanine, showed enhanced mTORC2 formation and signaling. This enhanced mTORC2 signaling promoted inactivation of GSK3β. Thus, we established the reciprocal activation of mTORC2 and GSK3β in GBM. To the best of our knowledge, this is the first report describing role of PTEN in mTORC2 formation by promoting Rictor phosphorylation (Thr1135) in GBM. Furthermore, the drug sensitivity of mTORC2 was evaluated. A newly identified carbazole alkaloid, mahanine, showed cytotoxicity in both PTEN(mu) and PTEN(wt) cells. It inhibited both mTORC1/2 and AKT completely in PTEN(mu) cells, whereas it inhibited only mTORC1 in PTEN(wt) cells. Cytotoxity and AKT-inhibitory activity of the mTORC1/2 inhibitor was increased either by depleting PTEN or in combination with phosphatidylinositol 3 kinase inhibitors in PTEN(wt) cells. In contrast, depletion of Rictor decreased the cytotoxicity of the mTORC1/2 inhibitor in PTEN(mu) cells. Thus, PTEN has an important role in mTORC2 formation and also influences the effectiveness of an mTORC1/2 inhibitor in GBM.

Sex differences in social focus across the life cycle in humans

Age and gender are two important factors that play crucial roles in the way organisms allocate their social effort. In this study, we analyse a large mobile phone dataset to explore the way life history influences human sociality and the way social networks are structured. Our results indicate that these aspects of human behaviour are strongly related to age and gender such that younger individuals have more contacts and, among them, males more than females. However, the rate of decrease in the number of contacts with age differs between males and females, such that there is a reversal in the number of contacts around the late 30s. We suggest that this pattern can be attributed to the difference in reproductive investments that are made by the two sexes. We analyse the inequality in social investment patterns and suggest that the age- and gender-related differences we find reflect the constraints imposed by reproduction in a context where time (a form of social capital) is limited.

Biological interactions of carbon-based nanomaterials: From coronation to degradation

Carbon-based nanomaterials including carbon nanotubes, graphene oxide, fullerenes and nanodiamonds are potential candidates for various applications in medicine such as drug delivery and imaging. However, the successful translation of nanomaterials for biomedical applications is predicated on a detailed understanding of the biological interactions of these materials. Indeed, the potential impact of the so-called bio-corona of proteins, lipids, and other biomolecules on the fate of nanomaterials in the body should not be ignored. Enzymatic degradation of carbon-based nanomaterials by immune-competent cells serves as a special case of bio-corona interactions with important implications for the medical use of such nanomaterials. In the present review, we highlight emerging biomedical applications of carbon-based nanomaterials. We also discuss recent studies on nanomaterial 'coronation' and how this impacts on biodistribution and targeting along with studies on the enzymatic degradation of carbon-based nanomaterials, and the role of surface modification of nanomaterials for these biological interactions.

FROM THE CLINICAL EDITOR

Advances in technology have produced many carbon-based nanomaterials. These are increasingly being investigated for the use in diagnostics and therapeutics. Nonetheless, there remains a knowledge gap in terms of the understanding of the biological interactions of these materials. In this paper, the authors provided a comprehensive review on the recent biomedical applications and the interactions of various carbon-based nanomaterials.

Social insect colony as a biological regulatory system: modelling information flow in dominance networks

