Dynamic stability of the euler nanobeam subjected to inertial moving nanoparticles based on the nonlocal strain gradient theory.

This research studied the dynamic stability of the Euler-Bernoulli nanobeam considering the nonlocal strain gradient theory (NSGT) and surface effects. The nanobeam rests on the Pasternak foundation and a sequence of inertial nanoparticles passes above the nanobeam continuously at a fixed velocity. Surface effects have been utilized using the Gurtin-Murdoch theory. Final governing equations have been gathered implementing the energy method and Hamilton's principle alongside NSGT. Dynamic instability regions (DIRs) are drawn in the plane of mass-velocity coordinates of nanoparticles based on the incremental harmonic balance method (IHBM). A parametric study shows the effects of NSGT parameters and Pasternak foundation constants on the nanobeam's DIRs. In addition, the results exhibit the importance of 2T-period DIRs in comparison to T-period ones. According to the results, the Winkler spring constant is more effective than the Pasternak shear constant on the DIR movement of nanobeam. So, a 4 times increase of Winkler and Pasternak constants results in 102 % and 10 % of DIR movement towards higher velocity regions, respectively. Furthermore, the effect of increasing nonlocal and material length scale parameters on the DIR movement are in the same order regarding the magnitude but opposite considering the motion direction. Unlike nonlocal parameter, an increase in material length scale parameter shifts the DIR to the more stable region.

Application of 3D, 4D, 5D, and 6D bioprinting in cancer research: what does the future look like?

The application of three- and four-dimensional (3D/4D) printing in cancer research represents a significant advancement in understanding and addressing the complexities of cancer biology. 3D/4D materials provide more physiologically relevant environments compared to traditional two-dimensional models, allowing for a more accurate representation of the tumor microenvironment that enables researchers to study tumor progression, drug responses, and interactions with surrounding tissues under conditions similar to in vivo conditions. The dynamic nature of 4D materials introduces the element of time, allowing for the observation of temporal changes in cancer behavior and response to therapeutic interventions. The use of 3D/4D printing in cancer research holds great promise for advancing our understanding of the disease and improving the translation of preclinical findings to clinical applications. Accordingly, this review aims to briefly discuss 3D and 4D printing and their advantages and limitations in the field of cancer. Moreover, new techniques such as 5D/6D printing and artificial intelligence (AI) are also introduced as methods that could be used to overcome the limitations of 3D/4D printing and opened promising ways for the fast and precise diagnosis and treatment of cancer.

FSHing for DNA Damage: Key Features of MutY Detection of 8-Oxoguanine:Adenine Mismatches.

ConspectusBase excision repair (BER) enzymes are genomic superheroes that stealthily and accurately identify and remove chemically modified DNA bases. DNA base modifications erode the informational content of DNA and underlie many disease phenotypes, most conspicuously, cancer. The "OG" of oxidative base damage, 8-oxo-7,8-dihydroguanine (OG), is particularly insidious due to its miscoding ability that leads to the formation of rare, pro-mutagenic OG:A mismatches. Thwarting mutagenesis relies on the capture of OG:A mismatches prior to DNA replication and removal of the mis-inserted adenine by MutY glycosylases to initiate BER. The threat of OG and the importance of its repair are underscored by the association between inherited dysfunctional variants of the MutY human homologue (MUTYH) and colorectal cancer, known as MUTYH-associated polyposis (MAP). Our functional studies of the two founder MUTYH variants revealed that both have compromised activity and a reduced affinity for OG:A mismatches. Indeed, these studies underscored the challenge of the recognition of OG:A mismatches that are only subtly structurally different than T:A base pairs. Since the original discovery of MAP, many MUTYH variants have been reported, with most considered to be "variants of uncertain significance." To reveal features associated with damage recognition and adenine excision by MutY and MUTYH, we have developed a multipronged chemical biology approach combining enzyme kinetics, X-ray crystallography, single-molecule visualization, and cellular repair assays. In this review, we highlight recent work in our laboratory where we defined MutY structure-activity relationship (SAR) studies using synthetic analogs of OG and A in cellular and in vitro assays. Our studies revealed the 2-amino group of OG as the key distinguishing feature of OG:A mismatches. Indeed, the unique position of the 2-amino group in the major groove of OGsyn:Aanti mismatches provides a means for its rapid detection among a large excess of highly abundant and structurally similar canonical base pairs. Furthermore, site-directed mutagenesis and structural analysis showed that a conserved C-terminal domain ß-hairpin "FSH'' loop is critical for OG recognition with the "His" serving as the lesion detector. Notably, MUTYH variants located within and near the FSH loop have been associated with different forms of cancer. Uncovering the role(s) of this loop in lesion recognition provided a detailed understanding of the search and repair process of MutY. Such insights are also useful to identify mutational hotspots and pathogenic variants, which may improve the ability of physicians to diagnose the likelihood of disease onset and prognosis. The critical importance of the "FSH" loop in lesion detection suggests that it may serve as a unique locus for targeting probes or inhibitors of MutY/MUTYH to provide new chemical biology tools and avenues for therapeutic development.

