A theoretical framework to three-dimensional ultrasound reconstruction from irregularly sampled data

Several techniques have been described in the literature in recent years for the reconstruction of a regular volume out of a series of ultrasound (US) slices with arbitrary orientations, typically scanned by means of US freehand systems. However, a systematic approach to such a problem is still missing. This paper focuses on proposing a theoretical framework for the 3-D US volume reconstruction problem. We introduce a statistical method for the construction and trimming of the sampling grid where the reconstruction will be carried out. The results using in vivo US data demonstrate that the computed reconstruction grid that encloses the region-of-interest (ROI) is smaller than those obtained from other reconstruction methods in those cases where the scanning trajectory deviates from a pure straight line. In addition, an adaptive Gaussian interpolation technique is studied and compared with well-known interpolation methods that have been applied to the reconstruction problem in the past. We find that the proposed method numerically outperforms former proposals in several control studies; subjective visual results also support this conclusion and highlight some potential deficiencies of methods previously proposed.     

A three-dimensional metal–organic framework for a guest-free ultra-low dielectric material

A three-dimensional metal–organic framework compound [NH₂(CH₃)₂]₂[Zn₃(bpdc)₄]·3DMF (1) shows two step dielectric relaxation and its guest-free framework (1′) possesses an ultra-low κ value of 1.80 (at 100 kHz, it is the lowest value for MOFs reported to date) over a wide temperature range and high thermal stability.

A MOFs compound [NH₂(CH₃)₂]₂[Zn₃(bpdc)₄]·3DMF (1) shows two step dielectric relaxation and its guest-free framework (1′) possesses an ultra-low κ value of 1.80 (at 100 kHz) over a wide temperature range and high thermal stability.

