cssi/SciSciGPT-SciSciNet huggingface dataset:
Mixed-dimensional van der Waals heterostructures

The isolation of a growing number of two-dimensional (2D) materials has inspired worldwide efforts to integrate distinct 2D materials into van der Waals (vdW) heterostructures. Given that any passivated, dangling-bond-free surface will interact with another through vdW forces, the vdW heterostructure concept can be extended to include the integration of 2D materials with non-2D materials that adhere primarily through non-covalent interactions. We present a succinct and critical survey of emerging mixed-dimensional (2D + nD, where n is 0, 1 or 3) heterostructure devices. By comparing and contrasting with all-2D vdW heterostructures as well as with competing conventional technologies, we highlight the challenges and opportunities for mixed-dimensional vdW heterostructures.
Virtual microfluidics for digital quantification and single-cell sequencing

We have developed hydrogel-based virtual microfluidics as a simple and robust alternative to complex engineered microfluidic systems for the compartmentalization of nucleic acid amplification reactions. We applied in-gel digital multiple displacement amplification (dMDA) to purified DNA templates, cultured bacterial cells and human microbiome samples in the virtual microfluidics system, and demonstrated whole-genome sequencing of single-cell MDA products with excellent coverage uniformity and markedly reduced chimerism compared with products of liquid MDA reactions.
Estimating the Malaria Attributable Fever Fraction Accounting for Parasites Being Killed by Fever and Measurement Error

Malaria is a major health problem in many tropical regions. Fever is a characteristic symptom of malaria. The fraction of fevers that are attributable to malaria, the malaria attributable fever fra...
Cyclin CYB-3 controls both S-phase and mitosis and is asymmetrically distributed in the early C. elegans embryo

In early C. elegans embryos the timing of cell division is both invariant and developmentally regulated, yet how the cell cycle is controlled in the embryo and how cell cycle timing impacts early development remain important, unanswered questions. Here, I focus on the cyclin B3 ortholog CYB-3, and show that this cyclin has the unusual property of controlling both the timely progression through S-phase and mitotic entry, suggesting that CYB-3 is both an S-phase-promoting and mitosis-promoting factor. Furthermore, I find that CYB-3 is asymmetrically distributed in the two-cell embryo, such that the somatic precursor AB cell contains ∼2.5-fold more CYB-3 than its sister cell, the germline progenitor P1 CYB-3 is not only physically limited in P1 but also functionally limited, and this asymmetry is controlled by the par polarity network. These findings highlight the importance of the CYB-3 B3-type cyclin in cell cycle regulation in the early embryo and suggest that CYB-3 asymmetry helps establish the well-documented cell cycle asynchrony that occurs during cell division within the P-lineage.
Relationship Between Body Fat and Physical Fitness in Army ROTC Cadets.

ABSTRACTThe Army Physical Fitness Test (APFT), including timed push-ups, sit-ups, and run, assesses physical performance for the Army. Percent body fat is estimated using height and circumference measurements. The objectives of the study were to (a) compare the accuracy of height and circumference measurements to other, more accepted, body fat assessment methods and (b) determine the relationships between body composition and APFT results. Participants included Reserve Officer Training Corps (ROTC) cadets (n = 11 males, 2 females, 21.6 ± 3.5 years) from a midwestern university). At one visit, percent body fat was assessed using height and circumference measurements, air-displacement plethysmography, and bioelectrical impedance analysis. APFT results were provided by the ROTC director. All assessment methods for percent body fat were strongly associated (r ≥ 0.7, p < 0.01), implying that height and circumference measurement is a practical tool to estimate percent body fat of ROTC cadets. Total APFT score w...
Characterization of spin-orbit fields in InGaAs quantum wells

Coherent electron spin dynamics in 10-nm-wide InGaAs/InAlAs quantum wells is studied from 10 K to room temperature using time-resolved Kerr rotation. The spin lifetime exceeds 1 ns at 10 K and decreases with temperature. By varying the spatial overlap between pump and probe pulses, a diffusive velocity is imprinted on the measured electron spins and a spin precession in the spin-orbit field is measured. A Rashba symmetry of the spin-orbit interaction is determined. By comparing the spatial precession frequency gradient with the spin decay rate, an upper limit for the Rashba coefficients α of 2 × 10−12 eVm is estimated.
Elastic deformation during dynamic force measurements in viscous fluids

Abstract Understanding and harnessing the coupling between lubrication pressure and elasticity provides materials design strategies for applications such as adhesives, coatings, microsensors, and biomaterials. Elastic deformation of compliant solids caused by viscous forces can also occur during dynamic force measurements in instruments such as the surface forces apparatus (SFA) or the atomic force microscope (AFM). We briefly review hydrodynamic interactions in the presence of soft, deformable interfaces in the lubrication limit. More specifically, we consider the scenario of two surfaces approaching each other in a viscous fluid where one or both surfaces is deformable, which is also relevant to many force measurement systems. In this article the basic theoretical background of the elastohydrodynamic problem is detailed, followed by a discussion of experimental validation and considerations, especially for the role of elastic deformation on surface forces measurements. Finally, current challenges to our understanding of soft hydrodynamic interactions, such as the consideration of substrate layering, poroelasticity, viscoelasticity, surface heterogeneity, as well as their implications are discussed.
On Face Numbers of Flag Simplicial Complexes

