Microfluidic system with cell-separating powers may unravel how novel pathogens attack

Microfluidic system with cell-separating powers may unravel how novel pathogens attack
An image of the in-droplet cell separation microfluidic chip, showing the microfluidic channels and electrodes. Enlarged view shows a host cell and pathogenic bacteria cells being separated to top and bottom within a single water-in-oil microdroplet. Credit: Dr. Arum Han/Texas A&M University College of Engineering

To develop effective therapeutics against pathogens, scientists need to first uncover how they attack host cells. An efficient way to conduct these investigations on an extensive scale is through high-speed screening tests called assays.


Researchers at Texas A&M University have invented a high-throughput cell separation method that can be used in conjunction with droplet microfluidics, a technique whereby tiny drops of fluid containing biological or other cargo can be moved precisely and at high speeds. Specifically, the researchers successfully isolated pathogens attached to host cells from those that were unattached within a single fluid droplet using an electric field.

“Other than cell separation, most biochemical assays have been successfully converted into droplet microfluidic systems that allow high-throughput testing,” said Arum Han, professor in the Department of Electrical and Computer Engineering and principal investigator of the project. “We have addressed that gap, and now cell separation can be done in a high-throughput manner within the droplet microfluidic platform. This new system certainly simplifies studying host-pathogen interactions, but it is also very useful for environmental microbiology or drug screening applications.”

The researchers reported their findings in the August issue of the journal Lab on a Chip.

Microfluidic devices consist of networks of micron-sized channels or tubes that allow for controlled movements of fluids. Recently, microfluidics using water-in-oil droplets have gained popularity for a wide range of biotechnological applications. These droplets, which are picoliters (or a million times less than a microliter) in volume, can be used as platforms for carrying out biological reactions or transporting biological materials. Millions of droplets within a single chip facilitate high-throughput experiments, saving not just laboratory space but the cost of chemical reagents and manual labor.

Biological assays can involve different cell types within a single droplet, which eventually need to be separated for subsequent analyses. This task is extremely challenging in a droplet microfluidic system, Han said.

“Getting cell separation within a tiny droplet is extremely difficult because, if you think about it, first, it’s a tiny 100-micron diameter droplet, and second, within this extremely tiny droplet, multiple cell types are all mixed together,” he said.

To develop the technology needed for cell separation, Han and his team chose a host-pathogen model system consisting of the salmonella bacteria and the human macrophage, a type of immune cell. When both these cell types are introduced within a droplet, some of the bacteria adhere to the macrophage cells. The goal of their experiments was to separate the salmonella that attached to the macrophage from the ones that did not.

For cell separation, Han and his team constructed two pairs of electrodes that generated an oscillating electric field in close proximity to the droplet containing the two cell types. Since the bacteria and

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Carter Estes: Effort to ban Trump officials from Harvard is a dangerous attack on free speech and education

My fi

My first year at the Harvard Kennedy School of Government hasn’t been what I expected — and I’m not just talking about all the restrictions to guard against the spread of COVID-19. I couldn’t have predicted that I’d be delivering a speech to my peers urging them to uphold free speech at one of America’s most prestigious centers of learning.

Unfortunately, I recently found myself on Zoom urging members of the Harvard Kennedy School Student Government to reject a student-led effort to restrict Trump administration officials from speaking at Harvard. 

While I am relieved that the student government ultimately rejected the restrictions, I remain disturbed that my peers would propose this action and that it actually could have passed. An education underpinned by conditions of censorship is not a real education. And those who seek an education should never demand protection from ideas. 

SOME HARVARD STUDENTS SAY NOT SO FAST ON TRUMP BAN

 I came to Harvard to learn. But institutions of higher education that allow for restrictions on information and dialogue —whether imposed by students or administrators — forfeit the title of “educational institution” in exchange for the title “indoctrination center.” The latter is not what I signed up for. I want Harvard to deliver the education it claims to offer. 

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I am shocked and disappointed that some of my fellow graduate students — who surely came to one of the world’s top government affairs graduate programs to grow intellectually and professionally—would make these demands. The authors of the letter calling for banning Trump officials from campus said the reason for the ban was to, ironically, stop the “subversion of democratic principles” by the Trump administration. But free speech is a democratic principle. 

 The authors of this letter seek to cancel debate and silence political opposition. They are terrified of having their world views challenged. But that’s exactly why earnest minds have traditionally come to Harvard.

The Kennedy School has hosted many controversial figures, including members of the Clinton and Nixon administrations, former Obama Attorney General Eric Holder, and the late secretary-general of the Palestine Liberation Organization, Saeb Erekat.