A molecular dynamics simulation of the effect of the toluene catalytic ratios and initial temperature on the catalytic combustion of air/methane inside a microchannel.

METHODS: This research studied the effect of initial temperature (300-400K), and atomic percentage of toluene catalyst (1-10%) on the atomic and thermal performance of air/methane catalytic combustion. The present study was performed using molecular dynamics (MD) simulation. CONTEXT: The results demonstrate that by increasing the initial temperature from 300 to 400 K, the maximum velocity and temperature increased from 0.52 Å/ps and 585 K to 0.72 Å/ ps and 629 K, respectively. Moreover, the heat flux, thermal conductivity, and combustion efficiency increased from 2020 W/m2, 1.45 W/mK, and 93% to 2208 W/m2, 1.55 W/mK, and 97% by increasing initial temperature to 400 K. On the other hand, by increasing the atomic percentage of toluene catalyst from 1% to 4%, the maximum velocity and temperature increased from 0.41Å/ps and 546 K to 0.49 Å/ ps and 573 K, respectively. Thermal conductivity and combustion efficiency increased from 1.451.22 W/mK and 77% to 1.33 W/mK and 89%. With further increasing of the catalyst to 10%, the thermal performance of sample declined. This decrease could be attributed to the agglomeration process, where an excessive amount of catalyst may lead to agglomeration, negatively affecting the structure's catalytic activity and overall thermal performance.

Therapeutic effect of sodium alginate on bleomycin, etoposide and cisplatin (BEP)-induced reproductive toxicity by inhibiting nitro-oxidative stress, inflammation and apoptosis.

Impaired spermatogenesis and male infertility are common consequences of chemotherapy drugs used in patients with testicular cancer. The present study investigated the effects of sodium alginate (NaAL) on testicular toxicity caused by bleomycin, etoposide, and cisplatin (BEP). Rats in group 1 received normal saline, while groups 2 and 3 were treated with 25 and 50 mg/kg of NaAL, respectively. Group 4 was treated with a 21-day cycle of BEP (0.5 mg/kg bleomycin, 5 mg/kg etoposide, and 1 mg/kg cisplatin), and groups 5 and 6 received BEP regimen plus 25 and 50 mg/kg of NaAL, respectively. Then, sperm parameters, testosterone levels, testicular histopathology and stereological parameters, testicular levels of malondialdehyde (MDA), nitric oxide (NO), and total antioxidant capacity (TAC), and the expression of apoptosis-associated genes including Bcl2, Bax, Caspase3, p53, and TNF-α were evaluated. Our findings revealed that NaAL improved sperm parameters, testosterone levels, histopathology, and stereology parameters in BEP-administrated rats. NaAL also improved testis antioxidant status by enhancing TAC and ameliorating MDA and NO. Further, modifications to the expression of Bcl2, Bax, Caspase3, p53, and TNF-α suggested that NaAL alleviated BEP-induced apoptosis and inflammation. Collectively, NaAL protects rats' testes against BEP-evoked toxicity damage through the modulation of nitro-oxidative stress, apoptosis, and inflammation.