Denham and Suciu (Pure Appl Math Q 3(1):25–60, 2007) and Panov and Ray (in: Harada, et al. (eds) Toric topology. Contemporary Mathematics, American Mathematical Society, Providence, 2008) computed the ranks of homotopy groups and the Poincare series of a moment-angle-complex $$\mathcal Z(\mathcal K$$ )/Davis–Januszkiewicz space $$DJ(\mathcal K)$$ associated to a flag simplicial complex $$\mathcal K.$$ In this note we revisit these results and interpret them as polynomial bounds on the face numbers of an arbitrary simplicial flag complex.
Analog circuit for sound localization applications

We describe an analog CMOS circuit that computes the time (phase) delay between two 10 kHz sinusoids. This circuit can be used in sound localization applications. We realize a locking range of 10-170 degrees in less than 1 ms that is robust over process variations. Two receivers placed at a distance from one another intercept a sinusoidal waveform emanating from a sound source. The phase difference between the two signals is detected by the circuit, which gives an estimation of the distance of the source from the receivers. This solution is simpler and more elegant than current digital techniques that require specialized DSP hardware to be implemented in real time.
Quasi-Cyclic LDPC Codes Based on Pre-Lifted Protographs

Quasi-cyclic low-density parity-check (QC-LDPC) codes based on protographs are of great interest to code designers because analysis and implementation are facilitated by the protograph structure and the use of circulant permutation matrices for protograph lifting. However, these restrictions impose undesirable fixed upper limits on important code parameters, such as minimum distance and girth. In this paper, we consider an approach to constructing QC-LDPC codes that uses a two-step lifting procedure based on a protograph, and, by following this method instead of the usual one-step procedure, we obtain improved minimum distance and girth properties. We also present two new design rules for constructing good QC-LDPC codes using this two-step lifting procedure, and in each case, we obtain a significant increase in minimum distance and achieve a certain guaranteed girth compared with one-step circulant-based liftings. The expected performance improvement is verified by simulation results.
Limited feedback in MISO systems with finite-bit ADCs

We analyze limited feedback in systems where a multiple-antenna transmitter sends signals to single-antenna receivers with finite-bit ADCs. If channel state information (CSI) is not available with high resolution at the transmitter and the precoding is not well designed, the inter-user interference is a big decoding challenge for receivers with low-resolution quantization. In this paper, we derive achievable rates with finite-bit ADCs and finite-bit CSI feedback. The performance loss compared to the case with perfect CSI is then analyzed. The results show that the number of bits per feedback should increase linearly with the ADC resolution to restrict the loss.
The Resolution of Distressed Financial Conglomerates

One of the most elegant legal innovations to emerge from the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 is the FDIC’s single-point-of-entry (SPOE) initiative, whereby regulatory authorities will be in a position to resolve the failure of large financial conglomerates (corporate groups with regulated financial entities as subsidiaries) by seizing a top-tier holding company, downstreaming holding-company resources to distressed subsidiaries, wiping out holding-company shareholders while simultaneously imposing additional losses on holding-company creditors, and allowing the government to resolve the entire group without disrupting the business operations of operating subsidiaries (even those operating overseas) or risking systemic consequences for the broader economy. Although there is much to admire in the creativity underlying SPOE, the approach’s design also raises a host of novel and challenging questions of implementation. This chapter explores a number of these questions and elaborates upon the following points. First, in contrast to traditional approaches to resolving financial conglomerates, SPOE is premised on the continued support of all material operating subsidiaries, thereby potentially extending the scope of government support and thus posing the possibility of mission creep and expanded moral hazard. Second, SPOE contemplates the automatic downstreaming of resources to operating subsidiaries in distress, but effecting that support is likely to be more difficult than commonly understood. If too much support is positioned in advance, there may be inadequate reserves at the top level to support a single subsidiary that gets into an unexpectedly large amount of trouble. Alternatively, if too many reserves are retained at the holding-company level, commitments of subsidiary support may not be credible (especially to foreign authorities) and it may become difficult legally and practically to deploy those resources in times of distress. SPOE is most easy to envision operating in conjunction with the FDIC’s expanded authority under its Orderly Liquidation Authority (OLA) established under Title II of the Dodd-Frank Act. However, the act’s preferred regime for resolving failed financial conglomerates is the U.S. Bankruptcy Code (where Lehman was resolved) and not OLA. Several complexities could arise were a bankruptcy court today called upon to implement an SPOE resolution plan. While many legal experts are working on legislative proposals to amend the Bankruptcy Code to facilitate SPOE resolutions, there are a number of legal levers that federal authorities could deploy under current law to increase the likelihood that the SPOE strategy could be effected through traditional bankruptcy procedures. The task would be challenging and would require considerable advanced planning. But there are substantial benefits to be had from taking steps now to increase the likelihood that the bankruptcy option represents a viable and credible alternative for effecting SPOE transactions without resort to OLA and Title II of the Dodd-Frank Act.
Entanglement dynamics in critical random quantum Ising chain with perturbations

