Just across town from the Library of Congress in Washington, D.C., stands Gallaudet University, an institute for higher learning for the deaf and hard-of-hearing. In 1864, President Abraham Lincoln signed the law that allowed the school to begin issuing college degrees, a milestone for deaf people seeking higher education. Edward M. Gallaudet (right) was the […]

The following is a guest post by Hanna Soltys, Reference Librarian, Prints & Photographs Division. The post was written with the help of Sara W. Duke, Curator of Popular and Applied Graphic Art.   While professional baseball’s Opening Day will take place at a later date, the spirit and excitement of the day still live […]

Spring has arrived. While some of us may have an opportunity to carefully step outside and view blossoms in our own neighborhood, others may not. Wherever you are, you can take a virtual stroll among the shoots and blossoms planted among the collections of the Prints & Photographs Division. Many images of gardens can be […]

The following is a post by Kristi Finefield, Reference Specialist in the Prints & Photographs Division, and member of the Picture This blog team. Images have a way of opening our eyes to new aspects of a well-known story. When I think of singer Marian Anderson, an image of her performing at the Lincoln Memorial […]

Visitors to the 1900 Paris Exposition would have had the opportunity to view an extraordinary display of photographs, charts, publications and other items meant to demonstrate the progress and resilience of African Americans in the United States, only a few decades after the abolition of slavery. The materials were assembled by African American intellectuals Thomas J. […]

The following is a guest post by Katherine Blood, Curator of Fine Prints, Prints & Photographs Division. As the Library of Congress marks its 220th year of serving the nation, the publication of a new guide tells two stories: how staff have for decades worked with art professionals to build the collections and how by […]

The following is a post by Kristi Finefield, Reference Specialist in the Prints & Photographs Division, and member of the Picture This blog team. As the Library of Congress marks its 220th year, we take the opportunity to explore one example of its efforts to sustain and celebrate the arts in its physical spaces. Above […]

Below is an interview with Elizabeth Lindqwister, the summer 2019 Liljenquist Family Fellow, and Prints & Photographs Division staff members, Karen Chittenden and Micah Messenheimer, about creating a Story Map focusing on the Civil War experience of Susie King Taylor. Many courageous people are pulling double and triple duty in this time of quarantine for […]

The only way to solubilize many antigens for immunoprecipitation is by denaturation. This cell lysis protocol is ideally suited for this purpose to release proteins from complex structures or reveal antibody epitopes hidden within native proteins. Short linear epitopes may not be accessible to antibodies within the native tertiary and quaternary protein structures, but they become exposed upon the unraveling of proteins, exposing their secondary structure. Antibodies otherwise not suitable for the immunoprecipitation of proteins prepared under nondenaturing conditions are now able to bind these antigens of interest in cell lysates prepared under denaturing conditions. These antibodies may also work well for immunoblotting purposes when the protein target is completely denatured. Harvested cells in this protocol are washed in tris-buffered saline (TBS) before lysis in 2% sodium dodecyl sulfate (SDS)-containing Lysis buffer for 10 min at 100°C. The resulting sample is diluted 20-fold in TBS to reduce the SDS concentration to ≤0.1% before the addition of an antibody for immunoprecipitation. Addition of 2% bovine serum albumin (BSA) or 0.1% Nonidet P-40 to the TBS before an immunoprecipitation, respectively, ensures either removal of SDS from the target protein or retaining denatured proteins in solution.

Differential detergent fractionation of cells is a rapid method for extraction of cytoplasmic and nuclear proteins in preparation of an immunoprecipitation. This method can be applied for use of adherent or suspension cells and can significantly reduce nonspecific background in an immunoprecipitation by separation of cellular compartments into individual fractions. The lysis of cells by differential detergents permits the rapid extraction of proteins from the cytoplasm (digitonin), the cytoplasmic membranes, and organelles (Triton X-100), and nucleoplasm (Tween/DOC), facilitated through the use of distinct extraction buffers. Cytoplasmic and nuclear matrix proteins as well as DNA are left behind during the detergent-based extraction.

This rapid and efficient method to prepare highly purified recombinant adeno-associated viruses (rAAVs) is based on binding of negatively charged rAAV capsids to an anion-exchange resin that is pH dependent.

This is a simple method for rapid preparation of recombinant adeno-associated virus (rAAV) stocks, which can be used for in vivo gene delivery. The purity of these vectors is considerably lower than that obtained by either CsCl gradient centrifugation or by combination of iodixanol gradient ultracentrifugation followed by column chromatography.

The most commonly used method for production of recombinant adeno-associated virus (rAAVs) in research laboratories is by transient triple transfection of 293 cells with AAV cis and trans plasmids and an adenovirus helper plasmid. This protocol describes the processes required to prepare the transfected cell suspension for virus purification.

