The recent rise of multidrug resistant microbial strains requires development of new and novel therapeutic alternatives. In this study, we present a novel antibacterial system that comprises of ...modified naturally abundant antimicrobial peptides in conjugation with silver nanoparticles. Further, we propose a simple route to incorporate a cysteine residue either at the N- or C-terminal of the parent peptide. Tagging a cysteine residue at the terminals not only enhances the binding propensity of the resultant peptide with the silver nanoparticle, but also increases its antimicrobial property against several pathogenic bacterial strains including K. pneumoniae. The minimum inhibitory concentration (MIC) values of the cysteine tagged nanoconjugates were obtained in the range of 5-15 μM compared to 50 μM for peptides devoid of the cysteines. The origin and mechanism of such improved activity of the conjugates were investigated using NMR spectroscopy and molecular dynamics (MD) simulations. The application of
C-isotope labelled media to track the metabolic lifecycle of E. coli cells provided further insights into the system. MD simulations showed that pore formation in membrane bilayer is mediated through a hydrophobic collapse mechanism. The design strategy described herein opens up new-avenues for using biocompatible nanomedicines as a potential alternative to conventional antibiotics.
Storage and controlled distribution of water have been key elements of a human strategy to overcome the space and time variability of water, which have been marked by catastrophic droughts and floods ...throughout the course of civilization. In the United States, the peak of dam building occurred in the mid‐20th century with knowledge limited to the scientific understanding and hydrologic records of the time. Ecological impacts were considered differently than current legislative and regulatory controls would potentially dictate. Additionally, future costs such as maintenance or removal beyond the economic design life were not fully considered. The converging risks associated with aging water storage infrastructure and uncertainty in climate in addition to the continuing need for water storage, flood protection, and hydropower result in a pressing need to address the state of dam infrastructure across the nation. Decisions regarding the future of dams in the United States may, in turn, influence regional water futures through groundwater outcomes, economic productivity, migration, and urban growth. We advocate for a comprehensive national water assessment and a formal analysis of the role dams play in our water future. We emphasize the urgent need for environmentally and economically sound strategies to integrate surface and groundwater storage infrastructure in local, regional, and national water planning considerations. A research agenda is proposed to assess dam failure impacts and the design, operation, and need for dams considering both paleo and future climate, utilization of groundwater resources, and the changing societal values toward the environment.
Plain Language Summary
Water storage and control have been key elements of a human strategy to overcome differences between water availability and water needs. The future promises changes to when and where water will be available and many regions in the USA will likely see an increase in the imbalance between existing water storage and evolving demands for water. This indicates the need for more storage or new dams to meet human and ecological needs. The current trend for removal of old, hazardous or unpopular dams now and into the future may impact regional groundwater outcomes, food and energy production, migration, and urban growth. We advocate for a formal analysis of the role dams play in the future of the USA's water landscape. We also stress the need for national water planning considerations to develop environmentally and economically sound strategies to integrate the management of surface and groundwater storage infrastructure in the USA.
Key Points:
Climate change projections suggest more hydrologic extremes. Are more dams subsequently needed?
Most US dams now exceed their economic design life and represent a need for infrastructure investment and recognition of associated risks
A national water assessment is needed to examine dam removal and modified storage provision options considering hydroclimatic risk exposure
Diagnosing potential predictability of global crop yields in the near term is of utmost importance for ensuring food supply and preventing socio-economic consequences. Previous studies suggest that a ...substantial proportion of global wheat yield variability depends on local climate and larger-scale ocean-atmospheric patterns. The science is however at its infancy to address whether synergistic variability and volatility (major departure from the normal) of multi-national crop yields can be potentially predicted by larger-scale climate drivers. Here, using observed data on wheat yields for 85 producing countries and climate variability from 1961-2013, we diagnose that wheat yields vary synergistically across key producing nations and can also be concurrently volatile, as a function of shared larger-scale climate drivers. We use a statistical approach called robust Principal Component Analysis (rPCA), to decouple and quantify the leading modes (PC) of global wheat yield variability where the top four PCs explain nearly 33% of the total variance. Diagnostics of PC1 indicate previous year's local Air Temperature variability being the primary influence and the tropical Pacific Ocean being the most dominating larger-scale climate stimulus. Results also demonstrate that world-wide yield volatility has become more common in the current most decades, associating with warmer northern Pacific and Atlantic oceans, leading mostly to global supply shortages. As the world warms and extreme weather events become more common, this diagnostic analysis provides convincing evidence that concurrent variability and world-wide volatility of wheat yields can potentially be predicted, which has major socio-economic and commercial importance at the global scale, underscoring the urgency of common options in managing climate risk.
