Anomalously Efficient Dehydrogenation of NH3 on Ir4+ and Ir5.

Gas-phase reactions of iridium cluster cations, Irn+ (n = 1-8), with ammonia are studied at near-thermal energies. In single collision reactions, dehydrogenation of NH3 proceeds at n = 1-5, and in particular, Ir4+ and Ir5+ are found to be significantly reactive. This size dependence is quite different from those of other platinum group metal cluster cations, where usually only the dimers are able to dehydrogenate NH3. Moreover, the sequentially dehydrogenated products, Ir4,5(NH)m+ (m = 2-5), are chiefly observed under multiple collision conditions. This observation suggests that the NH species on Ir4,5+ possibly encourages, or at least does not prohibit, the adsorption of the coming NH3 molecule and the dehydrogenation.

Activation of Methane by Tungsten Carbide and Nitride Cluster Cations.

Gas-phase reactions of tungsten carbide and nitride cluster cations, WnCm+ (n = 1-5, m ≤ 5) and WnNm+ (n = 1-6, m ≤ 2), with methane are investigated at near thermal energies. Most of the clusters react readily with CH4 to form WnCm+1H2+ or WnNmCH2+ under single collision conditions, in contrast to the almost no reactivity of pure tungsten clusters. This result indicates that the introduction of carbon or nitrogen atoms can enhance the reactivity of tungsten clusters toward the CH4 dehydrogenation. In addition, the formation and the release of an ethylene molecule are strongly suggested in the reaction of WC+ with CH4 as a minor reaction channel. Nearly all the nitride cluster cations, WnNm+ (n ≥ 2), exhibit higher reactivity than their corresponding carbides, WnCm+, whereas WN+ is less reactive than WC+. Furthermore, the multiple collision reactions of the highly reactive tungsten nitride species such as WN+ and W4N+ lead to the formation of WnNmCxH2x+ (x = 2, 3), which shows that the dehydrogenation of more than one CH4 molecule occurs.

PIEZO2 deficiency is a recognizable arthrogryposis syndrome: A new case and literature review.

PIEZO2 encodes a mechanically activated cation channel, which is abundantly expressed in dorsal root ganglion neuron and sensory endings of proprioceptors required for light touch sensation and proprioception in mice. Biallelic loss-of-function mutations in PIEZO2 (i.e., PIEZO2 deficiency) were recently found to cause an arthrogryposis syndrome. Sixteen patients from eight families have been reported to date. Herein we report a new case, including detailed clinical characteristics and courses as well as comprehensive neurological features. The patient was a 12-year-old girl presenting with congenital multiple contractures, progressive severe scoliosis, prenatal-onset growth impairment, motor developmental delay with hypotonia and myopathy-like muscle pathology, mild facial features, and normal intelligence. Her neurological features included areflexia, impaired proprioception, and decreased senses. Neurophysiological examination revealed decreased amplitude of sensory nerve action potentials, absent H reflex, and prolongation of central conduction times. Clinical exome sequencing revealed a novel homozygous frameshift mutation in PIEZO2 (NM_022068: c.4171_4174delGTCA: p.Val1391Lysfs*39) with no detectable mRNA expression of the gene. PIEZO2 deficiency represents a clinical entity involving characteristic neuromuscular abnormalities and physical features. Next generation sequencing-based comprehensive molecular screening and extensive neurophysiological examination could be valuable for diagnosis of the disorder.

Dehydrogenation of Methane by Partially Oxidized Tungsten Cluster Cations: High Reactivity Comparable to That of Platinum Cluster Cations.

Gas-phase reactivity of pure and partially oxidized tungsten atomic and cluster cations, Wn+ (n = 1-6) and WnOm+ (n = 1-5, m ≤ 6), with methane is studied at the collision energies from 0.1 to 1.0 eV under single collision conditions. The dehydrogenation of CH4 (i.e., the release of H2) is observed for most of WnOm+, whereas Wn+ (n ≥ 2) are almost unreactive. This result indicates that the reactivity of tungsten clusters can be enhanced by the addition of oxygen atoms. Moreover, the reaction cross section of WnOm+ strongly depends on the cluster composition, and some clusters such as W2O3+, W3O+, W3O5+, and W5O3+ exhibit high reactivity. It turns out that the reactivity of these clusters is roughly comparable to that of the typical platinum cluster cations, which are one of the most reactive clusters toward methane dehydrogenation. The reactivity of Wn+ and WnOm+ toward CH4 can be explained by a simple model of their orbital energies and the potential energy diagrams obtained by using the density functional theory calculations. The calculations also suggest that the oxygen atom(s) in WnOm+ is like a spectator and the formation of a hydroxyl group is not necessary for the cleavage of C-H bonds in CH4.

