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Could hotel service robots help the hospitality industry after COVID-19?

A new research study, investigating how service robots in hotels could help redefine leadership and boost the hospitality industry, has taken on new significance in the light of the seismic impact of the Covid-19 outbreak on tourism and business travel. The study by academics at The University of Surrey and MODUL University Vienna focuses on how HR experts perceive service robots and their impact on leadership and HR management in the hotel industry.

Lead author Dr Tracy Xu, Lecturer in Hospitality at The University of Surrey’s world-renowned School of Hospitality and Tourism Management, has had her paper published in the International Journal of Contemporary Hospitality Management. The research behind the paper involved speaking to 19 hotel HR experts to identify the key trends and major challenges that will emerge in the next ten years and how leaders should deal with the challenges brought about by service robot technologies.

Results showed that while service robots are anticipated to increase efficiency and productivity of hotel activities, they may also pose challenges such as high costs, skill deficits and significant changes to the organizational structure and culture of hotels. Therefore, the anticipated applications and integration of robotic technology will require leaders of the future to carefully consider the balance between the roles of service robots and human employees in the guest experience and to nurture a work environment that embraces open-mindedness and change.

The project finished in March 2020 just as COVID-19 broke out and as the virus rendered non-essential travel impossible, most hotels around the globe are feeling a catastrophic economic impact. There is now even more interest in developing innovative ways of deploying service robots across all economic sectors to limit human interaction. Considering the current pandemic, many industries are having to reinvent processes and systems to cope with a new isolated way of life. Robotic interaction in hotels could facilitate more socially distanced models of operation to enable a safer and faster reopening and recovery of some hotels.

Dr Xu said: “Application of service robots in the hotel industry is on the rise. With the added factor of a need to reassure potential guests that their stays will be compatible with minimised social contact and human interaction, this process could be accelarated. During the lockdown period it is likely that hotel managers will be planning for a ‘fresh start’ in the recovery and rebuilding period after the social isolation restrictions have been lifted and this is predicted to have a positive stimulus on the adoption of service robots.

“The anticipated applications and integration of robotic technology will require leaders of the future to carefully consider the balance between the roles of service robots and human employees in the guest experience and to nurture a work environment that embraces open-mindedness and change.”

Dr Xu was joined in her research by fellow Surrey colleague Mark Ashton, Teaching Fellow, and Jason Stienmetz, Assistant Professor at MODUL University Vienna.

Mr Ashton said: “This is the first type of study to examine hospitality leadership and human resource management in the context of robotized hotels and at a time where hotels seem to need it most. Forward-thinking businesses who are proactively prepared for the introduction of these exciting new technologies will benefit in the long term.”

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Supercapacitor promises storage, high power and fast charging

A new supercapacitor based on manganese oxide could combine the storage capacity of batteries with the high power and fast charging of other supercapacitors, according to researchers at Penn State and two universities in China.

“Manganese oxide is definitely a promising material,” said Huanyu “Larry” Cheng, assistant professor of engineering science and mechanics and faculty member in the Materials Research Institute, Penn State. “By combining with cobalt manganese oxide, it forms a heterostructure in which we are able to tune the interfacial properties.”

The group started with simulations to see how manganese oxide’s properties change when coupled with other materials. When they coupled it to a semiconductor, they found it made a conductive interface with a low resistance to electron and ion transport. This will be important because otherwise the material would be slow to charge.

“Exploring manganese oxide with cobalt manganese oxide as a positive electrode and a form of graphene oxide as a negative electrode yields an asymmetric supercapacitor with high energy density, remarkable power density and excellent cycling stability,” according to Cheng Zhang, who was a visiting scholar in Cheng’s group and is the lead author on a paper published recently in Electrochimica Acta.

The group has compared their supercapacitor to others and theirs has much higher energy density and power. They believe that by scaling up the lateral dimensions and thickness, their material has the potential to be used in electric vehicles. So far, they have not tried to scale it up. Instead, their next step will be to tune the interface where the semiconducting and conducting layers meet for even better performance. They want to add the supercapacitor to already developed flexible, wearable electronics and sensors as an energy supply for those devices or directly as self-powered sensors.

