Body dysmorphic disorder treatment: about a clinical case

Introduction

Body dysmorphic disorder (BDD) is a relatively common disorder characterized by a preoccupation with non-existent or slight defects in appearance. It was first described in 1886 by Morselli as dysmorphophobia.

Objectives

This work reviews the current available data on BDD and its treatment options and describes a clinical case that reports an improvement in symptomatology after surgery.

Methods

Non-systematic review of the literature with selection of scientific articles published in the past 10 years; by searching Pubmed and Medscape databases using the combination of MeSH descriptors. The following MeSH terms were used: “body dysmorphic disorder”, “dysmorphophobia”. Clinical file consultation.

Results

The usual treatment involves a combination of psychotherapy and pharmacotherapy. Antidepressant medication, mainly selective serotonin reuptake inhibitors (SSRIs) have been used. If the symptoms do not improve, a different SSRI can be considered or clomipramine, venlafaxine or second-generation antipsychotics can be useful.

Conclusions

The role of surgery remains controversial, several studies indicating that the symptoms typically worsen after an aesthetic procedure because the preoccupation shifts to a different body area. However a recent study reported 32 of the 41 patients that underwent surgery were highly satisfied with the outcome. In our clinical case, our patient, a 20-year-old female with non-delusional dysmorphic ideas about her nose initiated treatment with paroxetine with poor response and was, against medical opinion, submitted to a rhinoplasty. Three weeks after the surgery there was an improvement in preoccupation about her nose. More research should be made to clarify the role of surgery in this disorder that often lacks adequate therapeutical response.

Disclosure

No significant relationships.

Acceptance and Commitment Therapy for Psychosis. What’s the evidence?

Introduction

Cognitive behavioural therapy for psychosis as an adjuvant to pharmacological treatment has been been shown to be one of the most effective interventions for schizophrenia with benefits noted in even treatment resistant schizophrenia. Benefits have been mostly registered in the positive symptoms domain of schizophrenia. Acceptance and commitment therapy is a third generation Cognitive-Behavioural Therapy, empirically supported for a range of symptoms and conditions, including psychosis, with quickly increasing data. It targets experiential avoidance, which seems to be closely related with psychopathology. Its ability to also target affective symptoms can be an important advantage in the adjuvant treatment of psychosis.

Objectives

To critically review the evidence of acceptance and commitment therapy in psychosis.

Methods

Non-systematic review of the literature with selection of scientific articles published in the past 10 years; by searching Pubmed and Medscape databases using the combination of MeSH descriptors. The following MeSH terms were used: “schizophrenia”, “acceptance and commitment therapy”.

Results

Very few studies have been published on ACT and psychosis, with even less controlled trials and systematic reviews. So far there is convincing evidence for ACT reducing the frequency of hallucinations, increasing the outcomes of traumatic events associated with psychosis and having measurable effects on anxiety and help seeking behaviour.

Conclusions

As Acceptance and Commitment therapy evolves and more evidence arises a new kind of therapy with possible effects on both affective and positive symptoms in schizophrenia can emerge, allowing us to know what works for patients with psychosis and through what mechanisms and permitting the improvement of treatment strategies.

Disclosure

No significant relationships.

Seizures and alcohol withdrawal: A literature review

Introduction

Seizures occur in about 3% cases of alcohol withdrawal. They usually appear within 48 hours after abrupt cessation, and are characterized by a reduction in seizure threshold secondary to adaptation to alcohol. More than 50% of individuals will experience a new seizure and in 5% of these cases, progression to a sustained epilepticus status can occur.

Objectives

The aim is to do a review of the literature on alcohol withdrawal and the onset of seizures in individuals with alcohol addiction.

Methods

A literature review was conducted using the PubMed search database.

Results

Alcohol is a central nervous system (CNS) depressant and chronic consumption causes neuroadaptation in order to maintain homeostasis. This adaptation involves the upregulation of excitatory neurotransmitters systems and the downregulation of inhibitory ones. When consumption is abruptly discontinued, the depressive contribution of alcohol to a previously established balance is disrupted, resulting in withdrawal symptoms associated to a generalized CNS’ hyperexcitability state.Critical episodes increase the risk of delirium tremens, a fatal condition in 20% of untreated cases. Thus, the treatment and prevention of seizure recurrences is essential: the clinical guidelines of the American Society of Addiction Medicine 2020, offer an action proposal. Pharmacological therapy after seizures is the preferential treatment: intravenous administration of fast-acting benzodiazepines (lorazepam and diazepam) is the first line treatment.

Conclusions

It is essential to monitor signs and symptoms that alert us to the appearance of seizures associated to alcohol withdrawal, effectively treat these cases, prevent recurrences, and provide a quality follow-up for these patients.

