Structurally Diverse Pyrene-decorated Planar Chiral [2,2]Paracyclophanes with Tunable Circularly Polarized Luminescence between Monomer and Excimer.

We reported the synthesis of a series of structurally diverse CPL-active molecules, in which pyrene units were installed to chiral pm/po-[2,2]PCP scaffolds either with or without a triple bond spacer for pm/po-PCP-P1 and pm/po-PCP-P2, respectively. The X-ray crystallographic analyses revealed that these pyrene-based [2,2]PCP derivatives exhibited diverse structures and crystal packings in the solid phases. The pyrene-based [2,2]PCP derivatives exhibit various (chir)optical properties in organic solutions, depending on their respective structures. In a mixture of dioxane and water, pm/po-PCP-P1 emit green excimer fluorescence, whereas pm/po-PCP-P2 emit blue one. The chiroptical investigation demonstrated that Rp-pm-PCP-P1 and Rp-pm-PCP-P2 exhibited completely opposite CD and CPL signals even they possess the same chiral Rp-[2,2]PCP core. The same argument also holds for other chiral pyrene-based [2,2]PCP derivatives. The theoretical calculation revealed that these unusual phenomena were attributed to different orientation between transition electric dipole moments and the magnetic dipole moments originating from the presence or absence of a triple bond spacer. These pyrene-based [2,2]PCP derivatives display various colours and fluorescence emissions in the solid state and PMMA films, possibly due to the different packings as observed in the crystal structure. Moreover, these compounds also can interact with perylene diimide through π-π interactions, leading to near-white fluorescence.

Ring Rearrangement Reactions of 4-Alkenylisocoumarins and Photophysical Evaluation of Multi-Substituted Anthracene Products.

Herein we report that readily available 4-alkenylisocoumarins can be regarded as potent dienolate equivalents. For example, lactol silyl ethers derived from 4-alkenylisocoumarins were selectively converted to the corresponding benzo-homophthalates through a fluoride-induced ring opening step that was followed by a ring closure through a vinylogous intramolecular aldol condensation. Likewise, nucleophilic activation of 4-alkenylisocoumarins directly yields diversely poly-substituted naphthalenes and anthracenes without formation of any regioisomer. Photophysical evaluation of a set of thus obtained 1,3-di- and 1,3,4-trisubstituted anthracenes reveals their distinct intramolecular charge transfer (ICT) character during light absorption in polar solutions and excimer emission from the solid state when a face-to-face π-stacked molecular assembly is present in the crystal packing.

An analysis of long-term clinical outcome following the use of excimer laser coronary atherectomy in a large UK PCI center.

BACKGROUND: Excimer laser atherectomy (ELCA) is an established adjunctive technique to facilitate acute success in percutaneous coronary intervention (PCI). Despite this there are a lack of contemporary outcome data, particulary longer-term, forpatients treated with ELCA PCI. AIMS: To evaluate the contemporary use ofELCA in PCI, the frequency of periprocedural complications and the longer-term outcomes associated with ELCA PCI. METHODS: This was a retrospective study that included all patients undergoing PCI (with or without ELCA) between April 2005 and May 2021. Relevant features from all cases were downloaded from the patient record and matched to hospital data on mortality on November 22, 2022. Kaplan Meier curves were used to compare mortality between the ELCA PCI and non-ELCA PCI cohorts with a landmark at 1 year. Multivariable Cox regression was performed to assess whether ELCA PCI was independently associated with long-term mortality. RESULT: There were 21,256 patients in this analysis, of which 448 (2.1%) were treated with ELCA PCI. ELCA PCI was associated with a higher frequency of any periprocedural complication. Median follow-up was 2812 days (IQR, 1577-4245 days) with higher mortality in ELCA PCI (38.2% vs. 29.0%, p < 0.001). However, on multivariable analysis, ELCA PCI was not independently associated with long-term mortality. The TVR frequency in ELCA PCI was 16.7% but TVR was significantly higher for cases of in-stent restenosis (ISR) (29.5%). CONCLUSION: Despite ELCA PCI being used in higher risk populations with complex coronary artery disease there was no long-term increased mortality associated with the use of this device. ELCA PCI for ISR is highly effective and safe although TVR in this cohort remains high in long-term follow-up.