The National Natural Science Foundation of China and the Science Research Fund of Guizhou Province, China supported this research.

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Engineers demonstrate next-generation solar cells can take the heat, maintain efficiency

Perovskites with their crystal structures and promising electro-optical properties could be the active ingredient that makes the next generation of low-cost, efficient, lightweight and flexible solar cells.

A problem with the current generation of silicon solar cells is their relatively low efficiency at converting solar energy into electricity, said Vikram Dalal, an Iowa State University Anson Marston Distinguished Professor in Engineering, the Thomas M. Whitney Professor in Electrical and Computer Engineering and the director of Iowa State’s Microelectronics Research Center.

The best silicon solar cells in the laboratory are about 26% efficient while commercial cells are about 15%. That means bigger systems are necessary to produce a given amount of electricity, and bigger systems mean higher costs.

That has researchers looking for new ways to raise efficiency and decrease costs. One idea that could boost efficiency by as much as 50% is a tandem structure that stacks two kinds of cells on top of each other, each using different, complementary parts of the solar spectrum to produce power.

Perovskite promise, problems

Researchers have recently started looking at hybrid organic-inorganic perovskite materials as a good tandem partner for silicon cells. Perovskite calls have efficiency rates nearing 25%, have a complementary bandgap, can be very thin (just a millionth of meter), and can easily be deposited on silicon.

But Dalal said researchers have learned those hybrid perovskite solar cells break down when exposed to high temperatures.

That’s a problem when you try to put solar arrays where the sunshine is — hot, dry deserts in places such as the American southwest, Australia, the Middle East and India. Ambient temperatures in such places can hit the 120 to 130 degrees Fahrenheit and solar cell temperatures can hit 200 degrees Fahrenheit.

Iowa State University engineers, in a project partially supported by the National Science Foundation, have found a way to take advantage of perovskite’s useful properties while stabilizing the cells at high temperatures. They describe their discovery in a paper recently published online by the scientific journal American Chemical Society Applied Energy Materials.

“These are promising results in pursuit of the commercialization of perovskite solar cell materials and a cleaner, greener future,” said Harshavardhan Gaonkar, the paper’s first author who recently earned his doctorate in electrical and computer engineering from Iowa State and is now working in Boise, Idaho, as an engineer for ON Semiconductor.

Tweaking the material

Dalal, the corresponding author of the paper, said there are two key developments in the new solar cell technology:

First, he said the engineers made some tweaks to the makeup of the perovskite material.

They did away with organic components in the material — particularly cations, materials with extra protons and a positive charge — and substituted inorganic materials such as cesium. That made the material stable at higher temperatures.

And second, they developed a fabrication technique that builds the perovskite material one thin layer — just a few billionths of a meter — at a time. This vapor deposition technique is consistent, leaves no contaminants, and is already used in other industries so it can be scaled up for commercial production.

The result of those changes?

“Our perovskite solar cells show no thermal degradation even at 200 degrees Celsius (390 degrees Fahrenheit) for over three days, temperatures far more than what the solar cell would have to endure in real-world environments,” Gaonkar said.

And then Dalal did a little comparing and contrasting: “That’s far better than the organic-inorganic perovskite cells, which would have decomposed totally at this temperature. So this is a major advance in the field.”

Raising performance

The paper reports the new inorganic perovskite solar cells have a photoconversion efficiency of 11.8%. That means there’s more work ahead for the engineers.

“We are now trying to optimize this cell — we want to make it more efficient at converting solar energy into electricity,” Dalal said. “We still have a lot of research to do, but we think we can get there by using new combinations of materials.”

The engineers, for example, replaced the iodine common in perovskite materials with bromine. That made the cells much less sensitive to moisture, solving another problem with standard hybrid perovskites. But, that substitution changed the cells’ properties, reducing efficiency and how well they work in tandem with silicon cells.

And so the tweaks and trials will continue.