Comparison of the mechanical characteristics of produced nanofibers by electrospinning process based on different collectors.

Polymer nanofiber in nanofibrous membrane produced by electrospinning process can be employed in various fields such as medical engineering, environmental engineering, biotechnology, energy, tissue scaffolds, and protective clothing. In these applications, the mechanical properties of the nanofibrous membrane should be studied to get long-life durability. In the current study, nanofibers are obtained from electrospinning of polyacrylonitrile (PAN) solution in Dimethylformamide (DFM) solvent. Nanofibers are produced with disc, cylinder, wire drum, parallel bars and polygon collectors and their mechanical properties are examined and compared. For this study, a tensile testing machine with special jaws was applied. According to the Scanning Electron Microscope (SEM) images, the average diameter of the produced nanofibers ranges from 300 to 340 nm. In addition, nanofiber layers have a thickness of 0.03 mm. They were cut in the 10 × 25 mm2 size; then, the tensile test was performed. Results show that produced nanofiber layers by rotating cylinder collector have the highest ultimate strength while the disk collector results in the highest Young's modulus in produced samples.

Utility of vitamin C in ameliorating citalopram-induced testicular toxicity via modulating nitro-oxidative stress and apoptosis in mice.

There is a growing concern that antidepressant drugs impair sexual function and adversely impact spermatogenesis and male fertility. Vitamin C is a natural antioxidant that plays a vital role in the male reproductive system. The present study investigated the ameliorating potential of vitamin C against citalopram (CTL)-evoked testicular toxicity and spermatogenesis impairment in mice. Mice were randomly divided into six groups: control, CTL, vitamin C 100, vitamin C 200, CTL plus vitamin C 100, and CTL plus vitamin C 200. Adult male mice were intraperitoneally (ip) injected with 10 mg/kg of CTL for 35 days with or without vitamin C. At the end of the study, body and testes weight, sperm parameters, histopathology of testes, testosterone level, testicular levels of malondialdehyde (MDA), nitric oxide (NO), total antioxidant capacity (TAC), and apoptosis (TUNEL assay) were evaluated. Our findings revealed that vitamin C restored spermatogenesis by improving sperm count, motility, viability, morphology, and chromatin integrity. Testosterone levels and testes histopathology were significantly improved in the vitamin C-administrated groups. Furthermore, vitamin C administration markedly alleviated CTL-induced nitro-oxidative damage, enhancing TAC levels, and reducing NO and MDA levels. Whilst CTL therapy induced a significant increase in the number of TUNEL-positive cells compared to the control, the administration of vitamin C significantly prevented the apoptotic effects of CTL. Together, vitamin C therapy protects against CTL-induced testicular damage via mitigating nitro-oxidative stress and apoptosis, which provides evidence for vitamin C as a beneficial therapy against antidepressant drug-associated reproductive toxicity and male sub/infertility.

Evaluation of Choroidal Vascularity Index in Keratoconus Patients: Does Choroidal Vascularity Change in Keratoconus?

