Two-dimensional heavy fermions in the van der Waals metal CeSiI.

Heavy-fermion metals are prototype systems for observing emergent quantum phases driven by electronic interactions1-6. A long-standing aspiration is the dimensional reduction of these materials to exert control over their quantum phases7-11, which remains a significant challenge because traditional intermetallic heavy-fermion compounds have three-dimensional atomic and electronic structures. Here we report comprehensive thermodynamic and spectroscopic evidence of an antiferromagnetically ordered heavy-fermion ground state in CeSiI, an intermetallic comprising two-dimensional (2D) metallic sheets held together by weak interlayer van der Waals (vdW) interactions. Owing to its vdW nature, CeSiI has a quasi-2D electronic structure, and we can control its physical dimension through exfoliation. The emergence of coherent hybridization of f and conduction electrons at low temperature is supported by the temperature evolution of angle-resolved photoemission and scanning tunnelling spectra near the Fermi level and by heat capacity measurements. Electrical transport measurements on few-layer flakes reveal heavy-fermion behaviour and magnetic order down to the ultra-thin regime. Our work establishes CeSiI and related materials as a unique platform for studying dimensionally confined heavy fermions in bulk crystals and employing 2D device fabrication techniques and vdW heterostructures12 to manipulate the interplay between Kondo screening, magnetic order and proximity effects.

FunARTS, the Fungal bioActive compound Resistant Target Seeker, an exploration engine for target-directed genome mining in fungi.

There is an urgent need to diversify the pipeline for discovering novel natural products due to the increase in multi-drug resistant infections. Like bacteria, fungi also produce secondary metabolites that have potent bioactivity and rich chemical diversity. To avoid self-toxicity, fungi encode resistance genes which are often present within the biosynthetic gene clusters (BGCs) of the corresponding bioactive compounds. Recent advances in genome mining tools have enabled the detection and prediction of BGCs responsible for the biosynthesis of secondary metabolites. The main challenge now is to prioritize the most promising BGCs that produce bioactive compounds with novel modes of action. With target-directed genome mining methods, it is possible to predict the mode of action of a compound encoded in an uncharacterized BGC based on the presence of resistant target genes. Here, we introduce the 'fungal bioactive compound resistant target seeker' (FunARTS) available at https://funarts.ziemertlab.com. This is a specific and efficient mining tool for the identification of fungal bioactive compounds with interesting and novel targets. FunARTS rapidly links housekeeping and known resistance genes to BGC proximity and duplication events, allowing for automated, target-directed mining of fungal genomes. Additionally, FunARTS generates gene cluster networking by comparing the similarity of BGCs from multi-genomes.

Robust Surface States and Coherence Phenomena in Magnetically Alloyed SmB_{6}.

Samarium hexaboride is a candidate for the topological Kondo insulator state, in which Kondo coherence is predicted to give rise to an insulating gap spanned by topological surface states. Here we investigate the surface and bulk electronic properties of magnetically alloyed Sm_{1-x}M_{x}B_{6} (M=Ce, Eu), using angle-resolved photoemission spectroscopy and complementary characterization techniques. Remarkably, topologically nontrivial bulk and surface band structures are found to persist in highly modified samples with up to 30% Sm substitution and with an antiferromagnetic ground state in the case of Eu doping. The results are interpreted in terms of a hierarchy of energy scales, in which surface state emergence is linked to the formation of a direct Kondo gap, while low-temperature transport trends depend on the indirect gap.

Computed Tomography Diagnostic Abilities for Open-Globe Injuries in Pediatric Versus Adult Patients.