Gas-Phase Reactions of Copper Oxide Cluster Cations with Ammonia: Selective Catalytic Oxidation to Nitrogen and Water Molecules.

Reactions of copper oxide cluster cations, Cu nO m+ ( n = 3-7; m ≤ 5), with ammonia, NH3, are studied at near thermal energies using a guided ion beam tandem mass spectrometer. The single-collision reactions of specific clusters such as Cu4O2+, Cu5O3+, Cu6O3+, Cu7O3+, and Cu7O4+ give rise to the release of H2O after NH3 adsorption efficiently and result in the formation of Cu nO m-1NH+. These Cu nO m+ clusters commonly have Cu average oxidation numbers of 1.0-1.4. On the other hand, the formation of Cu nO m-1H2+, i.e., the release of HNO, is dominantly observed for Cu7O5+ with a higher Cu oxidation number. Density functional theory calculations are performed for the reaction Cu5O3+ + NH3 → Cu5O2NH+ + H2O as a typical example of H2O release. The calculations show that this reaction occurs almost thermoneutrally, consistent with the experimental observation. Further, our experimental studies indicate that the multiple-collision reactions of Cu5O3+ and Cu7O4+ with NH3 lead to the production of Cu5+ and Cu7O+, respectively. This suggests that the desirable NH3 oxidation to N2 and H2O proceeds on these clusters.

Effects of Second-Metal (Al, V, Co) Doping on the NO Reactivity of Small Rhodium Cluster Cations.

Reactions of pure and doped rhodium cluster cations, RhnX+ (n = 2-6; X = Al, V, Co, Rh), with NO molecules were investigated at near-thermal energy using a guided ion beam tandem mass spectrometer. We found that the doping with Al and V increases the total reaction cross section mostly. Under single-collision conditions, Rh2X+ reacts with NO to produce Rh2N+ with release of metal monoxide, XO, whereas RhnX+ (n = 3-6) adsorb NO. For the specific clusters RhnAl+ (n = 3 and 4) and RhnV+ (n = 4-6), the NO adsorption is often accompanied by the release of one Rh atom. In addition, we examined the reactions of Rh5X+ (X = Al, V, Co, Rh) with NO under multiple-collision conditions and observed the cluster dioxide formation and the N2 release, i.e., NO decomposition. Particularly, the V-doping is most effective for the NO decomposition. One possible explanation for the present results is that the formation of a stable dopant metal-oxygen bond directly leads to the increase of NO dissociative adsorption energy and the reduction of the energy barrier between the molecular and dissociative adsorption, thereby encouraging the NO decomposition on the small RhnX+ clusters studied.

Milder progressive cerebellar atrophy caused by biallelic SEPSECS mutations.

Cerebellar atrophy is recognized in various types of childhood neurological disorders with clinical and genetic heterogeneity. Genetic analyses such as whole exome sequencing are useful for elucidating the genetic basis of these conditions. Pathological recessive mutations in Sep (O-phosphoserine) tRNA:Sec (selenocysteine) tRNA synthase (SEPSECS) have been reported in a total of 11 patients with pontocerebellar hypoplasia type 2, progressive cerebellocerebral atrophy or progressive encephalopathy, yet detailed clinical features are limited to only four patients. We identified two new families with progressive cerebellar atrophy, and by whole exome sequencing detected biallelic SEPSECS mutations: c.356A>G (p.Asn119Ser) and c.77delG (p.Arg26Profs*42) in family 1, and c.356A>G (p.Asn119Ser) and c.467G>A (p.Arg156Gln) in family 2. Their development was slightly delayed regardless of normal brain magnetic resonance imaging (MRI) in infancy. The progression of clinical symptoms in these families is evidently slower than in previously reported cases, and the cerebellar atrophy milder by brain MRI, indicating that SEPSECS mutations are also involved in milder late-onset cerebellar atrophy.

Reactions of Ti- and V-Doped Cu Cluster Cations with Nitric Oxide and Oxygen: Size Dependence and Preferential NO Adsorption.