Methods for treating coronary eruptive calcified nodules.

Eruptive calcified nodules (CNs) are a manifestation of severely calcified plaques, which exist in acute coronary syndrome (ACS), non-ACS lesions. Optical coherence tomography is crucial for diagnosing and treating eruptive CNs in clinical practice. Management of eruptive CNs is still a challenge for interventional cardiologists. There have been significant advances in the treatment of eruptive CNs such as intravascular lithotripsy, excimer laser coronary atherectomy, rotational atherectomy, and orbital atherectomy. We find a range of treatment modalities to be effective under different conditions. The selection of these devices should be considered based on guidewire position, lesion characteristics, clinical manifestations, and operator's experiences.

Contrast-enhanced excimer laser stepwise approach during PCI for resistant coronary lesions.

BACKGROUND: The treatment of resistant coronary lesions (RCL) is a great challenge for interventional cardiologists. The excimer laser coronary atherectomy (ELCA) is a plaque modification tool based on a main mechanism of photomechanical effect leading to mechanical disruption of the plaque. Contrast dye injection during laser delivery has demonstrated to enhance its power. AIM: To evaluate the effectiveness and safety of the contrast-enhanced ELCA by a stepwise approach in the treatment of RCLs. METHODS: We retrospectively examined consecutive patients undergoing contrast-enhanced ELCA-assisted PCI between 2018 and 2021 at two Italian sites. RCLs were defined as novo or in-stent undilatable/uncrossable with conventional balloons (SC/NC balloon). The primary endpoint was ELCA technical success defined as the laser catheter crossing the entire length of the target lesion established by angiographic evidence of the catheter tip in the artery distal to the stenosis. RESULTS: We enrolled 114 patients who underwent contrast-enhanced ELCA-assisted PCI: 58% of the patients had acute coronary syndrome while the left anterior descending artery was the target vessel in 42.1% of cases. The target lesion was most commonly in-stent (56.2%). The 0.9 mm ELCA catheter tip was employed in 89.5% of cases. The most used frequency/fluency profile was 70/70 (39.5%). The use of contrast-enhanced ELCA was associated with high technical, procedural, and clinical success rates (97.4%, 93.7%, and 90.1%, respectively). CONCLUSIONS: The contrast-enhanced ELCA seems to be a safe and effective treatment option for the management of both de novo and in-stent-resistant coronary lesions.

Outcomes and Comparative Analysis of the Initial Results of Standard Balloon Angioplasty Versus Drug-Coated Balloons Alone Versus in Association With Laser-Excimer Atherectomy in the Treatment of Femoropopliteal Artery In-Stent Restenosis (INTACT).

BACKGROUND: Despite improved patency with newer-generation nitinol stents, one-half of patients will require secondary interventions for in-stent restenosis (ISR). The best treatment strategy remains unclear. This study aimed to compare drug-coated balloons (DCBs) used alone or in association with excimer laser atherectomy (ELA) to simple percutaneous transluminal angioplasty (PTA) in the treatment of femoropopliteal-ISR. METHODS: The INTACT trial is a multicenter, prospective, triple-arm randomized trial conducted across 14 centers from December 2015 to November 2019. Patients Rutherford Class 2-5 with ISR≥70% were followed-up for 18 months. The primary efficacy endpoint was recurrent ISR>70% by duplex ultrasound analysis. The primary safety endpoint was major adverse events (MAEs) defined as death, major amputation, or target lesion revascularization (TLR). RESULTS: Around 134 subjects were randomized to PTA alone (n=41), PTA+DCB (n=43) or PTA+ELA+DCB (n=50). Procedural success was similar (p=.74), as was clinical success (p=.17). The number of recurrent ISR>70% decreased after PTA+ELA+DCB (30.0%; p=.04) and PTA+DCB (30.2%; p=.05) compared to PTA alone (51.2%). Primary patency was higher after PTA+ELA+DCB (log-rank p=.04) and PTA+DCB (log-rank p=.02) compared to PTA alone at 12 months (78.7% and 70.4% vs 61.5%) and 18 months (61.6% and 67.7% vs 37.3%). Freedom from MAEs was lower after PTA+DCB (27.9%) compared to PTA alone (53.7%; p=.02) but did not differ with PTA+ELA+DCB (40.0%). It was primarily driven by TLR; 2 major amputations occurred after PTA+ELA+DCB (4.0%; p=.18). CONCLUSION: This independent study demonstrated a decrease in recurrent ISR>70% and increase in primary patency up to 18 months after PTA+ELA+DCB and PTA+DCB compared to PTA alone in the treatment of FP-ISR. It did not show an increase in MAEs but could have lacked power. CLINICAL IMPACT: This multicenter, prospective, triple-arm randomized, controlled trial focuses on the results of adjunctive therapies, such as excimer laser atherectomy (ELA) and/or drug-coated balloons (DCBs) in the treatment of in-stent restenosis (ISR) in femoropopliteal lesions in 134 patients. It has the originality of being an independent study funded by a grant from the French Ministry of Health. This study confirms a significant decrease in recurrent ISR >70% and increase in primary patency up to 18 months after the use of ELA+DCB and DCBs compared to simple percutaneous transluminal angioplasty in the treatment of femoropopliteal ISR without an increase in major adverse events.