Disclosure

No significant relationships.

From Akute Primäre Verruckheit to Bouffée Delirante: The background of Acute Transient Psychosis

Introduction

Ever since the end of the 19th century that descriptions of acute and transient psychosis (ATP) have been found in the literature. Psychiatrists from different countries gave different names for these types of episodes, throughout the ages. Those early descriptions were an important part of the development of the concept of acute and transient psychotic disorders (F23: ICD-10).

Objectives

This review aims to provide historical background of the development of different concepts to describe ATP.

Methods

Non-systematic review of literature on acute and transient psychotic disorders, bouffee delirante, brief psychotic disorder, atypical psychosis.

Results

In 1876, K.Westphal introduced the term akute primäre Verruckheit, refering to a sudden paranoia associated with delusion ideas and hallucinations. In 1895, Magnan described Bouffée delirante, characterized by a recorrent, sudden psychosis with polymorphic symptoms. Later (1924), the term cycloid psychosis was introduced by K.Kleist: phasic psychosis with good prognosis. Different concepts appeared throughout history: psychogenic psychosis (Wimmer,1916); atypical psychosis (Mitsuda,1942), holodisfrenia (Barahona,1957). Nowadays, the classification systems include many of these concepts in the same categories: Schizophreniform disorder, Brief psychotic disorder (DSM-5), and ATP (F23 in ICD-10).

Conclusions

All throughout the History of Psychiatry, there was an evolution of concepts associated to ATP. They were strongly influenced by different time epochs. It is important to have context on the historical background of the concepts used in the contemporaneous Psychiatry. Diagnosis is challenging due to their heterogeneous presentation. There are not many studies available, because of ATP’s low diagnostic stability.

Disclosure

No significant relationships.

Growing use of valproic acid in substance use disorders

Introduction

Valproic acid is an antiepileptic drug used in different fields of Psychiatry. It is known mostly for its use in managing patients with bipolar affective disorder. In psychiatry of addiction, there is still no approved indications for its usage, but it is widely prescribed in treating alcohol and cocaine abuse, due to the existence of studies in these addictions.

Objectives

This review aims to clarify the relation between valproic acid and dependences, particularly cocaine.

Methods

Non-systematic literature review using a PubMed search, using the following key words: “valproate”; “cocaine use”.

Results

Cocaine dependence can decrease GABA levels in humans. Valproic acid has multiple mechanisms that favour the synthesis of GABA, potentiating its release and postsynaptic GABAergic response. Because of this, valproic acid was found effective in promoting abstinence and in reducing the use of cocaine. There are studies that support the valproic acid’s use in alcohol and cocaine dependences. Valproic acid has been shown to be promising in relapse prevention. It has also showed efficacy in the management of impulsivity and irritability, what makes it useful in managing patients with borderline personality disorder – patients at higher risk for alcohol or substance use disorders.

Conclusions

Cocaine addiction involves different phenomena and may respond to distinct pharmacologic approaches. Although some studies need to be confirmed by larger clinical trials, valproic acid seems a promising agent as one of some potential treatments for cocaine dependence. Further studies are required in this field to come to more reliable conclusions.

Disclosure

No significant relationships.

Electroconvulsive therapy for Patients with Intellectual Disability. When and how?

Introduction

Intelectual disability is an illness with an important burden on patients and caregivers, especially when severe and when comorbidities such as other psychiatric disorders are present. There are case reports of treatment resistant self-aggression, agitation, epilepsy, catatonia and psychosis successfully treated with electroconvulsive therapy although controlled studies were not found.

Objectives

This work reviewed the current evidence for the use of electroconvulsive therapy in the management of patients with intellectual disability as well as its ethical and methodological implications.

Methods

Non-systematic review of the literature with selection of scientific articles published in the past 20 years; by searching Pubmed and Medscape databases using the combination of MeSH descriptors. The following MeSH terms were used: “electroconvulsive therapy”, “intellectual disability”.

Results

Patients with intellectual disability can have incapacitating comorbilities that greatly impair quality of life, and may require withdrawl from the community Treatment often differs from the general population as psychotropic medication can worsen other comorbilities. Electroconvulsive therapy can be a relevant treatment option for comorbidities in this population due to its safety profile. Ethical considerations should be taken into account, especially with non-verbal patients or when adequate representatives have not been chosen or cannot be reached. Different legal challenges may be present on different countries.

Conclusions

Electroconvulsive therapy and intellectual disability share the burdens of heavy stigma and low investment. Intellectual disability and it’s commorbidites present both a diagnostic and treatment challenge. Electroconvulsive therapy is an important weapon capable of restoring patients to their families and diminishing the burdens of caregivers and healthcare systems

Disclosure

No significant relationships.

