Self-assembly of lithographically patterned micropolyhedra

Nature utilizes self-assembly to create structures at a range of length scales. In addition, a variety of biological nanostructures such as viruses have polyhedral geometries and are formed using highly parallel assembly processes. In contrast, it is very challenging to assemble synthetic polyhedra with patterned surfaces at sub-millimeter scales using conventional engineering practices. Inspired by natural fabrication, this thesis is focused on understanding how to assemble such patterned micropolyhedra using both modeling and experiments. Specifically, my work is focused on the development of model polyhedral systems using lithography and self-assembly techniques, demonstrating material versatility and uncovering underlying geometric design rules using mathematical tools. I have investigated an algorithmic approach to self-assemble complex polyhedra such as truncated octahedra. Here, new geometric design rules related to compactness of the precursor nets and pathways were uncovered. I also have studied the influence of pathways and degrees of freedom of intermediates in the assembly of polyhedral isomers and these findings have been compared to geometric models of molecular isomers notably cyclohexane. In addition to a fundamental understanding of self-assembly of polyhedra, I have also explored applications of micropolyhedra. Importantly, I studied a molding process to enhance material versatility and fabricate soft-polyhedra composed of gels and polymers of importance in tissue engineering and biomaterials science. I also describe an approach to use polyhedra patterned with circuits and semiconductor chips to create 3D computational devices by aggregation. In summary, the thesis provides new insight and a robust engineering strategy to mass produce patterned micropolyhedra in a cost-effective manner with material versatility and high yield. In addition to demonstrated applications, we anticipate that these micro polyhedra will offer new capabilities in optics, electronics, robotics, materials science and biomedical engineering

Assembly of a 3D Cellular Computer Using Folded E-Blocks

The assembly of integrated circuits in three dimensions (3D) provides a possible solution to address the ever-increasing demands of modern day electronic devices. It has been suggested that by using the third dimension, devices with high density, defect tolerance, short interconnects and small overall form factors could be created. However, apart from pseudo 3D architecture, such as monolithic integration, die, or wafer stacking, the creation of paradigms to integrate electronic low-complexity cellular building blocks in architecture that has tile space in all three dimensions has remained elusive. Here, we present software and hardware foundations for a truly 3D cellular computational devices that could be realized in practice. The computing architecture relies on the scalable, self-configurable and defect-tolerant cell matrix. The hardware is based on a scalable and manufacturable approach for 3D assembly using folded polyhedral electronic blocks (E-blocks). We created monomers, dimers and 2 × 2 × 2 assemblies of polyhedral E-blocks and verified the computational capabilities by implementing simple logic functions. We further show that 63.2% more compact 3D circuits can be obtained with our design automation tools compared to a 2D architecture. Our results provide a proof-of-concept for a scalable and manufacture-ready process for constructing massive-scale 3D computational devices

Catastrophic health expenditure among geriatric population of Lucknow district, India

Background: Health system that is chiefly financed by out of pocket expenditure can have varying impact on patients belonging to different income groups. The main objective of the present study was to assess the health-care utilization pattern and socioeconomic features of elderly who incurred catastrophic health expenditure. Materials and Methods: A community-based cross-sectional study was conducted employing multi-stage sampling technique to collect data from a total of 404 elderly residing in Lucknow district. Data were collected on health care utilization and related health care expenditure with by the means of a questionnaire. Results: Out of 404 elderly, 15.8% incurred catastrophic expenditure. Among all the study participants, 33.1% who sought in-patient care and 13.8% who sought exclusive out-patient care incurred catastrophic health expenditure. Conclusion: Proportion of those facing catastrophic expenditure was high among lower income group. Thus, patients who lie at the bottom of income pyramid need higher protection as compared to those who are at the top

Prevalence of distressed financing among elderly in a North Indian District

Background: In some instances health related out of pocket expenditure can be catastrophic thus compelling individuals to raise money through unusual means. Such a situation becomes unavoidable if, there are either too many illnesses or shortage of money. We carried out this study to assess the proportion of elderly who availed distressed financing while availing health care and whether or not they avoided any health care need due to shortage of money. Methods: This was a community-based cross-sectional study. The present study was conducted on a total of 404 elderly residing in both the urban and rural parts of Lucknow district. Participants were selected from the community using multistage random sampling. Data was collected with the help of a pretested questionnaire, it collected information related to health care utilization, health care financing and health care need deferred due to shortage of money. Results: Overall the children were the most common source for healthcare financing and 16.8 % study participants faced financial hardship while availing health care. Most common reason for seeking distressed financing was for buying medicine (58.8%). Conclusion: Use of distressed financing was not uncommon. Families need to be protected from catastrophic health expenditure through an effective social insurance to prevent financial hardship

Metallurgical processes for the recovery and recycling of lanthanum from various resources—A review

Various processes for the recovery of lanthanum from metallurgical and non-metallurgical resources are reviewed. Lanthanum is present as a major constituent of monazite, fluorocarbonate ores, bauxite and associated residues, tailings and waste liquors of rare earths, aluminium, etc. Phosphate rock, optical glasses and Ni-MH batteries serve as the most recent and high concentration secondary resources of lanthanum. This review discusses the various methods of hydro-/pyro-metallurgical origin, leaching, solvent extraction, precipitation and other pre-treatment options for lanthanum recovery. A separate section on recovery of lanthanum by selective biosorption from various model and actual solutions is also included. The need to develop new extraction systems with high lanthanum selectivity in the areas of leaching and solvent extraction are probable improvement trend for the future