Social insects provide an excellent platform to investigate flow of information in regulatory systems since their successful social organization is essentially achieved by effective information transfer through complex connectivity patterns among the colony members. Network representation of such behavioural interactions offers a powerful tool for structural as well as dynamical analysis of the underlying regulatory systems. In this paper, we focus on the dominance interaction networks in the tropical social wasp Ropalidia marginata-a species where behavioural observations indicate that such interactions are principally responsible for the transfer of information between individuals about their colony needs, resulting in a regulation of their own activities. Our research reveals that the dominance networks of R. marginata are structurally similar to a class of naturally evolved information processing networks, a fact confirmed also by the predominance of a specific substructure-the 'feed-forward loop'-a key functional component in many other information transfer networks. The dynamical analysis through Boolean modelling confirms that the networks are sufficiently stable under small fluctuations and yet capable of more efficient information transfer compared to their randomized counterparts. Our results suggest the involvement of a common structural design principle in different biological regulatory systems and a possible similarity with respect to the effect of selection on the organization levels of such systems. The findings are also consistent with the hypothesis that dominance behaviour has been shaped by natural selection to co-opt the information transfer process in such social insect species, in addition to its primal function of mediation of reproductive competition in the colony.

Identification of different species of Bacillus isolated from Nisargruna Biogas Plant by FTIR, UV-Vis and NIR spectroscopy

Definitive identification of microorganisms, including pathogenic and non-pathogenic bacteria, is extremely important for a wide variety of applications including food safety, environmental studies, bio-terrorism threats, microbial forensics, criminal investigations and above all disease diagnosis. Although extremely powerful techniques such as those based on PCR and microarrays exist, they require sophisticated laboratory facilities along with elaborate sample preparation by trained researchers. Among different spectroscopic techniques, FTIR was used in the 1980s and 90s for bacterial identification. In the present study five species of Bacillus were isolated from the aerobic predigester chamber of Nisargruna Biogas Plant (NBP) and were identified to the species level by biochemical and molecular biological (16S ribosomal DNA sequence) methods. Those organisms were further checked by solid state spectroscopic absorbance measurements using a wide range of electromagnetic radiation (wavelength 200 nm to 25,000 nm) encompassing UV, visible, near Infrared and Infrared regions. UV-Vis and NIR spectroscopy was performed on dried bacterial cell suspension on silicon wafer in specular mode while FTIR was performed on KBr pellets containing the bacterial cells. Consistent and reproducible species specific spectra were obtained and sensitivity up to a level of 1000 cells was observed in FTIR with a DTGS detector. This clearly shows the potential of solid state spectroscopic techniques for simple, easy to implement, reliable and sensitive detection of bacteria from environmental samples.

Keeping it real: The importance of material characterization in nanotoxicology

Nanomaterials are small and the small size and corresponding large surface area of nanomaterials confers specific properties, making these materials desirable for various applications, not least in medicine. However, it is pertinent to ask whether size is the only property that matters for the desirable or detrimental effects of nanomaterials? Indeed, it is important to know not only what the material looks like, but also what it is made of, as well as how the material interacts with its biological surroundings. It has been suggested that guidelines should be implemented on the types of information required in terms of physicochemical characterization of nanomaterials for toxicological studies in order to improve the quality and relevance of the published results. This is certainly a key issue, but it is important to keep in mind that material characterization should be fit-for-purpose, that is, the information gathered should be relevant for the end-points being studied.

Should an increase in cerebral neurochemicals following head kicks in full contact karate influence return to play?

Background:

Cerebral neurochemicals are markers of traumatic brain injury (TBI).

Objectives:

The aim of the study was to determine whether kicks to the head (KTH) in full contact karate significantly increased serum concentrations of protein S-100B, and neurone specific enolase (NSE). Kicks to the body (KTB) were also quantified to asses muscle tissue injury. Muscle damage was assessed by analysis of serum total creatine kinase (CK).

Methods:

Twenty-four full contact karate practitioners were observed and filmed during actual competition and divided into two main groups post event: (1) Kicks to the head and body group (KTH): n = 12; mean ± SD; age, 30.4 ± 6.7 years; height, 1.74 ± 0.1 m; weight, 79.1 ± 2.1 kg; and (2): Kicks to the body group (KTB): n = 12; mean ± SD; age, 28.2 ± 6.5 years; height, 1.75 ± 0.1 m; weight, 79.2 ± 1.7 kg. The KTH group received direct kicks to the head, while group KTB received kicks and punches to the body. Blood samples were taken before and immediately post-combat for analysis of serum S-100B, NSE, CK and cardiac troponin.

