Stability and photocurrent enhancement of photodetectors by using core/shell structured CsPbBr3/TiO2 quantum dots and 2D materials.

Ultra-stable CsPbBr3 perovskite quantum dots (QDs) were prepared, and the performance of the photodetector fabricated from them was enhanced by 2D material incorporation. This multi-component photodetector appears to have good stability in the ambient utilization environment. All inorganic CsPbBr3 QDs are potential candidates for application in photodetection devices. However, QDs have several issues such as defects on the QD surface, degradation under environmental conditions, and unfavorable carrier mobility limiting the high performance of the photodetectors. This work addresses these issues by fabricating a core/shell structure and introducing 2D materials (MXenes, Ti3C2Tx) into the device. Here, three types of photodetectors with QDs only, QDs with a core/shell structure, and QDs with a core/shell structure and MXenes are fabricated for systematic study. The CsPbBr3/TiO2 photodetector demonstrated a two times photocurrent enhancement compared to bare QDs and had good device stability after TiO2 shell coating. After introducing Ti3C2Tx into CsPbBr3/TiO2, a significant photocurrent enhancement from nanoampere (nA) to microampere (µA) was observed, revealing that MXenes can improve the photoelectric response of perovskite materials significantly. Higher photocurrent can avoid signal interference from environmental noise for better practical feasibility. This study provides a systematic understanding of the photocurrent conversion of perovskite quantum dots that is beneficial in advancing optoelectronic device integration, especially for flexible wearable device applications.

The Hammersmith Score Optimises Patient Selection and Predicts for Overall Survival in Early-Phase Cancer Trial Participants Independent of Tumour Burden.

INTRODUCTION: As tumour response rates are increasingly demonstrated in early-phase cancer trials (EPCT), optimal patient selection and accurate prognostication are paramount. Hammersmith Score (HS), a simple prognostic index derived on routine biochemical measures (albumin <35 g/L, lactate dehydrogenase >450 IU/L, sodium <135 mmol/L), is a validated predictor of response and survival in EPCT participants. HS has not been validated in the cancer immunotherapy era. METHODS: We retrospectively analysed characteristics and outcomes of unselected referrals to our early-phase unit (12/2019-12/2022). Independent predictors for overall survival (OS) were identified from univariable and multivariable models. HS was calculated for 66 eligible trial participants and compared with the Royal Marsden Score (RMS) to predict OS. Multivariable logistic regression and C-index was used to compare predictive ability of prognostic models. RESULTS: Of 212 referrals, 147 patients were screened and 82 patients treated in EPCT. Prognostic stratification by HS identifies significant difference in median OS, and HS was confirmed as a multivariable predictor for OS (HR: HS 1 vs. 0 2.51, 95% CI: 1.01-6.24, p = 0.049; HS 2/3 vs. 0: 10.32, 95% CI: 2.15-49.62, p = 0.004; C-index 0.771) with superior multivariable predictive ability than RMS (HR: RMS 2 vs. 0/1 5.46, 95% CI: 1.12-26.57, p = 0.036; RMS 3 vs. 0/1 6.83, 95% CI: 1.15-40.53, p < 0.001; C-index 0.743). CONCLUSIONS: HS is a validated prognostic index for patients with advanced cancer treated in the context of modern EPCTs, independent of tumour burden. HS is a simple, inexpensive prognostic tool to optimise referral for EPCT.

Surgical management and post-operative functional outcomes of patients with a penile fracture-a single centre experience over 10 years.

BACKGROUND: Penile fractures are uncommon urological emergencies which occur when there has been a breach in the tunica albuginea of the corpora cavernosum that may be unilateral and bilateral and can extend to involve the urethra. AIM: To assess the management and outcomes of penile fractures in a single institution in Ireland. METHODS: A retrospective review of the emergency theatre logbooks was performed between 2011 and 2021 to identify patients who had undergone an exploration for a suspected penile fracture. OUTCOMES: Seventeen patients were initially identified on review of theatre logbooks as having an exploration for a suspected penile fracture. Two patients were excluded from the study due to a lack of clinical notes being available. A further 4 patients on chart review were found to not have a penile fracture at exploration. RESULTS: Eleven patients had a confirmed penile fracture intra-operatively, four of whom had an associated urethral injury. Nine (9/11) patients had preserved normal erections post-operatively documented on follow-up; two, however, reported erectile dysfunction requiring phosphodiesterase inhibitors. CLINICAL IMPLICATIONS: Our study supports urgent surgical exploration for penile fractures to ensure good functional outcomes. STRENGTHS AND LIMITATIONS: This is a retrospective review of theatre logbooks to identify patients with a suspected penile fracture. CONCLUSION: The results of our cohort show a good outcome of erectile function following surgical repair of a penile fracture (9/11; 82%). Four patients (4/11; 36%) had a urethral injury diagnosed intra-operatively, one of whom required a formal urethroplasty.

