Biosurfactants are surface-active molecules that are synthesised non-ribosomally by a wide range of microorganisms including bacteria, yeast and filamentous fungi. The bacterial genus
Serratia
is ...gaining international interest, as biosurfactants produced by this genus have emerged as a promising source of antimicrobial, antifouling and antitumour compounds that possess emulsification and surface activity. Various species of
Serratia
have been identified as biosurfactant producers, including
Serratia marcescens
,
Serratia rubidaea
and
Serratia surfactantfaciens
. Members of the
Serratia
genus have been reported to principally produce two classes of biosurfactants, namely lipopeptides and glycolipids. Lipopeptides produced by
Serratia
species include serrawettins and stephensiolides, while identified glycolipids include rubiwettins and rhamnolipids. This review will primarily focus on the classification of biosurfactants produced by
Serratia
species and the genes and mechanisms involved in the biosynthesis of these biosurfactant compounds. Thereafter, an indication of the primary growth conditions and nutrient composition required for the optimum production of biosurfactants by this genus will be outlined. An overview of the latest advances and potential applications of the biosurfactants produced by
Serratia
in the medical, pharmaceutical, agricultural and petroleum industries is also provided.
Estimating an earthquake's magnitude and location may not be necessary to predict shaking in real time; instead, wavefield‐based approaches predict shaking with few assumptions about the seismic ...source. Here, we introduce GRAph Prediction of Earthquake Shaking (GRAPES), a deep learning model trained to characterize and propagate earthquake shaking across a seismic network. We show that GRAPES’ internal activations, which we call “seismic vectors”, correspond to the arrival of distinct seismic phases. GRAPES builds upon recent deep learning models applied to earthquake early warning by allowing for continuous ground motion prediction with seismic networks of all sizes. While trained on earthquakes recorded in Japan, we show that GRAPES, without modification, outperforms the ShakeAlert earthquake early warning system on the 2019 M7.1 Ridgecrest, CA earthquake.
Plain Language Summary
Have you ever heard something through the grapevine? It often takes you by surprise to hear a message from someone other than the original source. You might have felt an earthquake in a similar way: experiencing shaking (the message) at your location rather than movement along a fault (the source). We apply grapevine‐style communication to earthquake early warning (EEW). The goal of EEW is to warn people to prepare for earthquake shaking before damaging seismic waves arrive at their location. We build on recent work that used deep learning and large earthquake data sets to predict earthquake shaking. We developed a deep learning algorithm called GRAPES which predicts shaking in a manner similar to a game of seismic telephone: when a seismic sensor detects shaking, it sends a message to its neighboring sensors, warning them to expect shaking soon. These sensors then pass on the message to their more distant neighbors along the grapevine. We show that the messages GRAPES learned to send between sensors are like seismic status updates: “I'm seeing this type of seismic wave right now”. We applied GRAPES to the 2019 M7.1 Ridgecrest, CA earthquake and it predicted shaking accurately and quickly.
Key Points
A deep learning network trained to predict ground motion learned an internal representation of the seismic wavefield
Individual neurons within the network activate with the arrival of P waves, S waves, surface waves, coda waves, and ambient noise
While trained on earthquakes in Japan, the model generalizes well to predicting ground motions for the 2019 Ridgecrest, CA earthquake
Sudden cardiac death due to ventricular tachyarrhythmias remains the major cause of mortality in the world. Heart failure, diabetic cardiomyopathy, old age-related cardiac dysfunction and inherited ...disorders are associated with enhanced propensity to malignant cardiac arrhythmias. Both defective mitochondrial function and abnormal intracellular Ca2+ homeostasis have been established as the key contributing factors in the pathophysiology and arrhythmogenesis in these conditions. This article reviews current advances in understanding of bidirectional control of ryanodine receptor-mediated sarcoplasmic reticulum Ca2+ release and mitochondrial function, and how defects in crosstalk between these two organelles increase arrhythmic risk in cardiac disease.