Over many years, the Xenopus laevis embryo has provided a powerful model system to investigate how mechanical forces regulate cellular function. Here, we describe a system to apply reproducible tensile and compressive force to X. laevis animal cap tissue explants and to simultaneously assess cellular behavior using live confocal imaging.

Purified RNA may need to be concentrated by precipitation for downstream applications. Precipitation of RNA with ethanol (or isopropanol) is the standard method to recover RNA from aqueous solutions.

In this protocol, DNA fragments are separated according to size by electrophoresis through low-melting-temperature agarose, and then recovered by melting the agarose and extracting with phenol:chloroform. The protocol works best for DNA fragments ranging in size from 0.5 to 5.0 kb. Yields of DNA fragments outside this range are usually lower, but often are sufficient for many purposes.

Mice, rats, or hamsters are immunized by giving biweekly injections of a purified antigen, cultured cells, or cDNA. For mice, if a pure, soluble protein antigen is being used and is abundant, a dose of 50–100 µg in adjuvant at each immunization is a sensible general recommendation; for rats and hamsters, a dose of 100–200 µg is sufficient. Lower doses can be used for antigens with higher immunogenicity. Adjuvants (Freund's, Ribi, Hunter's TiterMax, ImmunEasy, or Alum) should be mixed with the immunizing antigen for the first two immunizations only; Complete Freund's adjuvant is only used with the first immunization. Subsequent immunizations are performed in phosphate-buffered saline (PBS) or normal saline, with or without Incomplete Freund's adjuvant. The choice of adjuvant is dependent on the subclass of immunoglobulin required. Over the course of the 6-wk immunization schedule, each animal usually receives a total of six injections (three subcutaneous and three intraperitoneal). Once a good titer has developed against the antigen of interest, regular boosts and bleeds are performed to collect the maximum amount of serum. For rats and hamsters, boosts should be spaced every 2–3 wk, and serum samples of 400–500 µL should be collected 10–12 d after each boost. For mice, boosts should be spaced every 2–3 wk, and serum samples of 200–300 µL should be collected 10–12 d after each boost.

For most immunoblots developed with chemiluminescence or with fluorochrome-based detection systems, it is possible to remove the primary and secondary antibodies from the membrane without affecting the bound antigen. This allows you to reuse the membrane for detection of another protein antigen. The blots developed with chromogenic substrates can also be stripped of antibodies and reprobed, but the bands detected in the first round of immunoblotting will remain unaffected. Stripping and reprobing of the membrane are particularly useful when the amount of sample is limited or when it is important to accurately compare the signal between two different protein antigens in the same sample. Examples of such experiments include determining the levels of a protein antigen in a series of samples relative to the loading control and comparison of the phosphorylated form to the total levels of the protein in the sample.

Before probing blots for the presence of an antigen, the total composition of the transferred proteins can be determined by staining the nitrocellulose or polyvinylidene fluoride (PVDF) membrane. Staining for proteins is useful to determine the position of the non-prestained molecular weight markers or individual lanes on the gel and to ensure that efficient transfer has occurred. It can be also used to verify equal loading of the samples in the gel when a comparison of the protein of interest between the different samples is important. The conventional procedures such as Coomassie Blue and silver staining methods used for staining polyacrylamide gels are incompatible with immunoblotting. Ponceau S is the more common staining method in immunoblotting protocols because it is compatible with antibody–antigen binding, is cost efficient, and provides a good contrast between the stained bands and background. In this protocol, nitrocellulose or PVDF membrane is rinsed with ultrapure H₂O after the transfer of proteins. Ponceau S dye is applied as an acidic aqueous solution, and the proteins on the membrane are stained with red color. The membrane is briefly destained with water and can be photographed or scanned to obtain the image of the total protein staining. Individual lane positions or the molecular weight standards can be marked with a pencil, if required.

The Bradford assay is a quick and fairly sensitive method for measuring the concentrations of proteins. It is based on the shift in absorbance maximum of Coomassie Brilliant Blue G-250 dye from 465 to 595 nm following binding to denatured proteins in solution.

Successful modification of the bacterial artificial chromosome (BAC) after two-step BAC engineering is confirmed in two separate polymerase chain reactions (PCRs). The first reaction (5' co-integrate PCR) uses a forward 5' co-integrate primer (a sequence located upstream of the 5' end of the A-box) and a reverse 3' primer on the vector (175PA+50AT) or within the reporter sequence or mutated region as appropriate. The second reaction (3' co-integrate PCR) uses a forward 5' primer on the recA gene (RecA1300S) and a reverse 3' co-integrate primer (a sequence located downstream from the 3' end of the B-box). Those colonies shown to be positive in PCR analysis are further tested for sensitivity to UV light. After the resolution, colonies that have lost the excised recombination vector including sacB and recA genes become UV light sensitive.

