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Depression is a leading cause of disability which at its worst leads to suicide. Its treatment relies on psychotherapy in combination with certain antidepressants (AD

Microreactors can play a crucial role in synthesis and rapid testing of various nanocatalyst to be used in addressing the issue of environmental contamination. We have reported the rapid fabrication of polydimethylsiloxane (PDMS) and poly(methyl methacrylate) (PMMA)-based microreactor for the flow synthesis and enhanced inline photocatalysis of bismuth oxide (Bi2O3) nanoparticles. A T-shaped microreactor with uniform circular cross-sectional channel having inner diameter of 450 μm was utilized for synthesizing Bi2O3 nanoparticles with narrow size distribution. Further, photocatalytic dye degradation efficiency for methyl orange (MO) was recorded by coating these Bi2O3 nanoparticles within the inner walls of PMMA-based serpentine microreactors under visible light. The enhanced dye degradation efficiency of as high as 96% within just 15 min of irradiation is reported. A comparative analysis has also been done for both conventional as well as the in-channel photocatalysis highlighting the advantages of microreactor based photocatalysis over the conventional method. Bi2O3 nanoparticles also showed excellent stability even after three cycles indicating reusability of coated microreactors in photocatalysis. The small concentration of as synthesized Bi2O3 nanoparticles also demonstrated high efficacy for the inhibition of Escherichia coli bacterial pathogens.

The reversible solid oxide cell (RSOC) is an attractive technology to mutually convert power and chemicals at elevated temperatures. However, its development has been hindered mainly due to the absence of a highly active and durable fuel electrode. Here, we report a phase-transformed CoFe-Sr3Fe1.25Mo0.75O7−δ (CoFe-SFM) fuel electrode consisting of CoFe nanoparticles and Ruddlesden-Popper-layered Sr3Fe1.25Mo0.75O7−δ (SFM) from a Sr2Fe7/6Mo0.5Co1/3O6−δ (SFMCo) perovskite oxide after annealing in hydrogen and apply it to reversible CO/CO2 conversion in RSOC. The CoFe-SFM fuel electrode shows improved catalytic activity by accelerating oxygen diffusion and surface kinetics towards the CO/CO2 conversion as demonstrated by the distribution of relaxation time (DRT) study and equivalent circuit model fitting analysis. Furthermore, an electrolyte-supported single cell is evaluated in the 2:1 CO-CO2 atmosphere at 800°C, which shows a peak power density of 259 mW cm−2 for CO oxidation and a current density of −0.453 A cm−2 at 1.3 V for CO2 reduction, which correspond to 3.079 and 3.155 mL min−1 cm−2 for the CO and CO2 conversion rates, respectively. More importantly, the reversible conversion is successfully demonstrated over 20 cyclic electrolysis and fuel cell switching test modes at 1.3 and 0.6 V. This work provides a useful guideline for designing a fuel electrode through a surface/interface exsolution process for RSOC towards efficient CO-CO2 reversible conversion.

Does natural selection favor veridical percepts-those that accurately (if not exhaustively) depict objective reality? Perceptual and cognitive scientists standardly claim that it does. Here we formalize this claim using the tools of evolutionary game theory and Bayesian decision theory. We state and prove the "Fitness-Beats-Truth (FBT) Theorem" which shows that the claim is false: If one starts with the assumption that perception involves inference to states of the objective world, then the FBT Theorem shows that a strategy that simply seeks to maximize expected-fitness payoff, with no attempt to estimate the "true" world state, does consistently better. More precisely, the FBT Theorem provides a quantitative measure of the extent to which the fitness-only strategy dominates the truth strategy, and of how this dominance increases with the size of the perceptual space. The FBT Theorem supports the Interface Theory of Perception (e.g. Hoffman et al. in Psychon Bull Rev https://doi.org/10.3758/s13423-015-0890-8 , 2015), which proposes that our perceptual systems have evolved to provide a species-specific interface to guide adaptive behavior, and not to provide a veridical representation of objective reality.