Results:

Significant increases in serum concentrations of S-100B (0.12 ± 0.17 vs. 0.37 ± 0.26, µg.L−1) and NSE (11.8 ± 4.1 vs. 20.2 ± 9.1 ng.mL−1) were encountered after combat in the KTH group and CK (123 ± 53 vs. 184 ± 103 U.L−1) in the KTB group (all P <0.05).

Conclusions:

Head kicks in full contact karate cause elevation of neurochemical markers associated with damaged brain tissue. The severity of injury is related to the early post-traumatic release of protein S-100B and NSE. The early kinetics and appearance post injury can reflect intracranial pathology, and suggest S-100B and NSE are extremely sensitive prognostic markers of TBI.

Hybrid nanostructured C-dot decorated Fe3O4electrode materials for superior electrochemical energy storage performance

Here, the novel Fe₃O₄-C hybrid nanocomposite demonstrates high specific capacitance (S.C.) than the pristine Fe₃O₄nanospheres due to the presence of the highly conducting carbon quantum dots.

Dual effects of β-cyclodextrin-stabilised silver nanoparticles: enhanced biofilm inhibition and reduced cytotoxicity

The composition and mode of synthesis of nanoparticles (NPs) can affect interaction with bacterial and human cells differently. The present work describes the ability of β-cyclodextrin (β-CD) capped silver nanoparticles (AgNPs) to inhibit biofilm growth and reduce cytotoxicity. Biofilm formation of Staphylococcus epidermidis CSF 41498 was quantified by a crystal violet assay in the presence of native and capped AgNPs (Ag-10CD and Ag-20CD), and the morphology of the biofilm was observed by scanning electron microscope. The cytotoxicity of the AgNPs against HaCat cells was determined by measuring the increase in intracellular reactive oxygen species and change in mitochondrial membrane potential (ΔΨm). Results indicated that capping AgNPs with β-CD improved their efficacy against S. epidermidis CSF 41498, reduced biofilm formation and their cytotoxicity. The study concluded that β-CD is an effective capping and stabilising agent that reduces toxicity of AgNPs against the mammalian cell while enhancing their antibiofilm activity.

Enzymatic 'stripping' and degradation of PEGylated carbon nanotubes

Single-walled carbon nanotubes (SWCNTs) coated or functionalized with PEG chains of different molecular weight were assessed for their propensity to undergo biodegradation under in vitro conditions using recombinant myeloperoxidase (MPO) or ex vivo using freshly isolated primary human neutrophils. Our findings suggest that under natural conditions, a combined process of 'stripping' (i.e., defunctionalization) and biodegradation of PEG-SWCNTs might occur and that PEG-SWCNTs are a promising--and degradable--nanomedicine vector.

Collective foraging in heterogeneous landscapes

Animals foraging alone are hypothesized to optimize the encounter rates with resources through Lévy walks. However, the issue of how the interactions between multiple foragers influence their search efficiency is still not completely understood. To address this, we consider a model to study the optimal strategy for a group of foragers searching for targets distributed heterogeneously. In our model, foragers move on a square lattice containing immobile but regenerative targets. At any instant, a forager is able to detect only those targets that happen to be in the same site. However, we allow the foragers to have information about the state of other foragers. A forager who has not detected any target walks towards the nearest location, where another forager has detected a target, with a probability exp(-αd), where d is the distance between the foragers and α is a parameter characterizing the propensity of the foragers to aggregate. The model reveals that neither overcrowding (α → 0) nor independent searching (α → ∞) is beneficial for the foragers. For a patchy distribution of targets, the efficiency is maximum for intermediate values of α. In addition, in the limit α → 0, the length of the walks can become scale-free.