The design and synthesis of low dielectric constant (low-κ) materials has been a subject of interest in terms of their potential for use in high performance electronic devices. Materials with extremely low-dielectric constants have been targeted as interlayer dielectrics (ILD) because they decrease the cross-talk noise, propagation delay, and power dissipation in most electronic components. ^1–5 Indeed, the search for new low-κ materials replacing silicon dioxide (SiO₂) as an ILD has always been dictated by industrial needs, resulting in a strong connection between fundamental research and technology.⁶ Many materials have been proposed and studied as potential candidates; two major classes are dense organic polymers and porous inorganic-based materials. Some dense organic polymers could have κ below 2.2, but they suffer from concerns of low thermal stability and thermal conductivity. For porous inorganic-based low-κ materials, sol–gel silica, doped oxides and mesoporous silica have been extensively studied.⁷ but its low mechanical strength, wide pore size distribution, and hydrophilicity have been cited as concerns.As air or vacuums have the lowest dielectric constant (κ = 1.01), the partial replacement of solid network with air or a vacuum appears to be the more intuitive and direct option to the development of new low-κ ILD materials. Thus, as per the International Technology Roadmap for Semiconductors (ITRS), robust porous materials and air gap structures will become target low-κ materials in the near future.⁸ Metal–organic frameworks (MOFs) with a well-defined monodisperse porosity, large surface area, ultra-low densities, high stability and easy tunability of the surface and structural properties have potential for meet the demands for use as stable low-κ materials.⁹ MOFs have been extensively studied over the past decade for their applications in gas storage, sensors, chemical separation, catalysis, drug delivery and biomedical imaging.^10–12 However, their electrical properties and applications in microelectronics remain under researched.¹³ MOFs should be stiffer and harder than other low-density amorphous inorganic or organic polymers because of their ordered framework and rigid organic linkers. With tunable structural properties, high porosity, and thermal/mechanical stability, MOFs represent an ideal replacement as an ILD material. Hermann and coworkers presented a brief theoretical model for using MOFs as low-κ materials in microelectronics applications.¹⁴ However, these theoretical calculations did not take into account the orientational and ionic contributions to the molecular polarizability, which drastically contribute to the dielectric constant. These theoretical results encouraged us to search for new MOFs materials with experimentally ultra-low κ values.In this work, we report on the preparation of a MOFs, [NH₂(CH₃)₂]₂[Zn₃(bpdc)₄]·3DMF (1) (H₂bpdc = 4,4′-biphenyldicarboxylic acid), which have 3D frameworks with high thermal stability (Fig. S1^†) and a ultra-low κ values of its guest-free sample 1′. The 1′ possesses a very low κ values of 1.80 (at 100 kHz) and high thermal stability at temperatures up to 360 °C (Fig. S2^†), making it a potential candidate for use as an ILD. To the best of our knowledge, to date, the κ values of 1′ is the lowest value for MOFs reported. Furthermore, compound 1 shows dielectric relaxation and anomalies in the temperature range of 35–140 °C. Dielectric relaxation and anomalies of 1 is related to reorientation of the dipole moment of surface absorbed water and guest DMF molecules, respectively.The compound 1 was obtained from the solvothermal reaction of Zn(NO₃)₂·6H₂O, H₂bpdc and [NH₂(CH₃)₂]Cl in DMF. X-ray crystallographic analysis reveals that it crystallizes in the space group Pna2₁.^§ The asymmetric unit contains of three crystallographically distinct Zn²⁺ ions, four deprotonated bpdc²⁻ ligands, two [NH₂(CH₃)₂]⁺ ions and three free DMF molecules. Three crystallographically independent Zn²⁺ ions have two coordination modes (Fig. 1a). The Zn(1) and Zn(3) adopts a four-coordinated and formed slightly distorted tetrahedral geometry, and the Zn(2) adopts a six-coordinated geometry. O13 and O16 atoms originated from monodentate coordination of the bpdc²⁻ ligands and the other oxygen atoms are coordinated by μ2-modes bpdc²⁻ ligands to Zn²⁺ ions. The shortest and longest Zn–O distance is 1.881(10) and 2.088(9) Å, respectively. Each Zn(2) atom is connected Zn(1) atom and Zn(3) atom by three bridged bidentate bpdc²⁻ ligands to form trinuclear building blocks. As shown in Fig. 1b, trinuclear building blocks are further linked together by bpdc²⁻ ligands make up the 3D anionic framework with two different channels, and the channels is occupied by [NH₂(CH₃)₂]⁺ ions and disordered DMF guest molecules. Parallel to the ac plane, the monodentate bpdc²⁻ ligands bridge trinuclear building blocks to afford layers stacking, and the layers are pillared by bidentate bpdc²⁻ ligands to give rise to a regular 3D network (Fig. 1c), and channel dimensions is about 13 × 18 Å along the b-axis direction. The triangle cage was formed along the c-axis direction with small channel (Fig. 1d). Overall, two individual triangle cage are independent interpenetrated to form the entire framework of 1 (Fig. 1e). It should be noted that although the framework of 1 is interpenetration networks, it is still highly porous. After the removal of solvent molecules in the channels, the accessible volume of 1 is 40.2%.Open in a separate windowFig. 