We students are adults and we are fully capable of hearing uncomfortable and offensive information and arguments. It will only make us better.

 I am a conservative. Harvard is an overwhelmingly liberal institution. I have only benefitted by having my ideas and values challenged while studying here. But more than that, Harvard owes it to students like me to be honest about what it claims to offer — a rigorous intellectual environment and access to top leaders.

 Whether you agree with Trump policies or not, those who served in Trump administration have firsthand knowledge and experience in the highest levels of domestic and foreign policy. These players have impacted the world and we students can decide if their marks were good or bad, and conclude the missteps for ourselves.

 But the onus is on universities to uphold their missions. They need to teach their students

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Kenya university attack abettor commits suicide

NAIROBI, Kenya

Tanzanian citizen Rashid Charles Mbereso, who was handed down a life sentence for his role in the 2015 Garrisa University attack that claimed the lives of more than 140 students, committed suicide on Sunday, officials said.

Mbereso, 26, used a rope to hang himself in his cell block at the Kamiti Maximum prison in the Kenyan capital of Nairobi, police said in a statement.

He was a psychiatric patient on medication, and often quarreled with other prisoners, the press release said, adding that he took his life at around 1520 hours.

Mbereso, Hassan Edin Hassan and Mohammed Ali Abikar were found guilty by a Nairobi court of aiding militants in carrying out one of the deadliest terror attacks on Kenyan soil in Garissa.

On April 2, 2015, heavily armed gunmen stormed the university and shot dead two security guards before attacking students.

Somali-based al-Shabaab, which is affiliated to al Qaeda, had claimed the attack.

Kenya contributes troops to the African Union peacekeeping mission in Somalia, which has weakened al-Shabaab.

The group, fighting to overthrow the Somali government for years, has vowed to carry out terror attacks in Kenya until the East African country pulls out its soldiers from Somalia.



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IS attack on Afghan university leaves 22 dead

KABUL, Afghanistan — Islamic State militants in Afghanistan stormed Kabul University on Monday as it hosted a book fair attended by the Iranian ambassador, sparking an hours-long gunbattle and leaving at least 22 dead and 22 wounded at the war-torn country’s largest school.

Most of the casualties were students and there were fears the death toll could climb further with some of the wounded said to be in critical condition.

It was the second attack on an educational institution in Kabul in as many weeks.

The Taliban promptly issued a statement denying they took part in the assault, which came as the insurgents continue peace talks with representatives of Kabul’s U.S.-backed government, with the aim to help the United States finally withdraw from Afghanistan. Later in the day, the Islamic State group claimed responsibility for the attack.

As the attack unfolded, students and teachers were seen fleeing the part of the campus where law and journalism schools are located, while hand grenades exploded and automatic rifle fire could be heard. Scores of Afghan special forces surrounded the campus, shepherding teachers and students to safety.

The chaos subsided as the sun set over the Afghan capital and the Interior Ministry’s spokesman, Tariq Arian, said all three attackers involved in the assault were killed.

The Islamic State group said it targeted newly graduated “judges and investigators belonging to the apostate Afghan government” gathered at the campus, according to the SITE Intelligence Group, which monitors terror online messaging.

The IS statement claimed only two of its fighters were involved, and posted their photographs, which conflicted with the Afghan authorities’ report of three attackers. The claim did not indicate the IS intended to target the Iranian envoy or the book fair.

Last week, IS also claimed a brutal assault on a tutoring center in the Afghan capital’s mostly Shiite neighborhood of Dasht-e-Barchi that killed at least 24 students and wounded more than 100 others on Oct. 24.

The peace negotiations between the Taliban and the Kabul government, known as intra-Afghan talks, were part of a deal Washington signed with the insurgents in February. They are taking place in the Gulf Arab state of Qatar, and are seen as Afghanistan’s best chance at peace – though daily bloodshed has continued.

Five hours into the fighting on Monday, sporadic grenade explosions and automatic weapons fire still echoed down the empty streets surrounding the university’s fenced compound. Afghan troops stood guard.

Ahmad Samim, a university student, told journalists he saw militants armed with pistols and Kalashnikov assault rifles firing at the school, the country’s oldest with some 17,000 students. He said the attack happened at the university’s eastern side, where its law and journalism faculty teach.

Afghan media reported that a book exhibition was being held at the university and attended by a number of dignitaries at the time of the shooting. None of the dignitaries were reported hurt.

