Trisomy 21 placentas: histopathological and immunohistochemical findings using proliferating cell nuclear antigen

OBJECTIVE: The cause of growth retardation in trisomy 21 and other autosomal trisomies is not known, but may be the result of defective cell proliferation, slowing of the cell cycle, or placental structural abnormalities. Abnormalities of the fetal cell cycle may be reflected in placental growth and can be detected using proliferating cell nuclear antigen (PCNA). METHODS: Twelve second-trimester and six third-trimester trisomy 21 placentas were examined histopathologically and stained immunohistochemically using antibodies to PCNA. Normal age-matched placentas were used as controls. RESULTS: The second-trimester trisomy 21 placentas all exhibited many large irregular hypovascular villi. The third-trimester trisomy 21 placentas showed two patterns: (i) many large, irregular hypovascular villi, and (ii) relatively normal-appearing villi with only a few abnormal villi and focal hypervascularity. PCNA staining was significantly greater in second-trimester placentas when compared to third-trimester placentas for both trisomy 21 and controls. There was no significant difference in PCNA staining in trisomy 21 placentas when compared to the normal age-matched controls. CONCLUSIONS: PCNA staining indicates no significant differences in proliferation between normal and trisomy 21 placentas. Trisomy 21 placentas show villus abnormalities, including hypovascularity.     

A Bipedal DNA Motor that Travels Back and Forth between Two DNA Origami Tiles

In this work, the successful operation of a dynamic DNA device constructed from two DNA origami building blocks is reported. The device includes a bipedal walker that strides back and forth between the two origami tiles. Two different DNA origami tiles are first prepared separately; they are then joined together in a controlled manner by a set of DNA strands to form a stable track in high yield as confirmed by single‐molecule fluorescence (SMF). Second, a bipedal DNA motor, initially attached to one of the two origami units and operated by sequential interaction with “fuel” and “antifuel” DNA strands, moves from one origami tile to another and then back again. The operational yield, measured by SMF, was similar to that of a motor operating on a similar track embedded in a single origami tile, confirming that the transfer across the junction from one tile to the other does not result in dissociation that is any more than that of steps on a single tile. These results demonstrate that moving parts can reliably travel from one origami unit to another, and it demonstrates the feasibility of dynamic DNA molecular machines that are made of more than a single origami building block. This study is a step toward the development of motors that can stride over micrometer distances.     

Patients with Turner's syndrome may have an inherent endometrial abnormality affecting receptivity in oocyte donation

OBJECTIVE: To evaluate whether endometrial receptivity is compromised in patients with premature ovarian failure (POF) due to Turner's syndrome who undergo oocyte donation. DESIGN: Retrospective analysis. SETTING: In vitro fertilization-ET units, anonymous oocyte donation program. PATIENTS: The study included 53 patients with POF who underwent oocyte donation. These included 7 patients with Turner's syndrome (45,X) who underwent 22 ET cycles, 15 women with Turner variants (mosaics, deletions, or isochromosomes) who underwent 36 ET cycles, and 31 other patients with POF and a normal karyotype who underwent 69 oocyte donation cycles. INTERVENTION: All patients on standby for donation were treated with E2 valerate 6 mg/d until oocytes became available; then P 100 mg/d was added. Oocyte donors were healthy women < 34 years who underwent IVF themselves. MAIN OUTCOME MEASURES: Clinical pregnancy rates (PRs), biochemical pregnancies, early abortions, and delivery rates were evaluated. RESULTS: Turner's syndrome patients had a significantly higher rate of biochemical pregnancies (22.7% versus 4.3%), a lower clinical PR (22.7% versus 33.3%), a significantly higher rate of early abortions (60% versus 8.7%), and a significantly lower rate of deliveries per pregnancy (20.0% versus 73.1%) compared with non-Turner patients. CONCLUSIONS: Patients with a complete or partial deficiency of an X chromosome have reduced PRs and an increase in early implantation failure after oocyte donation. This may indicate an inherent endometrial abnormality, possibly associated with a deficiency of X-linked genes regulating endometrial receptivity.     

Cost of unserved power in Karnataka,India

This paper proposes an empirical analysis concerning the cost of unserved energy (CUE) or value of lost load in agriculture and industrial sectors and provides insights that can provide useful inputs in designing effective policies for the power sector. About 500 manufacturing units and 900 farmers were surveyed in the south Indian state of Karnataka using a two-stage random sampling to provide interval estimates of CUE for the industrial and agricultural consumers. The results from the survey help in providing guidance on consumer perceptions and their willingness to pay different or higher tariffs. The estimated economic loss due to power outage in the agriculture sector varies from 1.9% to 3.6% of total State Domestic Product (SDP), i.e., Rs 950 billion at 1999/2000 prices, while in industry, the economic loss varies between 0.04% and 0.17% of total SDP depending upon the size of industry during the study period in 1999.     

Ca3Mn2O7-layered perovskites: Effects of La- and Y-doping on phase stability,microstructure, and thermoelectric transport

We investigate phase stability, microstructure, and thermoelectric transport of polycrystalline bulk Ca_3−xR_xMn₂O₇ samples prepared by standard solid-state reaction, where R = Y or La and 0 ≤ x ≤ 0.33. Ab-initio calculations predict that Y-doping at Ca-sites should reduce the potential energy barrier for electron transport, as opposed to La-doping. We find that Y-doping prompts transformation from Ca₃Mn₂O₇ to Ca₂MnO₄, whereas La-doping is accompanied by no phase transformation. La-doping significantly hinders grain growth, for example, the average grain size decreases from 4.44 ± 0.24 to 1.20 ± 0.03 μm for x = 0 (undoped) and x = 0.33 upon La-doping, respectively. Electrical conductivity and Seebeck coefficients are measured for the temperature range of 300–1300 K, and analyzed in terms of the small polaron hopping model. We find that Y-doping reduces the activation energy for conduction compared to La-doping, for example, 43 and 63 meV, respectively. This suggests that Y reduces the energy barrier for polaron transport, in accordance with computational predictions. This trend is further supported by calculations of selected electronic, structural, and vibrational properties, highlighting the intriguing correlation between electronic transport governed by small polarons and elastic properties, thereby shedding light on charge transport and thermoelectric properties of such layered perovskites.     

LEARNING OF RESOURCE ALLOCATION STRATEGIES FOR GAME PLAYING

Human chess players exhibit a large variation in the amount of time they allocate for each move. Yet, the problem of devising resource allocation strategies for game playing has not received enough attention. In this paper we present a framework for studying resource allocation strategies. We define allocation strategy and identify three major types of strategies: static, semi-dynamic, and dynamic. We then describe a method for learning semi-dynamic strategies from self-generated examples. We present an algorithm for assigning classes to the examples based on the utility of investing extra resources. The method was implemented in the domain of checkers, and experimental results show that it is able to learn strategies that improve game-playing performance.     

Style control in the quill document editing system

A critical problem in the design of editors for structured documents is that of style control, i.e. mapping the logical elements of the documents to their physical appearance on pages. This paper presents a novel approach to style control, used in the Quill document editing system that has been prototyped at the IBM Almaden Research Center. In our approach, the style control mechanism is an integral part of the editing system and consistent with the overall system architecture, in both its inner structure and its user interface. Properties that specify the formatting process, together with action routines for specifying complex semantics, are the basic style control primitives in the proposed approach.