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.

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.

Colloidal gold–antibody conjugates are easy to prepare and are an excellent choice for microscopic applications. Colloidal gold is an aqueous suspension of nanometer-sized particles of gold. Typically, chloroauric acid, HAuCl₄, is reduced with dilute solutions of sodium citrate, as described here. This will cause the gold to form small aggregates that will associate with proteins. Gold particles of specific sizes can be isolated and differentiated microscopically, allowing these particles to be used for multiple-label experiments. Colloidal gold-labeled antibodies are widely used in electron microscopy (EM), and can be used for light microscopy but require additional steps (silver enhancement).

There are many uses for antibodies labeled with metal ions. Most of these methods involve first attaching a metal chelator to the antibody molecule. This is achieved using standard cross-linking chemistry and then adding the desired metal at appropriate concentration and pH. The method described here outlines a basic procedure for creating a lanthanide conjugate. Lanthanide conjugates are used for proximity assays, as MRI contrast agents, or for mass cytometry experiments. Different metals and chelators can be substituted, but the basic procedures are similar.

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.

The liquidity trap is synonymous with ineffective monetary policy. The common wisdom is that, as the short-term interest rate nears its effective lower bound, monetary policy cannot do much to stimulate the economy. However, central banks have resorted to alternative instruments, such as QE, credit easing and forward guidance.

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.

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.

Using a cross-country sample of bank-dependent public fi rms we study the international spillovers of a change in banking regulation on corporate borrowing. For identi cation we examine how US rms' liabilities vis-a-vis banks, non-bank lenders and bond markets evolve after an increase in capital requirements implemented by the European Banking Authority (EBA) in 2011. We find that US firms experience a reduction in credit lines but not in term loans from EU banks.

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.

FSI Briefs No 3, April 2020. In response to the 2007-09 Great Financial Crisis (GFC), accounting standard setters introduced a new methodology to value loans based on expected credit losses (ECL). The previous approach, based on incurred losses, was viewed as procyclical and inconsistent with prudential objectives. In the wake of the Covid-19 pandemic, several prudential authorities and the Basel Committee on Banking Supervision (BCBS), introduced a series of measures to clarify how banks should consider various public and private debt relief programmes in their ECL estimates and in their calculation of regulatory capital. These measures are intended to incentivise banks to continue supporting the real economy, while reducing pressure on banks' ECL provisions, earnings and regulatory capital. Supervisory initiatives that provide capital relief should be augmented by severe constraints on the payment of dividends, bonuses and share buybacks. These joint actions will simultaneously expand banks' lending capacity and enhance their ability to absorb losses. Prudential authorities face difficult trade-offs as they confront the most severe economic crisis in modern times. Encouraging the use of flexibility in applicable accounting standards, while preserving market trust and transparency in the reported financial statements of banks, will be key in fostering both economic and financial stability.

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.

FSI Briefs No 4, April 2020. Currently, insurers are more likely to experience losses from financial market volatility than from higher insurance claims arising from Covid-19. Few insurance supervisors have seen a need to strengthen or adjust prudential requirements to insulate insurers from current financial market uncertainties. So far, authorities have responded mainly by taking measures to provide operational relief to insurers from regulatory and supervisory requirements so that they can continue providing insurance services. These measures will also help insurers to enhance risk monitoring of their Covid-19 financial exposures. Some authorities have set out expectations for insurers to conserve capital through prudent exercise of dividend and variable remuneration policies. The aim is to enhance their resilience against huge uncertainties from potential Covid-19 fallout. Other capital-related measures should relieve supervisory pressures and reduce the tendency of insurers to manage their investments in a procyclical manner. These measures include: extending the supervisory intervention ladder, triggering the countercyclical lever and recalibrating capital requirements. The far-reaching impact of Covid-19 calls for sustained vigilance by both supervisors and insurers. In the post-pandemic phase, the extraordinary measures currently warranted will need to be unwound through a carefully crafted exit strategy that preserves sound risk management practices and protects policyholders' interests.

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.

The Covid-19 shock is placing enormous strains on corporates cash buffers. Corporate financial statements from 2019 suggest that 50% of firms do not have sufficient cash to cover total debt servicing costs over the coming year. Credit lines could provide firms with additional liquidity. On average undrawn credit stood around 120% of debt servicing costs at end 2019. However, access is uneven and banks may be reluctant to renew or extend them in the current environment. Sticky operating expenses result in many firms running operating losses, placing an additional burden on cash buffers. Estimates indicate that following a 10% drop in revenues, operating expenses only fall by 6% on average. Simulations suggest that if revenues fall by 25% in 2020, then closing the entire funding gap with debt would raise firm leverage by around 10 percentage points.

The National Book Festival Presents series was created to provide a book festival experience to lovers of the event on a year-round basis. Because these programs can no longer be held at the Library, we are offering a virtual multipart series, with authors who have written books about widespread diseases and the worldwide response to them.

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+.

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

The graphic designer is receiving a Lifetime Achievement Award from Cooper Hewitt for her recognizable computer icons, typefaces and graphics

A new book explores the evolution of cartography throughout more than a century of commercial air travel

British product designer Lucy Hughes has invented a biodegradable plastic made from fish offcuts

Architects and planners from the Netherlands are advising coastal cities worldwide on how to live with water

From gas stations to public libraries, these celebrity architect-designed buildings are worth a road trip

The Wisconsin-born architect's buildings helped turn the city he once called an 'inglorious mantrap' into the center of the world