Pentoxifylline Plus Prednisolone versus Pentoxifylline Only for Severe Alcoholic Hepatitis: A Randomized Controlled Clinical Trial

Background:

Prednisolone and pentoxifylline (PTX) have been shown to be individually useful in severe alcoholic hepatitis with Maddrey discriminant function (MDF) score ≥32. Previous report suggests that PTX is probably superior to prednisolone alone. However the efficacy of PTX and prednisolone combination over PTX alone in the management of acute alcoholic hepatitis (MDF score ≥32) is yet unrevealed.

Aim:

The present study was initiated to find out the efficacy of combined pentoxifylline and prednisolone versus PTX alone in acute alcoholic hepatitis in respect of short and intermediate term outcomes.

Subjects and Methods:

A total of 124 patients with severe alcoholic hepatitis (MDF score ≥ 32) initially were evaluated. 62 patients who fulfilled the inclusion and exclusion criteria were randomized and divided into 2 groups. Group 1 received PTX only, whereas Group 2 received PTX plus Prednisolone. The total duration of follow-up was 12 months. Student's t-test, Chi-square test, the Kaplan-Meier methods were used for statistical analysis.

Results:

A total of 60 patients, 30 in each group were available for final analysis. In Group-1, 6 patients expired at the end of 1 year (5 within 3 months and another after 3 months). In Group 2, 10 patients expired at the end of 1 year (9 within 3 months and another after 3 months). Though survival probability is higher among Group 1 patients but the difference is not statistically significant.

Conclusion:

The combination of PTX plus Prednisolone yields no additional benefit in terms of mortality and morbidity from that of PTX monotherapy.

Microscopy of non-birefringent transmissive phase samples using Sagnac laser interferometer

A cyclic interferometer, appropriately combined with a long working distance microscope objective, is adapted for quantitative phase microscopy. In such an arrangement, the sample information, in terms of the diffracted orders emerging from the sample, is carried by both the counter propagating beams within the cyclic interferometer. However, positioning the sample close to the input/output cube beam splitter and use of a suitably converging laser beam of light as the input to the interferometer ensure that only one of the counter propagating beams carries the object information to the objective while the other beam, which serves as the reference, allows only the undiffracted component to contribute to the process of image formation. Use of suitable polarization optics renders the interferometer its polarization phase shifting property. Using the proposed arrangement, the experimental results showing the quantitative 3D phase rendering of polystyrene microspheres and micro-wells etched in glass are presented.

Extracellular entrapment and degradation of single-walled carbon nanotubes

Neutrophils extrude neutrophil extracellular traps (NETs) consisting of a network of chromatin decorated with antimicrobial proteins to enable non-phagocytic killing of microorganisms. Here, utilizing a model of ex vivo activated human neutrophils, we present evidence of entrapment and degradation of carboxylated single-walled carbon nanotubes (SWCNTs) in NETs. The degradation of SWCNTs was catalyzed by myeloperoxidase (MPO) present in purified NETs and the reaction was facilitated by the addition of H2O2 and NaBr. These results show that SWCNTs can undergo acellular, MPO-mediated biodegradation and imply that the immune system may deploy similar strategies to rid the body of offending microorganisms and engineered nanomaterials.

Multiscale instabilities in soft heterogeneous dielectric elastomers

The development of instabilities in soft heterogeneous dielectric elastomers is investigated. Motivated by experiments and possible applications, we use in our analysis the physically relevant referential electric field instead of electric displacement. In terms of this variable, a closed form solution is derived for the class of layered neo-Hookean dielectrics. A criterion for the onset of electromechanical multiscale instabilities for the layered composites with anisotropic phases is formulated. A general condition for the onset of the macroscopic instability in soft multiphase dielectrics is introduced. In the example of the layered dielectrics, the essential influence of the microstructure on the onset of instabilities is revealed. We found that: (i) macroscopic instabilities dominate at moderate volume fractions of the stiffer phase, (ii) interface instabilities appear at small volume fractions of the stiffer phase and (iii) instabilities of a finite scale, comparable to the microstructure size, occur at large volume fractions of the stiffer phase. The latest new type of instabilities does not appear in the purely mechanical case and dominates in the region of large volume fractions of the stiff phase.