Cerebrovascular disease in COVID-19: a systematic review and meta-analysis.

Background: The association between COVID-19 and acute cerebrovascular disease (CVD) has not been explored extensively. New data has come to light which may change previous results. Methods: We queried the PubMed electronic database from its inception until February 2022 for studies evaluating the incidence of stroke in COVID-19 patients. Results of the analysis were pooled using a random-effects model and presented as odds ratios (ORs) with 95% confidence intervals (95% CIs). Results: 37 studies consisting of 294,249 patients were included in our analysis. Pooled results show that the incidence of acute CVD events in COVID-19 positive patients is 2.6% (95% CI: 2.0-3.3; P<0.001). Cardioembolic (OR=14.15, 95% CI: 11.01 to 18.19, P<0.00001) and cryptogenic (OR=2.87, 95% CI: 1.91 to 4.32, P<0.00001) etiologies were associated with COVID-19 positivity. Risk factors for CVD events in patients with COVID-19 were atrial fibrillation (OR=2.60, 95% CI: 1.15 to 5.87, P=0.02), coronary artery disease (OR=2.24, 95% CI: 1.38 to 3.61, P=0.0010), diabetes (OR=2.46, 95% CI: 1.36 to 4.44, P=0.003) and hypertension (OR=3.65, 95% CI: 1.69 to 7.90, P=0.005). Conclusion: COVID-19 infection is associated with an increased risk for acute CVD and is associated with cardioembolic and cryptogenic etiologies and the risk factors of atrial fibrillation, coronary artery disease, diabetes and hypertension in COVID-19 positive patients.

The oral microbiome of treated and untreated chronic HCV infection: A preliminary study.

OBJECTIVES: Chronic hepatitis C virus (HCV) infection is a debilitating disease that is lately treated using direct-acting antivirals (DAAs). Changes in the oral microbiome were detected in other liver diseases; however, oral microbiome was never investigated in patients having chronic HCV infection, whether pre- or post-treatment. MATERIALS AND METHODS: This case-control preliminary study enrolled three equal groups: Group (I): untreated HCV patients; group (II): HCV patients who achieved viral clearance after DAA administration; and group (III): healthy controls. For each participant, a buccal swab was harvested and its 16S rRNA was sequenced. RESULTS: The oral microbiome of chronic HCV patients had a significantly distinct bacterial community compared to healthy controls, characterized by high diversity and abundance of certain pathogenic species. These changes resemble that of oral lichen planus patients. After treatment by DAAs, the oral microbiome shifted to a community with partial similarity to both the diseased and the healthy ones. CONCLUSIONS: Chronic HCV is associated with dysbiotic oral microbiome having abundant pathogenic bacteria. With HCV clearance by DAAs, the oral microbiome shifts to approach the healthy composition.

ZnO Nanorods Coated Single-Mode-Multimode-Single-Mode Optical Fiber Sensor for VOC Biomarker Detection.

This work demonstrated a ZnO-coated optical fiber sensor for the detection of a volatile organic compound (VOC) biomarker for diabetes for detecting isopropanol (IPA) markers. A coreless silica fiber (CSF) was connected to a single-mode fiber (SMF) at both ends to achieve a SMF-CSF-SMF structure. CSF is the sensing region where multimode interference (MMI) generates higher light interaction at the interface between the fiber and sensing medium, leading to enhanced sensitivity. Optimization of the CSF length was conducted numerically to attain the highest possible coupling efficiency at the output. Surface functionalization was achieved via hydrothermal growth of ZnO nanorods directly onto the CSF at low temperatures. The optical fiber-based sensor was successfully fabricated and tested with 20%, 40%, 60%, 80%, and 100% of IPA. The sensor response was recorded using an optical spectrometer and analyzed for sensor sensitivity. The fabricated sensor shows the potential to detect isopropanol with the sensitivity of 0.053 nm/%IPA vapor. Further improvement of the sensor sensitivity and selectivity is also proposed for future work.