Purpose: To investigate the choroidal structure in keratoconic patients with different severity using the choroidal vascularity index (CVI) derived from image binarization on enhanced depth imaging optical coherence tomography scans (EDI-OCT). Methods: Sixty-eight eyes from 34 keratoconus (KCN) patients and 72 eyes from 36 healthy subjects were recruited in this prospective, noninterventional, comparative cross-sectional study. EDI-OCT was employed to measure choroidal parameters, including choroidal thickness (CT), total choroidal area (TCA), luminal area, stromal area, and CVI. Results: Subfoveal CT was 354.6 ± 66.8 µm in the control group and 371 ± 64.5 µm in the KCN group (P = 0.86). There was no significant difference between control and KCN groups in terms of TCA (0.66 ± 0.14 mm2 vs. 0.7 ± 0.12 mm2; P = 0.70), luminal area (0.49 ± 0.10 mm2 vs. 0.53 ± 0.08 mm2; P = 0.67), and stromal area (0.16 ± 0.05 mm2 vs. 0.17 ± 0.05 mm2; P = 0.84). CVI was also comparable in the control group (75.4% ±3.4%) and the KCN group (75.6% ±4.5%; P = 0.43). There was also no significant correlation between other choroidal parameters and KCN severity indices. Conclusion: It seems that CVI as well as other choroidal biomarkers were not significantly different between patients with KCN and healthy subjects.

The protective role of melatonin in citalopram-induced reproductive toxicity via modulating nitro-oxidative stress and apoptosis in male mice.

Citalopram is the most potent selective serotonin reuptake inhibitor, commonly prescribed as an antidepressant, which can cause sexual dysfunction. Melatonin is a natural, highly effective antioxidant playing a pivotal role in the male reproductive system. The present study aimed to explore the ameliorating potential of melatonin on citalopram-evoked testicular toxicity and injury in mice. In this regard, mice were randomly divided into six groups: control, citalopram, melatonin 10 mg/kg, melatonin 20 mg/kg, melatonin 10 mg/kg plus citalopram, and melatonin 20 mg/kg plus citalopram. Adult male mice were intraperitoneally (i.p.) injected with 10 mg/kg of citalopram for 35 days with or without melatonin. At the end of the study, sperm parameters, testosterone level, testicular levels of malondialdehyde (MDA), nitric oxide (NO), total antioxidant capacity (TAC), and apoptosis (Tunel essay) were evaluated. Our findings revealed that melatonin restored spermatogenesis by improving sperm count, motility, viability, morphology, and chromatin integrity. Testosterone levels and the histopathology of the testes were markedly improved in the melatonin-administrated groups. Furthermore, citalopram administration significantly increased oxidative stress; however, melatonin restored antioxidant status by enhancing TAC levels and decreasing NO and MAD levels. More notably, citalopram therapy induced a significant increase in the number of Tunel-positive cells, while melatonin administration significantly mitigated the apoptotic impacts of citalopram. Together, melatonin therapy provides protection against citalopram-induced testicular damage via modulating nitro-oxidative stress and apoptosis, which provides evidence for melatonin as a promising treatment against antidepressant drug-associated reproductive toxicity and male sub/infertility.

Effects of Descemet Stripping Automated Endothelial Keratoplasty on Corneal Densitometry of Cases with Long-Standing Pseudophakic Bullous Keratopathy.

Purpose: To quantify the effects of Descemet stripping automated endothelial keratoplasty (DSAEK) on corneal clarity and densitometry of patients with long-standing pseudophakic bullous keratopathy (PBK) complicated with subepithelial fibrosis. Methods: Thirty-four eyes with PBK complicated with corneal edema for more than 6 months and subepithelial fibrosis were enrolled. All subjects underwent complete ophthalmic examination and corneal densitometry module of Pentacam HR, before and 1, 3, and 6 months after DSAEK. Results: Thirteen patients were excluded due to postoperative complications or missed to follow-up visits. Finally, twenty-one patients' data were analyzed. Corneal densitometry measures significantly decreased in all three layers (anterior, central, and posterior) 3 and 6 months after surgery compared to preoperative values; however, the differences did not reach statistical significance in the 1st month. Moreover, densitometry measurements were significantly lower at month 6 compared to month 1, but not at month 3 compared to month 1. Corneal densitometry of the anterior layer was significantly higher than central and posterior layers in 2 mm and 6 mm zones preoperatively and at all postoperative visits. Corneal light backscatter of each three layers was not statistically different between 0-2 mm and 2-6 mm in all pre- and postoperative visits. Conclusions: Corneal densitometry in cases of PBK begins to improve after DSAEK in different layers in a slow and continued trend which takes up to 6 months for an effect to be seen. Interestingly, this improvement is possible even in complicated corneas with long-standing edema. Hence, corneal densitometry can be used as an objective method for quantification of the outcome of DSAEK in complicated cases of PBK.

