Design of a 3D printed smartphone microscopic system with enhanced imaging ability for biomedical applications

Portable, low-cost smartphone platform microscopic systems have emerged as a potential tool for imaging of various micron and submicron scale particles in recent years (Ozcan; Pirnstill and Coté; Breslauer et al.; Zhu et al.). In most of the reported works, it involves either the use of sophisticated optical set-ups along with a high-end computational tool for postprocessing of the captured images, or it requires a high-end configured smartphone to obtain enhanced imaging of the sample. Present work reports the working of a low-cost, field-portable 520× optical microscope using a smartphone. The proposed smartphone microscopic system has been designed by attaching a 3D printed compact optical set-up to the rear camera of a regular smartphone. By using cloud-based services, an image processing algorithm has been developed which can be accessed anytime through a mobile broadband network. Using this facility, the quality of the captured images can be further enhanced, thus obviating the need for dedicated computational tools for postprocessing of the images. With the designed microscopic system, an optical resolution ∼2 µm has been obtained. Upon postprocessing, the resolution of the captured images can be improved further. It is envisioned that with properly designed optical set-up in 3D printer and by developing an image processing application in the cloud, it is possible to obtain a low-cost, user-friendly, field-portable optical microscope on a regular smartphone that performs at par with that of a laboratory-grade microscope. LAY DESCRIPTION: With the ever-improving features both in hardware and software part, smartphone becomes ubiquitous in the modern civilised society with approximately 8.1 billion cell phone users across the world, and ∼40% of them can be considered as smartphones. This technology is undoubtedly the leading technology of the 21st century. Very recently, various researchers across the globe have utilised different sensing components embedded in the smartphone to convert it into a field-portable low-cost and user-friendly tool which can be used for different sensing and imaging purposes. By using simple optical components such as lens, pinhole, diffuser etc. and the camera of the smartphone, various groups have converted the phone into a microscopic imaging system. Again, by removing the camera lenses of the phone, holography images of microscopic particles by directly casting its shadows on the CMOS sensor on the phone has been demonstrated. The holographic images have subsequently been processed using the dedicated computational tool, and the original photos of the samples can be obtained. All the reported smartphone-based microscopic systems either suffer from relatively low field-of-view (FOV), resolution or it needs a high computational platform. Present work, demonstrate an alternative approach by which a reasonably good resolution (<2 µm) along with high optical magnification (520×) and a large FOV (150 µm) has been obtained on a regular smartphone. For postprocessing of the captured images an image processing algorithm has been developed in the cloud and the same can be accessed by the smartphone application, obviating the need of dedicated computational tool and a high-end configured smartphone for the proposed microscope. For the development of the proposed microscopic system, a simple optical set-up has been fabricated in a 3D printer. The set-up houses all the required optical components and the sample specimen with the 3D-printed XY stage, and it can be attached easily to the rear camera of the smartphone. Using the proposed microscopic system, enhanced imaging of USAF target and red blood cells have been successfully demonstrated. With the readily available optical components and a regular smartphone, the net cost involvement is significantly low (less than $250, including the smartphone). We envisioned that the designed system could be utilised for point-of-care diagnosis in resource-poor settings where access to the laboratory facilities is very limited.

Buccal Mucosal Graft Urethroplasty in Patients Awaiting Renal Transplantation

OBJECTIVE

To assess the perioperative morbidity and early outcome of buccal mucosal graft (BMG) urethroplasty in patients with urethral stricture awaiting renal transplantation.

METHODS

Thirteen patients awaiting renal transplantation underwent BMG urethroplasty for long anterior urethral stricture between June 2011 and March 2013. The management issues, complications, and outcome of the BMG urethroplasty in this cohort of patients were studied.

RESULTS

Mean age of the patient was 38.7 ± 12.7 years. History of urethral manipulation was present in 8 patients. Mean stricture length was 6.92 ± 2.90 cm. Mean serum creatinine of the patient was 8.1 ± 3.6 mg%. Three patients required oral exploration for bleeding. Two patients had urinary extravasation, 3 patients had infected hematoma, and 1 patient developed dry gangrene of the glans. One patient had sepsis due to pyonephrosis in the postoperative period and succumbed to it. Mean follow-up of the patients was 34.54 ± 6.46 months. Three patients underwent VIU for recurrence of the stricture in the follow-up. At 3-month follow-up mean Qmax was 23.8 mL/sec, whereas at 6-month and 1-year follow-up, Qmax was 23.6 and 23.4 mL/sec, respectively.

CONCLUSION

This study shows a relatively higher complication rate of urethroplasty in prerenal transplant patients. Although the number of cases is too small to arrive at any definite conclusion, this study does gives an insight into the management issues, complications, and success of urethroplasty in this group of patients.

Finite element analysis of dental implant as orthodontic anchorage

AIM

The purpose of this three-dimensional (3D) finite element study was to investigate orthodontic loading simulation on a single endosseous implant and its surrounding osseous structure, to analyze the resultant stresses and to identify the changes in the bone adjacent to the implant following orthodontic loading.