As they move ahead, the engineers believe they’re on a proven path: “This study demonstrates a more robust thermal stability of inorganic perovskite materials and solar cells at higher temperatures and over extended periods of time than reported elsewhere,” they wrote in their paper. “(These are) promising results in pursuit of the commercialization of perovskite solar cell materials.”

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How APIs Can Block Suspicious Web Visitors Based on IP Address

We don’t want to allow signups from VPNs or proxies. Visitors could be using a VPN to mask their real location and bypass location restrictions. A visitor using TOR, which hides their real location and identity, might be trying to perform malicious activity on your site. So how can we block these users?

Most IP lookup services have some kind of threat database. These services allow us to check whether an IP is anonymous (using a TOR, a VPN, or a proxy), or a threat, such as a known spammer or hacker. We can use one of these services to detect malicious users and block them from signing up.

At ipdata, we have a database of 600 million malicious IPs which is updated every 15 minutes. Maxmind provide a GeoIP2 Anonymous IP Database which can detect anonymous IPs, but it doesn’t currently detect malicious IPs. AWS WAF has IP reputation lists which can be used to block anonymous users and IPs which have been flagged by Amazon’s internal threat intelligence.

Detecting threats with ipdata

The ipdata threat API can be used by making a simple GET request with the user’s IP address, such as https://api.ipdata.co/1.43.247.217/threat?api-key=test. It responds with an object containing all the information we need to make a decision about the user. Are they a known attacker or abuser? They’re a threat! Are they using TOR or a proxy? They’re anonymous.

{
  "is_tor": true,
  "is_proxy": false,
  "is_anonymous": true,
  "is_known_attacker": false,
  "is_known_abuser": false,
  "is_threat": false,
  "is_bogon": false
}

There’s another field in there too – is_bogon. This indicates that the IP has not been allocated or delegated by IANA or any RIRs, and is almost certainly from an attacker. Bogon IPs also include reserved private addresses, such as 192.168.0.0/16.

Blocking sign ups

Now that we know how to detect VPNs, proxies, and threats, let’s actually block these IPs from signing up using a small Node.js application that involves the Express.js. and Axios frameworks (both easily installed via NPM).

Here’s a simplified signup form in HTML, which should be saved to your web installation (or other HTML source directory) as signup.html.

<form action="/signup" method="POST">
  <input name="email" type="email" placeholder="Email address" />
  <input name="password" type="password" placeholder="Password" />
  <input type="submit" />
</form>

Now, we can build our Node application to serve the signup form and handle new signups.

const express = require("express");
const app = express();
const axios = require("axios");

// Get an ipdata API Key from here: https://ipdata.co/sign-up.html
const IPDATA_API_KEY = "test";
const getIpData = async (ip) => {
  const response = await axios.get(
    `https://api.ipdata.co/${ip}/threat?api-key=${IPDATA_API_KEY}`
  );
  return response.data;
};

// Serve the signup page
app.get("/signup", (req, res) =>
  res.sendFile("./signup.html", { root: __dirname })
);

// Handle a signup request
app.post("/signup", async (req, res) => {
  const ip = req.connection.remoteAddress;
  const ipdata = await getIpData(ip);
  const { is_threat, is_anonymous } = ipdata;
  if (is_threat) {
    res.status(403).send("Blocked IP");
    return;
  }
  if (is_anonymous) {
    res.status(403).send("VPNs are not allowed");
    return;
  }

  // Success! create the user...

  res.status(200).send("Welcome!");
});

app.listen(8000);

When a POST request is received by our server, we call the ipdata API to get additional metadata for the user’s IP. Using that, we block any IPs which are deemed to be a threat, along with anonymous IPs.

When testing it all together, it works like this:

Do you really need to?

Blocking anonymous traffic to your site is likely to catch out some genuine users. There are many valid reasons to use a VPN – some users may have privacy concerns, or they might have restricted Internet access due to their government, ISP, or work. Blocking anonymous traffic should be a last resort and is usually only necessary if there are some legal restrictions, such as media streaming rights or advertising. For these reasons, anonymous blocking will often be combined with blocking users from certain countries.