We simulate the entanglement dynamics in a critical random quantum Ising chain with generic perturbations using the time-evolving block decimation algorithm. Starting from a product state, we observe super-logarithmic growth of entanglement entropy with time. The numerical result is consistent with the analytical prediction of Vosk and Altman using a real-space renormalization group technique.
Moving on Towards a Workable Climate Regime

The Paris Agreement (PA) signed by 175 parties is now a Treaty since a quorum of signatories has been obtained. This Treaty is really the first important step taken to limit temperature increase, as pledges, if sustained and far more ambitious beyond 2030, would drastically limit the projected temperature increase from projections in the absence of measures to limit emissions of greenhouse gases. Contributions however fall short of the intentions to limit temperature increase to the +1.5 to +2 °C range since the onset of industrialization. Drawing on recent contributions, this paper reviews where we stand in tackling four challenges ahead: (i) taking fuller cognizance of the accumulating scientific evidence calling for urgent action; (ii) designing an architecture that will render effective the blend of ‘bottom-up’ and ‘top-down’ approaches; (iii) choosing policy options and tackling the slow transition to a low-carbon economy, and; (iv) raising finance and addressing burden sharing.
Diffusion of DNA-Binding Species in the Nucleus: A Transient Anomalous Subdiffusion Model.

Abstract Single-particle tracking experiments have measured escape times of DNA-binding species diffusing in living cells: CRISPR-Cas9, TetR, and LacI. The observed distribution is a truncated power law. Working backward from the experimental results, the observed distribution appears inconsistent with a Gaussian distribution of binding energies. Working forward, the observed distribution leads to transient anomalous subdiffusion, in which diffusion is anomalous at short times and normal at long times, here only mildly anomalous. Monte Carlo simulations are used to characterize the time-dependent diffusion coefficient D(t) in terms of the anomalous exponent α, the crossover time tcross, and the limits D(0) and D(∞) and to relate these quantities to the escape time distribution. The simplest interpretations identify the escape time as the actual binding time to DNA or the period of one-dimensional diffusion on DNA in the standard model combining one-dimensional and three-dimensional search, but a more complicated interpretation may be required. The model has several implications for cell biophysics. 1) The initial anomalous regime represents the search of the DNA-binding species for its target DNA sequence. 2) Non-target DNA sites have a significant effect on search kinetics. False positives in bioinformatic searches of the genome are potentially rate-determining in vivo. For simple binding, the search would be speeded if false-positive sequences were eliminated from the genome. 3) Both binding and obstruction affect diffusion. Obstruction ought to be measured directly, using as the primary probe the DNA-binding species with the binding site inactivated and eGFP as a calibration standard among laboratories and cell types. 4) Overexpression of the DNA-binding species reduces anomalous subdiffusion because the deepest binding sites are occupied and unavailable. 5) The model provides a coarse-grained phenomenological description of diffusion of a DNA-binding species, useful in larger-scale modeling of kinetics, FCS, and FRAP.
Dense Associative Memory is Robust to Adversarial Inputs

Deep neural networks (DNNs) trained in a supervised way suffer from two known problems. First, the minima of the objective function used in learning correspond to data points (also known as rubbish...
Physics of electronic transport in two-dimensional materials for future FETs

We discuss some basic physical properties of electron transport in two-dimensional materials. First, we discuss how the predicted thermodynamic instability of 2D crystals may influence charge transport via the coupling of electrons with acoustic flexural modes. We then review the properties of suspended and supported graphene and its ribbons and consider the problem of evaluating correctly the electron-phonon coupling in the case of phosphorene. Finally, we discuss the main features of 2D topological insulators and their possible use in transistors.
ATM and FIS data link services

The Federal Aviation Administration (FAA) currently has under development data link services for Air Traffic Management (ATM), Flight Information Service (FIS), and communications, navigation, and surveillance (CNS). These services will be provided over the Aeronautical Telecommunications Network (ATN), a worldwide data network intended to provide data communications connectivity among mobile aircraft, airlines, and civil aviation authorities. The ATM and FIS services currently under development are part of an evolutionary process that will begin, for the most part, with duplication of voice services. In the future, services will facilitate a common source of data for pilots, controllers, and flight planners, as well as computer-to-computer communications between ground based and airborne automation systems. These future services will provide benefits such as the use of optimum aircraft tracks and flight profiles. >
Learning from Inventory Availability Information: Evidence from Field Experiments on Amazon

