Making light work



A collaboration between McMaster and Harvard researchers has generated a new platform in which light beams communicate with one another through solid matter, establishing the foundation to explore a new form of computing.

Their work is described in a paper published in the Proceedings of the National Academy of Sciences.

Kalaichelvi Saravanamuttu, an associate professor of Chemistry and Chemical Biology at McMaster, explains that the technology brings together a form of hyrdrogel developed by the Harvard team with light manipulation and measurement techniques performed in her lab, which specializes in the chemistry of materials that respond to light.

The translucent material, which resembles raspberry Jell-O in appearance, incorporates light-responsive molecules whose structure changes in the presence of light, giving the gel special properties both to contain light beams and to transmit information between them.

Typically, beams of light broaden as they travel, but the gel is able to contain filaments of laser light along their pathway through the material, as though the light were being channeled through a pipe.

When multiple laser beams, each about half the diameter of a human hair, are shone through the same material, the researchers have established that they affect one another’s intensity, even without their optical fields overlapping at all – a fact that proves the gel is “intelligent.”

The interaction between those filaments of light can be stopped, started, managed and read, producing a predictable, high-speed output: a form of information that could be developed into a circuit-free form of computing, Saravanamuttu explains.

“Though they are separated, the beams still see each other and change as a result,” she says. “We can imagine, in the long term, designing computing operations using this intelligent responsiveness.”

While the broader concept of computing with light is a separate and developing field unto itself, this new technology introduces a promising platform, says Derek Morim, a graduate student in Saravanamuttu’s lab who is co-first author on the paper.

“Not only can we design photoresponsive materials that reversibly switch their optical, chemical and physical properties in the presence of light, but we can use those changes to create channels of light, or self-trapped beams, that can guide and manipulate light,” he says. “Further study may allow us to design even more complex materials to manipulate both light and material in specific ways.”

Amos Meeks, a graduate student at Harvard’s John A. Paulson School of Engineering and Applied Sciences, said the technology helps to advance the idea of all-optical computing, or computations done solely with beams of light.

“Most computation right now uses hard materials such as metal wires, semiconductors and photodiodes, to couple electronics to light,” says Meeks, who is also co-first author of the research. “The idea behind all optical computing is to remove those rigid components and control light with light. Imagine, for example, an entirely soft, circuitry-free robot driven by light from the sun.”

Derek Morim, co-first author on the new paper.

BY WADE HEMSWORTH
FEBRUARY 3, 2020

No more tough pills to swallow


Taking medicine can be a tough pill to swallow – literally.

For people who have difficulty swallowing – including children, older adults, or those with severe nausea – taking pills can be a high-stress, sometimes impossible method of drug delivery. And while liquid medication can sometimes be a substitute, dosing can be less precise with liquids than with pills.

Plus, any medication that has to go through the digestive system can lose significant amounts of its active ingredients, and can cause unwanted effects on the liver and other organs.

Now, two McMaster researchers in the Department of Chemistry and Chemical Biology have paired up with Rapid Dose Therapeutics, a drug delivery technology company, to develop a different way to administer medication: a thin film that dissolves in the mouth, bypassing the digestive system and delivering drugs quickly into the bloodstream.

Rapid Dose makes QuickStrip, a product similar to dissolvable mouthwash strips, but delivering much more than just fresh breath. QuickStrip is currently available as a variety of supplements, including vitamin B12, caffeine and melatonin.

With this new partnership, the researchers hope to expand the types of drugs that can be delivered via QuickStrip.

“I am delighted by the opportunity to partner with RDT on this important project, which aims to significantly expand the drug repertoire deliverable using QuickStrip technology,” says principal investigator Alex Adronov. “It is a challenging endeavour, however, one that promises to expand our options for pharmaceutical delivery.”

The project, which will be led by Adronov and co-investigator Harald Stover, has received an NSERC Collaborative Research and Development grant worth $540,000 over three years.

Image by Flickr Creative Commons
BY SARA LAUX
JANUARY 27, 2020

NSERC Undergraduate Student Research Awards for 2020 in Chemistry and Chemical Biology

All interested and highly qualified undergraduate students are encouraged to apply to the McMaster Department of Chemistry and Chemical Biology for an NSERC Undergraduate Student Research Award (USRA).  

Students receiving NSERC USRAs work full time for 16 weeks during the summer in one of the department’s research laboratories. USRAs provide students with invaluable research experience and unique learning opportunities in Chemistry and Chemical Biology.  

Students from McMaster or other universities are eligible, with preference given to students in Level II or Level III Honours Chemistry or Honours Chemical Biology programs.  

