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Teens and young adults who reduced their social media use by 50% for just a few weeks saw significant improvement in how they felt about both their weight and their overall appearance compared with peers who maintained consistent levels of social media use, according to research published by the American Psychological Association.
“Adolescence is a vulnerable period for the development of body image issues, eating disorders and mental illness,” said lead author Gary Goldfield, PhD, of Children’s Hospital of Eastern Ontario Research Institute. “Youth are spending, on average, between six to eight hours per day on screens, much of it on social media. Social media can expose users to hundreds or even thousands of images and photos every day, including those of celebrities and fashion or fitness models, which we know leads to an internalization of beauty ideals that are unattainable for almost everyone, resulting in greater dissatisfaction with body weight and shape.”
However, much of the psychological research on social media, body image and mental health is correlational, according to Goldfield, so it is uncertain whether people with body image and mental health issues spend more time on social media or if social media use leads to greater body image and mental health issues.
To better understand the causal effects of reducing social media use on body image, Goldfield and his colleagues previously conducted a pilot study with 38 undergraduate students with elevated levels of anxiety and/or depression. Some of the participants were asked to limit their social media use to no more than 60 minutes per day, while others were allowed unrestricted access. Compared with participants who had unlimited access, participants who restricted their use showed improvements in how they regarded their overall appearance (but not their weight) after three weeks. Due to the small sample size, though, the researchers were unable to conduct a meaningful analysis of the effect of gender.
The current experiment, involving 220 undergraduate students aged 17-25 (76% female, 23% male, 1% other) and published in the journal Psychology of Popular Media, sought to expand the pilot study and address the gender limitation. In order to qualify, participants had to be regular social media users (at least two hours per day on their smartphones) and exhibit symptoms of depression or anxiety.
For the first week of the experiment, all participants were instructed to use their social media as they normally would. Social media use was measured using a screen-time tracking program to which participants provided a daily screenshot. After the first week, half the participants were instructed to reduce their social media use to no more than 60 minutes per day. At the start of the experiment, participants also responded to a series of statements about their overall appearance (e.g., “I’m pretty happy about the way I look,”) and weight (e.g., “I am satisfied with my weight,”) on a 5-point scale, with 1 indicating “never” and 5 “always.” Participants completed a similar questionnaire at the end of the experiment.
For the next three weeks, participants who were instructed to restrict their social media use reduced it by approximately 50% to an average of 78 minutes per day versus the control group, which averaged 188 minutes of social media use per day.
Participants who reduced their social media use had a significant improvement in how they regarded both their overall appearance and body weight after the three-week intervention, compared with the control group, who saw no significant change. Gender did not appear to make any difference in the effects.
“Our brief, four-week intervention using screen-time trackers showed that reducing social media use yielded significant improvements in appearance and weight esteem in distressed youth with heavy social media use,” said Goldfield. “Reducing social media use is a feasible method of producing a short-term positive effect on body image among a vulnerable population of users and should be evaluated as a potential component in the treatment of body-image-related disturbances.”
While the current study was conducted as a proof of concept, Goldfield and his colleagues are in the process of conducting a larger study to see if reduction in social media use can be maintained for longer periods and whether that reduction can lead to even greater psychological benefits. More

A team of researchers at the University of California San Diego has made significant advances in solving some of the most vexing challenges in bioprinting 3D-engineered tissues while meeting the key requirements of high cell density, high cell viability and fine fabrication resolution.
The research led by nanoengineers at the UC San Diego Jacobs School of Engineering was published in the February 22, 2023 issue of Science Advances.
Bioprinting is based on 3D-printing technology, using cells and biopolymer to create biological structures and tissues. 3D-engineered tissues — lab-created yet functional human-like tissues made of living cells and biomaterial scaffolds — have great potential for biomedical applications, including drug testing and development, organ transplants, regenerative medicine, personalized medicine, disease modeling, and more. Their uses could add significant speed and integrity to the process of drug development, as well as helping to mitigate challenges associated with organ-donor shortage and immune rejection.
One of the most promising types of 3D-bioprinting is called digital light processing (DLP) bioprinting. Within this branch of 3D-bioprinting, progress has been impeded by practical and technical impediments. It has proven difficult to print tissues with high cell densities and finely resolved structures.
“After printing, we culture the construct to allow the cells to mature or reorganize into a functional tissue. Therefore, the cell is like a seed, and each cell type has a specific density at which they are most potent to sprout,” said Shaochen Chen, the nanoengineering professor leading the research team.
Using existing approaches, the more dense the presence of cells in bioink, which is a biocompatible polymer used in DLP-based 3D bioprinting, the more the light scatters, hindering printing resolution.