Estimation of Spleen Volume Using MRI Segmentation: Would One Slice Be Enough?

This study aimed to establish spleen volume in adult Sudanese using manual segmentation and the Cavalieri method with magnetic resonance images (MRI). A total of 345 abdominal MRI scans for adults were retrospectively studied for patients who underwent abdomen MRI between September to October 2016. The data were collected from two scanning centers in Khartoum, Sudan. For each series of sectional images, the spleen was manually segmented, and the volume was calculated using matrix laboratory (MATLAB) code. Furthermore, abdominal circumferences and diameters, in addition to L1 body dimension and spinal canal, were measured.  The mean splenic volume in our study was 187.2 cm3, without a significant change with age (P = 0.269). The average volume in males was 223.5 cm3 while in females it was 170.27 cm3. The average coefficient error (CE) was 0.029. A positive significant correlation was found between the volume and spleen length (beta standardized coefficient = 0.781, P < 0.05). The mean length was 9.18 cm. Additionally, our data showed an insignificant correlation between the volume and the other measurements, except for the abdomen transverse diameter (beta standardized coefficient = 0.267, P < 0.05).  The results of our study coincided with previous studies in the normal range of spleen volume and the strong correlation with length, regardless of the irregular shape of the spleen. In addition, manual segmentation was a reliable method to measure spleen volume objectively. However, our single-slice measurements were insufficient.

Transcriptomic Responses to Coaggregation between Streptococcus gordonii and Streptococcus oralis.

Cell-cell adhesion between oral bacteria plays a key role in the development of polymicrobial communities such as dental plaque. Oral streptococci such as Streptococcus gordonii and Streptococcus oralis are important early colonizers of dental plaque and bind to a wide range of different oral microorganisms, forming multispecies clumps or "coaggregates." S. gordonii actively responds to coaggregation by regulating gene expression. To further understand these responses, we assessed gene regulation in S. gordonii and S. oralis following coaggregation in 25% human saliva. Coaggregates were formed by mixing, and after 30 min, RNA was extracted for dual transcriptome sequencing (RNA-Seq) analysis. In S. oralis, 18 genes (6 upregulated and 12 downregulated) were regulated by coaggregation. Significantly downregulated genes encoded functions such as amino acid and antibiotic biosynthesis, ribosome, and central carbon metabolism. In total, 28 genes were differentially regulated in Streptococcus gordonii (25 upregulated and 3 downregulated). Many genes associated with transporters and a two-component (NisK/SpaK) regulatory system were upregulated following coaggregation. Our comparative analyses of S. gordonii-S. oralis with different previously published S. gordonii pairings (S. gordonii-Fusobacterium nucleatum and S. gordonii-Veillonella parvula) suggest that the gene regulation is specific to each pairing, and responses do not appear to be conserved. This ability to distinguish between neighboring bacteria may be important for S. gordonii to adapt appropriately during the development of complex biofilms such as dental plaque. IMPORTANCE Dental plaque is responsible for two of the most prevalent diseases in humans, dental caries and periodontitis. Controlling the formation of dental plaque and preventing the transition from oral health to disease requires a detailed understanding of microbial colonization and biofilm development. Streptococci are among the most common colonizers of dental plaque. This study identifies key genes that are regulated when oral streptococci bind to one another, as they do in the early stages of dental plaque formation. We show that specific genes are regulated in two different oral streptococci following the formation of mixed-species aggregates. The specific responses of S. gordonii to coaggregation with S. oralis are different from those to coaggregation with other oral bacteria. Targeting the key genes that are upregulated during interspecies interactions may be a powerful approach to control the development of biofilm and maintain oral health.

Efficacy of two-week therapy with doxycycline-based quadruple regimen versus levofloxacin concomitant regimen for helicobacter pylori infection: a prospective single-center randomized controlled trial.