With the rapid growth of Twitter in recent years, there has been a tremendous increase in the number of tweets generated by users. Twitter allows users to make use of hashtags to facilitate effective categorization and retrieval of tweets. Despite the usefulness of hashtags, a major fraction of tweets do not contain hashtags. Several methods have been proposed to recommend hashtags based on lexical and topical features of tweets. However, semantic features and data sparsity in tweet representation have rarely been addressed by existing methods. In this paper, we propose a novel method for hashtag recommendation that resolves the data sparseness problem by exploiting the most relevant tweet information from external knowledge sources. In addition to lexical features and topical features, the proposed method incorporates the semantic features based on word-embeddings and user influence feature based on users’ influential position. To gain the advantage of various hashtag recommendation methods based on different features, our proposed method aggregates these methods using learning-to-rank and generates top-ranked hashtags. Experimental results show that the proposed method significantly outperforms the current state-of-the-art methods.

Genomic selection (GS) is a popular breeding method that uses genome-wide markers to predict plant phenotypes. Empirical studies and simulations have shown that GS can greatly accelerate the breeding cycle, beyond what is possible with traditional quantitative trait locus (QTL) approaches. GS is a regression problem, where one often uses SNPs to predict the phenotypes. Since the SNP data are extremely high-dimensional, of the order of 100 K dimensions, it is difficult to make accurate phenotypic predictions. Moreover, finding the optimal prediction model is computationally very costly. Out of thousands of SNPs, usually only a few influence a particular phenotypic trait. We first of all show how ensemble-based regression techniques give better prediction accuracy compared to traditional regression methods, which have been used in existing papers. We then further improve the prediction accuracy by using an ensemble of feature selection and feature extraction techniques, which also reduces the time to compute the regression model parameters. We predict three traits: grain yield, time to 50% flowering and plant height for which the existing methods give an accuracy of 0.304, 0.627 and 0.341, respectively. Our proposed regression model gives an accuracy of 0.330, 0.674 and 0.458 for these traits. Additionally, we also propose a computationally efficient regression model that reduces the computation time by as much as 90% and gives an accuracy of 0.342, 0.580 and 0.411, respectively.

Herpes viruses have been described as markers of occult cancer and have also been implicated in oncogenesis. This group of viruses includes varicella-zoster virus (VZV) which is well-known for its ability to evade the immune response by lying dormant in the dorsal root ganglion of peripheral nerves. Although it is common knowledge that VZV reactivation causes herpes zoster (shingles), there have been no reports in literature of herpes zoster manifesting in the dermatomal territory of peripheral nerves involved by either benign or malignant tumors. We report two cases of patients with peripheral nerve tumors who presented with herpes zoster in the dermatomal distribution of the involved nerves. One patient had primary neurolymphomatosis, whereas the other had a sacral schwannoma. We believe these are the first cases to be reported that demonstrate herpes zoster at clinical presentation in patients with peripheral nerve tumors. This suggests that VZV may have the potential to cause peripheral nerve tumors via a complex interplay of viral oncogenes and alterations in host immunological responses.

The rapid expansion of the Internet and its connectivity has given tremendous growth to e-commerce sites. Product reviews form an indispensable part of e-commerce sites. However, it is challenging and laborious to go through hundreds of reviews. In this paper, we address the problem of summarizing reviews by means of informative and readable tags. We present a novel unsupervised method of generating tags and rank them based on relevance. We refine the generated tags using NLP syntactic rules to make them more informative. Our proposed Tagging Product Review (TPR) system takes into consideration the opinions expressed on the product or its aspects. We also address the problem of tag generation for cold products, which have only a limited number of reviews and that too, with very short content. We use transfer learning to build a tag cloud from popular product reviews and use it to identify good tags from cold product reviews. We evaluate our proposed system using online reviews of twelve products of varying popularity, collected from Amazon.com. Our result demonstrates the effectiveness of our approach at generating relevant tags compared to three popular baseline methods. Our proposed approach gives an average tag relevance score (NDCG) of around 79% for popular products and 85% for cold products. Our approach also gives an average precision of 89% for identifying correct tags. The results suggest that our TPR system successfully summarize reviews by means of tags.