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Many global environmental agendas, including halting biodiversity loss, reversing land degradation, and limiting climate change, depend upon retaining forests with high ecological integrity, yet the ...scale and degree of forest modification remain poorly quantified and mapped. By integrating data on observed and inferred human pressures and an index of lost connectivity, we generate a globally consistent, continuous index of forest condition as determined by the degree of anthropogenic modification. Globally, only 17.4 million km
of forest (40.5%) has high landscape-level integrity (mostly found in Canada, Russia, the Amazon, Central Africa, and New Guinea) and only 27% of this area is found in nationally designated protected areas. Of the forest inside protected areas, only 56% has high landscape-level integrity. Ambitious policies that prioritize the retention of forest integrity, especially in the most intact areas, are now urgently needed alongside current efforts aimed at halting deforestation and restoring the integrity of forests globally.
Aim
To review randomized controlled trials to assess efficacy of a prize‐based contingency management procedure in reducing substance use (where a drug‐free breath or urine sample provides a chance ...of winning a prize).
Methods
A meta‐analysis was conducted on papers published from January 2000 to February 2013 to determine the effect size of studies comparing prize‐based contingency management to a treatment‐as‐usual control condition (k = 19 studies). Parallel analyses evaluated the efficacy of both short‐ (k = nine studies) and long‐term outcomes (k = six studies) of prize‐based contingency management.
Results
The average end‐of‐treatment effect size (Cohen's d) was 0.46 95% confidence interval (CI) = 0.37, 0.54. This effect size decreased at the short‐term (≤3‐month) post‐intervention follow‐up to 0.33 (95% CI = 0.12, 0.54) and at the 6‐month follow‐up time‐point there was no detectable effect d = −0.09 (95% CI = −0.28, 0.10).
Conclusion
Adding prize‐based contingency management to behavioral support for substance use disorders can increase short‐term abstinence, but the effect does not appear to persist to 6 months.
Secondary peritonitis and intra-abdominal sepsis are a global health problem. The life-threatening systemic insult that results from intra-abdominal sepsis has been extensively studied and remains ...somewhat poorly understood. While local surgical therapy for perforation of the abdominal viscera is an age-old therapy, systemic therapies to control the subsequent systemic inflammatory response are scarce. Advancements in critical care have led to improved outcomes in secondary peritonitis. The understanding of the effect of secondary peritonitis on the human microbiome is an evolving field and has yielded potential therapeutic targets. This review of secondary peritonitis discusses the history, classification, pathophysiology, diagnosis, treatment, and future directions of the management of secondary peritonitis. Ongoing clinical studies in the treatment of secondary peritonitis and the open abdomen are discussed.
This study investigates changes in seismic velocities in the period 1999–2021 using about 700 permanent and temporary broadband seismic stations in the state of California. We compute single‐station ...cross‐correlations of the ambient seismic noise and use the coda‐wave interferometry to measure the changes in seismic velocities (dv/v) using a stretching technique. We focus on the 2–4 Hz frequency band and the upper 500 m of the near‐surface sensitivity. We discuss dv/v within the context of nonlinear elasticity. We fit models of thermoelastic strains, various hydrological models that diffuse rainwater, and slow‐dynamics healing models for the postseismic response of earthquakes. In general, we find that both thermoelastic strains and hydrological strains have a similar amplitude of impacts on dv/v. We find that the diffusion of rainwater using a drained response in a poroelastic medium explains most of the data. The best fit hydraulic diffusivity is high in the mountains and low in the basin. We find that the largest drop in seismic velocity occurs during the 2004–2005 wet winter and that the 2011–2016. Drought is characterized by a multiyear marked increase in dv/v. We interpret site‐specific variations with land subsidence or inflation detected by remote sensing. We also find a decade‐long postseismic response of two major earthquakes and bound the time scale of relaxation processes to a few years. Together, we see long‐term changes in seismic velocities showing a positive trend over two decades that we can interpret as long‐term lowering of the groundwater table.
Plain Language Summary
The multiyear droughts and sudden downpours cause stress to water management and natural hazards in California. This study investigates their impact on the subsurface seismic properties. Large seismic data archives such as reliable permanent seismic networks and large computing capabilities allow for a state‐wide, two‐decade‐long analysis of the changes in the shallow seismic structures. The near‐surface seismic velocities in the upper 500 m of the Earth's crust are strongly modulated by annual variations in air temperature and diffusion of rainfall. Due to extreme climate conditions in California, seismic velocities change by up to −2% during a single winter due to rain, and up to 2% during 20 years of progressively drying conditions. The recovery of fault‐zone materials near two significant earthquakes, the 1999 Hector Mine and 2010 El Mayor Cucapah earthquakes, indicates a relaxation process that can last decades and implies characteristic time scales of a few years and a spatial heterogeneity that coincide with deep crustal viscous properties. This study presents passive seismology as a tool to probe Earth's tectonic‐hydrological processes complementary to geodesy and hydrology.