BACKGROUND: Antibiotic-resistance reduces the efficacy of conventional triple therapy for Helicobacter Pylori infections worldwide, which necessitates using various treatment protocols. We used two protocols, doxycycline-based quadruple regimen and concomitant levofloxacin regimen. The aim was to assess the effectiveness of doxycycline-based quadruple regimen for treating Helicobacter Pylori infections compared with levofloxacin concomitant regimen as empirical first-line therapy based on intention-to-treat (ITT) and per-protocol analyses (PPA) in Syrian population. SETTINGS AND DESIGN: An open-label, randomised, parallel, superiority clinical trial. METHODS: We randomly assigned 78 naïve patients who tested positive for Helicobacter Pylori gastric infection, with a 1:1 ratio to (D-group) which received (bismuth subsalicylate 524 mg four times daily, doxycycline 100 mg, tinidazole 500 mg, and esomeprazole 20 mg, each twice per day for 2 weeks), or (L-group) which received (levofloxacin 500 mg daily, tinidazole 500 mg, amoxicillin 1000 mg, and esomeprazole 20 mg each twice per day for two weeks). We confirmed Helicobacter Pylori eradication by stool antigen test 8 weeks after completing the treatment. RESULTS: Thirty-nine patients were allocated in each group. In the D-group, 38 patients completed the follow-up, 30 patients were cured. While in the L-group, 39 completed the follow-up, 32patients were cured. According to ITT, the eradication rates were 76.92%, and 82.05%, for the D-group and L-group respectively. Odds ratio with 95% confidence interval was 1.371 [0.454-4.146]. According to PPA, the eradication rates were 78.9%, and 82.05% for the D-group and L-group respectively. The odds ratio with 95% confidence interval was 1.219 [0.394-3.774]. We didn't report serious adverse effects. CONCLUSIONS: Levofloxacin concomitant therapy wasn't superior to doxycycline based quadruple therapy. Further researches are required to identify the optimal first-line treatment for Helicobacter-Pylori Infection in the Syrian population. TRIAL REGISTRATION: We registered this study as a standard randomized clinical trial ( Clinicaltrial.gov , identifier- NCT04348786 , date:29-January-2020).

Draft genome sequence of Clostridium jeddahense EE-R19 isolated from an anaerobic digester.

OBJECTIVES: Clostridium species of the order Clostridiales are mostly strictly anaerobic rod-shaped bacteria. They can be detected in a variety of environments, including the intestines of humans and animals, soil, water, and biogas reactors. Species of the genus Clostridium are widely used in various biotechnological processes, but several of them have been identified as significant human pathogens. Therefore, investigation at the genome level is necessary to provide valuable information about the ecology, genetics, and phylogenetic diversity of various Clostridium species. DATA DESCRIPTION: In the present study, we report the whole genome sequence of Clostridium jeddahense strain EE-R19, which was isolated from a mesophilic anaerobic digester. The draft genome of C. jeddahense EE-R19 consisted of 59 contigs (> 500 bp), which amounted to 3,562,974 with an overall G + C content of 51.79%. The whole genome shotgun project of C. jeddahense EE-R19 has been deposited at DDBJ/ENA/GenBank under the accession number JAAVNF000000000.

Single-step 3D-printed integrated optical system and its implementation for a sensing application using digital light processing technology.

This study proposes a single-step integrated optical fabrication scheme utilizing a 3D printer using digital light processing technology. Strong light confinement in the fabricated structure is realized through the introduction of an elevated (tower-shaped) waveguide in a transparent photosensitive resin (PX-8880). The fabrication is optimized to maximize light confinement through varying the dimensions of the guiding region and the tower structure. Benefiting from the surface roughness produced by the slicing process in the 3D printing (50 µm resolution), the fabricated structure was tested for vapor sensing. Obvious intensity dynamics have been reported due to the change of the optical scattering due to the presence of vapor as well as polymer vapor interaction. Though the reported response time is long, further optimization can lead to practical operation time.

Draft genome sequence of Bacillus sp. EE-W1 isolated from a biogas reactor.

OBJECTIVES: The genus Bacillus comprises spore-forming rod-shaped Gram-positive bacteria, which usually grow aerobically or anaerobically. Members of this genus are common environmental microorganisms. Also, they can be monitored in the food production chain. Genome sequence of Bacillus sp. strain EE-W1 will provide helpful information to understand its ecology and genetics. Draft genome data may be useful in the field of using Bacillus species in industrial biotechnology. Also, these data can be a useful resource for the study of comparative genomics. DATA DESCRIPTION: Here, we present the draft genome sequence of Bacillus sp. strain EE-W1 isolated from a biogas reactor, Kazan, Russia. The assembled genome size was 5,769,164 bp, with a GC content 35.1%. This draft genome data can be accessed at DDBJ/ENA/GenBank under the accession WIPE00000000.

Extension of Iliac Branch Device Repair Into the Superior Gluteal Artery Is a Safe and Effective Maneuver.

