Of abscission and other breakthroughs

Plexiform fibrohistiocytic tumors are rare lesions of proposed myofibroblastic origin occurring primarily in infants and children. There is a characteristic biphasic histology comprised of both fibroblastic and histiocyte-like components. These tumors tend to be locally aggressive with prognosis dependent on completeness of resection. A previous cytogenetic case report of this tumor described a stemline clone with a karyotype of 46,XY,-6,-8, del(4)(q25q31),del(20)(q11.2),+der(8)t(8;?) (p22;?),+mar. We report a different cytogenetic finding in another plexiform fibrohistiocytic tumor which demonstrated a simpler karyotype of 46,XY,t(4;15)(q21;q15). The implications of cytogenetic heterogeneity in fibroblastic tumors is briefly discussed.     

Sliding mode cooperative motion control of dual arm manipulators

This paper presents a method for realizing cooperative control of dual-arm manipulators (RM-10A by Remotec Inc.) handling the same object in the presence of dynamic parameter uncertainties of both robots and object. When multiple robots handle the same object, both the position and the internal forces between the robots and the object should be controlled. In this paper, a sliding mode controller is derived for trajectory tracking of object position and internal forces. To show the effectiveness of the proposed controller, numerical simulations are performed for 12 axis dual-arm manipulators. This work was presented, in part, at the Third International Symposium on Artificial Life and Robotics, Oita, Japan, January 19–21, 1998     

A 2.5-V, 72-Mbit, 2.0-GByte/s packet-based DRAM with a 1.0-Gbps/pininterface

A 2.5-V, 72-Mbit DRAM based on packet protocol has been developed using (1) a rotated hierarchical I/O architecture to reduce power noise and to minimize the chip-size penalty associated with an 8-bit prefetch architecture implemented with 16 internal banks and 144 I/O lines, (2) a delay-locked-loop circuit using a high-speed and small-swing differential clock to achieve the peak bandwidth of 2.0 GByte/s in a single chip with low noise sensitivity, and (3) a flexible column redundancy scheme to efficiently increase redundancy coverage using a shifted I/O line scheme for multibank architecture     

Effects of thermoplastic resin content of anisotropic conductive films on the pressure cooker test reliability of anisotropic conductive film flip-chip assembly

The flip-chip technology using anisotropic conductive films (ACFs) is gaining growing interest due to its technical advantages such as environmentally friendly, simpler, and lower cost processes. Electrical performances and reliability of ACF flip-chip assembly depend on thermomechanical properties of ACF polymer resins. In this paper, the changes in ACF resin morphology due to the phase separation of thermoplastics, and subsequent changes of physical and mechanical properties were investigated as a function of thermoplastic contents of ACF formulation. Furthermore, the pressure cooker test (PCT) reliability of ACF flip-chip assemblies with various thermoplastic contents was also investigated. As thermoplastic contents increased, coefficient of thermal expansion (CTE) of ACFs increased, and elastic modulus (E′) of ACFs decreased. In contrast, water absorption rate decreased as thermoplastic content increased. As a result, PCT reliability of ACF flip-chip assembly was improved adding up to 50 wt.% content of thermoplastic. An erratum to this article is available at .     

Reaction Kinetics‐Mediated Control over Silver Nanogap Shells as Surface‐Enhanced Raman Scattering Nanoprobes for Detection of Alzheimer's Disease Biomarkers

It is very challenging to accurately quantify the amounts of amyloid peptides Aβ40 and Aβ42, which are Alzheimer's disease (AD) biomarkers, in blood owing to their low levels. This has driven the development of sensitive and noninvasive sensing methods for the early diagnosis of AD. Here, an approach for the synthesis of Ag nanogap shells (AgNGSs) is reported as surface‐enhanced Raman scattering (SERS) colloidal nanoprobes for the sensitive, selective, and multiplexed detection of Aβ40 and Aβ42 in blood. Raman label chemicals used for SERS signal generation modulate the reaction rate for AgNGSs production through the formation of an Ag‐thiolate lamella structure, enabling the control of nanogaps at one nanometer resolution. The AgNGSs embedded with the Raman label chemicals emit their unique SERS signals with a huge intensity enhancement of up to 10⁷ and long‐term stability. The AgNGS nanoprobes, conjugated with an antibody specific to Aβ40 or Aβ42, are able to detect these AD biomarkers in a multiplexed manner in human serum based on the AgNGS SERS signals. Detection is possible for amounts as low as 0.25 pg mL^?1. The AgNGS nanoprobe‐based sandwich assay has a detection dynamic range two orders of magnitude wider than that of a conventional enzyme‐linked immunosorbent assay.     