Accumulated melanin in molds provides wavelength-dependent UV tolerance.

Fungal contamination poses a serious threat to public health and food safety because molds can grow under stressful conditions through melanin accumulation. Although ultraviolet (UV) irradiation is popular for inhibiting microorganisms, its effectiveness is limited by our insufficient knowledge about UV tolerance in melanin-accumulating molds. In this study, we first confirmed the protective effect of melanin by evaluating the UV sensitivity of young and mature spores. Additionally, we compared UV sensitivity between spores with accumulated melanin and spores prepared with melanin biosynthesis inhibitors. We found that mature spores were less UV-sensitive than young spores, and that reduced melanin accumulation by inhibitors led to reduced UV sensitivity. These results suggest that melanin protects cells against UV irradiation. To determine the most effective wavelength for inhibition, we evaluated the wavelength dependence of UV tolerance in a yeast (Rhodotorula mucilaginosa) and in molds (Aspergillus fumigatus, Cladosporium halotolerans, Cladosporium sphaerospermum, Aspergillus brasiliensis, Penicillium roqueforti, and Botrytis cinerea). We assessed UV tolerance using a UV-light emitting diode (LED) irradiation system with 13 wavelength-ranked LEDs between 250 and 365 nm, a krypton chlorine (KrCl) excimer lamp device, and a low pressure (LP) Hg lamp device. The inhibition of fungi peaked at around 270 nm, and most molds showed reduced UV sensitivity at shorter wavelengths as they accumulated pigment. Absorption spectra of the pigments showed greater absorption at shorter wavelengths, suggesting greater UV protection at these wavelengths. These results will assist in the development of fungal disinfection systems using UV, such as closed systems of air and water purification.

Far-UVC 222 nm Treatment: Effects of Nitrate/Nitrite on Disinfection Byproduct Formation Potential.

Irradiation at far ultraviolet C (far-UVC) 222 nm by krypton chloride (KrCl*) excilamps can enhance microbial disinfection and micropollutant photolysis/oxidation. However, nitrate/nitrite, which absorbs strongly at 222 nm, may affect the formation of disinfection byproducts (DBPs). Herein, we evaluated model organic matter and real water samples and observed a substantial increase in the formation potential for trichloronitromethane (chloropicrin) (TCNM-FP), a nitrogenous DBP, by nitrate or nitrite after irradiation at 222 nm. At a disinfection dose of 100 mJ·cm-2, TCNM-FP of humic acids and fulvic acids increased from ∼0.4 to 25 and 43 µg·L-1, respectively, by the presence of 10 mg-N·L-1 nitrate. For the effect of nitrate concentration, the TCNM-FP peak was observed at 5-10 mg-N·L-1. Stronger fluence caused a greater increase of TCNM-FP. Similarly, the increase of TCNM-FP was also observed for wastewater and drinking water samples containing nitrate. Pretreatment using ozonation and coagulation, flocculation, and filtration or the addition of H2O2 can effectively control TCNM-FP. The formation potential of other DBPs was minorly affected by irradiation at 222 nm regardless of whether nitrate/nitrite was present. Overall, far-UVC 222 nm treatment poses the risk of increasing TCNM-FP of waters containing nitrate or nitrite at environmentally relevant concentrations and the mitigation strategies merit further research.