Many online retailers provide real-time inventory availability information. Customers can learn from the inventory level and update their beliefs about the product. Thus, consumer purchasing behavior may be impacted by the availability information. Based on a unique setting from Amazon lightning deals, which displays the percentage of inventory consumed in real time, we explore whether and how consumers learn from inventory availability information. Identifying the effect of learning on consumer decisions has been a notoriously difficult empirical question because of endogeneity concerns. We address this issue by running two randomized field experiments on Amazon in which we create exogenous shocks on the inventory availability information for a random subset of Amazon lightning deals. In addition, we track the dynamic purchasing behavior and inventory information for 23,665 lightning deals offered by Amazon and use their panel structure to further explore the relative effect of learning. We find evidence...
Generating the Möbius group with involution conjugacy classes

A {\it $k$-involution} is an involution with a fixed point set of codimension $k$. The conjugacy class of such an involution, denoted $S_k$, generates $\text{M\"ob}(n)$-the the group of isometries of hyperbolic $n$-space-if $k$ is odd, and its orientation preserving subgroup if $k$ is even. In this paper, we supply effective lower and upper bounds for the $S_k$ word length of $\text{M\"ob}(n)$ if $k$ is odd, and the $S_k$ word length of $\text{M\"ob}^+(n)$, if $k$ is even. As a consequence, for a fixed codimension $k$ the length of $\text{M\"ob}^{+}(n)$ with respect to $S_k$, $k$ even, grows linearly with $n$ with the same statement holding in the odd case. Moreover, the percentage of involution conjugacy classes for which $\text{M\"ob}^{+}(n)$ has length two approaches zero, as $n$ approaches infinity.
Bubbles for Fama

Abstract We evaluate Eugene F. Fama's claim that stock prices do not exhibit price bubbles. Based on US industry returns (1926‒2014) and international sector returns (1985‒2014), we present four findings (1) Fama is correct in that a sharp price increase of an industry portfolio does not, on average, predict unusually low returns going forward; (2) such sharp price increases predict a substantially heightened probability of a crash but not of a further price boom; (3) attributes of the price run-up, including volatility, turnover, issuance, and the price path of the run-up, help forecast an eventual crash; and (4) these attributes also help forecast future returns. Results hold similarly in US and international samples.
Group Scissor: Scaling Neuromorphic Computing Design to Large Neural Networks

Synapse crossbar is an elementary structure in neuromorphic computing systems (NCS). However, the limited size of crossbars and heavy routing congestion impede the NCS implementation of large neural networks. In this paper, we propose a two-step framework (namely, group scissor) to scale NCS designs to large neural networks. The first step rank clipping integrates low-rank approximation into the training to reduce total crossbar area. The second step is group connection deletion, which structurally prunes connections to reduce routing congestion between crossbars. Tested on convolutional neural networks of LeNet on MNIST database and ConvNet on CIFAR-10 database, our experiments show significant reduction of crossbar and routing area in NCS designs. Without accuracy loss, rank clipping reduces the total crossbar area to 13.62% or 51.81% in the NCS design of LeNet or ConvNet, respectively. The following group connection deletion further decreases the routing area of LeNet or ConvNet to 8.1% or 52.06%, respectively.
The kinetic Sunyaev Zel’dovich effect from reionization

Abstract During the epoch of reionization, local variations in the ionized fraction (patchiness) imprint arcminute-scale temperature anisotropies in the cosmic microwave background through the kinetic Sunyaev–Zel’dovich (kSZ) effect. We employ an analytic model of reionization devised by Furlanetto and coworkers to calculate the kSZ anisotropies for patchy reionization. We find that the angular power spectrum of the kSZ anisotropies depends strongly on the size distribution of the HII bubbles and on the duration of reionization. In addition, we show that upcoming measurements of the kSZ effect should be able to distinguish between several popular reionization scenarios. In particular, the amplitude of the patchy power spectrum for reionization scenarios in which the IGM is significantly ionized by Population III stars (or by mini-quasars/decaying particles) can be larger (or smaller) by over a factor of 3 than the amplitude in more traditional reionization histories (with temperature anisotropies that range between 0.5 and 3 μK at l = 5000).
ARE POST-TJR READMISSIONS ASSOCIATED WITH POORER FUNCTIONAL GAIN AFTER TJR?