There is a well-established association between tobacco consumption with asthma and chronic bronchitis (CB). This study aimed at estimating the prevalence of tobacco consumption and its association with asthma and CB in Kanpur, Uttar Pradesh, India. A cross-sectional household survey of 573 males was conducted during January–June 2015 in the Jajmau area of Kanpur, Uttar Pradesh, India. The questionnaire was designed to collect information on self-reported symptoms pertaining to asthma and CB, which were considered as response variables for the study. More than one-third of the respondents (36%) smoked tobacco and 44% consumed smokeless tobacco. Men who were aged 35 years and above were more prone to CB, with odds ratios (ORs) of 2.08 in model 1 and 1.84 in model 2. The prevalence of CB is higher among those from the Scheduled Castes and Scheduled Tribes (12.4%). People consuming any form of tobacco are more likely to get CB (OR = 5.22) than their counterparts who do not consume tobacco. The chances of getting asthma was higher among those who consumed any form of smokeless tobacco (OR = 1.34) and those who consume any form of tobacco (OR = 2.30) in model 2. Our study found a significant association between tobacco consumption (smoking and use of smokeless tobacco) with asthma and CB and the predictors that affect the pattern of tobacco consumption, such as respondents’ age, education level, caste, level of exposure to the media, and standard of living index.

The adverse effects of chemical nitrogen fertilizers affecting soil fertility, water pollution and native microorganisms, particularly cyanobacteria, in wetland rice cultivation have drawn global attention towards the use of alternative sources like N2-fixing cyanobacteria as a biofertilizer for sustainable rice farming. Although chemical nitrogen fertilizers are extensively used for obtaining higher rice yield, they are likely to have a deleterious effect on the growth and N2-fixation of diazotrophs, including cyanobacteria. In addition, biocides (herbicides and insecticides) are widely being used in rice cultivation for optimizing crop yield, but these chemicals also affects non-target organisms adversely. There are several reports indicating impacts of these agrochemicals on cyanobacteria, but most such studies were carried out under laboratory conditions. This article reviews information from different field evaluations on the impact of agrochemicals on cyanobacteria along with rice crop in wetland rice field ecosystem.

Many organisms capture or sense sunlight using rhodopsin pigments1,2, which are integral membrane proteins that bind retinal chromophores. Rhodopsins comprise two distinct protein families 1 , type-1 (microbial rhodopsins) and type-2 (animal rhodopsins). The two families share similar topologies and contain seven transmembrane helices that form a pocket in which retinal is linked covalently as a protonated Schiff base to a lysine at the seventh transmembrane helix2,3. Type-1 and type-2 rhodopsins show little or no sequence similarity to each other, as a consequence of extensive divergence from a common ancestor or convergent evolution of similar structures 1 . Here we report a previously unknown and diverse family of rhodopsins—which we term the heliorhodopsins—that we identified using functional metagenomics and that are distantly related to type-1 rhodopsins. Heliorhodopsins are embedded in the membrane with their N termini facing the cell cytoplasm, an orientation that is opposite to that of type-1 or type-2 rhodopsins. Heliorhodopsins show photocycles that are longer than one second, which is suggestive of light-sensory activity. Heliorhodopsin photocycles accompany retinal isomerization and proton transfer, as in type-1 and type-2 rhodopsins, but protons are never released from the protein, even transiently. Heliorhodopsins are abundant and distributed globally; we detected them in Archaea, Bacteria, Eukarya and their viruses. Our findings reveal a previously unknown family of light-sensing rhodopsins that are widespread in the microbial world.