Excimer Fluorescence of Acriflavine Dye in Glycerol and Ethylene Glycol.

This research investigates the excimerisation of acriflavine dye in ethylene glycol and glycerol solvents. Acriflavine, a member of the acridine dye family, exhibits unique fluorescence properties with applications in various fields, including cellular nucleus observation, nucleic acid analysis, and dye laser active media etc. The study explores the impact of solvent and concentration on acriflavine's emission properties, with a focus on excimer formation, which can influence its suitability as a dye laser active medium. UV-Visible absorption spectroscopy reveals concentration-dependent absorption profiles, with distinctive monomer bands. Steady-state fluorescence studies demonstrate the emergence of red-shifted excimer fluorescence bands as concentrations increase in both solvents. Temperature-dependent fluorescence studies reveal the dynamics of excimer formation, suggesting dynamic diffusion as the excimerisation mechanism. Time-resolved fluorescence spectroscopy confirms the singlet character of both monomer and excimer states, providing insights into the excimerisation process. Critical concentration values are determined, representing the equilibrium between monomeric and excimeric forms. The study also explores pH-induced spectral shifts, highlighting the influence of acidity on fluorescence properties. Overall, this research deepens our understanding of acriflavine's excimerisation in ethylene glycol and glycerol, offering insights that can enhance its diverse applications, especially in laser technologies.

Carbazole Integrated Tetrakis-(1 H-pyrrole-2-carbaldehyde): A Highly Selective Fluorescent Probe for HP2O73.

A new carbazole-coupled tetrakis-(1 H-pyrrole-2-carbaldehyde) anion receptor 1 has been designed and synthesized. Anion binding studies in organic media using fluorescence and UV-vis spectroscopy revealed that receptor 1 is capable of sensing HP2O73- with high selectivity. Addition of HP2O73- to THF solution of 1 resulted in the emergence of a new broad band at longer wavelength along with quenching of the original emission band forming a ratiometric response. Based on dynamic light scattering (DLS) experiment and fluorescence lifetime measurement, we propose that the emergence of new emission band in the presence of HP2O73- ion is due to the aggregation-induced excimer formation.

A Pyrene Coupled Azaine-linkage Chromo-fluorogenic Probe for Specific Detection of Sarin Gas Stimulant, Diethylchlorophosphate.

Owing to the extreme toxicity and easy synthesis protocol of G-series nerve agents, developing an efficient sensor for selective detection is necessary. Although various traditional methods are utilized to identify these nerve agents, chromo-fluorogenic probes have gained attractive attention from the scientific communities. In the present contribution, we have introduced a new symmetrical aza-substituted chromo-fluorogenic sensor, BPH, for specific detection of sarin gas, one of the fatal G-series nerve agents surrogate, diethylchlorophosphate (DCP). BPH shows a noticeable naked eye colorimetric change from pale yellow to light pink in the presence of DCP, displaying highly intense bright greenish cyan color photoluminosity under a 365 nm UV lamp,which is also manifested from the color chromaticity diagram. A BPH-staining paper stirps-based test kit experiment has been demonstrated for the on-site detection of nerve agent mimics. A more attractive and efficient application of BPH as a sarin gas vapor phase sensor mimics DCP in solid and solution phases. The BPH-based chromo-fluorogenic sensor shows excellent selectivity toward DCP with a detection and quantification limit in the µM range. This report invokes a new way for the researchers to detect DCP employing a simple chromo-fluorogenic sensor, which could be prepared by a time-saving, straightforward, handy protocol from the cost-effective starting materials.

Efficacy and safety of excimer light (308 nm) in the treatment of pityriasis lichenoides chronica.