Visualizing the mode of action and supramolecular assembly of teixobactin analogues in Bacillus subtilis.

Teixobactin has been the source of intensive study and interest as a promising antibiotic, because of its excellent activity against drug-resistant Gram-positive pathogens and its novel but not yet fully understood mechanism of action that precludes drug resistance. Recent studies have demonstrated that the mode of action of teixobactin is more complicated than initially thought, with supramolecular assembly of the antibiotic appearing to play a critical role in the binding process. Further studies of the interactions of teixobactin with bacteria and its molecular targets offer the promise of providing deeper insights into its novel mechanism of action and guiding the design of additional drug candidates and analogues. The current study reports the preparation and study of teixobactin analogues bearing a variety of fluorophores. Structured illumination microscopy of the fluorescent teixobactin analogues with B. subtilis enables super-resolution visualization of the interaction of teixobactin with bacterial cell walls and permits the observation of aggregated clusters of the antibiotic on the bacteria. Förster resonance energy transfer (FRET) microscopy further elucidates the supramolecular assembly by showing that fluorescent teixobactin molecules co-localize within a few nanometers on B. subtilis. Fluorescence microscopy over time with a fluorescent teixobactin analogue and propidium iodide in B. subtilis reveals a correlation between cell death and binding of the antibiotic to cellular targets, followed by lysis of cells. Collectively, these studies provide new insights into the binding of teixobactin to Gram-positive bacteria, its supramolecular mechanism of action, and the lysis of bacteria that follows.

The vibration study of a sandwich conical shell with a saturated FGP core.

This paper is provided to analyze the free vibration of a sandwich truncated conical shell with a saturated functionally graded porous (FGP) core and two same homogenous isotropic face sheets. The mechanical behavior of the saturated FGP is assumed based on Biot's theory, the shell is modeled via the first-order shear deformation theory (FSDT), and the governing equations and boundary conditions are derived utilizing Hamilton's principle. Three different porosity distribution patterns are studied including one homogenous uniform distribution pattern and two non-homogenous symmetric ones. The porosity parameters in mentioned distribution patterns are regulated to make them the same in the shell's mass. The equations of motion are solved exactly in the circumferential direction via proper sinusoidal and cosinusoidal functions, and a numerical solution is provided in the meridional direction utilizing the differential quadrature method (DQM). The precision of the model is approved and the influences of several parameters such as circumferential wave number, the thickness of the FGP core, porosity parameter, porosity distribution pattern, the compressibility of the pore fluid, and boundary conditions on the shell's natural frequencies are investigated. It is shown that the highest natural frequencies usually can be achieved when the larger pores are located close to the shell's middle surface and in each vibrational mode, there is a special value of the porosity parameter which leads to the lowest natural frequencies. It is deduced that in most cases, natural frequencies decrease by increasing the thickness of the FGP core. In addition, reducing the compressibility of the porefluid a small growth in the natural frequencies can be seen.

Role of Different Types of Contact Lenses in Epithelial Thickness.