A disproportionate share of the global economic and human losses caused by environmental shocks is borne by people in the developing nations. The mountain region of Hindu-Kush Himalaya (HKH) in South ...Asia is threatened by numerous flooding events annually. An efficient disaster risk reduction often needs to rest upon location-based synoptic view of vulnerability. Resolving this deficit improves the ability to take risk reduction measures in a cost-effective way, and in doing so, strengthens the resilience of societies to flooding disasters. The central aim of this research is to identify the vulnerable locations across HKH boundary from the perspective of reported history of economic and human impacts due to occurrence of flooding disasters. A detailed analysis indicates a very high spatial heterogeneity in flooding disaster occurrence in the past 6 decades. The most recent decade reported highest number of disasters and greater spatial coverage as compared to the earlier decades. The data indicates that, in general, economic impacts of flooding disasters were notably higher in Pakistan, Afghanistan and Nepal. On the other hand, vulnerability scenarios with respect to human impacts were diverse for different countries. In terms of morbidity and mortality, Bangladesh, Pakistan, Bhutan and India were detected to be most susceptible to human impacts. Although Bhutan had seen lesser number of flooding disasters, higher population living within disaster prone region make them vulnerable. In summary, complex interactions between natural and socio-economic conditions play a dominant role to define and characterize the type and magnitude of vulnerability of HKH countries to disaster occurrence and their economic and human impacts.
Dust reverberation mapping of Z229–15 Mandal, Amit Kumar; Rakshit, Suvendu; Stalin, C S ...
Monthly Notices of the Royal Astronomical Society,
03/2021, Letnik:
501, Številka:
3
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
We report results of the dust reverberation mapping (DRM) on the Seyfert 1 galaxy Z229–15 at z = 0.0273. Quasi-simultaneous photometric observations for a total of 48 epochs were acquired ...during the period 2017 July to 2018 December in B, V, J, H and Ks bands. The calculated spectral index (α) between B and V bands for each epoch was used to correct for the accretion disc (AD) component present in the infrared light curves. The observed α ranges between −0.99 and 1.03. Using cross-correlation function analysis we found significant time delays between the optical V and the AD corrected J, H and Ks light curves. The lags in the rest frame of the source are $12.52^{+10.00}_{-9.55}$ d (between V and J), $15.63^{+5.05}_{-5.11}$ d (between V and H) and $20.36^{+5.82}_{-5.68}$ d (between V and Ks). Given the large error bars, these lags are consistent with each other. However, considering the lag between V and Ks bands to represent the inner edge of the dust torus, the torus in Z229–15 lies at a distance of 0.017 pc from the central ionizing continuum. This is smaller than that expected from the radius luminosity (R−L) relationship known from DRM. Using a constant α = 0.1 to account for the AD component, as is normally done in DRM, the deduced radius (0.025 pc) lies close to the expected R−L relation. However, usage of constant α in DRM is disfavoured as the α of the ionizing continuum changes with the flux of the source.
The
S. aureus
extracellular adherence protein (Eap) and its homologs, EapH1 and EapH2, serve roles in evasion of the human innate immune system. EapH1 binds with high-affinity and inhibits the ...neutrophil azurophilic granule proteases neutrophil elastase, cathepsin-G and proteinase-3. Previous structural studies using X-ray crystallography have shown that EapH1 binds to neutrophil elastase and cathepsin-G using a globally similar binding mode. However, whether the same holds true in solution is unknown and whether the inhibitor experiences dynamic changes following binding remains uncertain. To facilitate solution-phase structural and biochemical studies of EapH1 and its complexes with neutrophil granule proteases, we have characterized EapH1 by multidimensional NMR spectroscopy. Here we report a total of 100% of the non-proline backbone resonance assignments of EapH1 with BMRB accession number 50,304.