Students must discuss their application and research projects with a potential supervisor before submission to the Department. Part one of the NSERC USRA Form 202 is completed on-line by the student, while part two is completed by the successful applicant’s research supervisor when requested. For more information please contact Linda Spruce in the Department of Chemistry & Chemical Biology Office, ABB 156, by phone at ext. 23490, or by email at sprucel@mcmaster.ca.  

Students with NSERC USRA awards will receive the following total stipends over 16 weeks (35 hrs/wk):

     $7840 – students completing level II
     $8100 – students completing level III
     $8500 – students completing level IV

Information about the NSERC USRA program and appropriate forms are available on the NSERC website: http://www.nserc-crsng.gc.ca/Students-Etudiants/UG-PC/USRA-BRPC_eng.asp

Your application should include:
·         a copy of the completed Form 202 Part I
·         an up to date copy of your transcript (an official transcript is not necessary at this stage)
·         this form, signed by the potential supervisor.

Please send your application to Linda Spruce in the Department of Chemistry and Chemical Biology Office (ABB 156) no later than 4:30 p.m. on Monday, February 24, 2020. Note that students applying for USRA will be considered for the Audrey Cameron scholarships should they be unsuccessful in the NSERC competition.


Applicant Name:                                                        Applicant Student ID#:  



Potential Supervisor Name:                                      Potential Supervisor Signature:

Catalyst breaks sulfur–sulfur bonds to give new life to tired tyres

An image showing car tyres

Process recovers organic components that can become new elastomers

Researchers from Canada have demonstrated a mild chemical approach for reclaiming organic polymers from waste tyre rubber. Their Lewis acid-catalysed reductive silylation process could reduce the environmental impact of used sulfur-crosslinked elastomers.

‘The recovery of vulcanised rubbers is a major environmental problem, whose solution is still open,’ comments Carlos Scuracchio, who works on rubber recycling at the Federal University of São Carlos, Brazil. The high stability of vulcanised tyre rubber makes it challenging to recycle; toxic constituents may leach into the environment from used tyre stockpiles and fires at such locations can be dangerous, very polluting and difficult to arrest. 

Michael Brook from McMaster University, who led the team behind the new silylation process has first-hand experience of tyre fires. ‘About 15 years or 20 years ago, not far from where I live in Hamilton, there was a really bad tyre fire. The byproducts of that were not good news for the local environment.’ 

Now, Brook’s team has shown that hydrosilanes, catalysed by B(C6F5)3, can effectively reduce sulfur–sulfur bonds in complex sulfur-crosslinked tyre rubbers in yields of up to 90%. They demonstrated their process on bicycle inner tubes, solid tyres and tyre crumb, and the resulting polymeric, silyl-protected thiolated oils were straightforward to separate by filtration or centrifugation. The team also showed they could radically or oxidatively crosslink the resulting oils to generate new elastomers, from which they created a new toy tyre as a proof of concept.

A scheme showing how the reductive silylation of RS-SR bonds to silyl thio ethers using a variety of hydrosilicones occurs in the presence of B(C6F5)3
Source: © Michael Brook/McMaster University
Reductive silylation of RS–SR bonds to silyl thio ethers using a variety of hydrosilicones in the presence of B(C6F5)3 could be developed into a recycling process for car tyres

‘We were surprised that you could actually get the rubber to dissolve and be converted back to liquid polymeric materials. I didn’t expect it to happen quite as well as it did,’ explains Brook. He says there is ‘really very little out there in the literature’ on the depolymerisation of sulfur-cured rubbers, and that ‘if there were a commercially viable process, people would be using it’. However, with 10wt% of ‘quite expensive’ catalyst being required to reduce the used tyre rubber, Brook clarifies that ‘there’s no way in my view that today this is a commercial process. But I think it opens the door into thinking about different ways to degrade the rubbers to make useful polymers again.’ The team are already optimising the process to reduce the quantity of catalyst it requires.

‘Most rubber recycling techniques generate materials that are difficult to mould and process and have quite different properties from the original raw materials,’ adds Scuracchio. ‘At this point, a very interesting part of the work is that the rubber can be processed without worrying about possible contamination, and the material produced is a rheologically simple oil capable of being moulded and transformed back into a solid product. This factor makes the method very promising in the field of rubber recycling.’