Real-time edge detection by cyclic-path polarization interferometer

In a triangular path cyclic interferometer employing a polarizing beam splitter (PBS), the two counterpropagating beams are orthogonally polarized. A sample placed almost equidistant from the PBS is imaged by a lens placed in the path of the emerging beams so that two defocused images of the sample are recorded on a CCD. Using a linear polarizer in the path of the orthogonally polarized imaging beams, it is possible to achieve amplitude subtraction between the two images, resulting in an edge-enhanced image of the sample. The proposed real-time edge-enhancement technique is experimentally demonstrated.

Mechanisms of carbon nanotube-induced toxicity: focus on pulmonary inflammation

Carbon nanotubes have gained tremendous interest in a wide range of applications due to their unique physical, chemical, and electronic properties. Needless to say, close attention to the potential toxicity of carbon nanotubes is of paramount importance. Numerous studies have linked exposure of carbon nanotubes to the induction of inflammation, a complex protective response to harmful stimuli including pathogens, damaged or dying cells, and other irritants. However, inflammation is a double-edged sword as chronic inflammation can lead to destruction of tissues thus compromising the homeostasis of the organism. Here, we provide an overview of the process of inflammation, the key cells and the soluble mediators involved, and discuss research on carbon nanotubes and inflammation, including recent studies on the activation of the so-called inflammasome complex in macrophages resulting in secretion of pro-inflammatory cytokines. Moreover, recent work has shown that inflammatory cells i.e. neutrophils and eosinophils are capable of enzymatic degradation of carbon nanotubes, with mitigation of the pro-inflammatory and pro-fibrotic effects of nanotubes thus underscoring that inflammation is both good and bad.

Screening obesity by direct and derived anthropometric indices with evaluation of physical efficiency among female college students of kolkata

BACKGROUND

The available information regarding the obesity pattern of the undergraduate female students of Kolkata is inadequate, though there are several reports which indicate the complications and/or awful consequences of obesity on female health particularly, during the reproductive years.

AIM

The present investigation has thus been carried out to report their present physiological status along with the prevalence of obesity, based on their body mass index (BMI), some direct and derived anthropometric indices, and physical fitness.

SUBJECTS AND METHODS

This small-scale cross-sectional study conducted in randomly selected 100 female students of different colleges of Kolkata with the age of 18-22 [mean age 20.4 (2.3)] years. Measurements of body composition included total 24 variables, with thirteen direct and eleven derived anthropometric variables; while physical efficiency parameters were physical fitness index, VO2max, energy expenditure and anaerobic power. The data of the experimental group were compared with those of the control group by t-test, using SPSS v.15.0 and MS-Excel v.2013.

RESULTS

Analysis of collected data showed majority of the students have normal range of BMI (67.95%), but, 21.95% of students found to be overweight and 3.84% are obese. They also showed higher fat mass [14.40 (4.11)], but, lower waist-to-hip ratio and conicity index. They were found to have poor to moderate physical fitness [57.60 (3.90)] and higher energy expenditure [5.61 (0.72)].

CONCLUSION

The findings of the present obesity screening reports almost one of four female students (24 out of 100 participants) are overweight/obese, indicated higher body fat distribution and increased propensity of being obese with age. Thus, the overall data along with their low physical fitness points out to health risks among female undergraduates of Kolkata.