BACKGROUND: In some cases of complex aortoiliac endovascular repair, the hypogastric landing zone is suboptimal or even insufficient. This study aimed at the technical feasibility and at the outcome of iliac branch device (IBD) deployment with extension of the IBD into the superior gluteal artery (SGA). MATERIALS AND METHODS: This study involves a retrospective analysis of a prospectively maintained single-center cohort of patients with implantation of IBD for aortoiliac and postdissection aneurysms. The IBD cohort with landing zones in the hypogastric main trunk (IIA IBD) was compared with the IBD cohort with landing zones in the SGA (SGA IBD). The main outcome parameters were primary technical success, patency of the hypogastric branch, and freedom from IBD-specific secondary interventions within 30 days. Other outcomes of interest were long-term patency and freedom from buttock claudication, as well as the incidence of endoleaks. Group comparisons were made by univariate significance tests, and freedom from reintervention was analyzed with the Kaplan-Meier-method. RESULTS: From January 2015 to October 2017, a total of 46 IBDs were implanted in 40 patients (39 male; mean age, 71.9 ± 9.1 years). Nineteen of 46 (41.3%) IBDs were extended with at least one bridging stent graft into the SGA because of aneurysmal or short internal iliac artery (IIA). Technical success was achieved in 97.8% (96.3% for IIA IBD vs. 100% for SGA IBD, P = 0.163), and the primary ipsilateral limb patency rate was 100% within 30 days after the procedure. During a mean follow-up period of 19.8 ± 10.0 months (24.7 ± 10.8 for IIA IBD vs. 25.1 ± 9.8 for SGA IBD, P = 0.461), 11.1% IBDs in the IIA IBD group and 15.8% IBDs in the SGA IBD group needed secondary interventions (P = 0.33). Follow-up revealed no patients suffering from persistent buttock claudication or erectile dysfunction. One patient in the SGA IBD group died at late follow-up from a non-aneurysm-related cause. CONCLUSIONS: Extension of IBD into the SGA is a technically feasible and safe maneuver in the treatment of aortoiliac aneurysms with outcomes comparable to those when IBDs extend to the main trunk of the hypogastric artery.

An Analytical Model for Describing the Power Coupling Ratio between Multimode Fibers with Transverse Displacement and Angular Misalignment in an Optical Fiber Bend Sensor.

The power coupling ratio between step-index multimode fibers caused by combined transversal and angular misalignment is calculated. A theoretical description of the coupling efficiency between two optical fibers based on geometrical optics is provided. The theoretical calculations are collaborated by experiments, determining the power coupling ratio between three output fibers with an axial offset and angular misalignment with a single input fiber. The calculation results are in good agreement with experimental results obtained using a previously fabricated optical fiber sensor for monitoring physiological parameters in clinical environments. The theoretical results are particularly beneficial for optimizing the design of optical fiber bending sensors that are based on power coupling loss (intensity) as the measurement interrogation requires either axial displacement, angular misalignment, or both.

Transcriptional profiling of coaggregation interactions between Streptococcus gordonii and Veillonella parvula by Dual RNA-Seq.

Many oral bacteria form macroscopic clumps known as coaggregates when mixed with a different species. It is thought that these cell-cell interactions are critical for the formation of mixed-species biofilms such as dental plaque. Here, we assessed the impact of coaggregation between two key initial colonizers of dental plaque, Streptococcus gordonii and Veillonella parvula, on gene expression in each partner. These species were shown to coaggregate in buffer or human saliva. To monitor gene regulation, coaggregates were formed in human saliva and, after 30 minutes, whole-transcriptomes were extracted for sequencing and Dual RNA-Seq analysis. In total, 272 genes were regulated in V. parvula, including 39 genes in oxidoreductase processes. In S. gordonii, there was a high degree of inter-sample variation. Nevertheless, 69 genes were identified as potentially regulated by coaggregation, including two phosphotransferase system transporters and several other genes involved in carbohydrate metabolism. Overall, these data indicate that responses of V. parvula to coaggregation with S. gordonii are dominated by oxidative stress-related processes, whereas S. gordonii responses are more focussed on carbohydrate metabolism. We hypothesize that these responses may reflect changes in the local microenvironment in biofilms when S. gordonii or V. parvula immigrate into the system.

Urinary catheters in the emergency department: a prospective audit to improve quality control.