INTRODUCTION: Pityriasis lichenoides chronica is the chronic end of the spectrum of pityriasis lichenoides which have several forms of papulosuamous conditions. Several treatments obtained complete clearance of the condition including phototherapy and specifically narrow band ultraviolet B. The Excimer light 308 is a monochromatic light that acts within the ultraviolet B wavelength and used as a targeted phototherapy in several skin conditions. METHODS: Thirty-four patients with histopathologically diagnosed pityriasis lichenoides chronica underwent treatment with biweekly sessions of excimer light 308 nm. Treatment continued until complete clearance was obtained or to a maximum of 48 sessions (24 weeks). RESULTS: Thirty-one patients obtained complete clearance with no recurrence till the end of the study period, two patients had partial response and only one patient showed poor response to treatment. CONCLUSION: Excimer light can be a safe and effective treatment of pityriasis lichinoides chronica in different ages and genders.

Phototherapy for vitiligo: A narrative review on the clinical and molecular aspects, and recent literature.

BACKGROUND: Vitiligo is characterized by depigmented patches resulting from loss of melanocytes. Phototherapy has emerged as a prominent treatment option for vitiligo, utilizing various light modalities to induce disease stability and repigmentation. AIMS AND METHODS: This narrative review aims to explore the clinical applications and molecular mechanisms of phototherapy in vitiligo. RESULTS AND DISCUSSION: The review evaluates existing literature on phototherapy for vitiligo, analyzing studies on hospital-based and home-based phototherapy, as well as outcomes related to stabilization and repigmentation. Narrowband ultra-violet B, that is, NBUVB remains the most commonly employed, studied and effective phototherapy modality for vitiligo. Special attention is given to assessing different types of lamps, dosimetry, published guidelines, and the utilization of targeted phototherapy modalities. Additionally, the integration of phototherapy with other treatment modalities, including its use as a depigmenting therapy in generalized/universal vitiligo, is discussed. Screening for anti-nuclear antibodies and tailoring approaches for non-photo-adapters are also examined. CONCLUSION: In conclusion, this review provides a comprehensive overview of phototherapy for vitiligo treatment. It underscores the evolving landscape of phototherapy and offers insights into optimizing therapeutic outcomes and addressing the challenges ahead. By integrating clinical evidence with molecular understanding, phototherapy emerges as a valuable therapeutic option for managing vitiligo, with potential for further advancements in the field.

Combination of 308-nm excimer laser and piperine promotes melanocyte proliferation, migration, and melanin content production via the miR-328/SFRP1 axis.

OBJECTIVE: Both piperine and a 308-nm excimer laser have significant curative effects on vitiligo. This study mainly explored the molecular mechanism of a 308-nm excimer combined with piperine in regulating melanocyte proliferation. METHODS: Epidermal melanocytes were cultured in piperine solution, and the cells were irradiated by an XTRAC excimer laser treatment system at 308-nm output monochromatic light. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were for detecting the expression levels of genes or proteins. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and Transwell method was for assessing cell viability and migration capacity. The content of melanin was also detected. RESULTS: The combination of the 308-nm excimer laser and piperine enhanced the cell proliferation, migration, and melanin production of melanocytes and upregulated the level of miR-328, and restraint of miR-328 reversed the influence of the 308-nm excimer laser and piperine. Secreted frizzled-related protein 1 (SFRP1) is a direct target gene of miR-328, and miR-328 can inhibit the expression of SFRP1 and elevate the protein level of the Wnt/ß-catenin signaling pathway. CONCLUSION: The 308-nm excimer laser combined with piperine may be more efficient than piperine alone in the remedy of vitiligo, and the miR-328/SFRP1 and Wnt/ß-catenin pathways are participated in the proliferation, migration, and melanin synthesis of melanocytes.

Excimer laser coronary angioplasty combined with drug-coated balloon in the treatment of in-stent restenosis.

