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\"It was one of history's great vanishing acts. As early as 3500 BCE, scribes in the mud-walled city-state of Sumer used a reed stylus to press tiny wedge-shaped symbols into clay. For three thousand years, the script chronicled the military conquests, scientific discoveries, and epic literature of the grand kingdoms of Mesopotamia - Assyria, Babylon, the mighty Achaemenid Empire - along with precious minutia about everyday life so long ago. But as the palaces of these once great kingdoms sank beneath the desert sands, the meaning of these characters was lost. London, 1857. Colossal sculptures of winged bulls and alabaster bas-reliefs depicting cities under siege and vassals bearing tributes to Biblical kings lined the halls of the British Museum. In the Victorian era's obsession with the triumph of human progress, the mysterious kingdoms of ancient Mesopotamia - the very cradle of civilization - had captured the public imagination. Yet Europe's best philologists struggled to decipher the strange characters. Cuneiform seemed to have thousands of symbols - with some scholars claiming each could be pronounced in up to eight, nine, even ten different ways. Others insisted they'd cracked the code and deciphered inscriptions that corresponded precisely to the Old Testament - proving the veracity of the Word of God. Was it all a hoax? A delusion? A rollicking adventure through the golden age of archaeology, The Writing on the Wall tracks the decades-long race to decipher the oldest script in the world. It's the story of a swashbuckling young archeologist, a suave British military officer, and a curmudgeonly Irish rector, all vying for glory - from the ruins of Persepolis to the opulence of Ottoman-era Baghdad - in a quest to unearth the relics of lost civilizations and unlock the secrets of humanity's past\"-- Provided by publisher.

Hydrogel materials have become a versatile platform for in vitro cell culture due to their ability to simulate many aspects of native tissues. However, precise spatiotemporal presentation of peptides and other biomolecules has remained challenging. Here we report the use of light-sensing proteins (LSPs), more commonly used in optogenetics research, as light-activated reversible binding sites within synthetic poly(ethylene glycol) (PEG) hydrogels. We used LOVTRAP, a two component LSP system consisting of LOV2, a protein domain that can cycle reversibly between “light” and “dark” conformations in response to blue light, and a z-affibody, Zdark (Zdk), that binds the dark state of LOV2, to spatiotemporally control the presentation of a recombinant protein within PEG hydrogels. By immobilizing LOV2 within PEG gels, we were able to capture a recombinant fluorescent protein (used as a model biomolecule) containing a Zdk domain, and then release the Zdk fusion protein using blue light. Zdk was removed from LOV2-containing PEG gels using focused blue light, resulting in a 30% reduction of fluorescence compared to unexposed regions of the gel. Additionally, the reversible binding capability of LOVTRAP was observed in our system, enabling our LOV2 gels to capture and release Zdk at least three times. By adding a Zdk domain to a recombinant peptide or protein, dynamic, spatially constrained displays of non-diffusing ligands within a PEG gel could feasibly be achieved using LOV2.

This year's Best American Magazine Writing features outstanding writing on contentious issues including incarceration, policing, sexual assault, labor, technology, and environmental catastrophe. Selections include Paul Ford's ambitious \"What Is Code?\" (Bloomberg Businessweek), an innovative explanation of how programming works, and \"The Really Big One,\" by Kathryn Schulz (The New Yorker), which exposes just how unprepared the Pacific Northwest is for a major earthquake. Joining them are Meaghan Winter's exposé of crisis pregnancy centers (Cosmopolitan) and a chilling story of police prejudice that allowed a serial rapist to run free (the Marshall Project in partnership with ProPublica). Also included is Shane Smith's interview with Barack Obama about mass incarceration (Vice). Other selections demonstrate a range of long-form styles and topics across print and digital publications. The imprisoned hacker and activist Barrett Brown pens hilarious dispatches from behind bars, including a scathing review of Jonathan Franzen's fiction (The Intercept). \"The New American Slavery\" (Buzzfeed) documents the pervasive exploitation of guest workers, and Luke Mogelson explores the purgatorial fate of an undocumented man sent back to Honduras (New York Times Magazine). Joshua Hammer harrowingly portrays Sierra Leone's worst Ebola ward as even the staff succumb to the disease (Matter). And in \"The Friend,\" Matthew Teague's wife is afflicted with cancer, his friend moves in, and the result is a devastating narrative of relationships and death (Esquire). The collection concludes with Jenny Zhang's \"How It Feels,\" an unconventional meditation on the intersection of teenage cruelty and art (Poetry).