Introduction CMS is now publicly reporting 30-day readmission rates following total joint replacement (TJR) by hospital and is planning the collection of patient-reported function and pain after TJR. Nationally, 5% of patients are readmitted to the hospital after TJR for both medical and orthopedic-related issues. However, the relationship between readmission and functional gain and pain relief after TJR has not been evaluated. Methods Clinical data on 2990 CMS patients from over 150 surgeons practicing in 22 US states who elected primary unilateral TJR in 2011–2012 were identified. Measures include pre-operative demographics, BMI, medical and musculoskeletal comorbidities, pain and function (KOOS/HOOS; SF36) and 6 month post-TJR pain and function. Data were merged with CMS claims to verify 30-day readmissions. Descriptive statistics and multivariate models adjusted for covariates and clustering within site were performed. Results Overall 4.7% of patients were readmitted; 2.0% due to limb related diagnoses. Readmitted patients had significantly greater number of medical comorbidities; more severe OA in non-operated knees and hips; were more likely to smoke; and have poorer pre-TJR function (all p<0.05). After TJR, a greater proportion of readmitted patients had poor global function (PCS<30= 14% vs. 8%; p<0.008) but knee/hip function was similar in both groups. Joint pain improvement did not differ by readmit status. Conclusion In this national representative cohort of CMS patients, patients readmitted within 30 days after TJR had poorer global function but similar joint specific function as non-readmitted patients. Readmitted patients also had significantly more medical comorbidities, more severe osteoarthritis in non-operated knees and hips; were more likely to smoke; and have poorer pre-TJR function. The overall rate of FORCE-TJR CMS patients readmitted within 30 days (4.7%) is consistent with national CMS analyses (5%). Of interest, in our cohort, readmitted patients had poorer global function after surgery, but similar joint specific (hip/knee) function compared to patients who were not readmitted. They also had poorer pre-THR function, and more severe OA in other joints, which may contribute to their overall lower global function scores. As CMS moves to use PROs in its bundled payment, these data support the importance of hip/knee-specific PRO measures to assess THR outcomes in quality of care programs and CMS reporting programs.
How to establish a successful ex vivo lung perfusion program.

Donor lung shortage is a major limiting factor in lung transplantation. Multiple methods have been used to expand the number of transplanted lungs. Ex vivo lung perfusion (EVLP) is utilized to accept non-standard lungs and to perfuse them in a physiologic setting in order to assess their suitability for transplantation. As EVLP has gained broader utilization in the armamentarium of the lung transplant process, more centers have identified a need to develop an EVLP program. Here we discuss the steps that are useful in establishing a successful EVLP program. We carefully considered various factors which are important in implantation this technology step by step focusing on liaison, logistics, and organization.
Intron DNA Sequences Can Be More Important Than the Proximal Promoter in Determining the Site of Transcript Initiation

To more precisely define the positions from which certain intronic regulatory sequences increase mRNA accumulation, the effect of a UBIQUITIN intron on gene expression was tested from six different positions surrounding the transcription start site (TSS) of a reporter gene fusion in Arabidopsis thaliana The intron increased expression from all transcribed positions but had no effect when upstream of the 5'-most TSS. While this implies that the intron must be transcribed to increase expression, the TSS changed when the intron was located in the 5'-untranslated region (UTR), suggesting that the intron affects transcription initiation. Remarkably, deleting 303 nucleotides of the promoter including all known TSSs and all but 18 nucleotides of the 5'-UTR had virtually no effect on the level of gene expression as long as an intron containing stimulatory sequences was included. Instead, transcription was initiated in normally untranscribed sequences the same distance upstream of the intron as when the promoter was intact. These results suggest that certain intronic DNA sequences play unexpectedly large roles in directing transcription initiation and constitute a previously unrecognized type of downstream regulatory element for genes transcribed by RNA polymerase II.
The Hilbert Space of Quantum Gravity Is Locally Finite-Dimensional

We argue in a model-independent way that the Hilbert space of quantum gravity is locally finite-dimensional. In other words, the density operator describing the state corresponding to a small region of space, when such a notion makes sense, is defined on a finite-dimensional factor of a larger Hilbert space. Because quantum gravity potentially describes superpositions of different geometries, it is crucial that we associate Hilbert-space factors with spatial regions only on individual decohered branches of the universal wave function. We discuss some implications of this claim, including the fact that quantum-field theory cannot be a fundamental description of nature.
An examination of how middle school science teachers conduct collaborative inquiry and reflection about students' conceptual understanding

This qualitative case study examined how middle school science teachers conducted collaborative inquiry and reflection about students’ conceptual understanding, and how individual teachers in the middle school science group acted and made reflections in response to their collaborative inquiry. It also examined external influences that affected the teachers’ ability to engage in collaborative inquiry. Observational, written, and interview data were collected from observations of teachers’ face-to-face meetings and reflections, individual interviews, a focus group interview, and online reflections. The results of this study revealed that collaborative inquiry is a form of professional development that includes answering curricular questions through observation, communication, action, and reflection. This approach was developed and implemented by middle school science teachers. The premise of an inquiry is based on a need with students. Middle school science teachers came to consensus about actions to affect students’ conceptual understanding, took action as stated, and shared their reflections of the actions taken with consideration to current and upcoming school activities. Activities involved teachers brainstorming and sharing with one another, talking about how the variables were merged into their curriculum, and how they impacted students’ conceptual understanding. Teachers valued talking with one another about science content and pedagogy, but did find the inquiry portion of the approach to require more development. The greatest challenge to conducting collaborative inquiry and reflection was embedding teacher inquiry within a prescribed inquiry that was already being conducted by the Sundown School District. Collaborative inquiry should be structured so that it meets the needs of teachers in order to attend to the needs of students. A conducive atmosphere for collaborative inquiry and reflection is one in which administrators make the process mandatory and facilitate the process by removing an existing inquiry.
Bladder cancer in the elderly