The phenomenology of motivation

Introduction

The concept of motivation pervades our professional and personal lives. Motivation is almost impossible to be observed directly, it is a construct for the interpretation of a behaviour that “calls the attention”.

Objectives

This work reviews the current available data on the phenomenological description of motivation and the abnormalities of motivation.

Methods

Non-systematic review of the literature with selection of scientific articles published in the past 10 years; by searching Pubmed and Medscape databases using the combination of MeSH descriptors. The following MeSH terms were used: “motivation”, “psychopathology”, “phenomenology”.

Results

Abnormalities in motivation may involve diminution or exacerbation. Anhedonia is the absence of pleasure in relation to usually pleasurable activities, it occurs in depression and schizophrenia where the pleasurable intrinsic motivation that acts as incentive for behaviour may be lost. In mania it may be increased so that mundane activities become unduly fascinating and rewarding.

Conclusions

Countless theories have been proposed to explain human motivation but each sheds light on specific aspects of motivation, neglecting others. This diversity creates confusion because most theories have areas of conceptual overlap and disagreement. To facilitate the development of studies, an agreement should be achieved on an operational definition of motivation.

Disclosure

No significant relationships.

Shame and psychopathology. Its role in the genesis and perpetuation of different disorders

Introduction

Shame is a profound negative emotion that can sometimes be cover up by guilt and remain undiagnosed. Shame and guilt have been described as self-conscious and moral emotions as they both involve self-evaluation and lay a role in facilitating moral conduct. They derive from the notion of responsibility, but some authors suggest that while guilt focuses only on the act at hand shame focuses on the one executing it. The self is the object.

Objectives

To review the literature on shame and its role in different disorders both as a causing agent and as a perpetuating agent

Methods

Non-systematic review of the literature with selection of scientific articles published in the past 20 years; by searching Pubmed and Medscape databases using the combination of MeSH descriptors. The following MeSH terms were used: “shame”, “psychopathology.

Results

Since shame globally decreases self-esteem and is an awareness of personal flaws it can lead to the feelings of helplessness and the development or worsening of mental disorders. As such it is no wonder to find shame being studied in many different forms, more and less structured with important connections being made with social anxiety, eating disorders, dysmorphic disorders, personality disorders and bereavement.

Conclusions

Shame’s role, independently from guilt can have an impact on both the genesis and perpetuation of mental disorders. Its study can uncover missing links between different types of experiences and the pathological reactions that may subsequently follow.

Disclosure

No significant relationships.

Electroconvulsive therapy for Depression in Anorexia Nervosa. A review

Introduction

Anorexia nervosa has an important burden on both patients and families, with important comorbidities such as depression and obsessive symptoms. These are more resistant to pharmacological treatment than in non-anorexia patients, due to both biological and psychological mechanisms. Electroconvulsive therapy is the best available therapy for treatment resistant depression making it a treatment to consider in treatment resistant depression in anorexia though only case reports exist.

Objectives

To review the current evidence for electroconvulsive therapy of depression in patients with anorexia nervosa as well as it’s ethical challenges

Methods

Non-systematic review of the literature with selection of scientific articles published in the past 10 years; by searching Pubmed and Medscape databases using the combination of MeSH descriptors. The following MeSH terms were used: “electroconvulsive therapy”, “anorexia nervosa”.

Results

Electroconvulsive therapy in anorexia has no controlled trials with mostly case reports available on scientific databases. It presents important challenges due to patient age, medical status and ethical challenges. Even less evidence exist for electroconvulsive therapy in children and adolescents than for adults, anorexia can complicate medical status presenting an anesthetic and life-support challenge and it’s egosyntonicity can place a legal and ethical challenge when patient refuses treatment.

Conclusions

Anorexia has a dramatic burden on patients and families affected, with integrated evidence-based treatment being necessary both for treating the current episode and for remission prevention. Case-reports show that electroconvulsive therapy can play a role on treatment resistant depression in anorexia.

Disclosure

No significant relationships.

Cannabis use and cognitive impairment in schizophrenia

Introduction

Neurocognitive deficits amongst patients with schizophrenia are considered one of schizophrenia’s central features. These deficits appear to be present from the first episode of psychosis (FEP) and certain cognitive impairments could be components of a genetic vulnerability to schizophrenia. Regarding research on cannabis and cognition in schizophrenia, different studies have assessed neurocognitive functions: memory, attention/vigilance, processing speed, verbal learning, executive functions, and verbal fluency.

Objectives

The aim is to do a review of recent findings concerning the association of cannabis use with cognition in schizophrenia.