Hydrogels are widely used as three-dimensional (3D) tissue engineering scaffolds due to their tissue-like water content, as well as their tunable physical and chemical properties. Hydrogel-based scaffolds are generally associated with nanoscale porosity, whereas macroporosity is highly desirable to facilitate nutrient transfer, vascularization, cell proliferation and matrix deposition. Diverse techniques have been developed for introducing macroporosity into hydrogel-based scaffolds. However, most of these methods involve harsh fabrication conditions that are not cell friendly, result in spherical pore structure, and are not amenable for dynamic pore formation. Human tissues contain abundant microchannel-like structures, such as microvascular network and nerve bundles, yet fabricating hydrogels containing microchannel-like pore structures remains a great challenge. To overcome these limitations, here we aim to develop a facile, cell-friendly method for engineering hydrogels with microchannel-like porosity using stimuli-responsive microfibers as porogens. Microfibers with sizes ranging 150–200 μm were fabricated using a coaxial flow of alginate and calcium chloride solution. Microfibers containing human embryonic kidney (HEK) cells were encapsulated within a 3D gelatin hydrogel, and then exposed to ethylenediaminetetraacetic acid (EDTA) solution at varying doses and duration. Scanning electron microscopy confirmed effective dissolution of alginate microfibers after EDTA treatment, leaving well-defined, interconnected microchannel structures within the 3D hydrogels. Upon release from the alginate fibers, HEK cells showed high viability and enhanced colony formation along the luminal surfaces of the microchannels. In contrast, HEK cells in non-EDTA treated control exhibited isolated cells, which remained entrapped in alginate microfibers. Together, our results showed a facile, cell-friendly process for dynamic microchannel formation within hydrogels, which may simultaneously release cells in 3D hydrogels in a spatiotemporally controlled manner. This platform may be adapted to include other cell-friendly stimuli for porogen removal, such as Matrix metalloproteinase-sensitive peptides or photodegradable gels. While we used HEK cells in this study as proof of principle, the concept described in this study may also be used for releasing clinically relevant cell types, such as smooth muscle and endothelial cells that are useful for repairing tissues involving tubular structures.

The club is nearly deserted, most of its members having fled to Australia, New Zealand, Great Britain, South Africa, or other countries in Africa that offer more stability and security. Since the defeat of Ian Smith's white-minority government and the onset of black-majority rule in 1980, the club has opened its doors to all Zimbabweans, black and white.