OBJECTIVE: To evaluate the potential role of different types of contact lenses, such as soft (SCL), hard (HCL), and mini scleral (SCCL), in corneal epithelial thickness with anterior segment optical coherence tomography (AS-OCT). METHODS: In this cross-sectional study, patients who used contact lens at recent 6 months were recruited consecutively from September 2019 to October 2019, and the epithelial thicknesses of the cornea were obtained by AS-OCT and compared with control subjects who did not use contact lens. RESULTS: In total, 184 eyes (115 subjects) were included; of them, 75 eyes were keratoconic (KCN) and 109 eyes were nonkeratoconic (non-KCN). Twenty eyes in KCN and 79 eyes of non-KCN group had no history of contact lens use and were included for comparison with KCN and non-KCN contact lens users, respectively. Mean duration of contact lens wearing was 75.63±50.42 months. The epithelial thickness of non-KCN SCL group was thinner than that of non-KCN control subjects all over the cornea, whereas the epithelium of non-KCN HCL was thinner at central site as well as nasal and temporal paracentral and midperipheral areas. Epithelial thickness of the KCN HCL group was not different from the KCN control subjects in all sectors. The KCN SCCL group had thinner epithelium at nearly all peripheral sectors as well as inferior, inferotemporal, inferonasal, and nasal midperipheral sectors compared with KCN control subjects. CONCLUSION: The corneal epithelium was thinner at the peripheral zones in KCN SCCL users; at both peripheral and central zones in non-KCN SCL users and in central zones in non-KCN HCL users.

Clinical outcomes of transepithelial photorefractive keratectomy with epithelial ablation targeting actual epithelial thickness vs default laser platform values.

PURPOSE: To investigate the clinical outcomes of transepithelial photorefractive keratectomy (tPRK) with actual epithelial thickness vs default software values. SETTING: Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. DESIGN: Prospective controlled study. METHODS: Patients with refractive spherical error of -1.50 to -7.00 diopters (D) and refractive astigmatism up to 4.00 D were consecutively enrolled and divided into 2 groups: group 1 undergone tPRK with actual central and peripheral epithelial thickness input in right eyes, group 2 undergone tPRK with actual central and 10 mm higher peripheral epithelial thickness in right eyes. Left eyes in both groups underwent tPRK with default protocol. Outcome measures were induced refractive error, achieved optical zone (OZ), and wasted stromal tissue. RESULTS: 83 patients were included in this study. Mean ± SD of induced spherical equivalent was +0.15 ± 0.39 D and +0.01 ± 0.35 D in right and left eyes of group 1 (P = .01) and +0.04 ± 0.22 D and +0.03 ± 0.23 D in right and left eyes of group 2 (P = .75), respectively. There was no statistically significant difference between wasted tissue between right and left eyes in group 1 and group 2 (P = .77 and P = .49, respectively). OZ contraction was significantly higher in right compared with left eyes in group 1 (P = .05), but not in group 2 (P = .95). CONCLUSIONS: In tPRK, refractive outcomes, wasted tissue, and OZ contraction depend little on preexisting corneal epithelial thickness in corneas with normal range epithelial thickness. However, OZ contraction may be a concern in lower amount of ablations.

The Effects of Acute and Long-Term Whole-Body Vibration Training on the Postural Control During Cognitive Task in Patients With Chronic Ankle Instability.

CONTEXT: Chronic ankle instability (CAI) is a common problem associated with impaired postural stability. Whole-body vibration (WBV) has been developed to improve muscle function and reportedly improves postural stability. The aim of this study was to evaluate the effect of 12 sessions of WBV on postural control during standing postural task in participants with CAI. DESIGN: A controlled clinical trial study. METHODS: Sixteen participants with CAI and 16 healthy participants aged between 20 and 40 years included in this study. They received WBV (30-Hz frequency, 3 series of four 45-s exercises with a 45-s rest) for a total of 12 sessions, 2 session per week for 6 weeks. Postural control was assessed by center of pressure (COP) parameters, including mean and SD in the anterior-posterior and medial-lateral displacement during single-leg standing. Assessments were done before and immediately after the first session and after the 12th session of WBV, with opened and closed eyes associated with easy and difficult cognitive tasks. RESULTS: The results showed that the SD of COP displacement in the x-axis was significant in eyes opened and SD of COP displacement in the x- and y-axes were significant between groups in the eyes-opened, and eyes-closed conditions (P < .05). Analysis of variance indicated that the effect of WBV training was significant for the mean of COP displacement in the y-axis. Post hoc indicated that the effect of 12 sessions of WBV on the mean of COP displacement was significant in the CAI group (P < .05). However, the acute effect of WBV was not significant on the COP displacement in all axes (P > .05). CONCLUSION: Higher postural sway associated with postural cognitive interactions might be considered in the rehabilitation of CAI. Twelve sessions of WBV might induce some improvement in postural control with the method of WBV used in this study.