Abstract Introduction Age is now widely accepted as the greatest single risk factor for developing bladder cancer, and bladder cancer is considered as primarily a disease of the elderly. Because of the close link between age and incidence of bladder cancer, it can be expected that this disease will become an enormous challenge with the growth of an aging population in the years ahead. Methods Using MEDLINE, a search of the literature between January 1966 and July 2007 was performed to describe normative physiologic changes associated with aging, elucidate genetic and epigenetic alterations that associate aging with bladder cancer and its phenotypes; and to characterize how aging influences efficacies, risks, side effects, and potential complications of the treatments needed for the various stages of bladder cancer. Results We discuss influence of aging on host physiology, genetic and epigenetic changes, environmental influences, and host factors in the development and treatment of bladder cancer. Treatments with intravesical bacille Calmette Guerin, radical cystectomy, and perioperative chemotherapy are less well tolerated and have poorer response in elderly patients compared with their younger counterparts. Elderly patients face both clinical and broader institutional barriers to appropriate treatment and may receive less aggressive treatment and sub-therapeutic dosing. However, when appropriately selected, elderly patients tolerate and respond well to cancer treatments. Conclusions The decision to undergo treatment for cancer is a tradeoff between loss of function and/or independence and extension of life, which is complicated by a host of concomitant issues such as comorbid medical conditions, functional declines and “frailty”, family dynamics, and social and psychologic issues. Chronological age should not preclude definitive surgical therapy. It is imperative that healthcare practitioners and researchers from disparate disciplines collectively focus efforts towards gaining a better understanding of what the consequences of bladder cancer and its treatments are for older adults and how to appropriately meet the multifaceted medical and psychosocial needs of this growing population.
Efficient modification of λ-DNA substrates for single-molecule studies.

Single-molecule studies of protein-nucleic acid interactions frequently require site-specific modification of long DNA substrates. The bacteriophage λ is a convenient source of high quality long (48.5 kb) DNA. However, introducing specific sequences, tertiary structures, and chemical modifications into λ-DNA remains technically challenging. Most current approaches rely on multi-step ligations with low yields and incomplete products. Here, we describe a molecular toolkit for rapid preparation of modified λ-DNA. A set of PCR cassettes facilitates the introduction of recombinant DNA sequences into the λ-phage genome with 90–100% yield. Extrahelical structures and chemical modifications can be inserted at user-defined sites via an improved nicking enzyme-based strategy. As a proof-of-principle, we explore the interactions of S. cerevisiae Proliferating Cell Nuclear Antigen (yPCNA) with modified DNA sequences and structures incorporated within λ-DNA. Our results demonstrate that S. cerevisiae Replication Factor C (yRFC) can load yPCNA onto 5′-ssDNA flaps, (CAG)13 triplet repeats, and homoduplex DNA. However, yPCNA remains trapped on the (CAG)13 structure, confirming a proposed mechanism for triplet repeat expansion. We anticipate that this molecular toolbox will be broadly useful for other studies that require site-specific modification of long DNA substrates.
A grid-based approximation algorithm for the minimum weight triangulation problem

Given a set of n points on a plane, in the Minimum Weight Triangulation problem, we wish to find a triangulation that minimizes the sum of Euclidean length of its edges. This incredibly challenging problem has been studied for more than four decades and has been only recently shown to be NP-Hard. In this paper we present a novel polynomial-time algorithm that computes an expected 14-approximation of the minimum weight triangulation---a constant that is significantly smaller than what has been previously known. For every integer q ≥ 1, we also show that our triangulation is simultaneously a 14-approximation of a triangulation that minimizes the q-norm of its edge costs, i.e., the sum of qth powers of all its edges. In our algorithm, we use grids to partition the edges into levels where shorter edges appear at smaller levels and edges with similar lengths appear at the same level. We then triangulate the point set incrementally by introducing edges in increasing order of their levels. We introduce the edges of any level i + 1 in two steps. In the first step, we partition the boundary of any non-triangulated face into reflex chains and add edges between successive chains using a variant of the well-known ring heuristic to generate a partial triangulation [Equation]. In the second step, we greedily add non-intersecting level i + 1 edges to [Equation] in increasing order of their length and obtain a partial triangulation Ai+1. The ring heuristic is known to yield only an O(log n)-approximation even for a convex polygon and the greedy heuristic achieves only a [Equation]-approximation. Therefore, it is surprising that their combination leads to an improved approximation ratio of 14. For the proof, we identify several useful properties of [Equation] and combine it with a new Euler characteristic based technique to show that [Equation] has more edges than [Equation] here [Equation] is the partial triangulation consisting of level ≤ i edges of some minimum weight triangulation. We then use a simple greedy stays ahead proof strategy to bound the approximation ratio.
Keynote lecture 3: content-adaptive efficient resource allocation for packet-based video transmission