Methods

A literature review was conducted using the PubMed search database.

Results

Patients with schizophrenia and concomitant cannabis use are associated with worse performance in immediate verbal learning, and in some studies with worse working memory performance. There is an improvement of verbal memory when they cease the cannabis’ consumption. Regarding attention capacity and memory types assessed, the results are controversial. In FEP, heavy cannabis use during the previous year correlates with slower processing speed. Also, FEP-patients with cannabis use but no family history of psychosis perform worse in executive functions, while those with a family history of psychosis perform better.

Conclusions

The studies of psychosis, cannabis and cognition differ in relevant aspects, which might be connected to the result variability. Therefore, before solid conclusions can be reached, it is important to carry out longitudinal studies to understand the changes in the cognitive variables, which can depend on the pattern of cannabis’ use (concurrent or prior to the FEP). Possible confounding variables that might be present should be acknowledged.

Disclosure

No significant relationships.

Clinicopathological features of cutaneous reactions after mRNA-based COVID-19 vaccines

BACKGROUND

Cutaneous reactions, mostly on injection site after mRNA-based COVID-19 vaccines, have been reported but not with detailed histopathological characterization.

OBJECTIVES

Characterization and classification of these reactions in a clinical and pathological point of view.

METHODS

Monocentric case series of 11 patients with cutaneous manifestations, clinically and histologically characterized after COVID-19 vaccination.

RESULTS

From January to June 2021, we recorded 11 cutaneous reactions to mRNA COVID-19 vaccines from BNT162b2 (n = 8) and mRNA-1273 (n = 3). Generalized reactions showing erythematous rash or purpura were the most common clinical presentation, and drug-reaction-like pattern was the most common histological finding.

CONCLUSIONS

A proper clinicopathological classification will be helpful in the early diagnosis and management of the cutaneous reactions to mRNA COVID-19 vaccines.

Covid 2019 and suicide - a global pandemic: How to prevent?

Introduction

The mental health effects of Coronavirus2019(COVID-19) outbreak might be profound, including higher suicide rates.This phenomena is likely to become a more pressing concern as the pandemic spreads.While remarkable social distancing interventions have been implemented to reduce the rate of new infections,the potential for adverse outcomes on suicide risk is high, especially among vulnerable populations.

Objectives

The aim is to do a review of the literature of suicide prevention during the COVID-19 outbreak.

Methods

Non-systematic review of the literature with selection of scientific articles published in the last 7 months; by searching the Pubmed databases, the following MeSH terms were used: Suicide prevention; COVID-19

Results

In order to prevent suicide, urgent consideration must be extend beyond general mental health approaches. A wide-ranging interdisciplinary response that recognises how the pandemic might heighten risk is needed. The application of knowledge about effective suicide prevention is the key. Mental health services should develop clear remote assessment and care pathways, and staff training to support new ways of dealing with. Publications on mental health and psychological effects of COVID-19 outbreak provide important information and recommendations for all three levels of suicide prevention: primary, secondary, and tertiary.

Conclusions

The challenge of the COVID-19 outbreak might bring with it an opportunity to advance the field of suicide prevention and, thus, to save lives, which also represent a public health priority. The mental health community, backed by active vigilance and international collaboration, should be prepared and can use this challenging period to advance suicide prevention.

Washing COVID-19 away: COVID-19 and obsessive compulsive disorder

Introduction

We are facing a crisis caused by an extremely infectious disease, Covid-19. The mechanisms of infection and transmission of this coronavirus are largely unknown but some of the clearer recommendations are washing hands and surfaces. Obsessive-Compulsive Disorder has a lifetime prevalence of 2-3%, among the multiple symptoms, fear of dirt or being contaminated, and excessive washing are the most common affecting about 50% of patients.

Objectives

We reviewed the available information to understand if there are changes in OCD symptoms during the pandemic.

Methods

Non-systematic review of the literature with selection of scientific articles published in the past 6 months; by searching Pubmed and Medscape databases using the combination of MeSH descriptors. The following MeSH terms were used: Covid-19; SARS-Cov2; pandemic; obsessive compulsive disorder; OCD.

Results

From a theoretical point of view, the increased frequency of hand washing and the importance of following hand-washing steps can add to a ritualistic pattern, also cleaning hands every time a person comes from outside or contacts with others can be justified as a preventive action rather than considered a problem and it can be “normalized” by others as a pandemic response.

Conclusions

In conclusion, there is evidence that during quarantine an overall increase in obsession and compulsion severity emerged with contamination symptoms associated with worse outcomes. There is data on an increase in relapses with patients not asking for help in a timely manner. The current situation is unpredictable and rapidly changing. It is likely that more information about this topic will arise in the next months.