Primary Results of Medial Epicondylar Osteotomy in Patients with Severe Bilateral Varus Knee Candidate for Total Knee Replacement.

Total knee arthroplasty is a challenging task in patients with severe varus deformity. In most of these patients, an extensive medial release is needed that may lead to instability. Medial epicondylar osteotomy may be a better substitute for complete medial collateral release. Fourteen patients with bilateral knee osteoarthritis and severe varus deformity were enrolled in this study. In one side, the patients underwent medial epicondylar osteotomy for mediolateral imbalance if the only option was superficial medial collateral ligament (MCL) release. In contralateral side, the extensive medial release was performed and MCL was released either by pie-crusting technique or by subperiosteally release. The results of the two sides were compared. Patients were followed up for 12 months after the operation. Physical examination, clinical questionnaires, and radiography findings were recorded. Union of the osteotomies fragment and complications was evaluated. The mean varus angle before surgery was 21.6 ± 4.7 degrees, which was corrected to 8.6 ± 2.9 degrees after operation with an extensive medial release. The mean varus angle of contralateral side was 22.6 ± 1.7 degrees, which was corrected to 7.5 ± 2.3 degrees following medial femoral epicondyle osteotomy. There was no significant difference in varus correction (p = 0.1). Medial joint line opening in valgus stress test was 2.7 ± 0.4 mm in the osteotomized side and 3.5 ± 0.9 mm in contralateral side. Mean range of motion for the osteotomized side was 97.8 ± 4.3 degrees and 100.7 ± 2.7 degrees for contralateral side (p = 0.6). Nonunion occurred in a case in the osteotomized side and no medial instability was observed in medial release or osteotomies sides. No statistical difference was recorded based on clinical questionnaires (Oxford and WOMAC [Western Ontario and McMaster Universities Osteoarthritis Index] scores). Medial epicondylar osteotomy is a safe technique with the well-controlled medial extensive release in the patients with severe varus deformity during total knee arthroplasty.

One-Stage Posterior Only Corpectomy and Fusion in the Treatment of a Unique Acute Low Lumbar L4 Burst Fracture Without Neurologic Deficit: A Case Presentation.

L4 and L5 fractures are different from those at the thoracolumbar area. These differences include anatomy, biomechanics, classification, and treatment possibilities. Given the accessible literature and lack of high-quality information about the management of low lumbar fractures, we describe the case of a young 26-year-old male was referred to our emergency medical center with a severe L4 vertebral body comminuted burst fracture with complete spinal canal compression (AO type 4). Incredible, all neurological functions were intact initially. The patient was cured through a one-stage posterior only vertebrectomy and fusion with preservation of all neurological functions. Clinical and radiologic follow-up was satisfactory after 2 years. In more severe lumbar injuries, decisions contain spinal decompression and stabilization through a posterior or anterior approach based on the surgeon's favorite. In our experience in this patient, a posterior approach only was used both for decompression and stabilization without routine challenging existing in anterior approaches.

MyoRing Implantation with and without Corneal Collagen Crosslinking for the Management of Keratoconus.

