Instruments that measure the properties of light, known as spectrometers, are widely used in physical, chemical, and biological research. These devices are usually too large to be portable, but MIT scientists have now shown they can create spectrometers small enough to fit inside a smartphone camera, using tiny semiconductor nanoparticles called quantum dots.
Such devices could be used to diagnose diseases, especially skin conditions, or to detect environmental pollutants and food conditions, says Jie Bao, a former MIT postdoc and the lead author of a paper describing the quantum dot spectrometers in the July 2 issue of Nature.
This work also represents a new application for quantum dots, which have been used primarily for labeling cells and biological molecules, as well as in computer and television screens.
“Using quantum dots for spectrometers is such a straightforward application compared to everything else that we’ve tried to do, and I think that’s very appealing,” says Moungi Bawendi, the Lester Wolfe Professor of Chemistry at MIT and the paper’s senior author.
The earliest spectrometers consisted of prisms that separate light into its constituent wavelengths, while current models use optical equipment such as diffraction gratings to achieve the same effect. Spectrometers are used in a wide variety of applications, such as studying atomic processes and energy levels in physics, or analyzing tissue samples for biomedical research and diagnostics.
Replacing that bulky optical equipment with quantum dots allowed the MIT team to shrink spectrometers to about the size of a U.S. quarter, and to take advantage of some of the inherent useful properties of quantum dots.
Quantum dots, a type of nanocrystals discovered in the early 1980s, are made by combining metals such as lead or cadmium with other elements including sulfur, selenium, or arsenic. By controlling the ratio of these starting materials, the temperature, and the reaction time, scientists can generate a nearly unlimited number of dots with differences in an electronic property known as bandgap, which determines the wavelengths of light that each dot will absorb.
However, most of the existing applications for quantum dots don’t take advantage of this huge range of light absorbance. Instead, most applications, such as labeling cells or new types of TV screens, exploit quantum dots’ fluorescence—a property that is much more difficult to control, Bawendi says. “It’s very hard to make something that fluoresces very brightly,” he says. “You’ve got to protect the dots, you’ve got to do all this engineering.”
Scientists are also working on solar cells based on quantum dots, which rely on the dots’ ability to convert light into electrons. However, this phenomenon is not well understood, and is difficult to manipulate.
On the other hand, quantum dots’ absorption properties are well known and very stable. “If we can rely on these properties, it is possible to create applications that will have a greater impact in the relative short term,” Bao says.
The new quantum dot spectrometer deploys hundreds of quantum dot materials that each filter a specific set of wavelengths of light. The quantum dot filters are printed into a thin film and placed on top of a photodetector such as the charge-coupled devices (CCDs) found in cellphone cameras.
The researchers created an algorithm that analyzes the percentage of photons absorbed by each filter, then recombines the information from each one to calculate the intensity and wavelength of the original rays of light.
The more quantum dot materials there are, the more wavelengths can be covered and the higher resolution can be obtained. In this case, the researchers used about 200 types of quantum dots spread over a range of about 300 nanometers. With more dots, such spectrometers could be designed to cover an even wider range of light frequencies.
“Bawendi and Bao showed a beautiful way to exploit the controlled optical absorption of semiconductor quantum dots for miniature spectrometers. They demonstrate a spectrometer that is not only small, but also with high throughput and high spectral resolution, which has never been achieved before,” says Feng Wang, an associate professor of physics at the University of California at Berkeley who was not involved in the research.
If incorporated into small handheld devices, this type of spectrometer could be used to diagnose skin conditions or analyze urine samples, Bao says. They could also be used to track vital signs such as pulse and oxygen level, or to measure exposure to different frequencies of ultraviolet light, which vary greatly in their ability to damage skin.
“The central component of such spectrometers—the quantum dot filter array—is fabricated with solution-based processing and printing, thus enabling significant potential cost reduction,” Bao adds.
Androgenetic alopecia is an often hereditary condition with thinning of the hair into vellus hairs which occurs in males and females according to a male pattern (Hamilton classification) or a female pattern (ludwig classification)
It is psychologically devastating and treatments include topical (minoxidil), oral (finasteride) treatments sometimes so ineffective that the only solution is wearing a wig.
Mesotherapy has been used for over 40 years and consists of local injections but little evidence to this day exists that it would be effective. More recently* platelet rich plasma (PRP) injections have been used for this indication (it was previously used mainly in joint conditions)
Even with a relatively short time* it has been used, evidence (although not enough yet) shows that it might show some effectiveness.