OBJECTIVES: The aim of this study was to compare the role of computed tomography (CT) in the diagnosis of open-globe trauma and intraocular foreign body (IOFB) in pediatric and adult age groups. METHODS: Medical records of cases with open-globe trauma at Inonu University Hospital's Ophthalmology Emergency Service were retrospectively evaluated. Preoperative orbital CT images of the cases obtained at emergency services and their clinical and/or surgical findings were compared in pediatric and adult groups. RESULTS: We included 47 eyes of 47 cases aged 18 years and below (pediatric group) and 85 eyes of 82 cases over 18 years (adult group). The mean ± SD age was 10.80 ± 5.11 years (range, 2-18 years) in the pediatric group and 46.34 ± 19.01 years (range, 19-82 years) in the adult group. Computed tomography images revealed 21.7% of the cases with corneal lacerations, 55.5% with scleral lacerations, and 91.6% with corneoscleral lacerations in the pediatric group, whereas the respective numbers were 48.4%, 66.6%, and 61.9% in the adult group. The detection rates of corneal penetrations and vitreous hemorrhage with CT were significantly lower in the pediatric group than in the adult group (P < 0.05). The CT scans diagnosed 66.6% of the pediatric cases and 90% of the adult cases with an IOFB. CONCLUSIONS: Corneal lacerations and IOFBs can be missed, especially in the pediatric group, because the eye is smaller in adults. Pediatric patients with a history of ocular trauma should undergo an examination under general anesthesia followed by surgical exploration if necessary.

Comparison of Nd:YAG laser (532 nm green) vs diode laser (810 nm) photocoagulation in the treatment of retinopathy of prematurity: an evaluation in terms of complications.

PURPOSE: To compare the anterior and posterior segment complications of diode (810 nm) laser photocoagulation (LPC) and Nd:YAG (532 nm green) LPC in the treatment of retinopathy of prematurity (ROP). PATIENTS AND METHODS: The 84 eyes of 43 patients treated with diode LPC (group 1) and 58 eyes of 31 patients treated with Nd:YAG LPC (group 2) for ROP in our clinic were enrolled in the study. Medical records of all patients were investigated retrospectively. The patients in each group were examined in terms of birth weights, gestational weeks, stage of retinopathy, number of lasers pots, laser parameters, and anterior and posterior complications of LPC. RESULTS: The mean birth weeks of group 1 patients were postmenstrual 27.7 ± 2.5 (23-33), while the mean birth weights were 1006.0 ± 334.5 (540-1980) grams. The mean birth weeks of group 2 patients were postmenstrual 27.4 ± 2.6 (23-33), while the mean birth weights were 1073.8 ± 329.2 (480-1720) grams. The mean numbers of laser spots were 1036.0 ± 515.2 (430-2410) in group 1 per eye, while the mean numbers of laser spots were 1085.4 ± 526.0 (445-2530) in group 2 per eye (p ≥ 0.05). Additional laser application was performed in four eyes (4.8%) in group 1 and four eyes (6.9%) in group 2. Four eyes (4.8%) treated with diode LPC and one eye (1.7%) treated with Nd:YAG laser developed retinal detachment. Two eyes of a patient (3.4%) applied Nd:YAG LPC developed cataract. CONCLUSION: Cataract may develop when Nd:YAG laser is used; however, posterior segment complications may be more likely to appear with the use of diode laser in these cases.

Origin of the temperature dependence of the energy gap in Cr-doped Bi2Se3.

Recent progress in impurity-doped topological insulators has shown that the gap at the Dirac point shrinks with reducing temperature. This is an obstacle for experimental realization of the quantum anomalous Hall effect at higher temperature due to the requirement of a larger energy gap. In order to solve this puzzle, we study the gap at the Dirac point by performing temperature-dependent photoemission spectroscopy and X-ray diffraction experiments in Cr-doped Bi2Se3. Our valence band photoemission study revealed that the gap alters with temperature due to residual gas condensation on the sample surface with cooling. Residual gas on the sample surface creates an electron doping effect that modifies the chemical potential of the system resulting in the change of the gap size with variable temperature. Furthermore, such electron doping can weaken the ferromagnetism and lead to a bulk band contribution in the transport measurements. Therefore, such effects can hinder the existence of the quantum anomalous Hall state at higher temperatures. Hence, this work can pave the way for future studies towards a high-temperature quantum anomalous Hall effect.