Key Points
Environmental factors considerably change near‐surface seismic velocity over decades
There is a long‐term increase in seismic velocities in California due to increased drought conditions
The decade‐long recovery from large earthquakes of sites very close to faults indicates postseismic strain localization and a delayed healing
We examine the importance of indirect network effects in the U.S. video game market between 1994 and 2002. The diffusion of game systems is analyzed by the interaction between console adoption ...decisions and software supply decisions. Estimation results suggest that introductory pricing is an effective practice at the beginning of the product cycle, and expanding software variety becomes more effective later. We also find a degree of inertia in the software market that does not exist in the hardware market. This observation implies that software providers continue to exploit the installed base of hardware users after hardware demand has slowed.
This paper provides an overview of the current literature and scientific evidence surrounding inorganic nitrate (NO3-) supplementation and its potential for improving human health and physical ...performance. As indicative of the ever-expanding organic and natural food consumer market, athletes and health enthusiasts alike are constantly searching for ingredient-specific "super foods" and dietary supplements capable of eliciting health and performance benefits. Evidence suggests that NO3- is the viable active component within beetroot juice (BRJ) and other vegetables, responsible for health-promoting and ergogenic effects. Indeed, multiple studies support NO3- supplementation as an effective method to improve exercise performance. NO3- supplementation (either as BRJ or sodium nitrate NaNO3-) has also demonstrated modest benefits pertaining to cardiovascular health, such as reducing blood pressure (BP), enhancing blood flow, and elevating the driving pressure of O2 in the microcirculation to areas of hypoxia or exercising tissue. These findings are important to cardiovascular medicine/exercise physiology and suggest a possible role for NO3- supplementation: (1) as a low-cost prevention and treatment intervention for patients suffering from blood flow disorders; and (2) an effective, natural ergogenic aid for athletes. Benefits have been noted following a single bolus, as well as daily supplementation of NO3-. While results are promising, additional research is needed to determine the impact of NO3- supplementation on anaerobic exercise performance, to identify principle relationships between isolated nitrate and other ingredients found in nitrate-rich vegetables (e.g., vitamin C, polyphenols, fatty acids, thiocyanate), to explore the specific dose-response relationships needed to elicit health and ergogenic benefits, to prolong the supplementation period beyond a relatively short period (i.e., >15 days), to determine if more robust effects can be observed with longer-term treatment, and to fully examine the safety of chronic NO3- supplementation, as this continues to be a concern of some.
Ethidium monoazide bromide (EMA) and propidium monoazide (PMA), in combination with amplicon-based sequencing (ABS) and quantitative polymerase chain reaction (qPCR) assays, were compared for the ...detection of viable bacterial species in rainwater. The ABS α- and β-diversity indices indicated that, in comparison to the untreated samples, both EMA and PMA reduced the detection of non-viable bacteria in the rainwater samples. However, while comparable results were obtained for the detection of the most abundant bacterial families and genera in the rainwater samples for both the EMA and PMA pre-treatments; the EMA pre-treatment produced highly significant differences in the relative abundance of the dominant bacterial families and genera, and significantly decreased the detection of “unclassified” bacteria in comparison to the untreated samples (i.e. unclassified genera: untreated 46.7% versus EMA-treated 39.7%). Additionally, the inclusion of EMA and PMA allowed for the increased detection of less abundant pathogenic bacteria in the rainwater samples, such as
Clostridium
,
Listeria
and
Streptococcus
spp. The qPCR assays also indicated that the EMA and PMA pre-treatments were comparable for the detection of intact and potentially viable
Acinetobacter
,
Legionella
and
Pseudomonas
spp. The combination of viability pre-treatments with ABS thus offers a comprehensive monitoring approach to detect less abundant bacterial genera and/or pathogens, which may pose a health risk to the end-users (prioritise target organisms) of unpiped environmental water sources. Moreover, the subsequent combination of the viability pre-treatments with qPCR allows for the specific detection and quantification of these pathogenic genera, which increases analysis sensitivity and allows for the application of risk assessment and water safety strategies.
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