Study 1: Platelet-rich plasma for androgenetic alopecia: a pilot study.
Two injections of a leukocyte platelet-rich plasma with the addition of concentrated plasmatic proteins were administered at baseline and after 3 months (single spin at baseline and double-spin centrifugation at 3 months). Photographs were taken at baseline and after 6 months, and 2 independent evaluators rated them.
Results show that some improvement was observed in almost all patients and the proportion of patients improving importantly clinical was 40.6% for one evaluator and 54.7% for the other.
Study 2: Platelet-rich plasma in androgenic alopecia: myth or an effective tool.
Khatu SS, More YE, Gokhale NR, Chavhan DC, Bendsure N.
11 patients suffering from hair loss due to androgenic alopecia and not responding to 6 months treatment with minoxidil and finasteride were included in this study. The hair pull test was performed before every treatment session.
A volume of 2-3 cc PRP was injected in the scalp. The treatment was repeated every two weeks, for a total of four times. The outcome was assessed after 3 months by clinical examination, macroscopic photos, hair pull test and patient’s overall satisfaction.
Results after 3 weeks show:
a significant reduction in hair loss was observed between first and fourth injection.
Hair count increased from average number of 71 hair follicular units to 93 hair follicular units. -Therefore, average mean gain is 22.09 follicular units per cm(2.)
After the fourth session, the pull test was negative in 9 patients.
Conclusion: These two studies suggest that PRP might be effective in the treatment of androgenetic (androgenic) alopecia. Although study 2 is stronger evidence-based medicine than study 1, further studies, such as randomized-control ones are warranted to further investigate this method.
The Viennese physician Josef Breuer (1842-1925) has a unique and prominent place in the history of psychotherapy. From 1880-82, while treating a patient known as Anna O., Breuer developed the cathartic method, or talking cure, for treating nervous disorders. As a result of that treatment, he formulated many of the key concepts that laid the foundation for modern psychotherapy. This month marked the 90th anniversary of Breuer’s death, offering an opportunity to reflect on the value of his contributions.
Breuer is best known for his collaboration with Sigmund Freud and for introducing Freud to the case of Anna O. (whose real name was Bertha Pappenheim). The ideas emerging from that case so fascinated Freud that he devoted the rest of his career to developing them, in the form of psychoanalysis. The two men co-authoredStudies on Hysteria, published in 1895, which is considered the founding text of psychoanalysis. However, the significance of Breuer’s contributions goes well beyond his role as Freud’s mentor and collaborator. In fact, Breuer laid the groundwork for modern talk therapy by, for example, considering all aspects of his patients’s life and personality and focusing on emotional expression as opposed to the Freudian emphasis on insight and interpretation.
I discovered Breuer early in my training as a therapist, after I realized that helping my clients gain insight into their problems, as the principal focus of treatment, was rarely effective in causing fundamental change. I found Freud’s technique of free association unhelpful, because many clients who are anxious or depressed have difficulty associating freely. The most therapeutic sessions were the ones that elicited an emotional response from my clients. If I could guide them to access feelings and memories, relevant to their area of concern, they would often report a sense of something shifting inside them, which dramatically accelerated the process of growth and change.
I wanted to learn how to elicit those types of experiences consistently and began to explore techniques such as hypnosis, mindfulness and focusing, all of which involve subtle shifts in the client’s state of awareness. While studying the literature to understand the nature of these changes, I was led to Breuer’s description of the cathartic method and his work with Anna O. in Studies on Hysteria. Breuer’s ideas were strikingly relevant to modern views of therapy, and my work with clients, and I was surprised they were not more widely known.
Breuer’s theoretical essay in Studies on Hysteria repays close reading, as many of the observations in it are remarkably prescient. The essay is more than sixty pages long and provides a comprehensive account of the nature, cause and treatment of mental illness with astonishing clarity, rigor and depth of insight. In 1955, James Strachey, the English translator of Studies on Hysteria, described the essay as “very far from being out of date; on the contrary, it conceals thoughts and suggestions which have even now not been turned to sufficient account.” His statement is just as true today.
According to Breuer’s theory of hysteria, the illness begins when someone is exposed to psychic trauma, which he defined as any situation with a risk of serious physical or emotional injury. If the individual is unable to feel and express the emotions related to the traumatic experience, they are dissociated, that is, isolated in a separate state of consciousness that is inaccessible to ordinary awareness. Here, Breuer acknowledged and built on the pioneering work of French psychiatrist, Pierre Janet, who was the first to assert the importance of dissociation in mental illness. Breuer called this altered state of consciousness the hypnoid state, owing to its similarity to the state induced by hypnosis. Recovery and healing require accessing and expressing the dissociated emotions, through catharsis, and integrating them with the ideas in normal consciousness, a process he called associative correction.