Correction: Origin of the temperature dependence of the energy gap in Cr-doped Bi2Se3.

Correction for 'Origin of the temperature dependence of the energy gap in Cr-doped Bi2Se3' by Turgut Yilmaz et al., Phys. Chem. Chem. Phys., 2018, DOI: 10.1039/c7cp08049b.

Toxic effects of systemic cisplatin on rat eyes and the protective effect of hesperidin against this toxicity.

CONTEXT: In the present study, cisplatin (CP) induced eye toxicity and the beneficial effect of hesperidin (HP) was investigated. METHODS: Twenty-eight rats were equally divided into four groups; the first group was kept as control. In the second and third group, CP and HP were given at the doses of 7 mg/kg and 50 mg/kg/d, respectively. In the fourth group, CP and HP were given together at the same doses. Tissue samples were collected on day 14 of CP treatment. RESULTS: The results demonstrated that CP caused a significant increase in thiobarbituric acid reactive substances (TBARS) levels and decrease of glutathione levels and antioxidant enzyme activity (catalase, superoxide dismutase and glutathione peroxidase) in eye tissues compared to other groups, HP prevented these effects of CP. Besides, CP led to histopathological damage in the retina and cornea. On the other hand, HP treatment prevented histopathological effects of CP. CONCLUSION: CP had severe dose-limiting toxic effects and HP treatment can be beneficial against the toxic ocular effects of CP. Thus, it appears that co-administration of HP with CP may be a useful approach to attenuate the negative effects of CP on the eye.

Low-energy electronic structure in the unconventional charge-ordered state of ScV6Sn6.

Kagome vanadates AV3Sb5 display unusual low-temperature electronic properties including charge density waves (CDW), whose microscopic origin remains unsettled. Recently, CDW order has been discovered in a new material ScV6Sn6, providing an opportunity to explore whether the onset of CDW leads to unusual electronic properties. Here, we study this question using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy (STM). The ARPES measurements show minimal changes to the electronic structure after the onset of CDW. However, STM quasiparticle interference (QPI) measurements show strong dispersing features related to the CDW ordering vectors. A plausible explanation is the presence of a strong momentum-dependent scattering potential peaked at the CDW wavevector, associated with the existence of competing CDW instabilities. Our STM results further indicate that the bands most affected by the CDW are near vHS, analogous to the case of AV3Sb5 despite very different CDW wavevectors.

Reversible non-volatile electronic switching in a near-room-temperature van der Waals ferromagnet.

Non-volatile phase-change memory devices utilize local heating to toggle between crystalline and amorphous states with distinct electrical properties. Expanding on this kind of switching to two topologically distinct phases requires controlled non-volatile switching between two crystalline phases with distinct symmetries. Here, we report the observation of reversible and non-volatile switching between two stable and closely related crystal structures, with remarkably distinct electronic structures, in the near-room-temperature van der Waals ferromagnet Fe5-δGeTe2. We show that the switching is enabled by the ordering and disordering of Fe site vacancies that results in distinct crystalline symmetries of the two phases, which can be controlled by a thermal annealing and quenching method. The two phases are distinguished by the presence of topological nodal lines due to the preserved global inversion symmetry in the site-disordered phase, flat bands resulting from quantum destructive interference on a bipartite lattice, and broken inversion symmetry in the site-ordered phase.

Comparison of Visual Field Parameters in Early and Advanced Stages of Multiple Sclerosis Patients Without a History of Optic Neuritis.