Can atypical antipsychotic drugs cause hepatotoxicity?

Introduction

Neuropsychiatric drugs account for 16% of drugs that can lead to hepatotoxicity and psychiatric patients can have multiple comorbidities that can increase the incidence of liver disorders such as alcoholism, drug abuse and polymedication. The continuous use of atypical antipsychotic drugs (AAD) has raised questions over their tolerability over endocrine, metabolic and cardiovascular systems. They are also associated with mild elevation of aminotransferases and occasionally cause idiosyncratic liver injury with varying phenotypes. Hepatotoxicity is defined based on biological parameters such as elevation of alkaline phosphatase enzyme, SGPT, SGOT and GGT or clinical abnormalities (jaundice and hepatitis).

Objectives

This work reviewed the current available evidence on the hepatic damage produced by AAD.

Methods

Non-systematic review of the literature with selection of scientific articles published in the past 10 years; by searching Pubmed and Medscape databases using the combination of MeSH descriptors. The following MeSH terms were used: atypical antipsychotic drugs; hepatotoxicity; hepatic; Olanzapine; Clozapine; Risperidone; Aripiprazol; Paliperidone.

Results

Atypical Antipsychotic Drugs are generally well tolerated and hepatic alterations are in general very low or rare. The cases published were observed with Clozapine, Olanzapine and Risperidone. Atypical Antipsychotic drugs have a better profile than Chlorpromazine.

Conclusions

In conclusion, the hepatic injury generally occurs within the first weeks of treatment and is usually reversible with drug withdrawal. Hepatic check-ups may be relevant, especially in the beginning of treatment.

Disclosure

No significant relationships.

Stigmatization as a barrier in opioid substitution therapy patients

Introduction

Goffman defined stigma as an “attribute that is deeply discrediting” and in the last two decades research on this subject grew substantially.Opioids were ranked as the second most common form of illicit drug used worldwide and there is consensus in the literature that opioid substitution therapy (OST), methadone or buprenorphine, are the most effective treatments, although remain underutilized. People with an history of substance use disorders (SUD) are widely stigmatized, a significant barrier to detection and treatment efforts. Care workers were cited as the second most common source of stigma.

Objectives

The aim is to do a review of the literature of stigma as a significant barrier to OST and present several potential strategies to reduce stigma.

Methods

Non-systematic review of the literature with selection of scientific articles published in the last 5 years; by searching the Pubmed and Medscape databases using the combination of MeSH descriptors. The following MeSH terms were used: Opioid Use Disorder; Stigma; Opioid Substitution Therapy

Results

OST providers should actively bring up the topic of stigma in clinic appointments to determine whether the patient is experiencing stigma, and if so, whether it is adversely affecting their ability to continue in the treatment. More active measures need to be taken to help reducing the stigma through public awareness campaigns at local levels, continuing education of health care providers regarding substance OST, and greater incorporation of family members into the program.

Conclusions

In conclusion, further research is required to understand and address this issue.

Disclosure

No significant relationships.

Suicide: The pandemic inside the pandemic

Introduction

Covid-19 was declared a pandemic by the WHO on March 11th and efforts have been made to minimize the impact that this new disease can produce. The mental health effects of this pandemic can be severe considering that each year close to 800.000 people die by suicide. This pandemic could increase those numbers, although this is not inevitable.

Objectives

This work reviewed the current available data on possible causes for a suicide rate increase and to try to understand if suicide is already increasing worldwide.

Methods

Non-systematic review of the literature with selection of scientific articles published in the past 6 months; by searching Pubmed and Medscape databases using the combination of MeSH descriptors. The following MeSH terms were used: Covid-19; suicide; SARS-Cov2; pandemic.

Results

Multiple factors can account for an increase in suicide rates such as isolation with a sense of decreased belongingness and increased burdensomeness. A synergy with known suicide precipitants can also occur such as domestic violence, intra-familiar conflicts, alcohol consumption and access to means. Media communication can represent a danger with constant reports about the crisis. And lastly the loss of employment and financial stressors can produce an important impact.

Conclusions

In conclusion, Covid-19 will produce an important impact in many spheres of society, one of which will be mental health. If at the start of this crisis a widespread sense of solidarity was present with the maintenance of precipitant factors for suicide we expect to see an increase in suicide rates.

Controlling the shape of a tapered nanowire: lessons from the Burton-Cabrera-Frank model

The propagation of sidewall steps during the growth of nanowires is calculated in the frame of the Burton-Cabrera-Frank model. The stable shape of the nanowire comprises a cylinder section on top of a cone section: their characteristics are obtained as a function of the radius of the catalyst-nanowire area, the desorption-limited diffusion length of adatoms on the terraces, and the sticking of adatoms at step edges. The comparison with experimental data allows us to evaluate these last two parameters for InP and ZnTe nanowires; it reveals a different behavior for the two materials, related to a difference by an order of magnitude of the desorption-limited diffusion length.