If we compare Breuer’s theory with Freud’s formulation of psychoanalysis, there are three main differences: psychic trauma (Breuer) vs. sexual conflict (Freud) as the primary cause of psychopathology, hypnoid states (dissociation) vs. repression (defense) as the primary mechanism, and emotional expression (catharsis) vs. interpretation (analysis) as the primary means of recovery. Ironically, in each of those points, the modern view of psychotherapy has increasingly come to favor Breuer.
A large and growing body of evidence, compiled by researchers such as Bessel van der Kolk, points to the central role of trauma in the origin of psychopathology. Understanding the effects of trauma is now a major focus of medical research, driven by the urgent need to find effective treatments for PTSD. Breuer’s work is also highly relevant to clinical practice. His concept of the hypnoid state, for example, is remarkably similar to, and provides a unifying link between, techniques such as mindfulness, focusing, neurofeedback and EMDR(Eye Movement Desensitization and Reprocessing) that are of importance in therapy today.
The publication of Studies on Hysteriamarked the end of the Breuer-Freud collaboration. Freud increasingly grew to believe that conflicts related to sexuality played an essential role in all cases of hysteria. Breuer acknowledged the importance of sexuality but considered it only one of many factors. Instead, Breuer asserted the phenomenon of dissociation due to trauma, which was implicit in his theory of hypnoid states, was more fundamental.
In a letter to the Swiss psychiatrist Auguste Forel in 1907, Breuer wrote, “this immersion in the sexual in theory and practice is not to my taste.” He went on to write, “Freud is a man given to absolute and exclusive formulations: this is a psychical need, which in my opinion, leads to excessive generalization.” Freud for his part was skeptical of the whole concept of hypnoid states. In Five Lectures on Psychoanalysis, he wrote that “Breuer’s theory of ‘hypnoid states’ turned out to be impeding and unnecessary, and it has been dropped by psycho-analysis today.”
Freud also promoted the idea that Breuer was too cautious and conservative to recognize the true importance of sexuality. To support this view, Freud claimed Breuer had abruptly terminated his work with Anna O., and resolved never to work with hysterical patients again, because she developed strong sexual feelings towards him. This view was asserted as fact by Freud’s biographer, Ernest Jones, and came to define the conventional view of the matter.
However, there is no reliable basis for Freud’s claim. Psychoanalyst and Freud biographer Louis Breger writes: “Freud’s version of what happened is simply not true. It is an example of the “resistance” argument that he later used to dismiss everyone who raised questions about his theory of sexuality: They could not accept it because it was too personally threatening.” Freud would later use a similar argument with many of his followers who disagreed with him, including Carl Jung, Alfred Adler, Sandor Ferenczi and Otto Rank. Breger goes on to assert: “The truth is that Breuer did not flee from Bertha but remained involved with her treatment for several years.”
In The Interpretation of Dreams, Freud wrote: “An intimate friend and a hated enemy have always been necessary requirements of my emotional life. I always knew how to provide myself with both over and over…sometimes the two were united within the same person.” That statement is remarkably descriptive of Freud’s relationship with Breuer.
It is notable that Breuer had been more than a collaborator to Freud, who was 14 years younger, lending him money, referring patients to his practice, and welcoming him into his home. Yale historian Peter Gay, in his biography of Freud, wrote, “His disagreeable grumbling about Breuer in the 1890s is a classic case of ingratitude, the resentment of a proud debtor against his benefactor.”
Breuer never publicly challenged Freud or responded to his criticisms, choosing instead to withdraw from the field of psychology to focus on his medical practice. Freud had the field all to himself and his writings decisively shaped the public view of Breuer, which persists to this day.
Setting aside personal details, the key question is whose ideas were more valid, and in that regard history is squarely on the side of Breuer. Freud’s emphasis on sexuality as the dominant factor shaping human development and causing psychopathology is no longer taken seriously today. Instead, the role of dissociation due to trauma is increasingly recognized as more fundamental. Also, most therapists today realize the importance of helping clients access and integrate painful emotions due to past trauma, which is the essence of Breuer’s cathartic method.