State Observer for DES Under Partial Observation with Time Petri Nets

This paper deals with a state observation approach for Discrete Event Systems with a known behavior. The system behavior is modeled using a Time Petri Net model. The proposed approach exploits temporal constraints to assess the system state and therefore detect and determine faults given partial observability of events. The goal here is to track the system state and to identify the event scenarios which occur on the system. Our approach uses the class graph of the Time Petri Net which models the complete system behavior to develop a state observer which is a base to perform online fault detection and diagnosing.

A qualitative study on the comfort and fit of ladies' dress shoes

The perceived differences between comfortable and uncomfortable shoes and the fit preferences in the different regions of ladies' shoes were explored. Twenty Hong Kong Chinese females participated in the study. Each participant wore and rated the different aspects of their own comfortable and uncomfortable shoes. The Wilcoxon signed rank tests showed significant differences in ten perceived characteristics between the comfortable and uncomfortable shoes. Among the ten were tactile, auditory and olfactory sensations. The ten items reliably (Cronbach alpha>0.9) distinguished between comfortable and uncomfortable shoes. There were no significant differences between comfortable and uncomfortable shoes for aesthetic-related characteristics. Further analysis on the fit ratings showed a significant impact on the fit preferences in the Toe region (p<0.0001), Metatarsophalangeal (MPJ) region (p<0.0001), Arch region (p=0.002) and Ingress/egress opening (p<0.001). Knowing the preferred type of fit can help establish a specification for comfortable shoes and also brings out the criteria that a comfortable shoe does not necessarily have the same perceived fit in every region of a shoe.     

Molecular Biology to Radiation Oncology: A Model for Translational Research? Opportunities in basic and translational research. From a workshop sponsored by the National Cancer Institute, Radiation Research Program, January 26-28, 1997, Bethesda, Maryland

Many exciting discoveries are being made that are providing new insights into how molecules, cells and tissues respond to ionizing radiation. There remains a need, however, to translate these findings into more effective treatments for cancer patients, including those treated with radiation therapy. This complex task will require the collaboration of scientists studying molecular, cellular and tissue responses, and those performing clinical trials of emerging therapies. The Radiation Research Program of the National Cancer Institute sponsored a workshop entitled "Molecular Biology to Radiation Oncology: A Model for Translational Research?" to bring together basic scientists and clinicians to exchange ideas and fundamental concepts and to identify opportunities for future research and collaboration. Four broad topics were addressed: signal transduction and apoptosis, the cell cycle, repair of radiation damage, and the microenvironment. The development, selection and use of appropriate experimental models is crucial to finding and developing new therapies, and opportunities exist in this area as well. This paper and the accompanying paper by Coleman and Harris that provides the viewpoint of radiation oncologists (Radiat. Res. 150, 134-147, 1998) summarize the background concepts and opportunities for translational research identified by the workshop participants.     

Hemodynamic and inotropic effects of milrinone after heart transplantation in the setting of recipient pulmonary hypertension

The complementary fragments of human Hb alpha, alpha1-30, and alpha31-141 are spliced together by V8 protease in the presence of 30% n-propanol to generate the full-length molecule (Hb alpha-semisynthetic reaction). Unlike the other protease-catalyzed protein/peptide splicing reactions of fragment complementing systems, the enzymic condensation of nonassociating segments of Hb alpha is facilitated by the organic cosolvent induced alpha-helical conformation of product acting as the "molecular trap" of the splicing reaction. The segments alpha24-30 and alpha31-40 are the shortest complementary segments that can be spliced by V8 protease. In the present study, the chemistry of the contiguous segment (product) alpha24-40 has been manipulated by engineering the amino acid replacements to the positions alpha27 and alpha31 to delineate the structural basis of the molecular trap. The location of Glu27 and Arg31 residues in the contiguous segment alpha24-40 (as well as in other larger segments) is ideal to generate (i, i + 4) side-chain carboxylate-guanidino interaction in its alpha-helical conformation. The amino acid residue replacement studies have confirmed that the side chains at alpha27 and alpha31 facilitate the semisynthetic reaction. The relative influence of the substitute at these sites on the splicing reaction depends on the chemical nature of the side chain and the location. The gamma-carboxylate guanidino side-chain interaction appears to contribute up to a maximum of 85% of the thermodynamic stability of the molecular trap. The studies also demonstrate that the thermodynamic stability of the molecular trap is determined by two interdependent conformational aspects of the peptide. One is an amino acid-sequence-specific event that facilitates the induction of an alpha-helical conformation to the contiguous segment in the presence of organic cosolvent that imparts some amount of protease resistance to Glu30-Arg31 peptide bond. The second structural aspect is a site-specific event, an i, i + 4 side-chain interaction in the alpha-helical conformation of the peptide which imparts an additional thermodynamic stability to the molecular trap. The results suggest that conformationally driven "molecular traps" of protease-mediated ligation reactions of peptides could be designed into products to facilitate the modular assembly of peptides/proteins.