Toughening and asymmetry in peeling of heterogeneous adhesives

The effective adhesive properties of heterogeneous thin films are characterized through a combined experimental and theoretical investigation. By bridging scales, we show how variations of elastic or adhesive properties at the microscale can significantly affect the effective peeling behavior of the adhesive at the macroscale. Our study reveals three elementary mechanisms in heterogeneous systems involving front propagation: (i) patterning the elastic bending stiffness of the film produces fluctuations of the driving force resulting in dramatically enhanced resistance to peeling; (ii) optimized arrangements of pinning sites with large adhesion energy are shown to control the effective system resistance, allowing the design of highly anisotropic and asymmetric adhesives; (iii) heterogeneities of both types result in front motion instabilities producing sudden energy releases that increase the overall adhesion energy. These findings open potentially new avenues for the design of thin films with improved adhesion properties, and motivate new investigations of other phenomena involving front propagation.

Self-referenced rectangular path cyclic interferometer with polarization phase shifting

A polarization phase shifting interferometer using a cyclic path configuration for measurement of phase nonuniformities in transparent samples is presented. A cube beam splitter masked by two linear polarizers is used to split the source wavefront into two counter propagating linearly polarized beams that pass through the sample. At the output of the interferometer, the two orthogonally polarized beams are rendered circularly polarized in the opposite sense through the use of a quarter wave plate. Finally, phase shifting is achieved by rotating a linear polarizer before the recording plane. In a rectangular path interferometer, although the two counter propagating wavefronts are laterally folded with respect to each other in the interferometer arms, the beams finally emerge mutually unfolded at the output of the interferometer. This phenomenon is utilized to create a reference if the sample is introduced in one lateral half of the beam in any one of the interferometer arms. The polarization phase shifting technique is used to generate four phase-shifted interferograms, which are utilized to evaluate the phase profile of the phase sample. Experimental results presented validate the proposed technique.

A study on evalution of antidepressant effect of imipramine adjunct with Aswagandha and Bramhi

Depressive disorders increase the risks of self-harm or even suicide in patients. Indigenous drugs are being tried to treat such patient along with conventional antidepressant drugs. This study was planned to investigate the antidepressant action of Ashwagandha and Bramhi and also to confirm its efficacy in the behavioural despair animal model of depression. Normal saline as control (5 ml/kg), Imipramine as standard (16, 32, 64 mg/ kg) and Ashwagandha (50, 100, 150 mg/kg), Bramhi (20, 40, 80 mg/kg) as test drugs were introduced to the albino rats weighing between 200-250 gm for 2 weeks, 1 hr before electric shock in Learned helplessness test (LHT) and swimming in Forced swimming test (FST). Effects of individual drugs as well as their combination were evaluated. Avoidance response, escape failure and immobility period in case of Imipramine and Ashwagandha showed highly significant (p < 0.01) result on individual use. There was no significant result in case of Bramhi used alone except in escape failure and immobility period (FST), where at higher doses it showed significant (p < 0.01) result. But combination of Bramhi and Ashwagandha in low doses with low dose of Imipramine gave a highly significant result (p < 0.01) in all the parameters. Ashwagandha had significant antidepressant action, but Bramhi had not when used alone. Combination of these two indigenous drug with Imipramine showed high efficacy in animal model.

Kurt Semm: A laparoscopic crusader

A brief biography of Kurt Semm, the pioneer of laparoscopic appendectomy and inventor of various laparoscopic instruments are done, with special reference to his struggle to establish the foundation of minimally invasive surgery amongst his contemporary surgeons.

A Theory of Shape-Memory Thin Films with Applications

Shape-memory alloys have the largest energy output per unit volume per cycle of known actuator systems [1]. Unfortunately, they are temperature activated and hence, their frequency is limited in bulk specimens. However, this is overcome in thin films; and hence shape-memory alloys are ideal actuator materials in micromachines[l]. The heart of the shape-memory effect lies in a martensitic phase transformation and the resulting microstructure. It is well-known that microstructure can be significantly different in thin films as compared to bulk materials. In this paper, we report on a theory of single crystal martensitic this films. We show that single crystal films of shape memory material offer interesting possibilities for producing very large deformations, at small scales.