Probing the light hole/heavy hole switching with correlated magneto-optical spectroscopy and chemical analysis on a single quantum dot

A whole series of complementary studies have been performed on the same single nanowire containing a quantum dot: cathodoluminescence spectroscopy and imaging, micro-photoluminescence spectroscopy under magnetic field and as a function of temperature, and energy-dispersive x-ray spectrometry and imaging. The ZnTe nanowire was deposited on a Si₃N₄ membrane with Ti/Al patterns. The complete set of data shows that the CdTe quantum dot features the heavy-hole state as a ground state, although the compressive mismatch strain promotes a light-hole ground state as soon as the aspect ratio is larger than unity (elongated dot). A numerical calculation of the whole structure shows that the transition from the heavy-hole to the light-hole configuration is pushed toward values of the aspect ratio much larger than unity by the presence of a (Zn, Mg)Te shell, and that the effect is further enhanced by a small valence band offset between the semiconductors in the dot and around it.

High-Fidelity and Ultrafast Initialization of a Hole Spin Bound to a Te Isoelectronic Center in ZnSe

We demonstrate the optical initialization of a hole-spin qubit bound to an isoelectronic center (IC) formed by a pair of Te impurities in ZnSe, an impurity-host system providing high optical homogeneity, large electric dipole moments, and potentially advantageous coherence times. The initialization scheme is based on the spin-preserving tunneling of a resonantly excited donor-bound exciton to a positively charged Te IC, thus forming a positive trion. The radiative decay of the trion within less than 50 ps leaves a heavy hole in a well-defined polarization-controlled spin state. The initialization fidelity exceeds 98.5% for an initialization time of less than 150 ps.

[Atypical scurvy associated with anorexia nervosa]

INTRODUCTION

Scurvy, or "Barlow's disease", is a widely described disease involving cutaneous and mucosal lesions resulting from vitamin C deficiency. Herein, we report a case of scurvy in a 48-year-old woman that was unusual in its atypical cutaneous-mucosal presentation as well as its association with anorexia nervosa.

PATIENTS AND METHODS

A 48-year-old woman treated for depression for several years was admitted to hospital for her impaired general state of health. Over the last year, she had presented palmoplantar rash and episodes of perimalleolar oedema. The clinical examination showed the patient to have wasting syndrome, with a BMI of 11.9kg/m², lower-limb oedema, palmoplantar fissures, geographic tongue, telogen effluvium and purpuric petechiae on her right knee. However, no gingival bleeding was noted and there was no loss of tooth enamel. The remainder of the clinical examination was normal. Blood tests revealed extremely low vitamin C levels without any other associated deficiencies, as well as laboratory signs of cytolysis and anicteric cholestasis without inflammatory syndrome. The diagnosis of anorexia nervosa was made by psychiatrists, despite the unusual age of onset. Favorable clinical outcome was rapidly achieved via a one-month course of vitamin C supplements at a daily dose of 1g.

DISCUSSION

The absence of classical buccal-dental symptoms and the presence of keratotic dermatosis with fissures and ulcers on the hands and feet are atypical in scurvy; however, this diagnosis was confirmed by the existence of purpura evoking capillary fragility, the patient's drastically low vitamin C level and the rapid subsidence of symptoms following treatment with oral vitamin C alone. Anorexia nervosa was doubtless the cause of deficiency. This situation is rare and a systematic review of the literature in Medline via PubMed showed that only three reports of scurvy associated with mental anorexia have been published since 1975.

Quantitative Reconstructions of 3D Chemical Nanostructures in Nanowires

Energy dispersive X-ray spectrometry is used to extract a quantitative 3D composition profile of heterostructured nanowires. The analysis of hypermaps recorded along a limited number of projections, with a preliminary calibration of the signal associated with each element, is compared to the intensity profiles calculated for a model structure with successive shells of circular, elliptic, or faceted cross sections. This discrete tomographic technique is applied to II-VI nanowires grown by molecular beam epitaxy, incorporating ZnTe and CdTe and their alloys with Mn and Mg, with typical size down to a few nanometers and Mn or Mg content as low as 10%.