This study compared the visual field parameters of multiple sclerosis patients without optic neuritis in early versus advanced stage of the disease. Patients were divided into two groups: group 1 (early stage, n = 14) constituted of patients with Expanded Disability Status Scale scores <3 and group 2 (advanced stage, n = 13) constituted of patients with Expanded Disability Status Scale scores ≥3. Mean visual acuities in both groups were similar (p = 0.674). Mean sensitivity, mean defect, loss of variance, reliability factor parameters (Octopus 101 perimeter) of groups 1 and 2 were 24.17 ± 3.62, 21.81 ± 3.04; 4.14 ± 3.05, 6.49 ± 2.58; 21.61 ± 22.17, 33.31 ± 18.67; and 1.57 ± 2.79, 2.59 ± 3.09, respectively. Compared with group 1, mean sensitivity was significantly lower in group 2 (p = 0.013). Mean defect (p = 0.004) and loss of variance (p = 0.042) parameters in group 2 were significantly higher than in group 1. Mean reliability factor was similar between two groups (p = 0.211). Multiple scleorisis may alter visual field parameters without severe loss of visual acuity by possibly involving optic pathways other than optic nerve.

The effect of anisometropic amblyopia on retrobulbar blood flow parameters. Anisometropic amblyopia and retrobulbar blood flow.

To look for a correlation between or the effect of anisometropia amblyopia on retrobulbar blood flow parameters. Peak systolic velocity (PSV) and end-diastolic velocity (EDV) of the ophthalmic artery (OA), central retinal artery (CRA), and temporal posterior ciliary artery (tPCA) were measured with color Doppler imaging, and systolic/diastolic ratio, resistivity index (RI), and pulsatility index (PI) were computed in 42 patients with anisometropic amblyopia. The mean PSV of OA, CRA, and tPCA in amblyopic and fellow eyes were 62.69 ± 24.04, 62.64 ± 20.18; 9.28 ± 3.71, 10.27 ± 4.18; 10.81 ± 4.59, 11.28 ± 4.91, respectively. The mean EDV of OA, CRA, and tPCA in amblyopic and fellow eyes were 15.87 ± 11.31, 14.52 ± 6.54; 2.48 ± 1.17, 2.62 ± 2.06; 3.04 ± 2.34, 3.14 ± 2.18, respectively. The mean RI of OA, CRA, and tPCA in amblyopic and fellow eyes were 0.76 ± 0.08, 0.76 ± 0.08; 0.72 ± 0.08, 0.74 ± 0.95; 0.72 ± 0.09, 0.72 ± 0.08, respectively. The mean PI of OA, CRA, and tPCA in amblyopic and fellow eyes were 1.77 ± 0.42, 1.81 ± 0.46; 01.58 ± 0.42, 1.59 ± 0.43; 1.54 ± 0.43, 1.58 ± 0.49, respectively. There was no statistically significant difference in any of the measured parameters between the amblyopic and fellow eyes. Anisometropic amblyopia did not cause any change in retrobulbar blood flow in amblyopic eyes.

Characteristics of pellet injuries to the orbit.

PURPOSE: To investigate the features of orbital injuries by pellets fired from the front. DESIGN: Retrospective, 4 cases of pellet injuries. METHODS: Five orbits of 4 patients who sustained pellet injuries received from the front were reviewed retrospectively. The course of injury and results were assessed. Radiological examinations were reviewed. The patients were evaluated between December 1996 and June 2004. RESULTS: Five orbits of 4 patients sustained injuries caused by pellets fired from an anterior direction. The globe in the injured orbit was intact in 2 cases. Severe loss of vision was also present in these 2 globes due to optic nerve involvement. Final visual acuity was down to no light perception in 4 eyes and limited to light perception in 1 eye. CONCLUSIONS: The prognosis of orbital pellet injuries is, unfortunately, poor. A pellet passing through the floor of the orbit often causes double perforation of the globe and, once in the orbital aperture, it travels towards the apex as a result of the conical shape of the orbit and lodges in the optic canal or its entrance, severely damaging the optic nerve. Surgery or other treatments are usually unsuccessful. Even if the globe is intact, vision is usually severely impaired.

A case of ectopic cilia.