Blocking threats, however, is a clear and easy way to reduce fraudulent activity on your website. Don’t just block malicious IPs from signing up – stop them from accessing your site all together. Your real users shouldn’t notice at all, but the security of their accounts will be strengthened.

Conclusions

Blocking users from signing up using a VPN or proxy is easy, and there are plenty of options. If you want to stop all traffic from any VPN, consider blocking the requests using a firewall, like AWS WAF. Whilst blocking threats is a quick-win for your security, blocking anonymous traffic might impact legitimate users – potentially resulting in lost orders or frustrated users – so use it with caution and only where needed.

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Engineers make a promising material stable enough for use in solar cells

Soft and flexible materials called halide perovskites could make solar cells more efficient at significantly less cost, but they’re too unstable to use.

A Purdue University-led research team has found a way to make halide perovskites stable enough by inhibiting the ion movement that makes them rapidly degrade, unlocking their use for solar panels as well as electronic devices.

The discovery also means that halide perovskites can stack together to form heterostructures that would allow a device to perform more functions.

The results published in the journal Nature on Wednesday (April 29). Other collaborating universities include Shanghai Tech University, the Massachusetts Institute of Technology, the University of California, Berkeley, and the U.S. Department of Energy’s Lawrence Berkeley National Laboratory.

Researchers already have seen that solar cells made out of perovskites in the lab perform just as well as the solar cells on the market made of silicon. Perovskites have the potential to be even more efficient than silicon because less energy is wasted when converting solar energy to electricity.

And because perovskites can be processed from a solution into a thin film, like ink printed on paper, they could be more cheaply produced in higher quantities compared to silicon.

“There have been 60 years of a concerted effort making good silicon devices. There may have been only 10 years of concerted effort on perovskites and they’re already as good as silicon, but they don’t last,” said Letian Dou (lah-TEEN dough), a Purdue assistant professor of chemical engineering.

A perovskite is made up of components that an engineer can individually replace at the nanometer scale to tune the material’s properties. Including multiple perovskites in a solar cell or integrated circuit would allow the device to perform different functions, but perovskites are too unstable to stack together.

Dou’s team discovered that simply adding a rigid bulky molecule, called bithiophenylethylammonium, to the surface of a perovskite stabilizes the movement of ions, preventing chemical bonds from breaking easily. The researchers also demonstrated that adding this molecule makes a perovskite stable enough to form clean atomic junctions with other perovskites, allowing them to stack and integrate.

“If an engineer wanted to combine the best parts about perovskite A with the best parts about perovskite B, that typically can’t happen because the perovskites would just mix together,” said Brett Savoie (SAHV-oy), a Purdue assistant professor of chemical engineering, who conducted simulations explaining what the experiments revealed on a chemical level.

“In this case, you really can get the best of A and B in a single material. That is completely unheard of.”

The bulky molecule allows a perovskite to stay stable even when heated to 100 degrees Celsius. Solar cells and electronic devices require elevated temperatures of 50-80 degrees Celsius to operate.

These findings also mean that it could be possible to incorporate perovskites into computer chips, the researchers said. Tiny switches in computer chips, called transistors, rely on tiny junctions to control electrical current. A pattern of perovskites might allow the chip to perform more functions than with just one material.

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A breakthrough in estimating the size of a (mostly hidden) network

A newly discovered connection between control theory and network dynamical systems could help estimate the size of a network even when a small portion is accessible.

Understanding the spread of coronavirus may be the most alarming and recent example of a problem that could benefit from a fuller knowledge of network dynamical systems, but scientists and mathematicians have been grappling for years with ways to draw accurate inferences about these complex systems by working with partial data from available measurements.

In a new Physical Review Letters paper, New York University Tandon School of Engineering Institute Professor Maurizio Porfiri demonstrates a profound connection between mathematical control theory and the problem of determining the size of a network dynamical system from the time series of some accessible units. For homogeneous networks — in which every unit plays the same — accessing a mere 10% of the units could be sufficient to exactly infer the size of the entire network, Porfiri concludes.