OBJECTIVES: The aim of this study is to investigate the safety and efficacy of excimer laser coronary angioplasty (ELCA) combined with drug-coated balloons (DCBs) in the treatment of in-stent restenosis (ISR), and to explore whether the contrast injection technique would improve the neointimal tissue ablation of ELCA. METHODS: We studied patients diagnosed with ISR between January 2019 and October 2022 at two medical centers. These patients underwent DCB angioplasty guided by optical coherence tomography (OCT). Based on whether ELCA was performed before DCB treatment, patients were categorized into two groups: the ELCA + DCB group and the DCB group. All patients underwent clinical follow-up 1 year after the procedure. The primary endpoint was the 1-year rate of target lesion revascularization (TLR), which was defined as any repeat percutaneous intervention or bypass surgery on the target vessel conducted to address restenosis or other complications related to the target lesion. The secondary endpoints including immediate luminal gain (ΔMLA, defined as the difference in minimum lumen area before and after the intervention). RESULTS: A total of 85 lesions in 75 patients were included. The mean age of the study population was 64.2 ± 12.0 years, with 81.3% male. Baseline clinical characteristics were well-balanced, and procedural success was 100% in both groups. The ELCA + DCB group (n = 24) exhibited a greater ΔMLA compared to the DCB group (n = 61) (3.57 ± 0.79 mm² vs. 2.50 ± 1.06 mm², [95% confidence interval, CI: 0.57-1.69], p < 0.001), The reduction in 1-year TLR was more frequently observed in patients from the ELCA + DCB group compared to the DCB group (hazard ratio 0.33 [95% CI: 0.11-0.99]; log-rank p = 0.048). The exploratory analysis showed that ELCA with contrast infusion is associated with greater acute lumen gain compared to ELCA with saline infusion (p < 0.001). CONCLUSIONS: The combination of ELCA and DCB is a safe and effective treatment strategy for in-stent stenosis. Additionally, compared with saline injection, ELCA with contrast injection is associated with greater acute lumen gain. However, the optimal contrast agent concentration and long-term outcome of the contrast injection technique need confirmation through larger sample sizes and prospective studies.

308 nm excimer laser and tacrolimus ointment in the treatment of facial vitiligo: a systematic review and meta-analysis.

This study aimed to investigate the effects and safety of 308 nm excimer laser (308 nm EL) and tacrolimus ointment (TO) in the treatment of facial vitiligo (FV). We searched Cochrane Library, PUBMED, EMBASE, CNKI, and WANGFANG from inception to June 1, 2023. Outcomes included overall response rate (ORR), total adverse reaction rate (TARR), recurrence rate at 3-month (RR-3) and recurrence rate at 6-month (RR-6). The outcome data were presented as odds ratios (OR) with 95% confidence intervals (CI). The risk of bias was assessed by Cochrane risk-of-bias tool and data analysis was performed by RevMan 5.4 software. This study included a total of 19 trials involving 2085 patients. When comparing 308 nm EL monotherapy with 308 nm EL plus TO, significant differences in the ORR (OR = 4.29, 95% CI [2.97, 6.19], I2 = 0%, P < 0.001), RR-3 (OR = 0.18, 95% CI [0.05, 0.69], I2 = 0%, P = 0.01), and RR-6 (OR = 0.38, 95% CI [0.14, 1.03], I2 = 39%, P = 0.06) were found between the two managements. When comparing TO monotherapy with TO plus 308 nm EL, its results showed significant differences in the ORR (OR = 4.21, 95% CI [2.90, 6.11], I2 = 0%, P < 0.001), TARR (OR = 0.42, 95% CI [0.22, 0.81], I2 = 4%, P = 0.009), and RR-3 (OR = 0.32, 95% CI [0.01, 8.03], P = 0.49) between the two modalities. The results of this study suggest that the combination of 308 nm EL and TO is more effective than either treatment alone for the treatment of FV.

Excimer light effect on neurogenic inflammation in active versus stable psoriasis lesions.

Neurogenic inflammation, mediated by T helper 17 cell (Th17) and neurons that release neuropeptides such as substance P (SP), is thought to play a role in the pathogenesis of psoriasis. Excimer light is used in the treatment of psoriasis via induction of T cell apoptosis. The objective of this study is to study the effect of excimer light on active versus stable psoriasis and investigate the levels of substance P and its receptor in both groups. The study included 27 stable and 27 active psoriatic patients as well as 10 matched healthy controls. Clinical examination (in the form of local psoriasis severity index (PSI) and visual analogue scale (VAS)) was done to determine disease severity, level of itching, and quality of life. Tissue levels of SP and neurokinin-1 receptor (NK-1R) were measured by ELISA before and after 9 excimer light sessions in 43 patients. A statistically significant lower levels of PSI and VAS were reached after therapy with no significant difference between the stable and active groups. The mean tissue levels of SP before therapy were significantly higher than the control group. Lower levels of SP and NK-1 receptor were found after treatment overall and in each group. Excimer therapy can be effective for both stable and active plaque psoriasis and this effect could be partly through its role on ameliorating the neurogenic inflammation.