Biocides (herbicides and insecticides) are intensively being used in rice cultivation, despite several adverse non-target effects on native cyanobacteria. Comparative effects of three herbicides (benthiocarb, butachlor, and 2,4-D) and four insecticides (furadon, phorate, methyl parathion, and ekalux) were studied at field-recommended doses. Field experiments of rice were carried out for three consecutive seasons in completely randomized block designs in both rainy and winter croppings at the Central Rice Research Institute, Cuttack, India. Toxicities of seven biocides individually to native cyanobacteria growing with rice crops in wetland fields were assessed for growth and acetylene reduction activity (ARA); several crop parameters of paddy were estimated concomitantly. It was observed that applications of butachlor and benthiocarb individually significantly decreased growth (15.86 and 17.50%), ARA (0.16 and 0.68%), and N-yield (0.26 and 0.85%) of the native cyanobacteria, whereas these parameters increased (24.04% in growth, 0.25% in ARA, and 0.40% in N-yield) due to the application of 2,4-D. Of the tested insecticides, furadon, phorate, and methyl parathion enhanced the growth (17.8, 10.7, and 11.7%), N2-fixation (0.10, 0.097, and 0.074%), and N-yield (0.16, 0.18, and 0.20%) of cyanobacteria, whereas ekalux had no significant effect on cyanobacteria. On the basis of cyanobacterial parameters, biocides could be recommended for rice crops in the order furadon < phorate < methyl parathion < ekalux. Applications of 2,4-D and furadon individually in comparison to the rest other biocides enhanced rice yield. These finding could help to revise integrated strategies of weed and pest management in wetland rice agriculture to save non-target soil microorganisms, particularly cyanobacteria.

We report on the in situ synthesis and stabilization of manganese dioxide (MnO2) onto four different silk yarns (mulberry, tasar, muga and eri silks). A new ultrasound-assisted procedure was used to reduce permanganate (MnO4 −) and yielded MnO2 nanoparticles (NPs) on/in the different silk fibers. Using a factorial design we assessed the influence of the silk type, manganese precursor concentration, sonication time, and temperature. The results indicated no measurable effect of the process parameters on the silk structures, but significant correlation with the rate of degradation of methylene blue (MB) and the fraction of permanganate consumed. Further optimization of the factorial model identified the optimal process conditions for each silks: mulberry (150 min sonication, 20 mM permanganate), eri (360 min, 10 mM), tasar (150 min, 10 mM) and Muga (20 min, 10 mM). The operational stability (successive catalysis) of the optimum hybrids showed good performance over 5 cycles and most importantly reduced direct dye absorption relatively to dye oxidation. Overall, we found that all silks could template the formation and stabilization of different MnO2 polymorphs and yielded catalytic instead of stoichiometric hybrid fibers.

The diazotrophic cyanobacteria are known to play an important role in nitrogen economy of wetland rice ecosystem. Due to intensive use of nitrogenous fertilizers in rice cultivation, maintenance of soil health has become a challenging task. In this context, a systematic study was conducted in flooded rice field to determine the effects of different doses of commonly used urea and ammonium sulphate nitrogenous fertilizers on native cyanobacterial biomass, N2-fixation and N-yield at various stages of rice plants. The results clearly demonstrated that both urea and ammonium sulphate inhibited cyanobacterial growth and N2-fixation at different stages of rice crop. Maximum growth and N2-fixation were observed at heading stage of rice plant at 60 days after transplantation when compared with early and late stages of rice crop. Of the two fertilizers, urea was found more inhibitory to cyanobacteria and among the two seasons, these fertilizers were more inhibitory in the dry than in the wet season. This study suggests that N fertilizers need to be used judiciously in rice cultivation so that both cyanobacterial contribution and high rice yield are ensured.