But the same approach fails for heterogeneous networks, which are far more common in the field of complex systems: Think of the early stage of the novel coronavirus outbreak, in which every person experienced a widely different range of contacts due to their social and professional lives. Hence, the author recommends prudence in the inference of the size of a network dynamical system from available measurements when information on the nature of the network is lacking.

“From natural to technological settings, network dynamical systems constitute a powerful approach to study collective dynamics. The size of the system is arguably its most fundamental property, but seldom do we have access to such critical information,” Porfiri explained. His research provides mathematical proof for a model-free approach published last year by researchers from the University of Oldenberg and the Technical University of Dresden.

Porfiri holds appointments in NYU Tandon’s Departments of Mechanical and Aerospace Engineering; Biomedical Engineering; and Civil and Urban Engineering, as well as its Center for Urban Science and Progress.

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A non-invasive way of monitoring diabetes

Saliva could be used instead of blood to monitor diabetes in a method proposed in research involving the University of Strathclyde.

The test has been developed as an alternative to the current prevalent practice of monitoring blood glucose, which can be invasive, painful and costly.

Lab tests of the saliva process had an accuracy rate of 95.2%. The research shows promising results for monitoring diabetes, which affects an estimated 425 million people worldwide — around half of them undiagnosed.

The research has been published in the journal PLOS ONE. It also involved partners at the Federal University of Uberlandia in Minas Gerais, Brazil, the University of Vale do Paraíba in Sao Paolo, Brazil and the University of Saskatchewan in Canada.

Dr Matthew Baker, a Reader in Strathclyde’s Department of Pure and Applied Chemistry and lead researcher in the project, said: “Frequent monitoring of diabetes is essential for improved glucose control and to delay clinical complications related to the condition. Early screening is also paramount in reducing these complications worldwide.

“Blood analysis for screening, monitoring and diagnosing diabetes is widely practised but is quite invasive and painful. The constant need of piercing the fingers several times daily for most patients may lead to the development of finger calluses, as well as difficulty in obtaining blood samples; furthermore, not everyone would want to give blood and there are circumstances in which it could be dangerous.

“Saliva reflects several physiological functions of the body, such as emotional, hormonal, nutritional and metabolic, and so its biomarkers could be an alternative to blood for robust early detection and monitoring. It is easy to collect, non-invasive, convenient to store and requires less handling than blood during clinical procedures, while also being environmentally efficient. It also contains analytes with real-time monitoring value which can be used to check a person’s condition.”

Dr Robinson Sabino-Silva, an associate professor at Federal University of Uberlandia (UFU) and a partner in the research, said: “The present protocol used in the infrared platform is able to detect spectral biomarkers without reagents. The combination of a non-invasive salivary collection and a reagent-free analysis permit us to monitor diabetes with a sustainable platform classified as green technology.”

The lab tests used a scientific system known as Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. This has been used in the diagnosis of several diseases, although its applications in the monitoring of diabetic treatment have begun to emerge only recently. Samples were assessed in three categories — diabetic, non-diabetic and insulin-treated diabetic — and two potential diagnostic biomarkers were identified.

The researchers are hopeful that the process they have developed could be used for both Type 1 and Type 2 diabetes, although further study will be required to confirm this.

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Speeding-up quantum computing using giant atomic ions

An international team of researchers have found a new way to speed up quantum computing that could pave the way for huge leaps forward in computer processing power.

Scientists from the University of Nottingham and University of Stockholm have sped-up trapped ion quantum computing using a new experimental approach — trapped Rydberg ions; their results have just been published in Nature.

In conventional digital computers, logic gates consist of operational bits that are silicon based electronic devices. Information is encoded in two classical states (“0” and “1”) of a bit. This means that capacities of a classical computer increase linearly with the number of bits. To deal with emerging scientific and industrial problems, large computing facilities or supercomputers are built.