Development of a Small-Footprint 50 MHz Linear Array: Fabrication and Micro-Ultrasound Imaging Demonstration.

Compact high-frequency arrays are of interest for clinical and preclinical applications in which a small-footprint or endoscopic device is needed to reach the target anatomy. However, the fabrication of compact arrays entails the connection of several dozens of small elements to the imaging system through a combination of flexible printed circuit boards at the array end and micro-coaxial cabling to the imaging system. The methods currently used, such as wire bonding, conductive adhesives, or a dry connection to a flexible circuit, considerably increase the array footprint. Here, we propose an interconnection method that uses vacuum-deposited metals, laser patterning, and electroplating to achieve a right-angle, compact, reliable connection between array elements and flexible-circuit traces. The array elements are thickened at the edges using patterned copper traces, which increases their cross-sectional area and facilitates the connection. We fabricated a 2.3 mm by 1.7 mm, 64-element linear array with elements at a 36 µm pitch connected to a 4 cm long flexible circuit, where the interconnect adds only 100 µm to each side of the array. Pulse-echo measurements yielded an average center frequency of 55 MHz and a -6 dB bandwidth of 41%. We measured an imaging resolution of 35 µm in the axial direction and 114 µm in the lateral direction and demonstrated the ex vivo imaging of porcine esophageal tissue and the in vivo imaging of avian embryonic vasculature.

Eclipsed and Twisted Excimers of Pyrene and 2-Azapyrene: How Nitrogen Substitution Impacts Excimer Emission.

Due to their unique photophysical and electronic properties, pyrene and its analogues have been the subject of extensive research in recent decades. The propensity of pyrene and its derivatives to form excimers has found wide application in various fields. Nitrogen-substituted pyrene derivatives display similar photophysical properties, but for them, excimer emission has not been reported to date. Here, we use time-dependent density functional theory (TD-DFT) calculations to investigate the low-lying exciton states of dimers of pyrene and 2-azapyrene. The excimer equilibrium structures are determined and the contribution of charge transfer (CT) excitations and intermolecular interactions to the exciton states is disclosed using a diabatization procedure. The study reveals that the dimers formed by the two molecules have quite similar exciton-state patterns, in which the relevant CT contributions govern the formation of excimer states, along with the La/Lb state inversion. In contrast with pyrene, the dipole-dipole interactions in 2-azapyrene stabilize the dark eclipsed excimer structure and increase the barrier for conversion into a bright twisted excimer. It is suggested that these differences in the nitrogen-substituted derivative might influence the excimer emission properties.

LASIK is associated with early cataract surgery in healthy patients.

PURPOSE: To evaluate the association between LASIK and early cataract phacoemulsification surgery (PE). METHODS: A matched case-control study was conducted. Cases were otherwise healthy adults with a history of LASIK. Groups were paired according to corrected-distance visual acuity (CDVA), axial length, and cataract grade. RESULTS: A total of 213 patients were included. 85 patients were classified as post-LASIK group and 128 as controls. The mean age at the time of LASIK was 42.32 ± 9.24 years. The mean CDVA before PE was 0.29 ± 0.19 Log MAR in post-LASIK group and 0.34 ± 0.22 Log MAR in controls (p = 0.07). The mean axial length was 23.99 ± 1.78 mm in post-LASIK group and 23.62 ± 0.98 mm in controls (p = 0.085). The mean nuclear cataract grading was 1.36 in post-LASIK group and 1.47 in controls (p = 0.34). The mean age at the time of PE was 60.18 ± 7.46 years in post-LASIK group and 67.35 ± 9.28 in controls (p < 0.0005). The difference between the mean age of LASIK and the mean age of PE was 17.85 ± 5.72 years. There was a positive association between the post-LASIK group and the age of PE ≤ 55 years (OR: 4.917, 95% CI: 2.21-10.90, p < 0.001). CONCLUSION: LASIK may be associated with early PE. Patients with LASIK had a 7-year earlier PE compared to a matched control group.