Hispanic children of Mexican origin have a high incidence of NAFLD. Susceptibility has been linked to a combination of factors including an increasing epidemic of obesity in children and adolescents, an allele substitution in the PNPLA3 gene that reduces hepatic lipid catabolism, and an altered microbiome that may increase hepatic endotoxins. The combination of NAFLD and portal vein toxins secondary to an indigenous gut microbiome appear to lead to the early occurrence of NASH, which progresses to cirrhosis and early hepatocellular carcinoma. Early detection and treatment of hepatic changes are needed. Given the success of gastric bypass in reducing body weight, modifying the gut microbiome, and improving NAFLD/NASH in adults, a trial of gastric bypass in predisposed pediatric candidates should be undertaken.

In cyanobacterium Anabaena 7120, iron deficiency leads to oxidative stress with unavoidable consequences. Nitric oxide reduces pigment damage and supported the growth of Anabaena 7120 in iron-deficient conditions. Elevation in nitric oxide accumulation and reduced superoxide radical production justified the role of nitric oxide in alleviating oxidative stress in iron deficiency. Increased activities of antioxidative enzymes and higher levels of ROS scavengers (ascorbate, glutathione and thiol) in iron deficiency were also observed in the presence of nitric oxide. Nitric oxide also supported the membrane integrity of Anabaena cells and reduces protein and DNA damage caused by oxidative stress induced by iron deficiency. Results suggested that nitric oxide alleviates the damaging effects of oxidative stress induced by iron deficiency in cyanobacterium Anabaena 7120.

Comparative growth and N2-fixation of cyanobacteria, namely Aphanothece sp. (unicellular) and Gloeotrichia sp. (heterocystous, filamentous), were studied after their inoculation to rice crop in the absence and presence of urea nitrogen fertilizer. In the absence of N-fertilizer application (control), inoculation of both cyanobacterial species showed significant increase in growth and acetylene reduction activity (ARA), but gradual reduction in these parameters was observed at 30 and 60 kg N ha−1 of urea application. In inoculation of Gloeotrichia sp. at control, 30 and 60 kg N ha−1 increased grain yield significantly over uninoculated control in both wet and dry seasons, but grain yield with Aphanothece sp. inoculation was statistically similar to the control at N levels during both seasons. The inoculation study showed that heterocystous cyanobacteria contributed better than unicellular ones, and application of N-fertilizer adversely affected both growth and N2-fixation of native as well of inoculated cyanobacteria.

Oligomeric assembly is a common feature of membrane proteins and often relevant to their physiological functions. Determining the stoichiometry and the oligomeric state of membrane proteins in a lipid bilayer is generally challenging because of their large size, complexity, and structural alterations under experimental conditions. Here, we use high-speed atomic force microscopy (HS-AFM) to directly observe the oligomeric states in the lipid membrane of various microbial rhodopsins found within eubacteria to archaea. HS-AFM images show that eubacterial rhodopsins predominantly exist as pentamer forms, while archaeal rhodopsins are trimers in the lipid membrane. In addition, circular dichroism (CD) spectroscopy reveals that pentameric rhodopsins display inverted CD couplets compared to those of trimeric rhodopsins, indicating different types of exciton coupling of the retinal chromophore in each oligomer. The results clearly demonstrate that the stoichiometry of the fundamental oligomer of microbial rhodopsins strongly correlate with the phylogenetic tree, providing a new insight into the relationship between the oligomeric structure and function-structural evolution of microbial rhodopsins.

We propose that selection favors nonveridical perceptions that are tuned to fitness. Current textbooks assert, to the contrary, that perception is useful because, in the normal case, it is veridical. Intuition, both lay and expert, clearly sides with the textbooks. We thus expected that some commentators would reject our proposal and provide counterarguments that could stimulate a productive debate. We are pleased that several commentators did indeed rise to the occasion and have argued against our proposal. We are also pleased that several others found our proposal worth exploring and have offered ways to test it, develop it, and link it more deeply to the history of ideas in the science and philosophy of perception. To both groups of commentators: thank you. Point and counterpoint, backed by data and theory, is the essence of science. We hope that the exchange recorded here will advance the scientific understanding of perception and its evolution. In what follows, we respond to the commentaries in alphabetical order.