Quantum entanglement enhancing capacity

A quantum computer is operated using quantum gates, i.e. basic circuit operations on quantum bits (qubits) that are made of microscopic quantum particles, such as atoms and molecules. A fundamentally new mechanism in a quantum computer is the utilisation of quantum entanglement, which can bind two or a group of qubits together such that their state can no longer be described by classical physics. The capacity of a quantum computer increases exponentially with the number of qubits. The efficient usage of quantum entanglement drastically enhances the capacity of a quantum computer to be able to deal with challenging problems in areas including cryptography, material, and medicine sciences.

Among the different physical systems that can be used to make a quantum computer, trapped ions have led the field for years. The main obstacle towards a large-scale trapped ion quantum computer is the slow-down of computing operations as the system is scaled-up. This new research may have found the answer to this problem.

The experimental work was conducted by the group of Markus Hennrich at SU using giant Rydberg ions, 100,000,000 times larger than normal atoms or ions. These huge ions are highly interactive, and exchange quantum information in less than a microsecond. The interaction between them creates quantum entanglement. Chi Zhang from the University of Stockholm and colleagues used the entangling interaction to carry out a quantum computing operation (an entangling gate) around 100 times faster than is typical in trapped ion systems.

Chi Zhang explains, “Usually quantum gates slow down in bigger systems. This isn’t the case for our quantum gate and Rydberg ion gates in general! Our gate might allow quantum computers to be scaled up to sizes where they are truly useful!”

Theoretical calculations supporting the experiment and investigating error sources have been conducted by Weibin Li (University of Nottingham, UK) and Igor Lesanovsky (University of Nottingham, UK, and University of Tübingen, Germany). Their theoretical work confirmed that there is indeed no slowdown expected once the ion crystals become larger, highlighting the prospect of a scalable quantum computer.

Weibin Li, Assistant Professor, School of Physics and Astronomy at the University of Nottingham adds: “Our theoretical analysis shows that a trapped Rydberg ion quantum computer is not only fast, but also scalable, making large-scale quantum computation possible without worrying about environmental noise. The joint theoretical and experimental work demonstrate that quantum computation based on trapped Rydberg ions opens a new route to implement fast quantum gates and at the same time might overcome many obstacles found in other systems.”

Currently the team is working to entangle larger numbers of ions and achieve even faster quantum computing operations.

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Technique offers path for biomanufacturing medicines during space flights

An instrument currently aboard the International Space Station could grow E. coli bacteria in space, opening a new path to bio-manufacturing drugs during long term space flights. Research published today in Nature Microgravity used an Earth-bound simulator of the space station instrument to grow E. coli, demonstrating that it can be nurtured with methods that promise to be more suitable for space travel than existing alternatives.

“If we can get microorganisms to grow well in space, astronauts can use them to make pharmaceuticals on demand. This could be vital for survival on long missions where resupplying is not an option.” said Richard Bonocora, senior author and a faculty member in the Department of Biological Sciences at Rensselaer Polytechnic Institute. “Here we were asking: ‘Is there a better way to grow microorganisms that what is currently being used is space?’ And what we find is that — with shear force — yes, there likely is.”

With promising results, the team hopes to conduct a similar experiment aboard the space station. And while they’re starting with E. coli, the workhorse of molecular biology, the team hopes to eventually use the instrument to grow microorganisms with radiation resistance, which could protect developing pharmaceuticals from the ever-present radiation of space as they are produced.

Bacteria like E. coli need oxygen to grow, and the gold standard method for aerating bacteria in a liquid growth medium uses an orbital shaker, a machine that horizontally shakes a platform on which the vessels containing the liquid can be stowed. The shaker relies on the force of gravity to swirl the liquid contents, which rise and fall within a flask, mixing oxygen with the liquid.

But Bonocora and his research team believe an instrument sent to the space station in July, 2019 could do a better job. Inspired by the research of Rensselaer professor Amir Hirsa, the NASA-built instrument uses shearing force, the force created at the boundary of two bodies pushing in opposite directions from one another, similar to that which occurs at the fault lines between tectonic plates. The instrument uses a syringe to dispense a drop of liquid which forms a bubble. One side of the bubble adheres to a stationary ring, while the other side adheres to a thin ring that can rotate. The rotating ring creates shear force on the surface of the bubble, swirling its contents.