Ectopic cilia are the most rare of cilial anomalies. We report a 27-year-old man who presents with tarsal conjunctival symptomatic ectopic cilia. On slit-lamp examination eversion of the lower eyelid demonstrated that several black-white cilia were protruding from the conjunctiva.

Corrigendum to: The Association of Serum Vitamin D Levels with Pseudoexfoliation Glaucoma/Syndrome.

In the Original Article by Dikci et al. "The Association of Serum Vitamin D Levels with Pseudoexfoliation Glaucoma/ Syndrome" (Endocr Metab Immune Disord Drug Targets. 2019; 19(2):166-170) after publication of the article it has come to the corresponding author's attention that there were some errors in the article. In the introduction section, reference 3 should be changed as reference 2 (paragraph 1, line 4) and references 4-6 should be changed as references 3-6 (paragraph 1, lines 6,7). Reference numbers in the references section should be as follows. References 25-28 should be changed as references 7-10 respectively. References 7-24 should be changed as references 11-28 respectively.

The Association of Serum Vitamin D Levels with Pseudoexfoliation Glaucoma/Syndrome

OBJECTIVE: To investigate whether serum vitamin D levels have an effect on pseudoexfoliation (PEX) glaucoma/syndrome development and on the control of glaucoma in these cases. METHOD: A total of 31 cases with PEX glaucoma, 34 cases with the PEX syndrome and 43 control subjects of similar age and sex were included in the study. Vitamin D levels were compared between the groups and also between the cases where glaucoma surgery was performed or not. RESULTS: PEX glaucoma group consisted of 17 males and 14 females, PEX syndrome group of 27 males and 7 females, and the control group of 27 males and 16 females. The mean age was 70.9±8.9 years, 72.1±7.3 years, and 67.9±9.1 years in PEX glaucoma, syndrome and control group, respectively. Mean vitamin D levels were 9.4±7.7 ng/mL, 7.9±6,1 ng/mL, 11.5±14.2 ng/mL in PEX glaucoma, syndrome and control group, respectively (p>0.05). The mean serum vitamin D level was 8.04±4.7 ng/mL in those who underwent glaucoma surgery and 10.1±8.7 ng/mL in those who didn't undergo glaucoma surgery in PEX glaucoma group (p>0.05). No difference was found between the PEX glaucoma sub- groups in terms of the mean deviation when classified according to vitamin D levels (<10 ng/mL, ≥10 ng/mL) (p>0.05). CONCLUSION: Although we found no statistically significant difference between the PEX syndrome/glaucoma, and control group in terms of serum vitamin D levels, serum vitamin D levels were lower in PEX syndrome and glaucoma group than control group. Our results indicate that serum vitamin D levels have no effect on the development of PEX glaucoma/syndrome or the control of the disorder in cases with PEX glaucoma. However, these results need to be supported with further studies on a larger number of patients and with longer follow-up.

Which dose of bevacizumab is more effective for the treatment of aggressive posterior retinopathy of prematurity: lower or higher dose?

PURPOSE: To compare 0.5 mg and 0.625 mg of bevacizumab for treating aggressive posterior retinopathy of prematurity (AP-ROP). METHODS: The medical records of patients with AP-ROP who were administered intravitreal bevacizumab (IVB) as a primary treatment at a university clinic were evaluated retrospectively. Five eyes of three patients (Group 1) who received 0.625 mg/0.025 ml IVB and 10 eyes of another five patients (Group 2) who received 0.5 mg/0.02 ml IVB were evaluated. Laser photocoagulation was used as additional treatment after relapses. Anatomic results and complications were evaluated in both groups. RESULTS: We evaluated 15 eyes of eight patients (four girls and four boys) with a flat demarcation line at posterior zone 2 and plus disease or stage-3 disease in this study. The mean gestational age of the three babies in Group 1 was 26 ± 1 weeks and the mean birth weight was 835.33 ± 48.01 g. The corresponding values were 25.2 ± 1.6 weeks and 724 ± 139.03 g, respectively, for the five babies in Group 2. Retinal vascularization was completed at a mean postmenstrual duration of 53.6 ± 1.5 weeks without additional treatment in the five eyes in Group 1. Laser photocoagulation for relapse was administered to five of the 10 eyes in Group 2. Retinal vascularization was completed at a mean postmenstrual duration of 47.6 ± 1.5 weeks in the remaining five eyes. None of the patients developed complications such as cataract, glaucoma, retinal tear, retinal or vitreous hemorrhage, or retinal detachment. CONCLUSION: Although lower IVB doses in the treatment of AP-ROP are expected to be safer in terms of local and systemic side effects in premature infants, these patients may require additional treatment with IVB or laser photocoagulation.