Supporting video communication over lossy channels such as wireless networks and the Internet is a challenging task due to the stringent quality of service (QoS) required by video applications and the many channel impairments. Two important QoS characteristics for video are the degree of signal distortion and the transmission delay. Another important consideration is the cost associated with transmission, for example, the energy consumption in the wireless channel case and the cost for differentiated services in the Internet (with DiffServ) case. In this presentation we consider the joint adaptation of the source coding parameters, such as the quantization step-size and prediction mode, along with the physical layer resources, such as the transmission rate and power. Our goal is to provide acceptable QoS while taking into account system constraints such as the energy utilization. We discuss a general framework that allows a number of "resource/distortion" optimal formulations for balancing the requirements of different applications. We conclude the presentation with some of the grand opportunities and challenges in designing and developing video communication systems.
Pay for Performance and Beyond

Incentives are often associated with narrow financial rewards such as bonuses or executive stock options. But in general such rewards are just a small part of the design of incentives. Properly designed incentive systems have to take into account the full portfolio of activities that the agent can engage in, the array of instruments, many nonfinancial, that are available to influence individuals and consider the factors that motivate them in different settings. Thinking about incentives as a system of interacting instruments and influences has been a major advance in the economics of incentives in recent years. In this lecture I will describe the path from pay for performance to the broader view of incentive systems.
Review of ‘The Dilemma of the Multicystic Dysplastic Kidney’

The patient reports and review of the literature presented by Hartman et al 1 clearly document that multicystic kidneys are not always persistent asymptomatic masses. Clearly, they can be associated with significant morbidity. The natural history of retained multicystic kidney is, as the authors state, unclear, since most palpable multicystic lesions have been removed in the past. However, available data indicate to me that untoward events associated with retaining such dysplastic renal units are quite rare, and, therefore, a blanket recommendation for routine removal of all such lesions seems extreme. At our hospital in recent years, prenatal ultrasound examinations have identified multicystic kidneys that are not palpable at birth. In addition, our experience and that of others (E. Tank, MD, telephone conversation, Jan 15, 1986) suggest that some lesions that are palpable at birth shrink to minimal proportions when followed up for several months sonographically. Thus,
Importance of Cytotoxic Lymphocytes During Cytomegalovirus Infection in Renal Transplant Recipients

Abstract Thirty renal transplant recipients were studied prospectively to evaluate the relationship of cytomegalovirus-specific cytotoxic lymphocyte responses to clinical outcome during cytomegalovirus infection. Cytomegalovirus infection developed in 20 patients; of these 20, 14 had cytomegalovirus-specific cytotoxic lymphocyte responses whereas six did not. Clinical findings (fever, leukopenia, thrombocytopenia, or elevations in serum transaminase levels) were significantly more frequent among patients without responses than among patients with responses (p
Acute Renal Infarction: Diagnosis by Doppler Ultrasound

A young infant undergoing balloon angioplasty for pulmonic stenosis developed global right renal infarction as a complication of cardiac catheterization via the femoral vein. A second patient developed segmental infarction of a recently transplanted kidney due to occlusion of a polar artery. Although routine renal sonography of these patients was normal, duplex Doppler sonography documented the absence of renal arterial and venous flow.
Female Pseudohermaphroditism with Anorectal, Müllerian Duct, and Urinary Tract Malformations: Report of Four Cases

1. Feigin RD, Cherry JD: Textbook of pediatric infectious diseases. Philadelphia: WB Saunders, 1981;561. 2. Ward JR, Atcheson SG: Infectious arthritis. Med Clin North Am 1977;61:313. 3. Small CB, Slater LN, Lowy F, et al: Group B streptococcal arthritis in adults. Am J Med 1984;76:367. 4. Rizza CR: Management of patients with inherited blood coagulation defects. In: Bloom A, Thomas D, eds: Haemostasis and thrombosis. Edinburgh: Churchill Livingston, 1981;374. 5. Goldsmith JC, Silberstein PT, Fromm, RE, Walker DY: Hemophilic arthropathy complicated by polyarticular septic arthritis. Acta Haematot 1983;71:121. 6. Fauci AS, Dale DC, Balon JE: Glucocorticoid therapy: mechanisms of action and clinical considerations. Ann Intern Med 1976;84:304. 7. Miller EH, Flessa HC, Glueck HI: The management of deep soft tissue bleeding and hemarthrosis in hemophilia. Clin Orthop 1972;82:92. 8. Houghton GR: Septic arthritis of the hip in a hemophiliac. Clin Orthop 1977;129:233. 9. Mosely PE, Gold RM, Rodriguez-Erdmann F: Hemophilia, maintenance dialysis and septic arthritis. Arch Intern Med 1981;141:138. 10. Rosner SM, Bhogal RS: Infectious arthritis in a hemophiliac. J Rheumatol 1981;8:519. 11. Wilkins RM, Wiedel JD: Septic arthritis of the knee in a hemophiliac. J Bone Joint Surg 1983;65-A:267. 12. Hofman A, Wyatt R, Bybee B: Septic arthritis of the knee in a 12 year old hemophiliac. J Pediatr Orthop 1984;4:498.
Use of Bowel in Undiversion