The Ferric uptake regulator (Fur) protein is a global iron regulator found in most prokaryotes. Although the Fur protein is involved in a variety of metabolic pathways, it is specifically known for the regulation of several iron responsive genes. It binds to the highly conserved sequences located in the upstream promoter region known as iron boxes, using ferrous ion as a co-repressor. Apart from that, the Fur protein is also directly/indirectly involved in a variety of other crucial physiological pathways. Hence, understanding the mechanism of action and the mechanistic pathways of iron regulation by Fur is necessary and important. The basic understanding of the functioning and properties of Fur protein along with its role, interaction and regulation at various levels in cyanobacteria has been discussed in detail.

Curcuma longa L., commonly known as turmeric, is a rhizomatous herb of the family Zingiberaceae. It is mostly used as a spice, a coloring agent and broadly used in traditional medicine such as Ayurveda, Unani, etc., Turmeric rhizomes interact with a large numbers of rhizosphere-associated microbial species, and some enter the plant tissue and act as endophytes. Both rhizospheric and endophytic species are directly or indirectly involved in growth promotion and disease management in plants and also play an important role in the modulation of morphological growth, secondary metabolite production, curcumin content, antioxidant properties, etc. The present review focuses on the rhizobacterial and endophytic bacterial and fungal populations associated with the turmeric.

Highly iterated palindromes (HIP) have been used as high resolution molecular markers for assessing the genetic variability and phylogenetic relatedness of heterocystous cyanobacteria (subsections IV and V) representing 12 genera of heterocystous cyanobacteria, collected from different geographical areas of India. DNA fingerprints generated using four HIP markers viz. HIP-AT, HIP-CA, HIP-GC, and HIP-TG showed 100 % polymorphism in all the heterocystous cyanobacteria studied and each marker produced unique and strain-specific banding pattern. Furthermore, phylogenetic affinities based on the dendrogram constructed using HIP DNA profiles of heterocystous cyanobacteria suggest the monophyletic origin of this entire heterocystous clade along with a clear illustration of the polyphyletic origin of the branched Stigonematalean order (Subsection V). In addition, phylogenetic affinities were validated by principal component analysis of the HIP fingerprints. The overall data obtained by both the phylogeny and principal component assessments proved that the entire heterocystous clade was intermixed, and there are immediate needs for classificatory reforms that satisfy morphological plasticity and environmental concerns.

Cancer immunotherapy has become an important area for the future development of cancer therapy; this includes T-cell-based therapies that involve adoptive transfer of autologous T cells derived from the tumors or peripheral blood of cancer patients, vaccines, oncolytic virus therapy, and immunomodulatory antibodies and ligands. Here, we summarize the current approaches and clinical data in the field of adoptive T-cell transfer therapy using tumor-infiltrating lymphocytes (TILs) for metastatic melanoma. We also discuss current knowledge on the mechanism of transferred TILs in mediating tumor regression and the growing need for and recent advances in the identification of predictive biomarkers to better select patients for TIL therapy. The current technical limitations of current TIL expansion methods for out-scaling are discussed as well as how these are being addressed in order to further "industrialize" this form of cell therapy. Lastly, how TIL adoptive transfer can be incorporated into the current melanoma treatment continuum, especially as combination therapy with other immunomodulators and targeted drugs, is discussed.