While Afghan officials declined to discuss the bookfair, Iran’s semiofficial ISNA news agency reported Sunday that Iranian Ambassador

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At least 22 dead, 22 wounded in ISIS attack on Afghan university

KABUL, Afghanistan — Islamic State militants in Afghanistan stormed Kabul University on Monday as it hosted a book fair attended by the Iranian ambassador, sparking an hours-long gunbattle and leaving at least 22 dead and 22 wounded at the war-torn country’s largest school.

Most of the casualties were students and there were fears the death toll could climb further with some of the wounded said to be in critical condition.

It was the second attack on an educational institution in Kabul in as many weeks.

The Taliban promptly issued a statement denying they took part in the assault, which came as the insurgents continue peace talks with representatives of Kabul’s U.S.-backed government, with the aim to help the United States finally withdraw from Afghanistan. Later in the day, the Islamic State group claimed responsibility for the attack.

Gen. Scott Miller, who commands U.S. forces in Afghanistan, told the BBC that Afghan forces must be ready to defend their country. (Operation Resolute Support)

As the attack unfolded, students and teachers were seen fleeing the part of the campus where law and journalism schools are located, while hand grenades exploded and automatic rifle fire could be heard. Scores of Afghan special forces surrounded the campus, shepherding teachers and students to safety.

The chaos subsided as the sun set over the Afghan capital and the Interior Ministry’s spokesman, Tariq Arian, said all three attackers involved in the assault were killed.

The Islamic State group said it targeted newly graduated “judges and investigators belonging to the apostate Afghan government” gathered at the campus, according to the SITE Intelligence Group, which monitors terror online messaging.

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Gunmen attack Kabul University

Top of The World — our morning news roundup written by editors at The World. Subscribe here.

Gunmen stormed Kabul University in Afghanistan on Monday, leaving at least 19 dead and dozens wounded. The attack lasted hours across the campus with Afghan forces and US troops battling the gunmen, who detonated explosives and fired their weapons.

The devastating onslaught was the second attack on an educational institution in Kabul in just over a week. It took place as the university held a book fair attended by the Iranian ambassador to Afghanistan.

The Taliban, who are in peace-talk negotiations with the US-backed Afghan government, said their fighters were not involved in the assault. No other group immediately claimed responsibility. In photos and video posted to social media, students are shown fleeing and scrambling over the campus walls trying to escape.

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A massive typhoon struck provinces south of the Philippines capital of Manila on Sunday with winds of up to 190 mph. Government officials on Monday said 20 people were killed in Albay and Catanduane provinces in the wake of Typhoon Goni, up from the 16 people the country’s disaster agency previously reported. Amid the devastation, another storm, Atsani, is gaining strength over the Pacific Ocean and is expected to make landfall in the Philippines late this week.

And, authorities in Hong Kong arrested seven prominent Hong Kong opposition leaders on Sunday in the latest in a crackdown on anti-government activists. Police said Monday, the arrests were on charges related to obstructing a legislative council meeting in May and included former lawmakers and currently serving officials, as well as a legislator assistant. They have since been released on bail.

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Discussion: View of the 2020 US Election from abroad

The world is watching the 2020 US presidential election — there are global implications whomever is the winner. Join us for a live discussion with The World’s correspondents Shirin Jaafari and Jorge Valencia, moderated by senior editor Daisy Contreras, digging in on the big issues and providing the necessary  context and analysis from their reporting.

Watch a video of the conversation here.

Former presidential hopeful Julián Castro urges Latinos to vote for Biden

Since early summer, Julián Castro has been a surrogate for Democratic challenger Joe Biden on the campaign trail.

Castro was originally in the race saying many things others wouldn’t. He talked about abolishing the electoral college, had the most detailed immigration policy plan, and was vocally opposed to unrepresentative Iowa and New Hampshire going first in the primary process.

The former San Antonio mayor was also talking about racial justice issues long before George Floyd was killed this past spring. The tough-talking Texan hopes that in the next administration, issues like systemic racism — especially important to communities of color — won’t be sidelined.

Big chocolate companies use child labor. Can a 1789 US law hold them accountable for violations abroad?

The chocolate industry has a long documented problem with forced child

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ISIS attack on Afghan university leaves 22 dead, 22 wounded

KABUL, Afghanistan — Islamic State militants in Afghanistan stormed Kabul University on Monday as it hosted a book fair attended by the Iranian ambassador, sparking an hours-long gunbattle and leaving at least 22 dead and 22 wounded at the war-torn country’s largest school.

Most of the casualties were students and there were fears the death toll could climb further with some of the wounded said to be in critical condition.

It was the second attack on an educational institution in Kabul in as many weeks.