Bacterial artificial chromosome (BAC) clones are rendered electrocompetent and transformed with the recombinant shuttle vector, pLD53SCAB/AB-box. Cointegrates are selected by growth on chloramphenicol and ampicillin to ensure recombination of the shuttle vector into the BAC.

Plasmid DNA is prepared from the recombinant shuttle vector pLD53.SCAB/A-B created by cloning of the A and B homology arms for two-step bacterial artificial chromosome (BAC) engineering. To confirm that the A-box and B-box arms have been successfully incorporated into pLD53.SCAB, the pattern of enzyme digestion of the modified plasmid is compared with that of the unmodified pLD53.SCAB. Once the shuttle vector is shown to carry the proper sequences, it is ready for transfer into the BAC host.

This protocol describes the preparation of the shuttle vector before its introduction into bacterial artificial chromosome (BAC) host cells for BAC two-step engineering. The homology arm sequences, prepared previously, are introduced by ligation into the digested shuttle vector DNA to provide sites for recombination within the BAC clone. Crude lysates of individual bacterial transformants serve as templates in polymerase chain reaction (PCR) analysis to confirm the presence of the homology arms in the recombinant shuttle vector.

The 700-bp A homology arm (A-box) and the 700-bp B homology arm (B-box) are amplified by polymerase chain reaction (PCR) using purified bacterial artificial chromosome (BAC) DNA as template for two-step BAC engineering. The resulting A-box PCR product contains an AscI site at its 5' end (the 5' primer incorporates an AscI site, and the 3' primer does not incorporate any restriction sites). The B-box PCR product contains an XmaI site at its 3' end (the 5' primer does not incorporate any restriction sites, and the 3' primer incorporates an XmaI site). The amplification products are then digested with the appropriate restriction endonucleases to render them suitable for cloning into the shuttle vector.

In two-step bacterial artificial chromosome (BAC) engineering, a single plasmid is introduced into the BAC-carrying cell lines. The shuttle vector pLD53.SCAB (or pLD53.SCAEB) carries the recA gene and the R6K origin, which requires the protein to replicate. PIR2 cells, expressing , are typically used for the amplification of the vector and maintain about 15 copies/cell of the donor vector, which is relatively stable in this host.

We assess the dynamics of volatility spillovers among global systemically important banks (G-SIBs). We measure spillovers using vector-autoregressive models of range volatility of the equity prices of G-SIBs, together with machine learning methods. We then compare the size of these spillovers with the degree of systemic importance measured by the Basel Committee on Banking Supervision's G-SIB bucket designations.

Amid widespread sell-offs in risky asset classes, corporate bond exchange-traded funds (ETFs) traded at steep discounts to underlying asset values in March. Contributing factors were high market volatility, reduced risk-taking by dealers and investors' reaction to policy decisions. Policy interventions that improve market functioning in a given sector can have temporary yet important spillovers to other segments through portfolio rebalancing by investors.

CPMI report: Payment aspects of financial inclusion in the fintech era, April 2020

FSI Briefs No 1, April 2020. Regulatory policy responses should seek to support economic activity while preserving the financial system's soundness and ensuring transparency. The recommendation for banks to make full use of capital and liquidity buffers should go hand in hand with restrictions on dividends and bonuses and clarity concerning the process for rebuilding them. Flexibility in loan classification criteria for prudential and accounting purposes should be complemented with sufficient disclosure on the criteria banks use to assess creditworthiness. The publication of detailed guidance on the application of expected loss provisioning rules, combined with sensible transitional arrangements, may constitute a balanced approach to mitigating the unintended effects of the new accounting standards.

FSI Briefs No 2, April 2020. Guidance issued by financial sector authorities in response to the Covid-19 crisis seems to suggest that international efforts to come up with operational resilience standards should take into account at least the following elements: Critical/essential employees: identifying the critical functions and employees that support important business services, as well as ensuring employees' safety and that they can safely resume their duties (remotely, if necessary); IT infrastructure: ensuring that IT infrastructure can support a sharp increase in usage over an extended period and taking steps to safeguard information security; Third-party service providers: ensuring that external service providers and/or critical suppliers are taking adequate measures and are sufficiently prepared for a scenario in which there will be heavy reliance on their services; Cyber resilience: remaining vigilant in order to identify and protect vulnerable systems, and detect, respond and recover from cyber attacks..