Venlafaxine (VEN), a newer antidepressant of serotonin and noradrenaline reuptake inhibitor (SNRI) class, is commonly used worldwide for clinical management of various forms of depression even during pregnancy. The maternal and fetal safety of this drug has not been established well so far due to lack of metanalysis studies in clinical settings and controlled investigations in rodents as well as availability of contradictory information. Therefore, present study has been planned to investigate the maternal toxicity in relation to food intake and body weight gain; fetal toxicity as fetal weight at GD-19 and neonatal weight at birth; and postnatal development/growth in young-adult rat offspring. In this study selected doses of VEN (25, 40 and 50 mg/kg) were administered to pregnant rats from GD 5–21 through gavage. These doses were equivalent to human therapeutic dose range (75–375 mg/day). Maternal food intake and body weight gain were found substantially reduced due to drug induced hypophagia. The fetal body weight at GD-19 as well as neonatal birth weight of VEN exposed offspring was found significantly deficient which could not reach up to the control level till 8 weeks as compared to control. This study concludes that prenatal exposure of VEN not only induced maternal weight loss and food intake deficit but also induced long-lasting impact on fetal as well as neonatal development and growth in young-adult offspring. Further, cautions are required for weighing the risks and benefits to both fetus and pregnant mothers before recommendation of SNRIs in general and VEN in particular.

Ambient levels of viable bioaerosol were measured at four different sites on the campus of Jawaharlal Nehru University (JNU), New Delhi, India. Most of the viable bioaerosol was associated with the fungal fraction with the remainder due to bacteria. The highest concentrations of fungi were found at a health center (1,293 cfu/m3). The highest concentrations of both gram-positive (338.8 cfu/m2) and gram-negative (614 cfu/m2) bacteria were found at a garbage dump site. Gram-negative bacteria were found in larger numbers than gram-positive, possibly due to the higher ambient temperatures during their sampling. Most of the fungal bioaerosol identified is associated with immunotoxic diseases such as sick building syndrome and allergic diseases and was found in respirable fractions. Since the bacterial fractions were identified on the basis of morphology, i.e. only to the level of genus, their relationship to health effects could not be established. Although most of the sampling occurred indoors in naturally ventilated buildings, external temperature and humidity did not vary significantly during the study. Thus, it is more likely that the types of organisms and levels observed had more to do with the sources (decomposing garbage, spores carried from wooded areas, etc.) than the ambient or indoor environmental conditions.

Quantum mechanical simulations were performed to calculate the valence electron energy-loss spectra (VEELS) for hafnium oxide, hafnium silicate, silicon oxide and silicon systems using the full potential Linearized Augmented Plane Wave (LAPW) formalism within the Density Functional Theory (DFT) framework. The needed energy-loss function (ELF) was derived from the calculation of the complex dielectric tensor within the random phase approximation (RPA). The calculated spectra were compared with experimental scanning transmission electron microscopy (STEM)/EELS of atomic layer deposited (ALD) HfO2 on Si(100) to evaluate their use as a “fingerprint” method that can be used to distinguish among various polymorphs of HfO2 thin films and relate the fine structure to the electronic structure and local bonding environment. Calculated low-loss spectra are found to be in satisfactory agreement with experimental data. Also, the combination of such theoretical calculations and experimental data could be of key importance in our understanding of fundamental issues of these systems. Compared to energy-loss near edge structure (ELNES) or core energy-loss spectra, the ELF calculated for low-loss spectra is computationally less expensive and can prove useful for prompt analysis.

Thin films of hafnium oxide were deposited on silicon substrates using tetrakis-diethylamino hafnium as precursor. Two different oxidizers: (a) ozone/oxygen mixture, and (b) dry oxygen were used for comparative study of the effect of different oxidizers on the deposited films. The deposition using dry oxygen was carried out in a cold-wall rapid thermal processing metalorganic chemical vapor deposition (MOCVD) reactor, whereas ozone/oxygen mixture was used in a cold-wall atomic layer deposition (ALD) reactor. Annealing studies were carried out at 600 and 800°C in high-purity argon at atmospheric pressure. X-ray photoelectron spectroscopy (XPS) analyses of as-deposited and annealed films were performed to study the HfO2/Si interface. The films deposited using these two different oxidizers appeared to be of comparable quality. Silicon oxide formation at the interface occurred after annealing at 600°C and it increased upon further annealing at 800 °C.