MATERIALS AND METHODS

Two models were constructed using finite element method consisting of endosseous dental implant and the surrounding bone. In the first model, the contact between the implant and the bone was simulated showing no osseointegration, while the second model showed 100% osseointegration. Simulated horizontal loads of 20 N, at 90° from the long axis, were applied to the top of the implant. The study simulated loads in a horizontal direction, similar to a distalmesial orthodontic movement.

RESULTS

In the first model, the stress was mainly concentrated at the neck of the implant and at the closest surrounding bone. In the second model, the stress was chiefly concentrated at the neck of the implant at the level of the cortical superficial bone. The stresses decreased in the cancellous bone area. On the implant, the highest stress concentration was at the first cervical thread decreasing uniformly to the apex. The stress distribution on the mesial and distal sides showed that the maximum compressive stress was localized mesially and the maximum tensile stress distally. If both models are compared, it can be observed that the stresses were less and more evenly distributed in model 1 (initial stability) than in model 2 when osseointegration was assumed.

CONCLUSION

A lack of bony support for the implant represents an unfavorable situation from biomechanical point of view that should be considered and solved. As clinical problems mostly occur at the marginal bone region (bacterial plaque accumulation, overcontoured abutments, infections, osseous defects), attention should be focused on this region.

CLINICAL SIGNIFICANCE

When osseointegrated implants are primarily used as anchorage for orthodontic purposes and then as fixed prosthesis, the functional and structural union of titanium to bone should be preserved.

Apical force distribution due to orthodontic forces: a finite element study

AIM

This finite element study was conducted to calculate the distribution of stresses in the periodontal ligament when various orthodontic forces were applied, with emphasis on the effect on root apex.

MATERIALS AND METHODS

An in vitro finite element method was used to construct a three-dimensional finite element model of a maxillary central incisor, its periodontal ligament and alveolar bone was constructed on the basis of average anatomic morphology. To this model, five types of orthodontic forces namely tipping, bodily movement, intrusion, extrusion and rotations were applied at various points on the crown of the tooth model. After the application of the forces, initial stress and initial displacements of the periodontal ligament were evaluated. The principal stress obtained on the periodontal ligament due to various orthodontic loadings on the maxillary central incisor was analyzed using ANSYS 10 finite element software.

RESULTS

It showed that the greatest amount of relative stress at the apex of maxillary central incisor occurred with intrusion, extrusion and rotation. Bodily movement and tipping forces produce stress concentrated at the alveolar crest and not at the root apex.

CONCLUSION

Clinical implications of this study suggest that if the clinician is concerned about placing heavy stresses on the root apex, then vertical and rotational forces must be applied with caution.

CLINICAL SIGNIFICANCE

If heavy stresses are to be placed on the root apex, then vertical and rotational forces must be applied with caution during orthodontic therapy.

Culturable microbes in shallow groundwater underlying ornithogenic soil of Cape Hallett, Antarctica

The objective of this study was to investigate the culturable psychrotolerant microbial community in groundwater from Seabee Hook, Antarctica. Shallow groundwater can be present in coastal regions at higher latitudes during the Antarctic summer. Perched groundwater atop ice-cemented permafrost occurs on Seabee Hook, Cape Hallett, at depths from 5 to 80 cm below the soil surface. Compared with terrestrial water from other sites in Antarctica, the groundwater was high in salt and nutrients, reflecting proximity to the sea and ornithogenic soil. Microbial communities in groundwater samples from Seabee Hook exhibited aerobic metabolism of 14C-acetate at 5 degrees C. Numbers of culturable aerobic heterotrophs in the samples ranged from <10 to ca. 1 x 106 colony-forming units.mL-1, and similar numbers of microaerophiles and nitrate reducers were detected. In contrast, numbers of nitrifiers, sulfate reducers, and iron reducers were up to 1000-fold lower. All cultures were incubated at 5 degrees C. Aerobic heterotrophic bacteria isolated from the groundwater were assigned to Actinobacteria, Proteobacteria, or Bacteroidetes. The isolates were most similar to cultured bacteria from Antarctic soil or sediment and were cold, salt, and alkaline pH tolerant, indicating they are adapted to in situ conditions.

Late diagnosis of cryptorchidism: a failure of medical screening?

A retrospective review of hospital and available community records of 47 children undergoing orchidopexy in a district hospital was undertaken to determine adequacy of screening for cryptorchidism and factors associated with late referral. Twenty eight of these boys were previously examined on 108 occasions. Diagnosis was missed on 32 occasions and the record of 38 clinical examinations did not include position of testes. In the case of 16 boys (four under school age and 12 of school age) appropriate action was not taken once the diagnosis was made. Diagnosis was reliably made in school aged children but in children under the age of 1 year cryptorchidism was frequently missed by the examining doctor. It is suggested that criteria for diagnosis and referral should be agreed in any surveillance programme. Junior doctors in hospital responsible for routine clinical examination of children during admission and clinical medical officers or general practitioners during routine clinical examination of boys should be clearly instructed to examine and record the position of the testes.