Multiple Intravitreal Ranibizumab Injections for Persistant Choroidal Neovascularization Associated with Presumed Ocular Histoplasmosis Syndrome.

Presumed ocular histoplasmosis syndrome (POHS) is a clinical entity that is characterized by small, round, discrete, macular or mid peripheral atrophic (punched out) chorioretinal lesions (histo spots), peripapillary scarring, choroidal neovascularization (CNV), and the absence of anterior uveitis and vitritis. Diagnosis of this disorder is based upon characteristic clinical findings and a positive histoplasmin skin test or residence in an endemic region for Histoplasma capsulatum. There is no active systemic disease during diagnosis of POHS. Disciform scarring and macular CNV secondary to POHS is a well-known complication which leads to loss of visual acuity or visual disturbance. Without therapy, the visual prognosis in these patients is unfavorable. Submacular surgery, radiation, steroids, photodynamic therapy, and most recently anti-vascular endothelial growth factor therapy are current therapeutic options for this condition. We report a case with persistent CNV secondary to POHS in a middle-aged woman with moderate myopia and the clinical course of treatment with multiple intravitreal ranibizumab (Lucentis®, Novartis) injections.

Choroidal neovascularization secondary to ocular penetration during retrobulbar anesthesia and its treatment.

Retrobulbar anesthesia is still used before ocular surgery; however, it has various complications including ocular penetration. The penetration/perforation of the globe can cause complications such as endophthalmitis, retinal detachment, and scotoma. Choroidal neovascularization (CNV) is rarely seen, following choroidal rupture in penetrating eye injuries. Here, we present a patient who underwent a pars plana vitrectomy for vitreous hemorrhage secondary to ocular penetration during a retrobulbar injection for cataract surgery. This patient later developed CNV at the penetration site during follow-up. Physicians should remember that CNV can occur as an unusual late complication of ocular penetration during retrobulbar anesthesia.

Protective role of alpha-tocopherol on retinal injury in experimental uveitis in guinea pigs.

PURPOSE: PURPOSEof the study was to determine whether alpha-tocopherol (AT) can protect the retina from oxidative damage in experimental uveitis (EU). MATERIAL AND METHODS: The eyes of 36 adult male guinea pigs were studied. The guinea pigs were divided into three groups of 12 animals each. The first group was used as control. The right eyes of groups 2 and 3 received an intravitreal injection of bovine serum albumin for EU induction. At the same time and also on the consecutive third and fifth days, group 3 received intraperitoneal AT injections. The samples were collected on the eighth day. Retinal malondialdehyde (MDA) levels and the average thickness of the inner plexiform layer were measured and the histopathology of the eyes was studied. RESULTS: The MDA level was significantly lower in the control group than in the groups 2 (p<0.01) and 3 (p<0.05). When compared with the EU group 2, there was a significant lowering of MDA in the AT injected group 3 (p<0.01). The thickness of the inner plexiform layer in the control group 1 was significantly lower than in the other groups (p<0.01). Its thickness in the group 3 supplied with AT was significantly lower than in the group 2 (p<0.01). CONCLUSIONS: The data indicate that intraperitoneal AT administration protects against EU injury in the guinea pig retina as evidenced by the reduced MDA and the thickness of retina.