The Taliban promptly issued a statement denying it took part in the assault, which came as the insurgents continue peace talks with representatives of Kabul’s U.S.-backed government, with the aim to help the United States finally withdraw from Afghanistan. Later in the day, the Islamic State group claimed responsibility for the attack.

As the attack unfolded, students and teachers were seen fleeing the part of the campus where law and journalism schools are located, while hand grenades exploded and automatic rifle fire could be heard. Scores of Afghan special forces surrounded the campus, shepherding teachers and students to safety.

The chaos subsided as the sun set over the Afghan capital and the Interior Ministry’s spokesman, Tariq Arian, said all three attackers involved in the assault were killed.

The Islamic State group said it targeted newly graduated “judges and investigators belonging to the apostate Afghan government” gathered at the campus, according to the SITE Intelligence Group, which monitors terror online messaging.

The ISIS statement claimed only two of its fighters were involved, and posted their photographs, which conflicted with the Afghan authorities’ report of three attackers. The claim did not indicate the IS intended to target the Iranian envoy or the book fair.

Last week, ISIS also claimed a brutal assault on a tutoring center in the Afghan capital’s mostly Shiite neighborhood of Dasht-e-Barchi that killed at least 24 students and wounded more than 100 others on Oct. 24.

Five hours into the fighting on Monday, sporadic grenade explosions and automatic weapons fire still echoed down the empty streets surrounding the university’s fenced compound. Afghan troops stood guard.

Ahmad Samim, a university student, told journalists he saw militants armed with pistols and Kalashnikov assault rifles firing at the school, the country’s oldest with some 17,000 students. He said the attack happened at the university’s eastern side, where its law and journalism faculty teach.

 

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Gunmen storm Kabul University, killing 22, in second deadly attack on students in just over a week

By Abdul Qadir Sediqi, Orooj Hakimi and Hamid Shalizi

KABUL (Reuters) – Gunmen stormed Kabul University, killing at least 22 people including students in their classrooms, on Monday and Islamic State militants claimed responsibility for what President Ashraf Ghani called a “despicable act of terror”.

In a video message, Ghani, who once lectured at the university, announced a national day of mourning to honour the victims and offered his “condolences and profound sympathies to the nation” and the families of the victims.

“My heart is still beating for this academic institution,” he said. “Today’s attack has left us grief-stricken.”

Gunmen barged into Kabul University in the morning, killing students in their classrooms and firing on others as they fled, officials and witnesses said, in what was the second attack on an educational institution in the capital in just over a week.

The three attackers killed at least 22 people, including students, and wounded 22 others before Afghan security forces shot the gunmen dead, the health ministry said.

The attack was claimed by Islamic State, the jihadist group’s Amaq News Agency said. Amaq said the gunmen targeted a gathering being held to mark the completion of a training course at the university.

Photos shared by a senior government official showed students lying dead in classrooms, some next to their books. One student appeared to have been shot as he was climbing out of a window.

“They were shooting at every student they saw…They even shot at the students who were running away,” witness Fathullah Moradi told Reuters.

“This is the second attack on educational institutions in Kabul … Afghan children & youth need to feel safe going to school,” NATO Senior Civilian Representative to Afghanistan Stefano Pontecorvo said in a statement.

A suicide bomber killed 24 people including teenage students at an education centre in Kabul on Oct. 24. Islamic State claimed responsibility for that attack, without providing evidence.

Taliban insurgents issued a statement condemning the latest attack and denying any involvement.

Violence has plagued Afghanistan while government and Taliban negotiators have been meeting in Qatar to try to broker a peace deal and as the United States brings home its troops.

In a post on Twitter, the Presidential Palace announced a day of mourning on Tuesday, for which the Afghan flag will fly at half mast in the country and at its diplomatic missions around the world.

(Reporting by Abdul Qadir Sediqi, Orooj Hakimi and Hamid Shalizi; Additional reporting by Hameed Farzad in Kabul and Nayera Abdallah in Cairo; writing by Charlotte Greenfield and Gibran Peshimam; Editing by Mark Heinrich)

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At Least 19 People Are Killed In Attack On Kabul University : NPR

A man, wounded after gunmen stormed Kabul University, arrives in an ambulance at Isteqlal Hospital on Monday. At least 19 people died in the attack on Afghanistan’s largest university.

Wakil Kohsar/AFP via Getty Images


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Wakil Kohsar/AFP via Getty Images

A man, wounded after gunmen stormed Kabul University, arrives in an ambulance at Isteqlal Hospital on Monday. At least 19 people died in the attack on Afghanistan’s largest university.