1Structure of 1 (a) trinuclear metal cluster building blocks; (b) 3D anionic framework with two different channels; (c) regular channel along the b-axis direction; (d) the triangle cage along the c-axis direction; (e) two independent interpenetrated triangle cage.The temperature dependent dielectric properties were investigated in the temperature rang of 30–135 °C, and two-step dielectric relaxation were observed. As show in Fig. 2a, it is clear that compound 1 shows the first step dielectric relaxation in the temperature range of 30–80 °C. When 1 was heated from 30 to 37 °C, the dielectric constant progressive increased and reaches a maximum of 174.4 at 10³ Hz. Further increase in temperature results in the dielectric constant of 1 slowly decreasing and dielectric peak disappears. The first step dielectric relaxation is due to the relaxation of absorbed water molecules in the sample surface. The dielectric relaxation signal was not observed in the cooling process (from 95 °C to 30 °C) for losing surface water (Fig. 2b). The κ value is directly related to the polarization phenomena. The higher the polarization, the greater the increase in κ value will be. Usually, the MOF materials with low κ value feature the reorientational motions of polar guest molecules being restricted at low temperature or frameworks solvent-free. However, for 1, the thermally assisted dynamical dipole motion due to polar DMF molecules is appeared. The guest molecules get enough excitation thermal energy to be able to obey the change under the external electric field more easily in the high temperature regime, and the reorientational dynamics of guest molecules is activated above 105 °C. This in return enhances their contribution to the polarization leading to an sharp increase of dielectric permittivity value. At f = 10⁵ Hz, the dielectric constant reaches a maximum of 237, and then sharply decreased when the temperature increased. In the following cooling process, a very low κ value was observed and no dielectric relaxation was occurred (Fig. 2c). The second step dielectric relaxation at different frequency are shown in Fig. 2d, which can be ascribed to the guest polar DMF reorientational motions. In addition, the dielectric loss values shows similar features in the selected frequency range (Fig. S3^†).Open in a separate windowFig. 2(a) Temperature-dependent real part dielectric constant (ε′) in the temperature range of 30–95 °C at selected frequency of 1; (b) plots of ε′ vs. T in the 30–95 °C range at 5 × 10³ Hz with the heating (black dot) and cooling models (red dot); (c) plots of ε′ vs. T in the 100–135 °C range at 10⁵ Hz with the heating (black line) and cooling models (red line; (d) temperature-dependent ε′ in the temperature range of 30–135 °C.Removing polar guest molecules from the framework may be decreases the polarization and the possibility of any type of hydrogen bonding or ionic interactions between the framework and guest molecular, hence, the κ value will also decreases. The guest-free sample 1′ were obtained by simply heating method. The PXRD patterns of the 1 match well with the 1′ (Fig. S4^†), thus demonstrating the phase were unaltered. The dielectric properties of guest-free sample 1′ were investigated. As shown in Fig. 3, after removing the polar DMF molecules, a very low κ value of 1.78 at 100 kHz at 40 °C with a low dielectric loss (0.005) was observed (Fig. S5^†). It is very interesting as the temperature increase from 40 to 130 °C, κ value increases very slowly. κ value is 1.99 at 130 °C. With the ac electric field frequency increasing, the κ value slightly decrease (Fig. 3a). It is noteworthy that, to date, dielectric investigations of MOFs have received relatively little attention, although a few exciting examples have been reported. Only a limited number of MOFs have been reported to possess ultra-low κ value.^15,16 The ultra-low κ values for a few MOFs are shown in Table S2.^†17 To the best of our knowledge, the κ values of 1′ is the lowest value for MOFs reported. From the published paper and our results, to obtained the ultra-low κ MOFs, ligands should have high symmetry and small polarity and polar guest molecular should be avoid. Furthermore, some small counter ions could be decrease κ values. As the vacuum has the lowest dielectric constant, thus, κ values can be reduced significantly by increasing porosity of MOFs. High thermal stability and MOFs thin-film growth are required for the practical applications of ultra-low κ MOFs in microelectronics. ZIF-8 films with κ value of 2.4 were deposited on silicon wafers and characterized in order to assess their potential as future insulators (low-κ dielectrics) in microelectronics.¹⁸ We recently reported a hydrogen bonding MOFs [Zn(H₂EIDA)₂(H₂O)]·2DMF, which exhibited low-κ behaviour, but its thermal stability was not perfect.Open in a separate windowFig. 3Temperature-dependent real part dielectric constant (ε′) at selected frequency of 1′.     