Urinary undiversion is becoming an uncommon procedure because fewer patients are being diverted. The lessons learned from undiversion, however, have made possible early primary reconstructions in patients who would previously have been candidates for diversion. Intermittent clean catheterization and the use of bowel to augment or form a compliant storage vessel for urine have permitted reconstruction in patients with abnormal bladder and urethral function. Thus patients with neurogenic bladder or with severe lower urinary tract abnormalities can look forward to healthy kidneys and urinary continence without the use of appliances. Certainly there are yet many lessons to be learned, but the potential is just starting to be appreciated.
Stage I Nonseminomatous Germ Cell Testicular Tumor: Prediction of Metastatic Potential by Primary Histopathology

A study of 60 patients with clinical stage I nonseminomatous germ cell testicular tumor (NSGCT) was conducted to identify prognostic factors that may predict the likelihood of metastasis. Clinical features and histopathologic features of the primary testicular tumor were examined and analyzed for correlations with the presence of retroperitoneal nodal metastasis documented by surgery (N+) and with development of relapse (R+). Pathologic tumor stage greater than or equal to 2, with tumor extension into the tunica albuginea, rete testis, epididymis, or spermatic cord, was correlated with an increased rate of N+ compared with pathologic tumor stage I (P = .001). Vascular invasion was correlated with a higher rate of N+ (P = .05) and had a similar association with R+ (P = .08). Tumors containing less than 50% teratoma were found to have a higher rate of N+ than tumors with greater than or equal to 50% teratoma (P = .02). Based on the identified prognostic factors, a model for predicting the probability of retroperitoneal nodal metastasis in clinical stage I patients is proposed. The risk factors for nodal metastasis are: pathologic tumor stage greater than or equal to 2, vascular invasion, and less than 50% teratoma. Patients with none of the risk factors are considered at low risk and may be offered orchiectomy alone with surveillance for initial treatment. Patients with all three risk factors are at high risk and should be treated with a retroperitoneal lymph node dissection (RPLND) or possibly chemotherapy. Patients with one or two risk factors are at intermediate risk; it is recommended that they undergo RPLND. This risk model facilitates a rational approach to the management of clinical stage I NSGCT.
Transepithelial Movement of 3H-Androgen in Seminiferous and Epididymal Tubules: A Study Using In Vivo Micropuncture and In Vivo Microperifusion

In vivo micropuncture and a new system of in vivo microperifusion were used to examine the movement of 3H-androgen from blood to lumen and from interstitum to lumen in the rat testis and epididymis. Movement of 3H-androgen into the seminiferous tubule lumen was restricted, with intraluminal isotope concentrations plateauing at approximately 15% of extratubular isotope concentrations whether the 3H-androgen originated in the vascular or interstitial compartments. In the caput epididymidis, intraluminal 3H-androgen plateaued at approximately 35% of serum concentrations, but when 3H-androgens were presented directed to the basal aspect of the caput epididymidal epithelium, ‘H-androgen was transported into the lumen against a concentration gradient. Intraluminal isotope concentrations were >200% of those in the epididymal interstitial compartment. Similar results were found for the cauda epididymids. Factors controlling the proluminal movement of 3H-androgens in the rat testis and epididymis were therefore fundamentally different.
Prorenin as a Reproductive Hormone. New Form of the Renin System

Prorenin, the biosynthetic precursor of renin, is synthesized by the kidneys. Herein is reviewed recent evidence that the ovaries also secrete prorenin. It was found that prorenin is present in mature human ovarian follicular fluid in extremely high concentrations and that plasma prorenin levels increase transiently in blood during the menstrual cycle at the time of ovulation. No change in plasma active renin levels occurs at this time. Plasma prorenin level also increases 10-fold in pregnant women very soon after conception. The ovaries are apparently the source of this rise, since plasma prorenin levels did not increase in a pregnant woman with ovarian failure who received a donor egg. All of these changes in plasma prorenin levels appear to be caused by gonadotropic hormones. These results suggest a role for ovarian prorenin in human reproductive function. They may have relevance to studies of female infertility, birth control, and toxemia of pregnancy. They also suggest that a renin system exists that is regulated by changes in prorenin.
Imaging of the Kock Continent Ileal Urinary Reservoir

The Kock continent ileal urinary reservoir (Kock pouch) is a new urinary bypass system that can overcome some of the principal complications associated with other forms of urinary diversion. It is important to understand the anatomy and radiology of this new technique since radiologists play an important role in evaluating the function of the Kock pouch as well as assessing its complications. The authors review the clinical and radiographic findings in 193 patients who had undergone Kock pouch urinary diversion. Patients are evaluated radiographically in the immediate postoperative period and at regular postoperative intervals for as long as 3 years. Routine evaluation consists of Kock pouch cystography followed by intravenous urography. When indicated, computed tomography, ultrasound, and interventional radiologic procedures are used. The normal anatomy as well as the radiographic appearance of the Kock pouch is presented. In addition, the radiographic appearance of pouch complications and their frequenc...