Structure and morphology in diffusion-driven growth of nanowires: the case of ZnTe

Gold-catalyzed ZnTe nanowires were grown at low temperature by molecular beam epitaxy on a ZnTe(111) B buffer layer, under different II/VI flux ratios, including with CdTe insertions. High-resolution electron microscopy and energy-dispersive X-ray spectroscopy (EDX) gave information about the crystal structure, polarity, and growth mechanisms. We observe, under stoichiometric conditions, the simultaneous presence of zinc-blende and wurtzite nanowires spread homogeneously on the same sample. Wurtzite nanowires are cylinder-shaped with a pyramidal-structured base. Zinc-blende nanowires are cone-shaped with a crater at their base. Both nanowires and substrate show a Te-ended polarity. Te-rich conditions favor zinc-blende nanowires, while Zn-rich suppress nanowire growth. Using a diffusion-driven growth model, we present a criterion for the existence of a crater or a pyramid at the base of the nanowires. The difference in nanowire morphology indicates lateral growth only for zinc-blende nanowires. The role of the direct impinging flux on the nanowire's sidewall is discussed.

Penrose-Onsager criterion validation in a one-dimensional polariton condensate

We perform quantum tomography on one-dimensional polariton condensates, spontaneously occurring in linear disorder valleys in a CdTe planar microcavity sample. By the use of optical interferometric techniques, we determine the first-order coherence function and the amplitude and phase of the order parameter of the condensate, providing a full reconstruction of the single particle density matrix for the polariton system. The experimental data are used as input to theoretically test the consistency of the Penrose-Onsager criterion for Bose-Einstein condensation in the framework of nonequilibrium polariton condensates. The results confirm the pertinence and validity of the criterion for a nonequilibrium condensed gas.

Ultrafast room temperature single-photon source from nanowire-quantum dots

Epitaxial semiconductor quantum dots are particularly promising as realistic single-photon sources for their compatibility with manufacturing techniques and possibility to be implemented in compact devices. Here, we demonstrate for the first time single-photon emission up to room temperature from an epitaxial quantum dot inserted in a nanowire, namely a CdSe slice in a ZnSe nanowire. The exciton and biexciton lines can still be resolved at room temperature and the biexciton turns out to be the most appropriate transition for single-photon emission due to a large nonradiative decay of the bright exciton to dark exciton states. With an intrinsically short radiative decay time (≈300 ps) this system is the fastest room temperature single-photon emitter, allowing potentially gigahertz repetition rates.

Spontaneous pattern formation in a polariton condensate

Exciton-polariton condensation can be regarded as a self-organization phenomenon, where phase ordering is established among particles in the system. In such condensed systems, further ordering can occur in the particle density distribution, under particular experimental conditions. In this work we report on spontaneous pattern formation in a polariton condensate under nonresonant optical pumping. The slightly elliptical ring-shaped excitation laser that we employ forces condensation to occur into a single-energy state with periodic boundary conditions, giving rise to a multilobe standing-wave patterned state.

Polariton condensation in a one-dimensional disordered potential

We study the coherence and density modulation of a nonequilibrium exciton-polariton condensate in a one-dimensional valley with disorder. By means of interferometric measurements we evidence a modulation of the first-order coherence function and we relate it to a disorder-induced modulation of the condensate density, that increases as the pump power is increased. The nonmonotonic spatial coherence function is found to be the result of the strong nonequilibrium character of the one-dimensional system, in the presence of disorder.

Probing the dynamics of spontaneous quantum vortices in polariton superfluids

The experimental investigation of spontaneously created vortices is of utmost importance for the understanding of quantum phase transitions towards a superfluid phase, especially for two-dimensional systems that are expected to be governed by the Berezinski-Kosterlitz-Thouless physics. By means of time-resolved near-field interferometry we track the path of such vortices, created at random locations in an exciton-polariton condensate under pulsed nonresonant excitation, to their final pinning positions imposed by the stationary disorder. We formulate a theoretical model that successfully reproduces the experimental observations.

Coherent oscillations in an exciton-polariton Josephson junction

We report on the observation of spontaneous coherent oscillations in a microcavity polariton bosonic Josephson junction. Condensation of exciton polaritons here takes place under incoherent excitation in a double potential well naturally formed in the disorder. Coherent oscillations set on at an excitation power well above the condensation threshold. The time resolved population and phase dynamics reveal the analogy with the ac Josephson effect. A theoretical two-mode model describes the observed effects, explaining how the different realizations of the pulsed experiment can be in phase.

Dynamics of long-range ordering in an exciton-polariton condensate

We report on time-resolved measurements of the first order spatial coherence in an exciton-polariton Bose-Einstein condensate. Long-range spatial coherence is found to set in right at the onset of stimulated scattering, on a picosecond time scale. The coherence reaches its maximum value after the population and decays slowly, staying up to a few hundred picoseconds. This behavior can be qualitatively reproduced, using a stochastic classical field model describing interaction between the polariton condensate and the exciton reservoir within a disordered potential.