BIS Bulletin No 7, April 2020. Past epidemics had long-lasting effects on economies through illness and the loss of lives, while Covid-19 is marked by widespread containment measures and relatively lower fatalities among young people. The short-term costs of Covid-19 will probably dwarf those of past epidemics, due to the unprecedented and synchronised global sudden stop in economic activity induced by containment measures. The current estimated impact on global GDP growth for 2020 is around -4%, with substantial downside risks if containment policies are prolonged. Output losses are larger for major economies.

This paper studies the relationship between bank geographic complexity and risk. We use a unique dataset of 96 bank holding companies around the world to measure the geographic dispersion of their affiliates. We study how this dispersion interacts with economic and regulatory conditions to affect the riskiness of the bank.

BIS Bulletin No 8, April 2020. Information on local labour markets and Google searches can be used to construct a measure of the vulnerability of employment in different regions of the United States to the Covid-19 shock. Regional exposure to Covid-19 varies significantly, ranging from a low of 2% to a high of 98% of total local employment. We test for the usefulness of the Covid-19 exposure measure by showing that areas with higher exposure report more Google search queries related to the pandemic and unemployment benefits.

This paper reviews post-crisis financial regulatory reforms, examines how they fit together and identifies open issues. Specifically, it takes stock of the salient new features of bank and CCP international standards within a unified analytical framework.

BIS Bulletin No 9, April 2020. By allowing banks to run down some of their buffers, policymakers are sending a strong signal about their resolve to lessen the economic fallout from the pandemic. Such prudential measures complement the main policy levers: monetary and fiscal instruments. To avoid a reduction in credit to the real economy, authorities need to ensure that banks have the capacity and willingness to make use of the flexibility afforded by the buffer release. Payout restrictions on banks and risk-sharing between banks and the public sector will be key. For banks to continue playing a positive role in the supply of funding during the recovery, they should maintain usable buffers for a long period, as losses from a severe recession will take time to materialise.

Recent literature has highlighted that international trade is mostly priced in a few key vehicle currencies, and is increasingly dominated by intermediate goods and global value chains (GVCs). Taking these features into account, this paper reexamines the business cycle dynamics of international trade and its relationship with monetary policy and exchange rates.

Our ongoing celebration of the Library of Congress National Book Festival continues with Poets Laureate Tracy K. Smith and Robert Hass discussing the making of poetry, the position of Poet Laureate and their new books, "American Journal: Fifty Poems for Our Time" (edited by Smith) and "A Little Book on Form: An Exploration into the Formal Imagination of Poetry" (Hass), on the Poetry & Prose stage at the 2018 Festival.

Our ongoing celebration of the Library of Congress National Book Festival continues with presidential scholar Annette Gordon-Reed discussing "The Hemingses of Monticello: An American Family" on the Special Programs stage at the 2015 Festival.

Our ongoing celebration of the Library of Congress National Book Festival continues with crime writer Patricia Cornwell discussing "Red Mist,” her 19th Kay Scarpetta novel, on the Fiction & Mystery stage at the 2012 Festival.

Our ongoing celebration of the Library of Congress National Book Festival continues with young adult and fantasy author Leigh Bardugo discussing "Crooked Kingdom" on the Genre Fiction stage at the 2018 Festival. This post includes prompts for writing and thinking that young readers, families and teachers can use to explore the author and the author’s work—recommended for ages 13+.

Our ongoing celebration of the Library of Congress National Book Festival continues with former Secretary of State Condoleezza Rice discussing "Democracy: Stories from the Long Road to Freedom" on the Main Stage at the 2017 Festival.

Our ongoing celebration of the Library of Congress National Book Festival continues with two-time Pulitzer Prize-winning novelist Colson Whitehead discussing "Zone One" on the Poetry & Prose stage at the 2012 Festival.

Our ongoing celebration of the Library of Congress National Book Festival continues with historian Michael Beschloss discussing “Presidents of War” on the Main Stage at the 2019 Festival.

Our ongoing celebration of the Library of Congress National Book Festival continues with crime and mystery writer Karin Slaughter discussing "Broken," part of her Will Trent series, on the Fiction & Mystery stage at the 2010 Festival.

Our ongoing celebration of the Library of Congress National Book Festival continues with actor and author Neil Patrick Harris discussing "The Magic Misfits: The Minor Third." The event, part of the new year-long National Book Festival Presents series, took place in the Library’s Coolidge Auditorium. This post includes prompts for writing and thinking that young readers, families and teachers can use to explore the author and the author’s work—recommended for ages 8+.

Even celebrity chef Julia Child said that the sleek appliance made mixing 'marvelous'

Rural educator Frank Cyr had the vision and pull to force the nation to standardize the color of the ubiquitous vehicle

Open for visitors, these houses model upcycling at its finest

A prototype deployed in San Francisco Bay imagines the underside of a floating building as an upside-down artificial reef