DreamBooth3D: Subject-Driven Text-to-3D Generation

We present DreamBooth3D, an approach to personalize text-to-3D generative models from as few as 3-6 casually captured images of a subject. Our approach combines recent advances in personalizing text-to-image models (DreamBooth) with text-to-3D generation (DreamFusion). We find that naively combining these methods fails to yield satisfactory subject-specific 3D assets due to personalized text-to-image models overfitting to the input viewpoints of the subject. We overcome this through a 3-stage optimization strategy where we jointly leverage the 3D consistency of neural radiance fields together with the personalization capability of text-to-image models. Our method can produce high-quality, subject-specific 3D assets with text-driven modifications such as novel poses, colors and attributes that are not seen in any of the input images of the subject.Comment: Project page at https://dreambooth3d.github.io/ Video Summary at https://youtu.be/kKVDrbfvOo

Management of donor-specific antibodies in lung transplantation

The formation of antibodies against donor human leukocyte antigens poses a challenging problem both for donor selection as well as postoperative graft function in lung transplantation. These donor-specific antibodies limit the pool of potential donor organs and are associated with episodes of antibody-mediated rejection, chronic lung allograft dysfunction, and increased mortality. Optimal management strategies for clearance of DSAs are poorly defined and vary greatly by institution; most of the data supporting any particular strategy is limited to small-scale retrospective cohort studies. A typical approach to antibody depletion may involve the use of high-dose steroids, plasma exchange, intravenous immunoglobulin, and possibly other immunomodulators or small-molecule therapies. This review seeks to define the current understanding of the significance of DSAs in lung transplantation and outline the literature supporting strategies for their management

Raising awareness on solid waste management through formal education for sustainability: a developing countries evidence review

Solid Waste Management (SWM) is a multifaceted problem comprising political, socioeconomic, institutional, and environmental aspects. Due to exponential urban growth, it has become one of the most significant issues faced by urban spaces in developing countries. The gap in environmental knowledge among the youth and the old within developing countries contribute to ecological issues or waste management problems, resulting in unsustainable development, with important consequences in low-income countries. For that matter, a systematic review was conducted aiming to identify and analyse environmental knowledge, awareness, attitudes, and practice studies on SWM from 2010 to 2019 in developing countries. The evidence suggests that students at both secondary and tertiary levels have positive environmental attitudes, and high awareness of environmental issues, but there is a lack of practical education of teachers to guide students to put SWM into practice. Student’s low environmental knowledge is related to a deficiency in teachers’ practical experience in SWM for environmental sustainability. A relationship between teachers’ and students’ knowledge and attitudes towards SWM, as well as differences in awareness, attitude, and practices of SWM linked with education and age, were also found. This review also revealed that the lack of environmental education in most developing countries is caused by fragilities in practical environmental curricula of teachers to respond to modern-day environmental issues for sustainable development and cleaner production (CP). To bridge the knowledge gap between the youth and older people in SWM, environmental sustainability education should be integrated into schools at all levels within developing countries.info:eu-repo/semantics/publishedVersio

Differentiable volume rendering using signed distance functions

This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 55-58).Gradient-based methods are often used in a computer graphics and computer vision context to solve inverse rendering problems. These methods can be used to infer camera parameters, material properties, and even object pose and geometry from 2D images. One of the challenges that faces differentiable rendering systems is handling visibility terms in the rendering equation, which are not continuous on object boundaries. We present a renderer that solves this problem by introducing a form of visibility that is not discontinuous, and thus can be differentiated. This "soft visibility" is inspired by volumetric rendering, and is facilitated by our decision to represent geometry within the scene as a signed distance function. We also present methods for performing gradient descent upon distance fields while preserving Lipschitz continuity. Unlike most differentiable mesh-based renderers, our renderer can optimize between geometry of different homeomorphism classes in a variety of image-based shape fitting tasks.by Srinivas Kaza.M. Eng.M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Scienc

Techniques for Improved Speed and Accuracy in Layered Manufacturing

The ability to improve the construction accuracy and/or the build speed for layered manufacturing techniques is demonstrated using a series of new techniques: (1) Parts can be decomposed into sections which are constructed in parallel and then assembled. This reduced the build time and material waste for a sheet foam process. (2) A more accurate interface based on direct slicing ofthe CAD model can be used to eliminate the need for the intermediary tessellation file. (3) The layer thickness can be adapted based on the part's geometric complexity to increase the surface quality, build speed, and z-axis accuracy.Mechanical Engineerin