Reactions of copper cluster cations doped with an early transition metal atom, CunTi(+) (n = 4-15) and CunV(+) (n = 5-14, 16), with NO and O2 were investigated at a near-thermal collision energy using a guided ion beam tandem mass spectrometer. Most of the clusters adsorb NO and O2 under single collision conditions, and this reaction is often followed by the release of Cu atoms. For both Ti- and V-doped Cu clusters, the total cross sections for the reaction with NO increase gradually with the cluster size up to n ≈ 11 and then decrease rapidly, whereas those with O2 are almost constant in n ≤ 12 and then decrease. The size dependence of the reactivity toward NO is found to correlate with that of the adsorption energy calculated by the density functional theory method; CunTi(+) clusters exhibit the larger reaction cross sections when they have the larger adsorption energies. The calculations of CunTi(+) also show that a structural transition from a Ti-exposed structure to Ti-encapsulated one occurs around n = 12. This indicates that a geometric property of the clusters, i.e., the position of the dopant atom, is a determining factor of reactivity. In addition, the Ti- and V-doping dramatically improves the reactivity of Cu cluster cations toward NO but it does not affect that toward O2 significantly. As a result, most of the Ti- and V-doped Cu clusters are more reactive toward NO than toward O2. We also studied the multiple-collision reaction of Cu7Ti(+) with NO and obtained the cluster dioxide, Cu3TiO2(+), as a product ion, which suggests that the dissociation of NO and the subsequent formation/release of N2 take place.

Possibility of Using Standard Plates for Orbital Fracture.

OBJECTIVES: Absorbable plates are sometimes grafted for treating orbital fractures. These plates cannot be readily processed to fit the shape of the fracture site, particularly when the fracture encompasses a broad area from the medial toward the inferior wall. Preparing the plates in a standard shape beforehand will be useful. Thus, in this study, the authors measured the orbital wall distance in healthy orbits to determine the mean orbital size with the ultimate goal of developing and clinically applying a standard plate for orbital fracture. METHODS: Measurements were performed for the left eye orbit on computed tomography images using a three-dimensional medical image processing workstation. The authors measured the orbital wall distances and angle of healthy orbits in 40 males and 40 females to determine the mean size of the orbit. RESULTS: In healthy orbits, no significant difference was noticeable in the angle between medial wall and inferior wall between males and females. The medial, inferior, and medial + inferior wall distances were markedly longer in males than in females (P < 0.05). DISCUSSIONS: The orbital shapes had the same pattern in males and females. The standard plate would be adaptable to all cases if it were produced with the medial wall + inferior wall distance greater than the maximum value in males and trimmed to fit the orbit form of the patient. CONCLUSIONS: The results would be the basis of creating a standard plate and using it after appropriate adjustments.

Stability of Aluminum-Doped Copper Cluster Cations and Their Reactivity toward NO and O2.

Aluminum-doped copper cluster cations, CunAl(+), were produced via an ion sputtering method and analyzed by mass spectrometry. The measured size distributions show that Cu6Al(+) and Cu18Al(+) are highly stable species, which can be understood in terms of the electronic subshell 1P and 2S closings, respectively. Furthermore, the reactions of size-selected CunAl(+) (n = 4-6 and 8-16) with NO and O2 were studied at near thermal energies by using a tandem-type mass spectrometer. The doping of an Al atom improves the reactivity of the clusters toward NO in particular for n = 9, 11, 13, and 15, whereas it does not change the reactivity toward O2 significantly. Consequently, it was found that CunAl(+) (n = 9, 11, 13 and 15) are more reactive toward NO than toward O2. The high reactivity of Cu9Al(+) toward NO compared to that of Cu10(+) is explained in terms of the increase of the adsorption energy and the lowering of the barrier to dissociative adsorption, with the aid of calculations based on density functional theory. Moreover, the multiple-collision reactions of CunAl(+) (n = 9, 11, and 13) with NO result in the production of cluster dioxides, Cun-3AlO2(+), (i.e., release of N2), which clearly indicates that NO decomposition proceeds on these clusters.

Phenotypic spectrum of COL4A1 mutations: porencephaly to schizencephaly.

OBJECTIVE: Recently, COL4A1 mutations have been reported in porencephaly and other cerebral vascular diseases, often associated with ocular, renal, and muscular features. In this study, we aimed to clarify the phenotypic spectrum and incidence of COL4A1 mutations. METHODS: We screened for COL4A1 mutations in 61 patients with porencephaly and 10 patients with schizencephaly, which may be similarly caused by disturbed vascular supply leading to cerebral degeneration, but can be distinguished depending on time of insult. RESULTS: COL4A1 mutations were identified in 15 patients (21%, 10 mutations in porencephaly and 5 mutations in schizencephaly), who showed a variety of associated findings, including intracranial calcification, focal cortical dysplasia, pontocerebellar atrophy, ocular abnormalities, myopathy, elevated serum creatine kinase levels, and hemolytic anemia. Mutations include 10 missense, a nonsense, a frameshift, and 3 splice site mutations. Five mutations were confirmed as de novo events. One mutation was cosegregated with familial porencephaly, and 2 mutations were inherited from asymptomatic parents. Aberrant splicing was demonstrated by reverse transcriptase polymerase chain reaction analyses in 2 patients with splice site mutations. INTERPRETATION: Our study first confirmed that COL4A1 mutations are associated with schizencephaly and hemolytic anemia. Based on the finding that COL4A1 mutations were frequent in patients with porencephaly and schizencephaly, genetic testing for COL4A1 should be considered for children with these conditions.