Wakil Kohsar/AFP via Getty Images

Updated at 1:55 p.m. ET

Gunmen disguised as policemen stormed Kabul University in the Afghan capital in an hours-long assault on Monday, killing at least 19 people and wounding 22 more, including students who jumped out of windows to flee the attackers. It is the second attack on a learning center in Kabul in recent days, and comes amid a spike in violence across the country.

The assault coincided with a book fair that attracted senior Afghan and Iranian officials to the sprawling campus, including Iranian Ambassador Bahador Aminian. It was not immediately clear whether any of the officials were killed or wounded.

But it seems students were targeted in the well-coordinated attack. A 22-year-old public administration student said she heard a deafening blast. Then, “I saw with my own eyes, there were a lot of attackers in police uniforms,” said Nilofer Farahmand.

She says the assailants rushed to the law internship center, where she was in class. Someone yelled at students to flee, she said. Later, she learned on a WhatsApp group that gunmen had taken two classes hostage, and opened fire on the students and teachers.

Some students jumped out of their second-floor class windows to flee the gunmen, she said. Other students scaled over high university walls to flee the attackers, and at least two were admitted into a hospital, said Marco Puntin, of the medical aid group Emergency, which runs several faculties across Afghanistan.

Graphic photographs of the carnage were uploaded by Afghan reporters suggesting the extent of the horror within the university’s classrooms. One showed young men curled into a corner, blood pooled around them amid upturned chairs.

The Islamic State claimed responsibility for Monday’s attack, the second it has carried out in Kabul in less than 10 days, after a suicide bomber late last month blew himself up outside an education center, killing more than 20 people, including many students. ISIS also claimed responsibility for that attack – which was effectively a copy-cat of a 2018 attack by the extremist group on an education center that killed dozens of teenagers who were studying for university entrance exams.

The ISIS claim says two of its fighters attacked a group of graduating judges and investigators with their weapons and gunfire.

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19 dead, 22 wounded in attack on university in Afghanistan

KABUL, Afghanistan — Gunmen stormed Kabul University on Monday as it hosted a book fair attended by the Iranian ambassador to Afghanistan, sparking an hours-long gun battle and leaving at least 19 dead and 22 wounded at the war-torn country’s largest school.

The ministry’s spokesman, Tariq Arian, also said there were three attackers involved in the assault, all of whom were killed in the ensuing firefight. As the sun slowly set over the Afghan capital, there were few other details though the Taliban issued a statement denying they took part in the assault.

The attack came as the insurgents are continuing peace talks with the U.S.-backed government. Those negotiations, taking place in the Gulf Arab state of Qatar, aim to help the U.S. finally withdraw from America’s longest war, though daily bloodshed continues and an Islamic State affiliate launches its own attacks on Shiites in the country.

Five hours into the fighting, sporadic grenade explosions and automatic weapons fire echoed down the empty streets surrounding the university’s fenced compound. Afghan troops stood guard. Earlier, students were seen fleeing for their lives from the site.

“Unfortunately, there are casualties,” Arian said as the assault unfolded, without elaborating.

Ahmad Samim, a university student, told journalists he saw militants armed with pistols and Kalashnikov assault rifles firing at the school, the country’s oldest with some 17,000 students. He said the attack happened at the university’s eastern side where its law and journalism faculty teach.

Afghan media reported a book exhibition was being held at the university and attended by a number of dignitaries at the time of the shooting.

While Afghan officials declined to discuss the bookfair, Iran’s semiofficial ISNA news agency reported Sunday that Iranian Ambassador Bahador Aminian and cultural attaché Mojtaba Noroozi were scheduled to inaugurate the fair, which would host some 40 Iranian publishers. Iranian state television reported the attack occurred, but did not offer information on its officials.

Iranian diplomats have been targeted previously by attacks in the country and nearly sparked a war between the two countries. In 1998, Iran held the Taliban responsible for the deaths of nine Iranian diplomats who were working in its consulate in northern Afghanistan and sent reinforcements to the 580-mile-long border that Iran and Afghanistan share.

No group immediately took responsibility for the ongoing attack though the Taliban issued a statement saying they were not involved. However, suspicion immediately fell on the Islamic State group.

Last month, the Islamic State group sent a suicide bomber into an education center in the capital’s Shiite dominated neighborhood of Dasht-e-Barchi, killing 24 students and injuring more than 100. The Islamic State affiliate in Afghanistan has declared war on Afghanistan’s minority Shiite Muslims and have staged dozens of attacks since emerging in 2014.

Schools have been targeted for attacks in the past as well. Last year, a bomb outside of the Kabul University campus’ gates killed eight people. In 2016, gunmen attacked the American University in Kabul, killing 13.

Violence has been relentless in Afghanistan even

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