puparium = the hardened last larval skin which encloses the pupa in some insects, especially higher diptera; a pupa enclosed in a puparium.

Shingo Tamagawa, an animator closely associated with the studio Sunrise, was afraid he’d start hating his drawings, and even the act of drawing, if he continued to pursue the path he was on. “No matter how hard your work,” he explains in the new documentary Three Minutes, Three Years: Making Puparia, “animation is something that is consumable.” Disillusioned, he stopped drawing for over a year. In that time, ideas slowly started accumulating for a new short film. After three years of solo production, his three-minute indie film Puparia was completed. He released it in November on YouTube, where it has since been viewed more than a million times


‘Where did I park my car?’ Brain stimulation improves mental time travel

You might remember you ate cereal for breakfast but forget the color of the bowl. Or recall watching your partner put the milk away but can’t remember on which shelf. A new Northwestern Medicine study improved memory of complex, realistic events similar to these by applying transcranial magnetic stimulation (TMS) to the brain network responsible for memory.

Experimental design overview

The study authors used TMS with the goal of altering brain activity and memory for realistic events. Immediately following stimulation, subjects performed a memory task while having their brains scanned using functional magnetic resonance imaging (fMRI). Instead of showing study participants pictures or lists of words — typical practices in laboratory tests that analyze memory — participants in this study watched videos of everyday activities such as such as someone folding laundry or taking out the garbage.

Following stimulation, study participants more accurately answered questions about the content of the video clips, such as identifying the shirt color an actor was wearing or the presence of a tree in the background. Additionally, the study found that brain stimulation led to higher quality reinstatement of memories in the brain, which happens when the brain replays or relives an original event. Following stimulation, a person’s brain activity while watching a video more closely resembled their brain activity when remembering that same video.

Adapted and abridged from Source

Original paper: Hebscher, M., Kragel, J.E., Kahnt, T. and Voss, J.L., 2021. Enhanced reinstatement of naturalistic event memories due to hippocampal-network-targeted stimulation. Current Biology.

A guide to making high-performance, versatile solar cells

Improving solar cell design is integral for improving energy consumption. Scientists have lately focused on making solar cells more efficient, flexible, and portable to enable their integration into everyday applications. Consequently, novel lightweight and flexible thin film solar cells have been developed. It is, however, not easy to combine efficiency with flexibility. For a material (usually a semiconductor) to be efficient, it must have a small “band gap” — the energy required to excite charge carriers for electrical conduction — and should absorb and convert a large portion of the sunlight into electricity. Till date, no such efficient absorber suitable for thin film solar cells has been developed.

In a new study published in Applied Materials and Interfaces, scientists from Korea addressed this issue and proposed a novel solution in the form of “antiperovskite” oxides, denoted as Ba4Pn2O, with Pn as stand-in for Arsenic (As) or Antimony (Sb). Using density functional theory calculations, scientists investigated various physical properties of the antiperovskite oxides and revealed that they exhibit spontaneous electric polarization, making them ferroelectric in nature. Prof. Youngho Kang from Incheon National University, who led the study, explains, In the minimum energy configuration of the Ba4Pn2O structure, we found that the O ions and the Ba ions are displaced from their original positions in opposite directions. These displacements gave rise to a non-zero electric polarization, a classic signature of ferroelectricity.”

Since the spontaneous polarization assists in the separation of eleat their band gaps are ideal for efficient sunlight absorption,ctron-hole pairs, this implied that antiperovskite oxides could efficiently extract charge carriers. In addition, the calculations showed th allowing even a very thin layer of Ba4Pn2O to yield substantial photocurrent.

Adapted and abridged from Source

Original paper: Kang, Y. and Han, S., 2020. Antiperovskite oxides as promising candidates for high-performance ferroelectric photovoltaics: First-principles investigation on Ba4As2O and Ba4Sb2O. ACS Applied Materials & Interfaces12(39), pp.43798-43804.