References: This article is open access S Zheng et al, Green Chem., 2019, DOI: 10.1039/c9gc03545a

Royal Society of Chemistry - ChemistryWorld
BY RUTH ZADIK 17 DECEMBER 2019

 

Teaching-Track Assistant Professor

Department of Chemistry & Chemical Biology, McMaster University 

The Department of Chemistry & Chemical Biology invites applications for a teaching-track faculty position at the Assistant Professor level, effective July 1, 2020. Applicants must hold a Ph.D. in Chemistry at the time of appointment and should have a demonstrated record of teaching excellence at the undergraduate level. The duties will involve teaching a range of courses, including general (first-year) chemistry and higher level courses in Chemistry and/or Chemical Biology, as well as administrative service. Participation in curriculum development and/or undergraduate laboratory supervision may also be required. There is no expectation that the candidate will develop an independent research program or engage in collaborative research in the chemical sciences, but pedagogic research relevant to chemistry would be encouraged.  

McMaster University is a globally renowned institution of higher learning and a research community committed to advancing human and societal health and well-being. Our focus on collaboratively exchanging ideas and approaches makes us uniquely positioned to pioneer ground-breaking solutions to real-world problems leading to a Brighter World. The Faculty of Science works to create global impact by advancing scientific discovery and knowledge, and promoting greater understanding. Our innovative, interdisciplinary approach generates new methods and insights, results, and lasting change. 

McMaster University has a strong commitment to achieving diversity among faculty and staff that reflects the multicultural makeup of our student body. The successful candidate will be committed to inclusion and excellence. The search Committee is especially interested in candidates who can contribute, through their teaching and/or service, to the diversity of the academic community. Women and applicants from traditionally underrepresented populations are strongly encouraged to apply. Gender diversity is being addressed at McMaster University through our policies and actions. Recent actions in this area include the completion of a gender pay equity study and a resultant base salary adjustment applied to all female faculty members in July 2015, as well as a recent commitment by McMaster to the nation-wide Dimensions EDI charter (http://www.nserc-crsng.gc.ca/NSERC-CRSNG/EDI-EDI/Dimensions_Dimensions_eng.asp).

Faculty members at McMaster University enjoy a number of personal and professional benefits. University employees are offered an excellent benefits package that includes, but is not limited to, extended health care benefits, dental care, group life, long term disability, worldwide travel assistance, and a retirement plan. Progressive policies are in place to assist faculty members who become parents or are needed to care for family members. Salary will be commensurate with qualifications and experience.  

Applications must include a cover letter, curriculum vitae, a teaching dossier that includes a statement of teaching philosophy and evidence of teaching experience and effectiveness, and a one-page statement on equity and diversity. Applicants should also arrange to have three referees provide a confidential letter of reference, sent by e-mail to the Chair (chair@chemistry.mcmaster.ca). Reference letters should include the candidate’s name in the file name (Last_First.pdf) and should be submitted as a PDF, on letterhead, and from an email address that is associated with the institution or organization of origin. Complete applications must be made online at hr.mcmaster.ca/careers (Faculty Positions, Job ID 29497) to the attention of:
Dr. Gillian Goward, Professor & Chair
Department of Chemistry & Chemical Biology
McMaster University
1280 Main Street West
Hamilton, Ontario, Canada, L8S 4K1 

Review of complete applications will begin February 1, 2020, and continue until the position is filled. The effective date of appointment is expected to be on July 1, 2020. All applicants will receive an on-line confirmation of receipt of their application; however, only short-listed applicants will be contacted for interviews. 

All qualified candidates are encouraged to apply; however, Canadian citizens and permanent residents will be given priority. To comply with the Government of Canada’s reporting requirements, the University is obliged to gather information about applicants’ status as either Permanent Residents of Canada or Canadian citizens. Applicants need not identify their country of origin or current citizenship; however, all applications must include one of the following statements:
Yes, I am a citizen or permanent resident of Canada
No, I am not a citizen or permanent resident of Canada. 

McMaster University is located on the traditional territories of the Haudenosaunee and Mississauga Nations and, within the lands protected by the “Dish With One Spoon” wampum agreement. In keeping with its Statement on Building an Inclusive Community with a Shared Purpose, McMaster University strives to embody the values of respect, collaboration and diversity, and has a strong commitment to employment equity. The diversity of our workforce is at the core of our innovation and creativity and strengthens our research and teaching excellence. The University seeks qualified candidates who share our commitment to equity, diversity and inclusion. While all qualified candidates are invited to apply, we particularly welcome applications from women, persons with disabilities, First Nations, Métis and Inuit peoples, members of visible minorities, and LGBTQ+ persons.  

Job applicants requiring accommodation to participate in the hiring process should contact the Human Resources Service Centre at 905-525-9140 ext. 222-HR (22247) to communicate accommodation needs. 
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