INTRODUCTION: The best way to prevent urinary catheter related complications is to avoid unnecessary insertions of catheters and removing the catheters when they are no longer necessary. Previous studies have shown 47% documentation rate of urinary catheter (UC) insertion in the Emergency Department (ED) and have found one-sixth of patients in the ED have no indication for UC insertion. The aim of this audit was to record the indications and documentation of UC insertion in the ED and to propose an intervention to improve the quality of these processes. MATERIAL AND METHODS: A prospective audit was conducted in a tertiary university teaching hospital in Ireland over an eight-week period. A week-long intervention was conducted in the ED to educate staff, an ED doctor was involved in directly communicating this to the staff thereafter and concise labels were introduced to document relevant details about each UC insertion. The pre-intervention and post-intervention data was compared using Chi-Square tests. RESULTS: A total of 103 (50 pre-intervention and 53 post-intervention) consecutive age and gender matched patients were recruited in the audit over 8 weeks. The documentation for UC insertion improved by 22% (8% to 30%, (p <0.001, chi-square) while the non-indication for UC insertion reduced by 6% (36% to 30%, p = 0.53, chi-square). CONCLUSIONS: A simple intervention achieved significantly improved documentation of UC insertion and a trend toward increased appropriateness of UC insertion. This audit serves as an example to improve quality control around UC insertion which could be adopted in other institutions.

A Validation Study of a Polymer Optical Fiber Sensor for Monitoring Lumbar Spine Movement.

This study aims to investigate the validity and reliability of a novel plastic optical fiber (POF) sensor, which was developed to measure the angles of flexion, extension and lateral bend at the lumbar region. The angles of flexion, extension and lateral bend for a standing position were measured simultaneously using both the novel POF sensor of this investigation and the commercial Biometrics goniometer instrument. Each movement had two steps of bending which were 10° and 20° based on inclinometer readings. The POF sensor had good intra-rater reliability (Intraclass correlation coefficient, ICC = 0.61 to 0.83). Bland⁻Altman plots were used to study the agreement using these two sensors. There were proportional differences and bias between the POF sensor and Biometrics goniometer, as the zero points did not lie in the percentage difference region in the Bland⁻Altman plots. The proportional difference between these two likely reflects the different sizes and thus, measurement regions of the two sensors. There was also strong correlation between the two sensors (r > 0.77). Hence, the POF sensor could be of potential utility in measuring lumbar range of motion (ROM) in a manner which is minimally invasive, and where discrete sections of the spine are under specific investigation.

Ochratoxin A detection in coffee by competitive inhibition assay using chitosan-based surface plasmon resonance compact system.

This study demonstrates the evaluation of ochratoxin A (OTA) in coffee on compact surface plasmon resonance (SPR) biosensors based on crosslinked chitosan and carboxymethyl chitosan nanomatrix substrates. Ochratoxin A is a toxic secondary metabolite widely produced by Aspergillus and Penicillium fungi and requires regular quantification and detection in food samples. The gold coated SPR chips were synthesized with chitosan and carboxymethyl chitosan through spin coating technique. The SPR nanomatrix chips were used for the immobilization of ochratoxin A-bovine serum albumin (OTA-BSA) conjugate to develop a competitive inhibition immunoassay. The monoclonal ochratoxin A antibodies (mAb-OTA) were used as biological receptors for the detection of OTA in buffer and coffee samples. The limit of detection (LOD) in coffee for chitosan (CS) and carboxymethyl chitosan (CMC) substrates was 5.7 ng/mL and 3.8 ng/mL, respectively. Compact surface plasmon resonance (SPR) system based on chitosan-based (CS-AU) nanomatrix substrates provides a platform for the detection of ochratoxin A with high sensitivity, accuracy, ease-of-use and cost-effectiveness. This compact SPR system can be used at farm and industrial levels for the detection of OTA in food matrices.

Transformation optics based on unitary vectors and Fermat's principle for arbitrary spatial transformation design.

A methodology of designing an arbitrary transformation using transformation optics (TO) based on unitary vectors and Fermat's principle is presented. The TO equation is derived in terms of grid coordinates. The geometry of the transformed space is stored in the grid coordinates rather than the transformation functions. This allows the crafting of an arbitrary transformation by combining several transformation templates together. The touch interface is employed to intuitively apply the transformations. The resulting material parameters are calculated from the proposed method and verified using the anisotropic finite-difference frequency-domain method. Five examples are presented to demonstrate the capability of this method.