When Breuer developed the cathartic method to treat Anna O., he initiated several radical changes. First, he shifted the focus of therapy from suggestion by the therapist to self-discovery by the patient. Second, he expanded the scope of therapy from a narrow focus on treating symptoms to considering all aspects of the patient’s life and personality, thereby founding psychotherapy as a distinct discipline in its own right. Finally, he was the first person to treat mental illness through the long-term exploration of unconscious conflicts, and invented the talking cure, the treatment approach central to all forms of psychotherapy. While conventional wisdom assigns Freud credit for these achievements, the fact is they were all present in Breuer’s treatment of Anna O. before his collaboration with Freud began.
The key to Breuer’s greatness was that he had the intelligence and openness of mind to recognize that his patient had much to teach him, and the humility to value her experience over his authority as a physician. Ninety years after his death, Breuer’s ideas inform and enrich my work with clients every day, reminding me to learn from their perspective, respect the role of trauma and value emotional experience over insight.
Studies on Hysteria. Josef Breuer and Sigmund Freud. Translated from the German and edited by James Strachey. Hogarth Press, 1955.
The Life and Work of Josef Breuer. Albrecht Hirschmuller, New York University Press, 1978.
Freud: A Life For Our Time. Peter Gay, Macmillan, 1988.
A Dream of Undying Fame: How Freud Betrayed His Mentor and Invented Psychoanalysis. Louis Breger, Basic Books, 2009.
The Body Keeps the Score: Brain, Mind, and Body in the Healing of Trauma. Bessel van der Kolk, Viking, 2014.
Have you ever heard of Horizontal Gene Transfer(HGT)? In essence, the idea is that genes and DNA can be transferred between species in the same environment.
This idea is popular in relationship to single celled organisms, however this idea is contradictory to our old model of evolution, which stated that species would only evolve from the genetic information being passed down through the lineage of the species, and never cross pollenate between other species.
However, a research study from BioMed Central has recently uncovered new information regarding the transfer of genes in an environment, pointing to the idea that in reality – an environment is just as critical to the evolution of a species, and in fact affects the way that evolution happens.
Lead author Alastair Crisp from the University of Cambridge, UK, said: “This is the first study to show how widely horizontal gene transfer (HGT) occurs in animals, including humans, giving rise to tens or hundreds of active ‘foreign’ genes. Surprisingly, far from being a rare occurrence, it appears that HGT has contributed to the evolution of many, perhaps all, animals and that the process is ongoing, meaning that we may need to re-evaluate how we think about evolution.”
Beyond that, it also points to the possibility of something different occurring in our evolution… Perhaps something a little more “alien” in origin. Did we have some cross-species genetic manipulation that occurred at some early point in our history?Aliens?Martians? Human History Movie?
In humans, they confirmed 17 previously-reported genes acquired from HGT, and identified 128 additional foreign genes in the human genome that have not previously been reported.
A sprayable foam could help first responders stop bleeding from major injuries at an accident site or combat zone (Image from acs.org)
Using a material derived from shrimp shells, scientists have developed a foam that can be sprayed directly onto an open wound to quickly stop the bleeding. It could prove vital when treating injuries caused by street violence and military combat.
Injuries and violence account for nearly 1 out of every 10 deaths worldwide each year, according to the US Centers for Disease Control and Prevention. As many as 5.8 million people of all ages and social backgrounds die from violence-related injuries every year, the health protection agency says.
For some limb injuries, doctors can apply pressure to effectively halt the bleeding. The problem is that when dealing with certain injuries – trauma to the torso in particular – compression is not an option.
Meanwhile, “hemorrhage (severe blood loss) from traumatic injury is a leading cause of death for soldiers in combat and for young civilians,” Matthew Dowling and colleagues at the University of Maryland wrote in the journal ACS Biomaterials Science & Engineering, adding that the majority of hemorrhages that prove fatal are “non-compressible.”
The researchers added: “Currently, there is no effective way to treat such injuries.”
A solution has been found, however. “In this initial study, we demonstrate that a sprayable polymer-based foam can be effective at treating bleeding from soft tissue without the need for compression.”
The active material in the foam is a modified chitosan (a biopolymer derived from the shells of shrimp and other crustaceans), which “physically connects blood cells into clusters via hydrophobic interactions.”
When the unique foam is sprayed into an open cavity created by injury, it expands and forms a self-supporting barrier that counteracts the expulsion of blood from the cavity, the researchers say.
They have already tested their sprayed foam for its ability to arrest bleeding from an injury to the liver in pigs. The bleeding was stopped “within minutes” and without the need for external compression, the researchers reported. Blood loss was cut by 90 percent.