It has been understood for some time that cells are profoundly influenced by their environment. Recently, researchers have made great strides in engineering cell culture platforms that are both physiologically mimetic and reductionist, leading to more biologically relevant cell responses observed within analytically tractable experiments. Moving from stiff tissue culture plastic or glass into hydrogel-based cell culture keeps cells in contact with materials that are stiffness-matched to native tissues, and can reduce or delay de-differentiation into undesirable phenotypes. Incorporating biomolecules like specific adhesion ligands or growth factors into cell culture hydrogels can help drive specific biological outputs, and when coupled with patterning techniques can yield intentional, spatially defined heterogeneity within a cultured cell population. However, biological events or disease states are often are driven by biochemical dynamics, with the time course over which a signal is presented influencing whether cells respond physiologically or pathologically. Unfortunately, dynamic presentations of biomolecules are challenging to replicate within hydrogels due to a lack of ligation mechanisms suitable for dynamically linking relevant biomolecules into the hydrogel matrix in the presence of cells. In this work, novel protein-based ligation domains were engineered into new strategies for the time-varying presentation of recombinant biomolecules within cell culture hydrogels. SpyCatcher, a protein domain which forms a spontaneous covalent bond with a complementary peptide dubbed “SpyTag”, was used to form a site-specific linkage between a recombinant protein and a synthetic hydrogel. The ligation reaction was shown to proceed under mild conditions appropriate for cell culture, and by adding the cell-adhesive ligand RGDS to the SpyCatcher-tagged protein (forming RGDS-SC), cell spreading within a 3D hydrogel could be switched on by simply adding RGDS-SC topically to cell-laden hydrogels. SnoopCatcher, the chemically orthogonal cousin to SpyCatcher that binds the peptide “SnoopTag”, was then appended with the vascular endothelial growth factor-mimetic peptide QK (KLTWQELYQLKYKGI) to form QK-SnpC, and used in tandem with RGDS-SC to simultaneously control endothelial cell adhesion and mitotic stimulation on synthetic hydrogels containing both Tag peptides. The Catcher/Tag systems are advantageous due to their specificity and stability. However, their ligations are irreversible because they form covalent bonds. Incorporating the photocleavable fluorophore PhoCl into the backbone of RGDS-SC (forming PhoCl-SC) allowed for the reversible incorporation of a recombinant protein into synthetic hydrogels. SpyCatcher mediated the spontaneous ligation to SpyTag sites within the gel, and by applying 400 nm light, PhoCl was cleaved, thereby removing the N-terminal RGDS tag from the gel. This reversion was limited to one cycle, and so would not be appropriate for presenting a sequence of several biochemical signals, as would be seen by cells near an area of wound healing for instance. To develop a truly reversible conjugation mechanism, the optogenetic protein LOV2 was engineered into a blue light-mediated non-covalent ligation strategy. The LOVTRAP system, consisting of LOV2 and its binding partner Zdk, was shown to allow synthetic gels containing LOV2 to capture Zdk-tagged proteins in the dark, and then release them upon blue light exposure. Because LOV2 will reset to its dark state via thermal relaxation, this capture and release cycle could be repeated at least 3 times, indicating the reversible association of LOVTRAP was functional in a biomaterial setting. Protein-based ligation domains are simple to use, as they can be added to recombinant proteins genetically, and are inherently site-specific, alleviating worries that protein activity could be compromised upon conjugation to the gel. Moreover, the Catcher systems and LOVTRAP all bind to their binding partners spontaneously under cell culture conditions, reducing the chance that sensitive cell types would be perturbed by their use. These strategies greatly expand the tool kit for dynamically presenting biomolecules to cells via hydrogel immobilization.

Several engineering programs around the country either require or encourage a cooperative education experience as part of their curriculum. In this paper, we examine the effects of cooperative education on grade point average, length of time in school, and starting salary. Statistical analyses show that cooperative education programs have significant effects on all three dimensions. These results are useful not only to students deciding whether to participate in cooperative education programs, but also to administrators in determining the role of cooperative education in the engineering curriculum.

I stood in the corridor of a ramshackle building called Beit Agron in central Jerusalem, the headquarters for foreign journalists and military and government spokesmen, shaking with rage and humiliation. Seconds earlier, I’d been called a liar and then physically ejected from the office of the Israeli government press director. Now, as I took a deep breath and headed down the stairs, I thought back to the incident that had led to this point—an innocent comment I’d made two years earlier about a meal, a compliment that would brand me in some people’s eyes as a pro-Palestinian stooge—and

The narrative pieces together Nur's astonishing biography and follows him when he became mayor in 2010 and tried to restore confidence and bring back investment to the battered Somali capital. [...]it was the mayor's office that oversaw the erection of solar powered street lights -- which transformed the city.