The shearing instrument is currently being used to carry out Hirsa’s experiments studying the effects of shear stress on amyloid fibrils, clusters of proteins that are linked to neurodegenerative disease like diabetes, Alzheimer’s, and Parkinson’s.

On Earth, Bonocora used a knife-edge viscometer, an instrument designed by Hirsa’s group, in which the tip of a metal tube rotates — similar to the rotating ring in the space-based instrument — at the surface of liquid in a dish to simulate the shearing force. The experiment tested how well bacteria grew when aerated by the knife-edge viscometer and an orbital shaker, with both instruments used at various speeds.

At higher speeds, bacteria aerated by the knife-edge viscometer showed growth rates approaching that of the orbital shaker. Even at lower speeds shear force produced significantly more growth than samples of bacteria that were not mechanically aerated.

“This is a viable way of growing microorganisms. We’re starting on a new path, and now we need to think about a more real-life environment, such as on the space station,” said Bonocora.

“Space-based pharmaceutical manufacturing is a critical component of our efforts to safely send humans deeper into the solar system. This research is fundamental to that goal,” said Curt Breneman, dean of the School of Science. “The successful collaboration between Rick and Amir’s teams speaks to our long-standing ties to space exploration, and is one of many examples of the culture of ‘low walls’ to interdisciplinary research that we are proud to nurture at Rensselaer.”

Bonocora and Hirsa were joined by Joe Adams and Shreyash Gulati in this research. “Growth of microorganisms in an interfacially-driven space bioreactor analog” was supported with funding from NASA.

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Lipid gradient that keeps your eyes wet

New understandings of how lipids function within tears could lead to better drugs for treating dry eye disease.

A new approach has given Hokkaido University researchers insight into the synthesis and functions of lipids found in tears. Their findings, published in the journal eLife, could help the search for new treatments for dry eye disease.

The film of tears covering the eye’s surface is vital for eliminating foreign objects, providing oxygen and nutrients to the eye’s outer tissues, and reducing friction with the eyelid. The film is formed of an outer lipid layer and an inner liquid layer. The outer lipid layer, which is itself formed of two sublayers, prevents water evaporation from the liquid layer. Dry eye disease develops when the glands that produce these lipids dysfunction. However, it has remained unclear how those generally incompatible layers — water and lipid — can form and maintain tear films.

Hokkaido University biochemist Akio Kihara and colleagues wanted to understand the functions of a subclass of lipids called OAHFAs (O-Acyl)-ω-hydroxy fatty acids) that are present in the inner lipid sublayer (amphiphilic lipid sublayer) just above the liquid layer of the tear film. OAHFAs are known to have both polar and non-polar ends in its molecule, giving them affinity for both water and lipid.

To do this, they turned off a gene called Cyp4f39 in mice that is known for its involvement in ω-hydroxy fatty acid synthesis. Previous attempts at studying the gene’s functions in this way had led to neonatal death in mice, as it impaired the skin’s protective role. The team used a way to turn the gene off, except in the skin.

The mice were found to have damaged corneas and unstable tear films, both indicative of dry eyes. Further analyses showed that these mice were lacking OAHFAs and their derivatives in their tear films. Interestingly, the scientists also discovered that the OAHFA derivatives have polarities intermediate between OAHFAs and other lipids in the tear film. This strongly suggests that those lipids together form a polarity gradient that plays an important role in connecting the tear film’s inner liquid layer and outer lipid layer, helping the film spread uniformly over the surface of the eye.

“Drugs currently used in dry eye disease target the liquid layer of the tear film, but there aren’t any drugs that target its lipid layer,” says Akio Kihara. “Since most cases of dry eye disease are caused by abnormalities in the lipid layer, eye drops containing OAHFAs and their derivatives could be an effective treatment.”

Further studies are required to fully understand the functions and synthesis of OAHFAs.

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