Catalytic oxidation of CO with N2O on isolated copper cluster anions.

A catalytic redox reaction involving N2O and CO on size-selected copper cluster anions, Cun(-), was investigated in the gas phase using a guided ion-beam tandem mass spectrometer. When Cun(-) is exposed to a mixture of N2O and CO, CunO(-) is produced via the decomposition of N2O. Increase of the CO partial pressure results in the reproduction of Cun(-) and decrease of CunO(-) through the oxidation of CO. The present results demonstrate that a full catalytic cycle for the reaction, N2O + CO → N2 + CO2, takes place on copper cluster anions. Furthermore, in the investigations of the elementary reactions of Cun(-) + N2O and CunO(-) + CO, we found that the catalytic oxidation of CO with N2O on Cun(-) proceeds most efficiently at n = 7 in the size range of n = 5-16.

Reactions of size-selected copper cluster cations and anions with nitric oxide: enhancement of adsorption in coadsorption with oxygen.

Reactions of size-selected Cu(n)(±) and Cu(n)O(m)(±) (n = 3-19, m ≤ 9) clusters with NO were investigated in the near-thermal energy region under single collision conditions using a tandem-type mass spectrometer with two ion-guided cells. Oxygen atoms preadsorbed on the cluster can significantly enhance the NO adsorption probability and cause additional reactions. NO adsorption is observed particularly for anionic copper cluster dioxides, Cu(n)O2(-) (n ≥ 8), followed by the release of a Cu atom from Cu(n)O2(-) (n = 8, 10, and 12), which suggests that NO adsorbs strongly, i.e., dissociatively on these clusters. Density functional theory calculations support that dissociative adsorption of NO occurs in the reaction of Cu8O2(-) under the present experimental conditions. On the other hand, NO oxidation proceeds in reactions of oxygen-rich cluster cations such as Cu4O3(+), Cu6O5(+), Cu9O7(+), and Cu11O8(+).

Oxidation of CO and NO on composition-selected cerium oxide cluster cations.

The collisional reactions of composition-selected cerium oxide cluster cations, CenOm(+) (n = 2-6; m ≤ 2n), with CO and NO have been investigated under single collision conditions using a tandem mass spectrometer. At near-thermal energy, oxidation of CO and NO is observed only for the stoichiometric clusters, CenO2n(+) (n = 3-5), and the cross sections for the NO oxidation are found to be larger than those for the CO oxidation. In addition, the collision-energy dependence of the reaction cross sections reveals that the CO oxidation has a small activation barrier, whereas the NO oxidation is a barrierless process. These experimental findings are supported by density functional theory calculations.

Molecular mechanism for distinct neurological phenotypes conveyed by allelic truncating mutations.

The molecular mechanisms by which different mutations in the same gene can result in distinct disease phenotypes remain largely unknown. Truncating mutations of SOX10 cause either a complex neurocristopathy designated PCWH or a more restricted phenotype known as Waardenburg-Shah syndrome (WS4; OMIM 277580). Here we report that although all nonsense and frameshift mutations that cause premature termination of translation generate truncated SOX10 proteins with potent dominant-negative activity, the more severe disease phenotype, PCWH, is realized only when the mutant mRNAs escape the nonsense-mediated decay (NMD) pathway. We observe similar results for truncating mutations of MPZ that convey distinct myelinopathies. Our experiments show that triggering NMD and escaping NMD may cause distinct neurological phenotypes.

Orthodontic treatment in combination with Le Fort II bone distraction in patient with Apert syndrome.

We report a case of an 11-year-old girl presenting with Apert syndrome characterized by midface concavity, protrusion of the eyeballs, and ocular hypertelorism. She had class III anterior crossbite, narrow upper and lower arches, and marked crowding. Based on cephalometric analysis, anterior crossbite associated with marked midfacial hypoplasia was diagnosed. Orthodontic treatment in combination with Le Fort II maxillary distraction was scheduled. The dentition was laterally extended using a Rapid palatal expander in the upper jaw and a Bihelix in the lower jaw. Multi-bracket appliances were simultaneously applied for leveling. Next, Le Fort II maxillary osteotomy was performed to distract the midface bone 16 mm anteroinferiorly using a rigid external distraction system. Orthodontic treatment was completed at 3.8 years after initiation. Bone distraction moved the upper jaw anteriorly downward, and the lower jaw subsequently rotated posteriorly downward, leading to a marked improvement in facial appearance and occlusion. Elongation of the dorsum of the nose, in particular, allowed esthetic improvement of the saddle nose. These improvements remain stable at 2 years after orthodontic treatment.