PURPOSE: To evaluate the safety and efficacy of femtosecond laser-assisted MyoRing implantation with concurrent corneal collagen crosslinking (CXL) compared to MyoRing alone for the treatment of progressive keratoconus. METHODS: A total of 60 patients were enrolled in this randomized controlled trial. The patients were randomly allocated into two groups. In the first group, MyoRing was implanted, while in the second, it was inserted in the corneal stroma using the same technique, along with simultaneous CXL. Visual, refractive, topographic, and abberometric outcomes were measured preoperatively and at every postoperative visit. RESULTS: Data of 47 patients were available at the end of the study; 28 in the MyoRing group and 19 in the MyoRing + CXL group. The mean uncorrected distance visual acuity (UDVA) improved from 0.79 ± 0.39 logMAR to 0.52 ± 0.31 logMAR (P < 0.05) in the MyoRing + CXL group and from 0.65 ± 0.38 logMAR to 0.62 ± 0.23 logMAR (P = 0.70) in the MyoRing group. CDVA changed from 0.33 ± 0.19 logMAR to 0.25 ± 0.16 logMAR (P = 0.10) in the MyoRing + CXL group and 0.32 ± 0.22 logMAR to 0.33 ± 0.17 logMAR (P > 0.50) in the MyoRing group. The mean keratometry (Km) decreased from 47.5 ± 2.7 D to 43.8 ± 3.2 D (P < 0.001) in the MyoRing group and 49.3 ± 3.4 D to 45.1 ± 3.0 D (P < 0.001) in the MyoRing + CXL group. Besides, horizontal coma was significantly lower in the MyoRing + CXL group (P = 0.022). CONCLUSION: MyoRing insertion combined with CXL is a safe and effective method for the treatment of keratoconus. The visual and topographic outcomes were comparable to that for MyoRing insertion after 10 months; however, horizontal coma was significantly lower in the MyoRing + CXL group.

Charge transport in semiconductors assembled from nanocrystal quantum dots.

The potential of semiconductors assembled from nanocrystals has been demonstrated for a broad array of electronic and optoelectronic devices, including transistors, light emitting diodes, solar cells, photodetectors, thermoelectrics, and phase change memory cells. Despite the commercial success of nanocrystal quantum dots as optical absorbers and emitters, applications involving charge transport through nanocrystal semiconductors have eluded exploitation due to the inability to predictively control their electronic properties. Here, we perform large-scale, ab initio simulations to understand carrier transport, generation, and trapping in strongly confined nanocrystal quantum dot-based semiconductors from first principles. We use these findings to build a predictive model for charge transport in these materials, which we validate experimentally. Our insights provide a path for systematic engineering of these semiconductors, which in fact offer previously unexplored opportunities for tunability not achievable in other semiconductor systems.

A Fluorescent Teixobactin Analogue.

This report describes the first synthesis and application of a fluorescent teixobactin analogue that exhibits antibiotic activity and binds to the cell walls of Gram-positive bacteria. The teixobactin analogue, Lys(Rhod)9,Arg10-teixobactin, has a fluorescent tag at position 9 and an arginine in place of the natural allo-enduracididine residue at position 10. The fluorescent teixobactin analogue retains partial antibiotic activity, with minimum inhibitory concentrations of 4-8 µg/mL across a panel of Gram-positive bacteria, as compared to 1-4 µg/mL for the unlabeled Arg10-teixobactin analogue. Lys(Rhod)9,Arg10-teixobactin is prepared by a regioselective labeling strategy that labels Lys9 with an amine-reactive rhodamine fluorophore during solid-phase peptide synthesis, with the resulting conjugate tolerating subsequent solid-phase peptide synthesis reactions. Treatment of Gram-positive bacteria with Lys(Rhod)9,Arg10-teixobactin results in septal and lateral staining, which is consistent with an antibiotic targeting cell wall precursors. Concurrent treatment of Lys(Rhod)9,Arg10-teixobactin and BODIPY FL vancomycin results in septal colocalization, providing further evidence that Lys(Rhod)9,Arg10-teixobactin binds to cell wall precursors. Controls with either Gram-negative bacteria, or an inactive fluorescent homologue with Gram-positive bacteria, showed little or no staining in fluorescence micrographic studies. Lys(Rhod)9,Arg10-teixobactin can thus serve as a functional probe to study Gram-positive bacteria and their interactions with teixobactin.