Spleen cells from animals tolerant to a thymus-dependent antigen can be activated by lipopolysaccharide to synthesize antibodies against the tolerogen

Immunological tolerance was induced in adult mice by the injection of 5 mg of deaggregated hapten-protein conjugate. The tolerant state was confirmed 4-19 days later by the failure of such animals to mount an immune response against an aggregated form of the same thymus-dependent hapten-protein conjugate as well as by the inability of spleen cells from tolerant animals to respond to a thymus-independent hapten-carrier conjugate. Even though the animals were fully tolerant, their spleen cells were activated by lipopolysaccharide (LPS) in vitro to produce normal numbers of plaque-forming cells against the hapten. The finding that spleen cells from tolerant animals could be activated by LPS into synthesis of antibodies against the tolerogen indicates that tolerance to thymus-dependent antigens does not affect B cells, but presumably only T cells. It is suggested that the only stringent test for the existence of B-cell tolerance is the inability of polyclonal B-cell activators to activate antibody synthesis against the tolerogen. The findings make it unlikely that B-cell tolerance to autologous thymus- dependent antigens exists and further indicate that such antigens cannot deliver activating or tolerogenic signals to B cells, although they are competent to combine with and block the Ig receptors.     

Biomass-derived three-dimensional carbon framework for a flexible fibrous supercapacitor and its application as a wearable smart textile

High electrochemical performance and mechanical reliability are two important properties of the flexible fibrous supercapacitors (FFSCs) used in portable and wearable electronics. Herein, we introduce high-performance and stable FFSCs produced using Tetrapanax papyrifer with a honeycomb-like structure (the key material) acting as a frame for an activated carbon (AC) coating. The honeycomb-like structure facilitates penetration of electrolytes and electron transport in the AC particles. This reduces the contact resistance between the AC and current collector, thereby enhancing the electrochemical energy storage. The FFSCs possess long length and area specific capacitances of 20.8 mF cm⁻¹ and 83.9 mF cm⁻², respectively. In addition, the fabricated FFSCs display a maximum length (area) energy density of 3.98 μW h cm⁻¹ (16.1 μW h cm⁻²) at a power density of 0.07 mW cm⁻¹ (1.99 mW cm⁻²) and attain an excellent capacitance retention of 91% over 10 000 cycles. Moreover, the supercapacitors exhibit excellent mechanical flexibility with minor increase in capacitance upon bending. Three flexible fibrous supercapacitors in series power a red light-emitting diode, demonstrating the potential application of the flexible fibrous supercapacitors in smart textiles.

High electrochemical performance and mechanical reliability are two important properties of the flexible fibrous supercapacitors (FFSCs) used in portable and wearable electronics.     

Developing a framework to evaluate patient hoists

Manual handling of patients should be avoided as far as is reasonably practical. Hoist equipment must be appropriate for the specialty's needs and staff should be trained to use it correctly. Ease of use and patient comfort are important factors to consider when choosing hoists.     

A framework for the transition from nursing records to a nursing information system.

The future of patient record keeping is being developed now. Critical aspects are in place with the development of computer communication standards for health care. The Institute of Medicine's report on the computerized patient record has galvanized many in the health care field to rethink their methods of record keeping. Nurses need to examine the history of the nursing record and look toward the development of a comprehensive nursing information system. Nurses, along with the other disciplines, must examine what they want the system of the future to encompass. A suggested framework for the information system has four major nursing components: (1) data storage component, (2) transaction log, (3) nursing decision support systems, and (4) an engine to link and combine the first three components and to present a consistent easy-to-use interface to the nurse. Done properly, this approach will reduce the amount of time nurses spend charting, add dimension to their notation, and increase the efficiency of data usage for clinical practice. The nursing information system must allow information availability in a manner that accentuates quality practice while releasing the nurse from time-consuming record keeping. These goals are possible to meet, but only if nurses plan for the design now, before it becomes a fait accompli.     

Induction of megakaryocytes to synthesize and store a releasable pool of human factor VIII

Summary.  von Willebrand factor (VWF) is a complex plasma glycoprotein that modulates platelet adhesion at the site of a vascular injury, and it also serves as a carrier protein for factor (F)VIII. As megakaryocytes are the only hematopoietic lineage to naturally synthesize and store VWF within α-granules, this study was performed to determine if expression of a FVIII transgene in megakaryocytes could lead to trafficking and storage of FVIII with VWF in platelet α-granules. Isolex^® selected CD34+ cells from human G-CSF mobilized peripheral blood cells (PBC) and murine bone marrow were transduced with a retrovirus encoding the B-domain deleted form of human FVIII (BDD-FVIII). Cells were then induced with cytokines to form a population of multiple lineages including megakaryocytes. Chromogenic analysis of culture supernatant from FVIII-transduced human cells demonstrated synthesis of functional FVIII. Treatment of cells with agonists of platelet activation (ADP, epinephrine, and thrombin receptor-activating peptide) resulted in the release of VWF antigen and active FVIII into the supernatant from transduced cells. Immunofluorescence analysis of cultured human and murine megakaryocytes revealed a punctate pattern of staining for FVIII that was consistent with staining for VWF. Electron microscopy of transduced megakaryocytes using immunogold-conjugated antibodies colocalized FVIII and VWF within the α-granules. FVIII retained its association with VWF in human platelets isolated from the peripheral blood of NOD/SCID mice at 2–6 weeks post-transplant of transduced human PBC. These results suggest feasibility for the development of a locally inducible secretory pool of FVIII in platelets of patients with hemophilia A.     

A facile method to synthesize CoV2O6 as a high-performance supercapacitor cathode

Transition metal oxides can easily lose electrons and thus possess multiple accessible valences. Especially, if two different transition metals are combined, better capacity and cycling stability are achieved. In this study, a binary transition metal oxide, CoV₂O₆, was synthesized via a facile co-precipitation process for use as a supercapacitor cathode; the as-synthesized CoV₂O₆ exhibited high-capacity (306.6 F g⁻¹, 1 A g⁻¹ and 219.2 F g⁻¹, 20 A g⁻¹) and stable cycling stability, retaining 83.3% of its initial specific capacitance after 20 000 cycles. We believe that this facile synthesis process presents an effective method and a new opportunity for promoting the application of electrode materials based on binary transition metal oxides in supercapacitors.