We present the output data of Robust Principal Component Analysis (RPCA) applied to global crop yield variability of maize, rice, sorghum and soybean (MRSS) as presented in the publication “Climate ...drives variability and joint variability of global crop yields” (Najafi et al., 2019). Global maps of the correlation between all the principal components (PCs) acquired from the low rank matrix (L) of MRSS and Palmer Drought Severity Index (PDSI), air temperature anomalies (ATa) and sea surface temperature anomalies (SSTa) are provided in this article. We present co-varying countries, impacted cropland areas across global countries, and 10 global regions by climate and the association between PCs and multiple atmospheric and oceanic indices. Moreover, the joint dependency between PCs of MRSS yields are presented using two different approaches.
The Extracellular Adherence Protein (Eap) from
Staphylococcus aureus
is a potent inhibitor of the classical and lectin pathways of the complement system. Previous studies have shown that Eap binds ...with nanomolar affinity to complement component C4b and prevents C4b binding the pro-protease, C2, thereby inhibiting formation of the pro-C3 convertase shared by the classical and lectin pathways (Woehl et al. in J Immunol 193:6161–6171, 2014). The C4b-binding and complement-inhibitory properties of Eap from
S. aureus
strain Mu50 lie within the two C terminal-most Eap domains (i.e. Eap34) (Woehl et al. J Immunol 193:6161–6171, 2014). Interestingly, Eap34 binds C4b with an apparent K
D
that is nearly 100-fold tighter than that of either Eap3 or Eap4 alone (Woehl et al. in Protein Sci 26:1595–1608, 2017). This suggests that linking these two domains into a single molecule is a significant determinant of Eap function. To better understand this property at the structural level, we undertook a solution NMR study of the ~ 23 kDa Eap34 protein. In this communication, we report that greater than 98% of the total non-proline backbone residues have been assigned. These data have been deposited in the BMRB database under the accession number 50210.
In this study, long-term national-based yields of maize, rice, sorghum and soybean (MRSS) from 1961 to 2013 are decomposed using Robust Principal Component Analysis (RPCA). After removing outliers, ...the first three principal components (PC) of the persistent yield anomalies are scrutinized to assess their association with climate and to identify co-varying countries and crops. Sea surface temperature anomalies (SSTa), atmospheric and oceanic indices, air temperature anomalies (ATa) and Palmer Drought Severity Index (PDSI) are used to study the association between the PCs and climate. Results show that large-scale climate, especially El Niño-Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) are strongly correlated with crop yield variability. Extensive maize harvesting regions in Europe and North America, rice in South America, Oceania and east of Asia, sorghum in west and southeast of Asia, North America and Caribbean and soybean in North and South America, Oceania and south of Asia experienced the influence of local climate variability in this period. Sorghum yield variability across the globe exhibits significant correlations with many atmospheric and oceanic indices. Results indicate that not only do the same crops in many countries co-vary significantly, but different crops, in particular maize, in different PCs also co-vary with other crops. Identifying the association between climate and crop yield variability and recognizing similar and dissimilar countries in terms of yield fluctuations can be informative for the identified nations with regard to the periodic and predictable nature of many large-scale climatic patterns.
Display omitted
•Decomposing global yield anomalies of four staple crops•Investigating the most important modes of crop yield variability and their association with large- and local-scale climate•Identifying co-varying countries and joint dependencies between crop yields
ABSTRACT
While the temperature of the X-ray corona (kTe) in active galactic nuclei (AGNs) is known for many sources, its variation if any is limited to a handful of objects. This is in part due to ...the requirement of good signal-to-noise X-ray spectra, covering a wide range of energies. We present here results on the X-ray spectral analysis of 18 Seyferts, having more than one epoch of observations to look for variation in kTe. The data for a total of 52 epochs on these 18 AGNs were taken from observations carried out by NuSTAR in the 3−79 keV energy band. From phenomenological and physical model fits to the multiepoch data on these 18 sources from NuSTAR, we could constrain the cut-off energy (Ecut) in a large fraction of the sources. Also, from Comptonized model fits we could obtain kTe for our sample. Of the 18 sources, at the 90 per cent confidence level, evidence for variation in kTe was found for only one source namely MCG + 08-11-011. For this source between two epochs, separated by about 5 yr, we found kTe to decrease from 57$^{+29}_{-16}$ to 30$^{+11}_{-7}$ keV. During the same period, the flux decreased from (12.60 to 14.02) × 10−11 erg cm−2 s−1 and the optical depth increased from 1.68 to 2.73. We thus found a positive correlation between flux and coronal temperature with a reduction of about 40 per cent in optical depth. Our observations tend to favour the vertically outflowing corona scenario for the observed variation in kTe in MCG + 08-11-011.