The researchers reduced this light-scattering effect by tenfold, allowing them to print with high cell densities and high resolution thanks to the contrast agent iodixanol, a new ingredient in the bioink.
“Using iodixanol, we developed a refractive index-matched bioink for DLP-based bioprinting to mitigate the light scattering of the cells, concentrating the energy within the user-defined light pattern to improve the printing fidelity,” said Shangting You, a nanoengineering postdoc fellow at UC San Diego, member of Chen’s team and co-first author of the research paper.
For nearly two decades, Chen’s lab has helped steer in the development of DLP-based 3D printing and bioprinting techniques, helping create the foundation for modern 3D biomanufacturing.
How it works
DLP-based 3D bioprinting uses a digital micromirror device (DMD) to project a 2D cross-section of the 3D model to the photo-crosslinkable bioink. When exposed to light, the photocrosslinkable bioink, which can be either synthetic or natural, solidifies. Then, a motorized stage lifts up the bioink by a few tens microns to 200 microns, which allows uncured bioink to refill the gap. When the next cross-section is projected to the bioink, a new layer solidifies and the process repeats.

When all goes well, a newly formed layer precisely matches the shape of the projected cross-section. However, with existing methods, the incorporation of cells in the bioink can cause severe light scattering, which blurs the projected light in the bioink. As a result, the newly formed layers cannot replicate the fine details of the projected cross-sections.
Tuning the refractive index of the bioink minimizes this scattering effect and significantly improves the fabrication. The Chen Lab’s research shows that a ~50 µm feature size can be achieved in a refractive-index-matched gelatin methacrylate (GelMA) bioink with a cell density as high as 0.1 billion/mL.
This approach introduces a few novel technical innovations, including a hollow organic vascular network embedded in a cell-laden thick tissue, enabling it for perfused and long-term culture, and a snow-flake and spoke shape to showcase the high resolution for both positive and negative features.
The project was not without its challenges. “We have developed various bioink materials and several protocols for handling them,” said Yi Xiang, a nanoengineering PhD student at UC San Diego, member of Chen’s team and co-first author of the research paper. “But with the longer printing time for a larger tissue, any inconsistency and instability in the cells and in the biomaterial was amplified. Therefore, we had to modify and optimize both the material composition and the handling procedures.”
This project marks the first use of iodixanol as a bioink in DLP bioprinting, at a high cell density and with long intervals of exposure. “We performed a series of biological investigations to evaluate this impact and developed some post-printing procedures to sufficientlydissipate the iodixanol,” Xiang said.
With the improved printing resolution mediated by iodixanol, a high cell density, pre-vascularized tissue with an overall size of 17 x 11 x 3.6 mm3 was fabricated.
“In vitro culture of such a thick tissue has been hindered by the limited diffusion of oxygen and nutrients,” Chen said. “We were able to print perfusable vascular lumens embedded in the tissue with diameters ranging from 250 µm to 600 µm, which was interfaced with a perfusion system for long-term culture. We demonstrated that the vascular lumens were endothelialized, and the thick tissue remained viable for 14 days of culture.”
Next steps
The team continues to work on optimizing its materials system and bioprinting parameters for functional thick tissue fabrication and has filed a provisional patent covering this work.
Further next steps Chen suggests include developing precisely structured, high cell-density in vitro tissue models for improved histological and functional recapitulation, with an eye toward high cell-density large-tissue printing for tissue and organ transplants and replacements in human subjects.
Paper: “High Cell Density and High Resolution 3D Bioprinting for Fabricating Vascularized Tissues” in Science Advances
Coauthors include: Shangting You*, Yi Xiang* and Henry H. Hwang, Department of NanoEngineering, University of California San Diego; David B. Berry, Department of Orthopaedic Surgery, UC San Diego; Wisarut Kiratitanaporn, Department of Bioengineering, UC San Diego; Jiaao Guan, Department of Electrical and Computer Engineering, UC San Diego; Emmie Yao, Min Tang and Zheng Zhong, Department of NanoEngineering, UC San Diego; Xinyue Ma, School of Biological Sciences, UC San Diego; Daniel Wangpraseurt, Department of NanoEngineering and Scripps Institution of Oceanography, UC San Diego; Yazhi Sun, Department of NanoEngineering, UC San Diego; Ting-yu Lu, Materials Science and Engineering Program, UC San Diego; and Shaochen Chen, Department of NanoEngineering, Department of Bioengineering, Department of Electrical and Computer Engineering, and Materials Science and Engineering Program, UC San Diego. More