A facile chemical co-precipitation process to synthesize CoV₂O₆, which exhibits high capacity and cycling stability (83.3% after 20 000 cycles).     

Using a grid framework to aid constructive thinking

A transitional route to the recording of specialist practice for community nurses was undertaken via portfolio development. A grid system was developed to give a concise framework to follow.     

Strategies to synthesize various nanostructures of silver and their applications – a review

Due to their various beneficial application-based properties, such as behavior, structure, and size, the synthesis of silver nanoparticles (Ag-NPs) with different structures has become an interesting yet common task for researchers to produce nanostructures for applications in various fields. This is because silver nanoparticles have interesting and unique properties, such as optical and catalytic, resulting from their different structures and sizes. These properties extend the use of nanostructures in various fields of research, especially in medicine, pharmacy, electronics, etc. Also, variations in their parameters affect the structures and sizes of Ag-NPs. This review provides an overview/brief presentation of various methodologies used to synthesize different application-based silver nanoparticles and lists areas where these nanoparticles are suitable for use according to their specific structures and sizes.

Due to their various beneficial application-based properties, such as behavior, structure, and size, the synthesis of silver nanoparticles (Ag-NPs) with different structures has become an interesting yet common task for researchers to produce nanostructures for applications in various fields.     

Using a clinical postconference to introduce baccalaureate nursing students to a quality framework

Novice nurses are expected to contribute to an organization's quality initiatives and strategic goals. Therefore, it is imperative for nursing students to learn how a quality framework is woven within an organization. A figure was created that introduced baccalaureate nursing students to key quality concepts linking regulations, the organization, the quality department, and quality improvement (QI) methods. One important goal was to provide a visual framework that could facilitate clinical postconference discussions regarding the interrelationship of these concepts. Fifty-three undergraduate nursing students participated in a pilot over three semesters. Student response was heavily influenced based on their levels of training, which allowed for programmatic revisions each semester. Evaluation yielded improved QI knowledge and attitudes among advanced students (those in a senior transition course ready to graduate); it also served as a useful method to begin meeting the Quality and Safety Education for Nurses' QI competency.     

A framework to develop a clinical learning culture in health facilities: ideas from the literature

HENDERSON A., BRIGGS J., SCHOONBEEK S., & PATERSON K. (2011) A framework to develop a clinical learning culture in health facilities: ideas from the literature. International Nursing Review 58 , 196–202 Background: Internationally, there is an increase in demand to educate nurses within the clinical practice environment. Clinical practice settings that encourage teaching and learning during episodes of care delivery can be powerful in educating both the existing nursing workforce and nursing students. Aim: This paper presents a framework, informed by the literature, that identifies the key factors that are needed to encourage the interactions fundamental to learning in clinical practice. Key concepts: Learning occurs when nurses demonstrate good practice, share their knowledge through conversations and discussions, and also provide feedback to learners, such as students and novices. These types of interactions occur when positive leadership practices encourage trust and openness between staff; when the management team provides sessions for staff to learn how to interact with learners, and also when partnerships provide support and guidance around learning in the workplace. Application of concepts: This framework presents how the concepts of leadership, management and partnership interact to create and sustain learning environments. The feedback from proposed measurement tools can provide valuable information about the positive and negative aspects of these concepts in the clinical learning environment. Analysis of the subscales can assist in identifying appropriate recommended strategies outlined in the framework to guide nurses in improving the recognized deficits in the relationship between the concepts. Conclusion: Leadership, management and partnerships are pivotal for the creation and maintenance of positive learning environments. Diagnostic measurement tools can provide specific information about weaknesses across these areas. This knowledge can guide future initiatives.     

Drug delivery in polymeric micelles: from in vitro to in vivo.

A new drug delivery modality was developed based on drug encapsulation in polymeric micelles followed by a controlled release at the tumor site triggered by ultrasound focused on the tumor. Ultrasound not only released drug from micelles but also enhanced the local uptake of both free and encapsulated drug by tumor cells, thus providing effective drug targeting. The significant success of in vitro studies of this new drug delivery technique warranted extending studies to animal experiments. Here the results of the in vitro studies of the above technique are summarized and the first in vivo experiments using colon cancer model in rats are reported. The in vivo results showed that application of low-frequency ultrasound (20 and 70 kHz) significantly reduced the tumor size when compared with non-insonated controls; this result indicated in vivo drug targeting to tumors by ultrasound.