Comparison of adsorption probabilities of O2 and CO on copper cluster cations and anions.

Reactions of size-selected copper cluster cations and anions, Cu(n)(±), with O(2) and CO have been systematically investigated under single collision conditions by using a tandem-mass spectrometer. In the reactions of Cu(n)(±) (n = 3-25) with O(2), oxidation of the cluster is prominently observed with and without releasing Cu atoms at the collision energy of 0.2 eV. The reactivity of Cu(n)(+) is governed to some extent by the electronic shell structure; the relatively small reaction cross sections observed at n = 9 and 21 correspond to the electronic shell closings, and those at odd sizes in n ≤ 16 match with the clusters having no unpaired electron. On the other hand, the reactivity of Cu(n)(-) exhibits no remarkable decrease by the electronic shell closings and the even-numbered electrons. These behaviors may be due to an influence of the electron detachment of the reaction intermediate, Cu(n)O(2)(-). Both the cations and anions show the dominant formation of Cu(n-1)O(2)(±) in n ≤ 16 and Cu(n)O(2)(±) in n ≥ 17 in the experimental time window. By contrast, Cu(n)(-) (n = 3-11) do not react with CO at the collision energy of 0.2 eV, while Cu(n)(+) (n = 3-19) adsorb CO though the cross sections are relatively small. The difference in the reactivity between the charge states can be understood in terms of the frontier orbitals of the Cu cluster and O(2) or CO.

A case of pyruvate dehydrogenase E1α subunit deficiency with antenatal brain dysgenesis demonstrated by prenatal sonography and magnetic resonance imaging.

Prenatal depiction of brain dysgenesis in patients with pyruvate dehydrogenase complex (PDHc) deficiencies has been infrequently reported. As PDHc plays a critical role in the brain that obtains all of the energy from the aerobic oxidation of glucose, its deficiency is a severe inborn disorder of metabolism, which predominantly affects the nervous system. This report describes a case of PDHc deficiency with antenatal brain dysgenesis depicted in detail by fetal ultrasound and magnetic resonance imaging. This is the first case report clearly demonstrating the developing mechanism and time course of antenatal brain lesions in a patient with PDHc deficiency.

[A case of acute necrotizing encephalopathy and acute encephalopathy with biphasic seizures and late reduced diffusion].

Acute necrotizing encephalopathy (ANE) has a characteristic imagimg finding of bilateral symmetrical thalamic lesions. Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is characterized by biphasic clinical course and high intensity of subcortical white matter in MRI diffusion images appearing around the late seizure. We herein report a case of an 8-month-old girl who presented with fever and status epilepticus associated with human herpes 6 infection. Although MRI first demonstrated images of ANE, typical AESD images were observed several days after the onset. We therefore concluded that this case had a combination of ANE and AESD. A proper therapeutic strategy should be established, and acute encephalopathy needs to be better clarified by identifying diagnostic markers and improving the genetical analysis.

Straightforward factors for predicting the prognosis of blow-out fractures.

In blow-out fractures, some nonoperative cases have a poor outcome, and a method for accurate prognosis is required. To address this need, we retrospectively reviewed blow-out fractures presenting at Teikyo University Hospital between July 2004 and May 2007 and conducted a survey regarding diplopia and enophthalmos for nonoperative cases. Computed tomographic scan findings were divided according to fracture width and the degree of protrusion of the inferior rectus muscle into the maxillary sinus. We had 106 patients presenting with blow-out fractures, and 89 patients had been treated nonoperatively. In medial orbital wall fractures, no patient had diplopia, and 1 patient had enophthalmos after nonoperative treatment. In punched-out orbital floor fractures, all cases had diplopia when the fracture width was less than half the diameter of the globe, and the protrusion of the inferior rectus muscle into the maxillary sinus was half or more of its section. Even if the fracture width was less than half the diameter of the globe, 2 of 3 patients had enophthalmos when the protrusion of the inferior rectus muscle into the maxillary sinus was half or more of its section. Among the linear orbital floor fractures, 1 case required an emergency operation. We suggest a new algorithm for treatment of blow-out fractures based on computed tomographic scan findings that can also contribute to making a prognosis.