Given the growing importance of graphite in energy storage technologies, a team of Northwestern researchers has conducted a study exploring ways to reduce reliance on imports of the in high-demand mineral, which powers everything from electric vehicles (EVs) to cell phones.
The paper, which published this week in the journal Environmental Science and Technology, is the first natural and synthetic graphite material flow analysis for the U.S., and considers 11 end-use applications for graphite, two waste management stages and three recycling pathways.
“If we want to produce more batteries domestically, we’re going to need to increase our production of graphite,” said Northwestern University chemical engineer Jennifer Dunn. “But the question is, how can we do so in a way that contributes to decarbonization goals?”
Dunn is an associate professor of chemical and biological engineering at Northwestern’s McCormick School of Engineering and director of the Center for Engineering Sustainability and Resilience. The paper was co-authored by Jinrui Zhang, who at the time of the study initiation was a post-doctoral scholar in chemical and biological engineering, and Chao Liang, previously a member of Northwestern’s Institute for Sustainability and Energy (ISEN). Both co-authors are alumni of Dunn’s research group.
The U.S. uses mostly synthetic graphite, which is produced from by-products of the fossil fuel industry and creates a paradoxical relationship between graphite and technologies like electric vehicles (EVs) that aim to remove fossil fuel supply chains from transportation and cut greenhouse gas emissions.
Natural graphite, alternately, is sourced from mines and imported to the U.S. mostly from China. Nearly all the graphite used in the U.S. goes into electrodes for steel manufacturing. As the battery supply chain in the U.S. ramps up, measures like the Inflation Reduction Act seek to incentivize the use of domestically sourced materials — including graphite — in U.S.-made batteries.

Given the growing importance of graphite in energy storage technologies like lithium-ion batteries, the team carried out this analysis to characterize the major production routes of the mineral, its main uses and opportunities to reduce consumption through recycling. Data from 2018 — the most recent period with sufficient data for this type of analysis — was used for the study.
Most of the graphite consumed in the U.S. in 2018 was synthetic graphite, with 63% of this graphite produced domestically. Production of synthetic graphite emits more greenhouse gases than mining natural graphite (Natural graphite has between 62% and 89% lower greenhouse gas emissions). Synthetic graphite is also more expensive. However, the U.S. does not mine natural graphite but imports it, predominately from China.
As the only material that conducts electricity besides metal, the main use of graphite is for electrodes in steel making. As demand for low-carbon steel increases, more graphite may be consumed in electrode production. During steel making, graphite burns and dissipates — much like how graphite pencils start to disappear as you write with them. Though it is not impossible to recover dissipated graphite, it rarely is, diminishing opportunities to recover the mineral through recycling. Technologies to recover graphite from lithium-ion batteries are increasing in maturity but not yet common.
Dunn said that part of the focus on domestic sources and recycling of graphite-containing products like lithium-ion batteries is based on the current supply chain’s potential instability and projected increasing demand.
“You can recover some graphite from recycling lithium-ion batteries, but batteries last a while, so it may be a decade before you can get graphite back from EVs that reach the end of their life,” Dunn said. “However, we are also building the bioeconomy in the U.S., and that can include making graphite from biomass. This opens up another supply option beyond making graphite from fossil fuel industry by-products or mining.”
With the passage of the Inflation Reduction Act of 2022, more funding will move toward the use of domestically sourced and recycled graphite, and Dunn said the U.S. needs to be ready to make the shift.
The study, “Graphite flows in the U.S.: Insights into a key ingredient of the energy transition,” was supported by the National Science Foundation’s Future Manufacturing Program (NSF CMMI-2037026). More