Dynamics of the formation and decay of coherence in a polariton condensate

We study the dynamics of the formation and decay of a condensate of microcavity polaritons. We investigate the relationship among the number of particles, the emission linewidth, and its degree of linear polarization, which serves as the order parameter. Tracking the condensate formation, we show that coherence is not determined only by occupation of the ground state, bringing new insights into the determining factors for Bose-Einstein condensation.

Efficient Bragg diffraction in thin semiconductor two-dimensional gratings

Highly improved diffraction properties are demonstrated in a two-dimensional [2D] grating consisting of a transmission grating optically recorded in a semiconductor one-dimensional photonic crystal (1D-PC). Near unity internal diffraction efficiency, high wavelength selectivity, and Bragg diffraction regime operation are demonstrated when the read beam is set at Bragg incidence on the transmission grating while its wavelength corresponds to the band edge of the 3 microm thick 1D-PC. When the 2D grating is grown on a Bragg mirror, a single diffracted beam is obtained, which makes the device promising for optical signal processing.

Formation of an exciton polariton condensate: thermodynamic versus kinetic regimes

We measure the polariton distribution function and the condensation threshold versus the photon-exciton detuning and the lattice temperature in a CdTe microcavity under nonresonant pumping. The results are reproduced by simulations using semiclassical Boltzmann equations. At negative detuning we find a kinetic condensation regime: the distribution is not thermal and the threshold is governed by the relaxation kinetics. At positive detuning, the distribution becomes thermal and the threshold is governed by the thermodynamic parameters of the system. Both regimes are a manifestation of polariton lasing, whereas only the latter is related to Bose-Einstein condensation defined as an equilibrium phase transition.

Intrinsic decoherence mechanisms in the microcavity polariton condensate

The fundamental mechanisms which control the phase coherence of the polariton Bose-Einstein condensate (BEC) are determined. It is shown that the combination of number fluctuations and interactions leads to decoherence with a characteristic Gaussian decay of the first-order correlation function. This line shape, and the long decay times ( approximately 150 ps) of both first- and second-order correlation functions, are explained quantitatively by a quantum-optical model which takes into account interactions, fluctuations, and gain and loss in the system. Interaction limited coherence times of this type have been predicted for atomic BECs, but are yet to be observed experimentally.

Synchronized and desynchronized phases of exciton-polariton condensates in the presence of disorder

Condensation of exciton polaritons in semiconductor microcavities takes place despite in-plane disorder. Below the critical density, the inhomogeneity of the disorder limits the spatial extension of the ground state. Above the critical density, in the presence of weak disorder, this limitation is spontaneously overcome by the nonlinear interaction, resulting in an extended synchronized phase. In the case of strong disorder, several non-phase-locked condensates can be evidenced. The transition from a synchronized phase to a desynchronized phase is addressed by sampling the cavity disorder.

Second-order time correlations within a polariton Bose-Einstein condensate in a CdTe microcavity

Second-order time correlations of polaritons have been measured across the condensation threshold in a CdTe microcavity. The onset of Bose-Einstein condensation is marked by the disappearance of photon bunching, demonstrating the transition from a thermal-like state to a coherent state. Coherence is, however, degraded with increasing polariton density, most probably as a result of self-interaction within the condensate and scatterings with noncondensed excitons and polaritons. Such behavior clearly differentiates polariton Bose condensation from photon lasing.

CdSe quantum dot formation: alternative paths to relaxation of a strained CdSe layer and influence of the capping conditions

CdSe/ZnSe quantum dot formation is investigated by studying different steps of the growth. To precisely control the critical thickness of CdSe grown on a ZnSe buffer layer, the CdSe self-regulated growth rate in atomic layer epitaxy growth mode is determined by reflection high-energy electron diffraction (RHEED) measurements for a temperature range between 180 and 280 °C. Then, the two-dimensional-three-dimensional (2D-3D) transition of a strained CdSe layer on (001)-ZnSe induced by the use of amorphous selenium is studied. The formation of CdSe islands is found when 3 monolayers (ML) of CdSe are deposited. When only 2.5 ML of CdSe are deposited, another relaxation mechanism is observed, leading to the appearance of strong undulations on the surface. We also studied the evolution of the surface morphology when 2.7 ML are deposited, to study the boundary between those two phenomena. The influence of capping on quantum dot morphology is investigated. It is found that cadmium is redistributed within the layer during capping. Our results show that the cadmium distribution after capping depends on the capping temperature and on the strain of the CdSe layer. Cadmium incorporation after capping is also studied. It is found that the amount of incorporated cadmium depends on the strain of the CdSe layer before capping.