Robotic versus laparoscopic surgery for colonic disease: a meta-analysis of postoperative variables

An increasing number of studies have been published since the introduction of robotic technology into general surgery. Gastrointestinal surgery is an area of special interest for the robotic surgeon. Colonic surgery can be challenging depending on the disease and the operative approach. We seek to perform a meta-analysis comparing robotic surgery against laparoscopic surgery in this particular field.We performed a systematic search of MEDLINE database from January 2001 to July 2013 supplemented by manual searches of bibliographies of key relevant articles. Randomized controlled trials and cohort studies were selected for review and for collection of postoperative data (length of stay, time to first flatus and complications).After careful review, nine studies were considered for analysis. Non-pooled data showed a slight trend toward laparoscopy with increased number of events without statistical significance. Pooled data demonstrated a statistical significance for return to bowel function in the right and mixed robotic colectomy arm (WSMD −0.33, 95 % CI −0.5, −0.1; p < 0.005 and WSMD −0.26, 95 % CI −0.51, 0.0; p = 0.05). Pooled data of length of stay and complications showed no statistical significance between robotic and laparoscopic colonic surgery.Robotic surgery is a comparable option when dealing with colonic disease, either benign or malignant. No difference in complication rate or length of stay was found when comparing the two. Robotic surgery appears to have an advantage over laparoscopy in regards to return of bowel function when dealing with right colectomies

Impact of body mass index on progression of primary immunoglobulin a nephropathy

The role of obesity in the progression of primary glomerular diseases is controversial. A few studies report overweight/obesity as a risk factor for disease progression in immunoglobulin A nephropathy (IgAN), and the real impact of it still remains unclear. The aim of this study was to elucidate the effect of body mass index (BMI) on disease progression and proteinuria in patients with IgAN in Indian population. A cohort of biopsy-proven primary IgAN patients diagnosed between March 2010 and February 2015 who had a follow-up for a minimum of 12 months were included in the study. We defined two groups of patients according to the BMI value at diagnosis: non-obese group (Group N) with BMI 23 Kg/m2 as per Asia-Pacific task force criteria. Baseline characteristics were compared between the groups. The estimated glomerular filtration rate (eGFR) and urine protein-creatinine ratio (UPCR) were followed up at entry time, 6 months, 12 months, and at the end of follow-up. Outcomes studied were change in eGFR, proteinuria, and progression to end-stage renal disease. Statistical analysis was done using the Statistical Package for the Social Sciences version 15.0. Of 51 patients, 25 (49%) had BMI 23 kg/m2 (Group O) (P = 0.01). The baseline clinical, histopathological, and treatment characteristics of both the groups were comparable. The BMI at the time of diagnosis did not have any significant effect on eGFR (P = 0.41) or proteinuria (P = 0.99) at presentation. At the end of follow-up, both the groups had a similar reduction of proteinuria (UPCR) (P = 0.46) and eGFR (P = 0.20). Two patients in each group have reached chronic kidney disease Stage 5. In the present study, BMI at presentation did not have any impact on eGFR or proteinuria, either at diagnosis or at follow-up. It needs further large multicenter randomized control studies to see the effect of BMI on progression of IgAN

Role of corticosteroid therapy in IgA nephropathy; where do we stand?

Background: Current KDIGO guidelines suggest corticosteroids (CS) administration in IgA nephropathy (IgAN) with persistent proteinuria >1 g/d despite 3-6 months of supportive care and estimated glomerular filtration rate (eGFR) >50 mL/min/1.73 m2 . The benefits of CS in patients with eGFR 50 mL/min/1.73 m2 . Patients and Methods: A cohort of biopsy proven primary IgAN diagnosed between March 2010 - February 2015 who received oral CS with minimum follow-up of 6 months were included. They were categorized into two groups according to their eGFR (group 1 - eGFR 50 mL/min/1.73 m2 ). The eGFR and urine protein creatinine ratio (UPCR) were followed up at entry, 6 months, 12 months and at the end of follow-up. Outcomes studied were change in eGFR, proteinuria and progression to end-stage renal disease (ESRD). Results: Out of 44 patients, 23 were in group1 and 21 patients in group 2. At the end of follow-up, similar reduction of proteinuria (UPCR) was observed in both groups (P=0.62). However, group 1 had a significant fall in eGFR compared to improvement in group 2 (P=0.004). One in each group has reached CKD stage 5 (P=0.73). Conclusions: Addition of CS to conservative treatment in IgAN patients with initial eGFR50 mL/min/1.73 m2 )